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Ashraful Islam Khan - One of the best experts on this subject based on the ideXlab platform.
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o specific polysaccharide specific <B>MemoryB> B Cell responses in young children older children and adults infected with viBrio cholerae o1 ogawa in Bangladesh
Clinical and Vaccine Immunology, 2016Co-Authors: Amena Aktar, Taher Uddin, Fahima Chowdhury, Arifur M Rahman, Sadia Afrin, Omar M Faruk, Aklima Akter, Israk Nur M Sami, Tahirah Yasmin, Ashraful Islam KhanAbstract:Cholera caused By ViBrio cholerae O1 confers at least 3 to 10 years of protection against suBsequent disease regardless of age, despite a relatively rapid fall in antiBody levels in peripheral Blood, suggesting that <B>MemoryB> B Cell responses may play an important role in protection. The V. cholerae O1-specific polysaccharide (OSP) component of lipopolysaccharide (LPS) is responsiBle for serogroup specificity, and it is unclear if young children are capaBle of developing <B>MemoryB> B Cell responses against OSP, a T Cell-independent antigen, following cholera. To address this, we assessed OSP-specific <B>MemoryB> B Cell responses in young children (2 to 5 years, n = 11), older children (6 to 17 years, n = 21), and adults (18 to 55 years, n = 28) with cholera caused By V. cholerae O1 in Dhaka, Bangladesh. We also assessed <B>MemoryB> B Cell responses against LPS and viBriocidal responses, and plasma antiBody responses against OSP, LPS, and cholera toxin B suBunit (CtxB; a T Cell-dependent antigen) on days 2 and 7, as well as days 30, 90, and 180 after convalescence. In all age cohorts, viBriocidal responses and plasma OSP, LPS, and CtxB-specific responses peaked on day 7 and fell toward Baseline over the follow-up period. In comparison, we were aBle to detect OSP <B>MemoryB> B Cell responses in all age cohorts of patients with detectaBle responses over Baseline for 90 to 180 days. Our results suggest that OSP-specific <B>MemoryB> B Cell responses can occur following cholera, even in the youngest children, and may explain in part the age-independent induction of long-term immunity following naturally acquired disease.
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antigen specific <B>MemoryB> B Cell responses to enterotoxigenic escherichia coli infection in Bangladeshi adults
PLOS Neglected Tropical Diseases, 2014Co-Authors: Mohammad Murshid Alam, Mohammad Arif Rahman, Amena Aktar, Taher Uddin, Fahima Chowdhury, Arifur M Rahman, Sadia Afrin, Sarmin Aktar, Deena Al Mahbuba, Ashraful Islam KhanAbstract:Background Multiple infections with diverse enterotoxigenic E. coli (ETEC) strains lead to Broad spectrum protection against ETEC diarrhea. However, the precise mechanism of protection against ETEC infection is still unknown. Therefore, <B>MemoryB> B Cell responses and affinity maturation of antiBodies to the specific ETEC antigens might Be important to understand the mechanism of protection.
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<B>MemoryB> B Cell responses to viBrio cholerae o1 lipopolysaccharide are associated with protection against infection from household contacts of patients with cholera in Bangladesh
Clinical and Vaccine Immunology, 2012Co-Authors: Sweta M. Patel, Mohammad Murshid Alam, Mohammad Arif Rahman, Daniel T Leung, M. Mohasin, Ana A Weil, Fahima Chowdhury, Ashraful Islam Khan, Asrafuzzaman M Riyadh, Amena AktarAbstract:ABSTRACT ViBrio cholerae O1 causes cholera, a dehydrating diarrheal disease. We have previously shown that V. cholerae-specific <B>MemoryB> B Cell responses develop after cholera infection, and we hypothesize that these mediate long-term protective immunity against cholera. We prospectively followed household contacts of cholera patients to determine whether the presence of circulating V. cholerae O1 antigen-specific <B>MemoryB> B Cells on enrollment was associated with protection against V. cholerae infection over a 30-day period. Two hundred thirty-six household contacts of 122 index patients with cholera were enrolled. The presence of lipopolysaccharide (LPS)-specific IgG <B>MemoryB> B Cells in peripheral Blood on study entry was associated with a 68% decrease in the risk of infection in household contacts (P = 0.032). No protection was associated with cholera toxin B suBunit (CtxB)-specific <B>MemoryB> B Cells or IgA <B>MemoryB> B Cells specific to LPS. These results suggest that LPS-specific IgG <B>MemoryB> B Cells may Be important in protection against infection with V. cholerae O1.
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comparison of <B>MemoryB> B Cell antiBody secreting Cell and plasma antiBody responses in young children older children and adults with infection caused By viBrio cholerae o1 el tor ogawa in Bangladesh
Clinical and Vaccine Immunology, 2011Co-Authors: Mohammad Murshid Alam, Mohammad Arif Rahman, Sweta M. Patel, Daniel T Leung, M. Mohasin, Fahima Chowdhury, Asrafuzzaman M Riyadh, Ashraful Islam KhanAbstract:Children Bear a large component of the gloBal Burden of cholera. Despite this, little is known aBout immune responses to cholera in children, especially those under 5 years of age. Cholera vaccine studies have demonstrated lower long-term protective efficacy in young children than in older children and adults. <B>MemoryB> B Cell (MBC) responses may correlate with duration of protection following infection and vaccination. Here we report a comparison of immune responses in young children (3 to 5 years of age; n 17), older children (6 to 17 years of age; n 17), and adults (18 to 60 years of age; n 68) hospitalized with cholera in Dhaka, Bangladesh. We found that young children had lower Baseline viBriocidal antiBody titers and higher fold increases in titer Between day 2 and day 7 than adults. Young children had higher Baseline IgG plasma antiBody levels to ViBrio cholerae antigens, although the magnitudes of responses at days 7 and 30 were similar across age groups. As a surrogate marker for mucosal immune responses, we assessed day 7 antiBody-secreting Cell (ASC) responses. These were comparaBle across age groups, although there was a trend for older age groups to have higher levels of lipopolysaccharide-specific IgA ASC responses. All age groups developed comparaBle MBC responses to V. cholerae lipopolysaccharide and cholera toxin B suBunit at day 30. These findings suggest that young children are aBle to mount roBust viBriocidal, plasma antiBody, ASC, and MBC responses against V. cholerae O1, suggesting that under an optimal vaccination strategy, young children could achieve protective efficacy comparaBle to that induced in adults. Cholera is an acute dehydrating diarrheal disease caused predominantly By the ViBrio cholerae O1 or O139 serogroup. GloBally, the vast majority of cholera is caused By V. cholerae O1. Cholera is endemic in over 50 countries and affects 3 to 5 million people each year, causing more than 100,000 deaths (2, 41). In areas of the world in which cholera is endemic, children under 5 years of age have the highest Burden of disease (12, 31), and during cholera epidemics, children and adults are Both at risk of dehydrating illness (21, 24, 34). In a rural area of Bangladesh in which cholera is endemic, 80% of the population had detectaBle viBriocidal antiBodies By the age of 15 years (26). Similarly, in a recent oBservational study in urBan Bangladesh, household contacts of patients with V. cholerae O1 infection who were 5 years of age had a significantly higher risk of developing infection than older family memBers in a 21-day oBservational period following identification of the index household case (15).
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antigen specific <B>MemoryB> B Cell responses to viBrio cholerae o1 infection in Bangladesh
Infection and Immunity, 2009Co-Authors: Aaron M Harris, Regina C Larocque, Emily A Kendall, Azim Hossain, Fahima Chowdhury, Ashraful Islam Khan, Saruar M Bhuiyan, Atiqur Rahman, Jens Wrammert, Edward T RyanAbstract:Cholera, caused By ViBrio cholerae, is a noninvasive dehydrating enteric disease with a high mortality rate if untreated. Infection with V. cholerae elicits long-term protection against suBsequent disease in countries where the disease is endemic. Although the mechanism of this protective immunity is unknown, it has Been hypothesized that a protective mucosal response to V. cholerae infection may Be mediated By anamnestic responses of <B>MemoryB> B Cells in the gut-associated lymphoid tissue. To characterize <B>MemoryB> B-Cell responses to cholera, we enrolled a cohort of 39 hospitalized patients with culture-confirmed cholera and evaluated their immunologic responses at frequent intervals over the suBsequent 1 year. <B>MemoryB> B Cells to cholera antigens, including lipopolysaccharide (LPS), and the protein antigens cholera toxin B suBunit (CTB) and toxin-coregulated pilus major suBunit A (TcpA) were enumerated using a method of polyclonal stimulation of peripheral Blood mononuclear Cells followed By a standard enzyme-linked immunospot procedure. All patients demonstrated CTB, TcpA, and LPS-specific immunogloBulin G (IgG)and IgA <B>MemoryB> responses By day 90. In addition, these <B>MemoryB> B-Cell responses persisted up to 1 year, suBstantially longer than other traditional immunologic markers of infection with V. cholerae. While the magnitude of the LPS-specific IgG <B>MemoryB> B-Cell response waned at 1 year, CTB- and TcpA-specific IgG <B>MemoryB> B Cells remained significantly elevated at 1 year after infection, suggesting that T-Cell help may result in a more duraBle <B>MemoryB> B-Cell response to V. cholerae protein antigens. Such <B>MemoryB> B Cells could mediate anamnestic responses on reexposure to V. cholerae.
Fahima Chowdhury - One of the best experts on this subject based on the ideXlab platform.
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plasma and <B>MemoryB> B Cell responses targeting o specific polysaccharide osp are associated with protection against viBrio cholerae o1 infection among household contacts of cholera patients in Bangladesh
PLOS Neglected Tropical Diseases, 2018Co-Authors: Amena Aktar, Taher Uddin, Arifur M Rahman, Sadia Afrin, Aklima Akter, Tahirah Yasmin, Md Israk Nur Sami, Pinki Dash, Sultana Rownok Jahan, Fahima ChowdhuryAbstract:Background The mediators of protection against cholera, a severe dehydrating illness of humans caused By ViBrio cholerae, are unknown. We have previously shown that plasma IgA as well as <B>MemoryB> B IgG Cells targeting lipopolysaccharide (LPS) of ViBrio cholerae O1 correlate with protection against V. cholerae O1 infection among household contacts of cholera patients. Protection against cholera is serogroup specific, and serogroup specificity is defined By the O-specific polysaccharide (OSP) component of LPS. Therefore, we prospectively followed household contacts of cholera patients to determine whether OSP-specific immune responses present at the time of enrollment are associated with protection against V. cholerae infection. Methodology In this study, we enrolled two hundred forty two household contacts of one hundred fifty index patients who were infected with ViBrio cholerae. We determined OSP-specific <B>MemoryB> B Cells and plasma IgA, IgG and IgM antiBody responses on study entry (day 2). Principle findings The presence of OSP-specific plasma IgA, IgM, and IgG antiBody responses on study entry were associated with a decrease in the risk of infection in household contacts (IgA, p = 0.015; IgM, p = 0.01, and IgG, p = 0.024). In addition, the presence of OSP-specific IgG <B>MemoryB> B Cell responses in peripheral Blood on study entry was also associated with a decreased risk of infection (44% reduction; 95% CI: 31.1 to 99.8) in contacts. No protection was associated with cholera toxin B suBunit (CtxB)-specific <B>MemoryB> B Cell responses. Conclusion These results suggest that immune responses that target OSP, Both in plasma and <B>MemoryB> responses, may Be important in mediating protection against infection with V. cholerae O1.
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o specific polysaccharide specific <B>MemoryB> B Cell responses in young children older children and adults infected with viBrio cholerae o1 ogawa in Bangladesh
Clinical and Vaccine Immunology, 2016Co-Authors: Amena Aktar, Taher Uddin, Fahima Chowdhury, Arifur M Rahman, Sadia Afrin, Omar M Faruk, Aklima Akter, Israk Nur M Sami, Tahirah Yasmin, Ashraful Islam KhanAbstract:Cholera caused By ViBrio cholerae O1 confers at least 3 to 10 years of protection against suBsequent disease regardless of age, despite a relatively rapid fall in antiBody levels in peripheral Blood, suggesting that <B>MemoryB> B Cell responses may play an important role in protection. The V. cholerae O1-specific polysaccharide (OSP) component of lipopolysaccharide (LPS) is responsiBle for serogroup specificity, and it is unclear if young children are capaBle of developing <B>MemoryB> B Cell responses against OSP, a T Cell-independent antigen, following cholera. To address this, we assessed OSP-specific <B>MemoryB> B Cell responses in young children (2 to 5 years, n = 11), older children (6 to 17 years, n = 21), and adults (18 to 55 years, n = 28) with cholera caused By V. cholerae O1 in Dhaka, Bangladesh. We also assessed <B>MemoryB> B Cell responses against LPS and viBriocidal responses, and plasma antiBody responses against OSP, LPS, and cholera toxin B suBunit (CtxB; a T Cell-dependent antigen) on days 2 and 7, as well as days 30, 90, and 180 after convalescence. In all age cohorts, viBriocidal responses and plasma OSP, LPS, and CtxB-specific responses peaked on day 7 and fell toward Baseline over the follow-up period. In comparison, we were aBle to detect OSP <B>MemoryB> B Cell responses in all age cohorts of patients with detectaBle responses over Baseline for 90 to 180 days. Our results suggest that OSP-specific <B>MemoryB> B Cell responses can occur following cholera, even in the youngest children, and may explain in part the age-independent induction of long-term immunity following naturally acquired disease.
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antigen specific <B>MemoryB> B Cell responses to enterotoxigenic escherichia coli infection in Bangladeshi adults
PLOS Neglected Tropical Diseases, 2014Co-Authors: Mohammad Murshid Alam, Mohammad Arif Rahman, Amena Aktar, Taher Uddin, Fahima Chowdhury, Arifur M Rahman, Sadia Afrin, Sarmin Aktar, Deena Al Mahbuba, Ashraful Islam KhanAbstract:Background Multiple infections with diverse enterotoxigenic E. coli (ETEC) strains lead to Broad spectrum protection against ETEC diarrhea. However, the precise mechanism of protection against ETEC infection is still unknown. Therefore, <B>MemoryB> B Cell responses and affinity maturation of antiBodies to the specific ETEC antigens might Be important to understand the mechanism of protection.
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<B>MemoryB> B Cell responses to viBrio cholerae o1 lipopolysaccharide are associated with protection against infection from household contacts of patients with cholera in Bangladesh
Clinical and Vaccine Immunology, 2012Co-Authors: Sweta M. Patel, Mohammad Murshid Alam, Mohammad Arif Rahman, Daniel T Leung, M. Mohasin, Ana A Weil, Fahima Chowdhury, Ashraful Islam Khan, Asrafuzzaman M Riyadh, Amena AktarAbstract:ABSTRACT ViBrio cholerae O1 causes cholera, a dehydrating diarrheal disease. We have previously shown that V. cholerae-specific <B>MemoryB> B Cell responses develop after cholera infection, and we hypothesize that these mediate long-term protective immunity against cholera. We prospectively followed household contacts of cholera patients to determine whether the presence of circulating V. cholerae O1 antigen-specific <B>MemoryB> B Cells on enrollment was associated with protection against V. cholerae infection over a 30-day period. Two hundred thirty-six household contacts of 122 index patients with cholera were enrolled. The presence of lipopolysaccharide (LPS)-specific IgG <B>MemoryB> B Cells in peripheral Blood on study entry was associated with a 68% decrease in the risk of infection in household contacts (P = 0.032). No protection was associated with cholera toxin B suBunit (CtxB)-specific <B>MemoryB> B Cells or IgA <B>MemoryB> B Cells specific to LPS. These results suggest that LPS-specific IgG <B>MemoryB> B Cells may Be important in protection against infection with V. cholerae O1.
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comparison of <B>MemoryB> B Cell antiBody secreting Cell and plasma antiBody responses in young children older children and adults with infection caused By viBrio cholerae o1 el tor ogawa in Bangladesh
Clinical and Vaccine Immunology, 2011Co-Authors: Mohammad Murshid Alam, Mohammad Arif Rahman, Sweta M. Patel, Daniel T Leung, M. Mohasin, Fahima Chowdhury, Asrafuzzaman M Riyadh, Ashraful Islam KhanAbstract:Children Bear a large component of the gloBal Burden of cholera. Despite this, little is known aBout immune responses to cholera in children, especially those under 5 years of age. Cholera vaccine studies have demonstrated lower long-term protective efficacy in young children than in older children and adults. <B>MemoryB> B Cell (MBC) responses may correlate with duration of protection following infection and vaccination. Here we report a comparison of immune responses in young children (3 to 5 years of age; n 17), older children (6 to 17 years of age; n 17), and adults (18 to 60 years of age; n 68) hospitalized with cholera in Dhaka, Bangladesh. We found that young children had lower Baseline viBriocidal antiBody titers and higher fold increases in titer Between day 2 and day 7 than adults. Young children had higher Baseline IgG plasma antiBody levels to ViBrio cholerae antigens, although the magnitudes of responses at days 7 and 30 were similar across age groups. As a surrogate marker for mucosal immune responses, we assessed day 7 antiBody-secreting Cell (ASC) responses. These were comparaBle across age groups, although there was a trend for older age groups to have higher levels of lipopolysaccharide-specific IgA ASC responses. All age groups developed comparaBle MBC responses to V. cholerae lipopolysaccharide and cholera toxin B suBunit at day 30. These findings suggest that young children are aBle to mount roBust viBriocidal, plasma antiBody, ASC, and MBC responses against V. cholerae O1, suggesting that under an optimal vaccination strategy, young children could achieve protective efficacy comparaBle to that induced in adults. Cholera is an acute dehydrating diarrheal disease caused predominantly By the ViBrio cholerae O1 or O139 serogroup. GloBally, the vast majority of cholera is caused By V. cholerae O1. Cholera is endemic in over 50 countries and affects 3 to 5 million people each year, causing more than 100,000 deaths (2, 41). In areas of the world in which cholera is endemic, children under 5 years of age have the highest Burden of disease (12, 31), and during cholera epidemics, children and adults are Both at risk of dehydrating illness (21, 24, 34). In a rural area of Bangladesh in which cholera is endemic, 80% of the population had detectaBle viBriocidal antiBodies By the age of 15 years (26). Similarly, in a recent oBservational study in urBan Bangladesh, household contacts of patients with V. cholerae O1 infection who were 5 years of age had a significantly higher risk of developing infection than older family memBers in a 21-day oBservational period following identification of the index household case (15).
Daniel T Leung - One of the best experts on this subject based on the ideXlab platform.
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<B>MemoryB> B Cell responses to viBrio cholerae o1 lipopolysaccharide are associated with protection against infection from household contacts of patients with cholera in Bangladesh
Clinical and Vaccine Immunology, 2012Co-Authors: Sweta M. Patel, Mohammad Murshid Alam, Mohammad Arif Rahman, Daniel T Leung, M. Mohasin, Ana A Weil, Fahima Chowdhury, Ashraful Islam Khan, Asrafuzzaman M Riyadh, Amena AktarAbstract:ABSTRACT ViBrio cholerae O1 causes cholera, a dehydrating diarrheal disease. We have previously shown that V. cholerae-specific <B>MemoryB> B Cell responses develop after cholera infection, and we hypothesize that these mediate long-term protective immunity against cholera. We prospectively followed household contacts of cholera patients to determine whether the presence of circulating V. cholerae O1 antigen-specific <B>MemoryB> B Cells on enrollment was associated with protection against V. cholerae infection over a 30-day period. Two hundred thirty-six household contacts of 122 index patients with cholera were enrolled. The presence of lipopolysaccharide (LPS)-specific IgG <B>MemoryB> B Cells in peripheral Blood on study entry was associated with a 68% decrease in the risk of infection in household contacts (P = 0.032). No protection was associated with cholera toxin B suBunit (CtxB)-specific <B>MemoryB> B Cells or IgA <B>MemoryB> B Cells specific to LPS. These results suggest that LPS-specific IgG <B>MemoryB> B Cells may Be important in protection against infection with V. cholerae O1.
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<B>MemoryB> B Cell and Other Immune Responses in Children Receiving Two Doses of an Oral Killed Cholera Vaccine Compared to Responses following Natural Cholera Infection in Bangladesh
Clinical and Vaccine Immunology, 2012Co-Authors: Daniel T Leung, Mohammad Arif Rahman, Sweta M. Patel, Amena Aktar, M. Asrafuzzaman Riyadh, Taher Uddin, Amit Saha, M. Mohasin, Farhana Khanam, Mohammad Murshid AlamAbstract:Current oral cholera vaccines induce lower protective efficacy and shorter duration of protection against cholera than wild-type infection provides, and this difference is most pronounced in young children. Despite this, there are limited data comparing immune responses in children following wild-type disease versus vaccination, especially with regard to <B>MemoryB> responses associated with long-term immunity. Here, we report a comparison of immune responses in young children (2 to 5 years of age; n = 20) and older children (6 to 17 years of age; n = 20) given two doses of an oral killed cholera vaccine containing recomBinant cholera toxin B suBunit (CtxB) 14 days apart and compare these responses to those induced in similarly aged children recovering from infection with ViBrio cholerae O1 Ogawa in Bangladesh. We found that the two vaccine groups had comparaBle viBriocidal and lipopolysaccharide (LPS)-specific plasma antiBody responses. Vaccinees developed lower levels of IgG <B>MemoryB> B Cell (MBC) responses against CtxB But no significant MBC responses against LPS. In contrast, children recovering from natural cholera infection developed prominent LPS IgG and IgA MBC responses, as well as CtxB IgG MBC responses. Plasma LPS IgG, IgA, and IgM responses, as well as viBriocidal responses, were also significantly higher in children following disease than after vaccination. Our findings suggest that acute and <B>MemoryB> immune responses following oral cholera vaccination in children are significantly lower than those oBserved following wild-type disease, especially responses targeting LPS. These findings may explain, in part, the lower efficacy of oral cholera vaccination in children.
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comparison of <B>MemoryB> B Cell antiBody secreting Cell and plasma antiBody responses in young children older children and adults with infection caused By viBrio cholerae o1 el tor ogawa in Bangladesh
Clinical and Vaccine Immunology, 2011Co-Authors: Mohammad Murshid Alam, Mohammad Arif Rahman, Sweta M. Patel, Daniel T Leung, M. Mohasin, Fahima Chowdhury, Asrafuzzaman M Riyadh, Ashraful Islam KhanAbstract:Children Bear a large component of the gloBal Burden of cholera. Despite this, little is known aBout immune responses to cholera in children, especially those under 5 years of age. Cholera vaccine studies have demonstrated lower long-term protective efficacy in young children than in older children and adults. <B>MemoryB> B Cell (MBC) responses may correlate with duration of protection following infection and vaccination. Here we report a comparison of immune responses in young children (3 to 5 years of age; n 17), older children (6 to 17 years of age; n 17), and adults (18 to 60 years of age; n 68) hospitalized with cholera in Dhaka, Bangladesh. We found that young children had lower Baseline viBriocidal antiBody titers and higher fold increases in titer Between day 2 and day 7 than adults. Young children had higher Baseline IgG plasma antiBody levels to ViBrio cholerae antigens, although the magnitudes of responses at days 7 and 30 were similar across age groups. As a surrogate marker for mucosal immune responses, we assessed day 7 antiBody-secreting Cell (ASC) responses. These were comparaBle across age groups, although there was a trend for older age groups to have higher levels of lipopolysaccharide-specific IgA ASC responses. All age groups developed comparaBle MBC responses to V. cholerae lipopolysaccharide and cholera toxin B suBunit at day 30. These findings suggest that young children are aBle to mount roBust viBriocidal, plasma antiBody, ASC, and MBC responses against V. cholerae O1, suggesting that under an optimal vaccination strategy, young children could achieve protective efficacy comparaBle to that induced in adults. Cholera is an acute dehydrating diarrheal disease caused predominantly By the ViBrio cholerae O1 or O139 serogroup. GloBally, the vast majority of cholera is caused By V. cholerae O1. Cholera is endemic in over 50 countries and affects 3 to 5 million people each year, causing more than 100,000 deaths (2, 41). In areas of the world in which cholera is endemic, children under 5 years of age have the highest Burden of disease (12, 31), and during cholera epidemics, children and adults are Both at risk of dehydrating illness (21, 24, 34). In a rural area of Bangladesh in which cholera is endemic, 80% of the population had detectaBle viBriocidal antiBodies By the age of 15 years (26). Similarly, in a recent oBservational study in urBan Bangladesh, household contacts of patients with V. cholerae O1 infection who were 5 years of age had a significantly higher risk of developing infection than older family memBers in a 21-day oBservational period following identification of the index household case (15).
Mohammad Murshid Alam - One of the best experts on this subject based on the ideXlab platform.
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antigen specific <B>MemoryB> B Cell responses to enterotoxigenic escherichia coli infection in Bangladeshi adults
PLOS Neglected Tropical Diseases, 2014Co-Authors: Mohammad Murshid Alam, Mohammad Arif Rahman, Amena Aktar, Taher Uddin, Fahima Chowdhury, Arifur M Rahman, Sadia Afrin, Sarmin Aktar, Deena Al Mahbuba, Ashraful Islam KhanAbstract:Background Multiple infections with diverse enterotoxigenic E. coli (ETEC) strains lead to Broad spectrum protection against ETEC diarrhea. However, the precise mechanism of protection against ETEC infection is still unknown. Therefore, <B>MemoryB> B Cell responses and affinity maturation of antiBodies to the specific ETEC antigens might Be important to understand the mechanism of protection.
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study of avidity of antigen specific antiBody as a means of understanding development of long term immunological <B>MemoryB> after viBrio cholerae o1 infection
Clinical and Vaccine Immunology, 2013Co-Authors: Mohammad Murshid Alam, Mohammad Arif Rahman, Mohammad Arifuzzaman, Alaullah Sheikh, Edward T Ryan, Stephen B Calderwood, Shaikh Meshbahuddin Ahmad, Ismail M Hosen, Rasheduzzaman Rashu, Firdausi QadriAbstract:The avidity of antiBodies to specific antigens and the relationship of avidity to <B>MemoryB> B Cell responses to these antigens have not Been studied in patients with cholera or those receiving oral cholera vaccines. We measured the avidity of antiBodies to cholera toxin B suBunit (CTB) and ViBrio cholerae O1 lipopolysaccharide (LPS) in Bangladeshi adult cholera patients (n = 30), as well as vaccinees (n = 30) after administration of two doses of a killed oral cholera vaccine. We assessed antiBody and <B>MemoryB> B Cell responses at the acute stage in patients or prior to vaccination in vaccinees and then in follow-up over a year. Both patients and vaccinees mounted CTB-specific IgG and IgA antiBodies of high avidity. Patients showed longer persistence of these antiBodies than vaccinees, with persistence lasting in patients up to day 270 to 360. The avidity of LPS-specific IgG and IgA antiBodies in patients remained elevated up to 180 days of follow-up. Vaccinees mounted highly avid LPS-specific antiBodies at day 17 (3 days after the second dose of vaccine), But the avidity waned rapidly to Baseline By 30 days. We examined the correlation Between antigen-specific <B>MemoryB> B Cell responses and avidity indices for Both antigens. We found that numBers of CTB- and LPS-specific <B>MemoryB> B Cells significantly correlated with the avidity indices of the corresponding antiBodies (P < 0.05; Spearman's ρ = 0.28 to 0.45). These findings suggest that antiBody avidity after infection and immunization is a good correlate of the development and maintenance of <B>MemoryB> B Cell responses to ViBrio cholerae O1 antigens.
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<B>MemoryB> B Cell responses to viBrio cholerae o1 lipopolysaccharide are associated with protection against infection from household contacts of patients with cholera in Bangladesh
Clinical and Vaccine Immunology, 2012Co-Authors: Sweta M. Patel, Mohammad Murshid Alam, Mohammad Arif Rahman, Daniel T Leung, M. Mohasin, Ana A Weil, Fahima Chowdhury, Ashraful Islam Khan, Asrafuzzaman M Riyadh, Amena AktarAbstract:ABSTRACT ViBrio cholerae O1 causes cholera, a dehydrating diarrheal disease. We have previously shown that V. cholerae-specific <B>MemoryB> B Cell responses develop after cholera infection, and we hypothesize that these mediate long-term protective immunity against cholera. We prospectively followed household contacts of cholera patients to determine whether the presence of circulating V. cholerae O1 antigen-specific <B>MemoryB> B Cells on enrollment was associated with protection against V. cholerae infection over a 30-day period. Two hundred thirty-six household contacts of 122 index patients with cholera were enrolled. The presence of lipopolysaccharide (LPS)-specific IgG <B>MemoryB> B Cells in peripheral Blood on study entry was associated with a 68% decrease in the risk of infection in household contacts (P = 0.032). No protection was associated with cholera toxin B suBunit (CtxB)-specific <B>MemoryB> B Cells or IgA <B>MemoryB> B Cells specific to LPS. These results suggest that LPS-specific IgG <B>MemoryB> B Cells may Be important in protection against infection with V. cholerae O1.
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<B>MemoryB> B Cell and Other Immune Responses in Children Receiving Two Doses of an Oral Killed Cholera Vaccine Compared to Responses following Natural Cholera Infection in Bangladesh
Clinical and Vaccine Immunology, 2012Co-Authors: Daniel T Leung, Mohammad Arif Rahman, Sweta M. Patel, Amena Aktar, M. Asrafuzzaman Riyadh, Taher Uddin, Amit Saha, M. Mohasin, Farhana Khanam, Mohammad Murshid AlamAbstract:Current oral cholera vaccines induce lower protective efficacy and shorter duration of protection against cholera than wild-type infection provides, and this difference is most pronounced in young children. Despite this, there are limited data comparing immune responses in children following wild-type disease versus vaccination, especially with regard to <B>MemoryB> responses associated with long-term immunity. Here, we report a comparison of immune responses in young children (2 to 5 years of age; n = 20) and older children (6 to 17 years of age; n = 20) given two doses of an oral killed cholera vaccine containing recomBinant cholera toxin B suBunit (CtxB) 14 days apart and compare these responses to those induced in similarly aged children recovering from infection with ViBrio cholerae O1 Ogawa in Bangladesh. We found that the two vaccine groups had comparaBle viBriocidal and lipopolysaccharide (LPS)-specific plasma antiBody responses. Vaccinees developed lower levels of IgG <B>MemoryB> B Cell (MBC) responses against CtxB But no significant MBC responses against LPS. In contrast, children recovering from natural cholera infection developed prominent LPS IgG and IgA MBC responses, as well as CtxB IgG MBC responses. Plasma LPS IgG, IgA, and IgM responses, as well as viBriocidal responses, were also significantly higher in children following disease than after vaccination. Our findings suggest that acute and <B>MemoryB> immune responses following oral cholera vaccination in children are significantly lower than those oBserved following wild-type disease, especially responses targeting LPS. These findings may explain, in part, the lower efficacy of oral cholera vaccination in children.
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comparison of <B>MemoryB> B Cell antiBody secreting Cell and plasma antiBody responses in young children older children and adults with infection caused By viBrio cholerae o1 el tor ogawa in Bangladesh
Clinical and Vaccine Immunology, 2011Co-Authors: Mohammad Murshid Alam, Mohammad Arif Rahman, Sweta M. Patel, Daniel T Leung, M. Mohasin, Fahima Chowdhury, Asrafuzzaman M Riyadh, Ashraful Islam KhanAbstract:Children Bear a large component of the gloBal Burden of cholera. Despite this, little is known aBout immune responses to cholera in children, especially those under 5 years of age. Cholera vaccine studies have demonstrated lower long-term protective efficacy in young children than in older children and adults. <B>MemoryB> B Cell (MBC) responses may correlate with duration of protection following infection and vaccination. Here we report a comparison of immune responses in young children (3 to 5 years of age; n 17), older children (6 to 17 years of age; n 17), and adults (18 to 60 years of age; n 68) hospitalized with cholera in Dhaka, Bangladesh. We found that young children had lower Baseline viBriocidal antiBody titers and higher fold increases in titer Between day 2 and day 7 than adults. Young children had higher Baseline IgG plasma antiBody levels to ViBrio cholerae antigens, although the magnitudes of responses at days 7 and 30 were similar across age groups. As a surrogate marker for mucosal immune responses, we assessed day 7 antiBody-secreting Cell (ASC) responses. These were comparaBle across age groups, although there was a trend for older age groups to have higher levels of lipopolysaccharide-specific IgA ASC responses. All age groups developed comparaBle MBC responses to V. cholerae lipopolysaccharide and cholera toxin B suBunit at day 30. These findings suggest that young children are aBle to mount roBust viBriocidal, plasma antiBody, ASC, and MBC responses against V. cholerae O1, suggesting that under an optimal vaccination strategy, young children could achieve protective efficacy comparaBle to that induced in adults. Cholera is an acute dehydrating diarrheal disease caused predominantly By the ViBrio cholerae O1 or O139 serogroup. GloBally, the vast majority of cholera is caused By V. cholerae O1. Cholera is endemic in over 50 countries and affects 3 to 5 million people each year, causing more than 100,000 deaths (2, 41). In areas of the world in which cholera is endemic, children under 5 years of age have the highest Burden of disease (12, 31), and during cholera epidemics, children and adults are Both at risk of dehydrating illness (21, 24, 34). In a rural area of Bangladesh in which cholera is endemic, 80% of the population had detectaBle viBriocidal antiBodies By the age of 15 years (26). Similarly, in a recent oBservational study in urBan Bangladesh, household contacts of patients with V. cholerae O1 infection who were 5 years of age had a significantly higher risk of developing infection than older family memBers in a 21-day oBservational period following identification of the index household case (15).
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plasma and <B>MemoryB> B Cell responses targeting o specific polysaccharide osp are associated with protection against viBrio cholerae o1 infection among household contacts of cholera patients in Bangladesh
PLOS Neglected Tropical Diseases, 2018Co-Authors: Amena Aktar, Taher Uddin, Arifur M Rahman, Sadia Afrin, Aklima Akter, Tahirah Yasmin, Md Israk Nur Sami, Pinki Dash, Sultana Rownok Jahan, Fahima ChowdhuryAbstract:Background The mediators of protection against cholera, a severe dehydrating illness of humans caused By ViBrio cholerae, are unknown. We have previously shown that plasma IgA as well as <B>MemoryB> B IgG Cells targeting lipopolysaccharide (LPS) of ViBrio cholerae O1 correlate with protection against V. cholerae O1 infection among household contacts of cholera patients. Protection against cholera is serogroup specific, and serogroup specificity is defined By the O-specific polysaccharide (OSP) component of LPS. Therefore, we prospectively followed household contacts of cholera patients to determine whether OSP-specific immune responses present at the time of enrollment are associated with protection against V. cholerae infection. Methodology In this study, we enrolled two hundred forty two household contacts of one hundred fifty index patients who were infected with ViBrio cholerae. We determined OSP-specific <B>MemoryB> B Cells and plasma IgA, IgG and IgM antiBody responses on study entry (day 2). Principle findings The presence of OSP-specific plasma IgA, IgM, and IgG antiBody responses on study entry were associated with a decrease in the risk of infection in household contacts (IgA, p = 0.015; IgM, p = 0.01, and IgG, p = 0.024). In addition, the presence of OSP-specific IgG <B>MemoryB> B Cell responses in peripheral Blood on study entry was also associated with a decreased risk of infection (44% reduction; 95% CI: 31.1 to 99.8) in contacts. No protection was associated with cholera toxin B suBunit (CtxB)-specific <B>MemoryB> B Cell responses. Conclusion These results suggest that immune responses that target OSP, Both in plasma and <B>MemoryB> responses, may Be important in mediating protection against infection with V. cholerae O1.
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o specific polysaccharide specific <B>MemoryB> B Cell responses in young children older children and adults infected with viBrio cholerae o1 ogawa in Bangladesh
Clinical and Vaccine Immunology, 2016Co-Authors: Amena Aktar, Taher Uddin, Fahima Chowdhury, Arifur M Rahman, Sadia Afrin, Omar M Faruk, Aklima Akter, Israk Nur M Sami, Tahirah Yasmin, Ashraful Islam KhanAbstract:Cholera caused By ViBrio cholerae O1 confers at least 3 to 10 years of protection against suBsequent disease regardless of age, despite a relatively rapid fall in antiBody levels in peripheral Blood, suggesting that <B>MemoryB> B Cell responses may play an important role in protection. The V. cholerae O1-specific polysaccharide (OSP) component of lipopolysaccharide (LPS) is responsiBle for serogroup specificity, and it is unclear if young children are capaBle of developing <B>MemoryB> B Cell responses against OSP, a T Cell-independent antigen, following cholera. To address this, we assessed OSP-specific <B>MemoryB> B Cell responses in young children (2 to 5 years, n = 11), older children (6 to 17 years, n = 21), and adults (18 to 55 years, n = 28) with cholera caused By V. cholerae O1 in Dhaka, Bangladesh. We also assessed <B>MemoryB> B Cell responses against LPS and viBriocidal responses, and plasma antiBody responses against OSP, LPS, and cholera toxin B suBunit (CtxB; a T Cell-dependent antigen) on days 2 and 7, as well as days 30, 90, and 180 after convalescence. In all age cohorts, viBriocidal responses and plasma OSP, LPS, and CtxB-specific responses peaked on day 7 and fell toward Baseline over the follow-up period. In comparison, we were aBle to detect OSP <B>MemoryB> B Cell responses in all age cohorts of patients with detectaBle responses over Baseline for 90 to 180 days. Our results suggest that OSP-specific <B>MemoryB> B Cell responses can occur following cholera, even in the youngest children, and may explain in part the age-independent induction of long-term immunity following naturally acquired disease.
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antigen specific <B>MemoryB> B Cell responses to enterotoxigenic escherichia coli infection in Bangladeshi adults
PLOS Neglected Tropical Diseases, 2014Co-Authors: Mohammad Murshid Alam, Mohammad Arif Rahman, Amena Aktar, Taher Uddin, Fahima Chowdhury, Arifur M Rahman, Sadia Afrin, Sarmin Aktar, Deena Al Mahbuba, Ashraful Islam KhanAbstract:Background Multiple infections with diverse enterotoxigenic E. coli (ETEC) strains lead to Broad spectrum protection against ETEC diarrhea. However, the precise mechanism of protection against ETEC infection is still unknown. Therefore, <B>MemoryB> B Cell responses and affinity maturation of antiBodies to the specific ETEC antigens might Be important to understand the mechanism of protection.
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<B>MemoryB> B Cell responses to viBrio cholerae o1 lipopolysaccharide are associated with protection against infection from household contacts of patients with cholera in Bangladesh
Clinical and Vaccine Immunology, 2012Co-Authors: Sweta M. Patel, Mohammad Murshid Alam, Mohammad Arif Rahman, Daniel T Leung, M. Mohasin, Ana A Weil, Fahima Chowdhury, Ashraful Islam Khan, Asrafuzzaman M Riyadh, Amena AktarAbstract:ABSTRACT ViBrio cholerae O1 causes cholera, a dehydrating diarrheal disease. We have previously shown that V. cholerae-specific <B>MemoryB> B Cell responses develop after cholera infection, and we hypothesize that these mediate long-term protective immunity against cholera. We prospectively followed household contacts of cholera patients to determine whether the presence of circulating V. cholerae O1 antigen-specific <B>MemoryB> B Cells on enrollment was associated with protection against V. cholerae infection over a 30-day period. Two hundred thirty-six household contacts of 122 index patients with cholera were enrolled. The presence of lipopolysaccharide (LPS)-specific IgG <B>MemoryB> B Cells in peripheral Blood on study entry was associated with a 68% decrease in the risk of infection in household contacts (P = 0.032). No protection was associated with cholera toxin B suBunit (CtxB)-specific <B>MemoryB> B Cells or IgA <B>MemoryB> B Cells specific to LPS. These results suggest that LPS-specific IgG <B>MemoryB> B Cells may Be important in protection against infection with V. cholerae O1.
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<B>MemoryB> B Cell and Other Immune Responses in Children Receiving Two Doses of an Oral Killed Cholera Vaccine Compared to Responses following Natural Cholera Infection in Bangladesh
Clinical and Vaccine Immunology, 2012Co-Authors: Daniel T Leung, Mohammad Arif Rahman, Sweta M. Patel, Amena Aktar, M. Asrafuzzaman Riyadh, Taher Uddin, Amit Saha, M. Mohasin, Farhana Khanam, Mohammad Murshid AlamAbstract:Current oral cholera vaccines induce lower protective efficacy and shorter duration of protection against cholera than wild-type infection provides, and this difference is most pronounced in young children. Despite this, there are limited data comparing immune responses in children following wild-type disease versus vaccination, especially with regard to <B>MemoryB> responses associated with long-term immunity. Here, we report a comparison of immune responses in young children (2 to 5 years of age; n = 20) and older children (6 to 17 years of age; n = 20) given two doses of an oral killed cholera vaccine containing recomBinant cholera toxin B suBunit (CtxB) 14 days apart and compare these responses to those induced in similarly aged children recovering from infection with ViBrio cholerae O1 Ogawa in Bangladesh. We found that the two vaccine groups had comparaBle viBriocidal and lipopolysaccharide (LPS)-specific plasma antiBody responses. Vaccinees developed lower levels of IgG <B>MemoryB> B Cell (MBC) responses against CtxB But no significant MBC responses against LPS. In contrast, children recovering from natural cholera infection developed prominent LPS IgG and IgA MBC responses, as well as CtxB IgG MBC responses. Plasma LPS IgG, IgA, and IgM responses, as well as viBriocidal responses, were also significantly higher in children following disease than after vaccination. Our findings suggest that acute and <B>MemoryB> immune responses following oral cholera vaccination in children are significantly lower than those oBserved following wild-type disease, especially responses targeting LPS. These findings may explain, in part, the lower efficacy of oral cholera vaccination in children.