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Stephen P Mackessy - One of the best experts on this subject based on the ideXlab platform.
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colubrid venom composition an omics perspective
Toxins, 2016Co-Authors: Inacio L M Junqueiradeazevedo, Pollyanna Fernandes Campos, Ana Tung Ching Ching, Stephen P MackessyAbstract:Snake Venoms have been subjected to increasingly sensitive analyses for well over 100 years, but most research has been restricted to front-fanged snakes, which actually represent a relatively small proportion of extant species of advanced snakes. Because rear-fanged snakes are a diverse and distinct radiation of the advanced snakes, understanding venom composition among “colubrids” is critical to understanding the evolution of venom among snakes. Here we review the state of knowledge concerning rear-fanged snake venom composition, emphasizing those toxins for which protein or transcript sequences are available. We have also added new transcriptome-based data on Venoms of three species of rear-fanged snakes. Based on this compilation, it is apparent that several components, including cysteine-rich secretory proteins (CRiSPs), C-type lectins (CTLs), CTLs-like proteins and snake venom metalloproteinases (SVMPs), are broadly distributed among “colubrid” Venoms, while others, notably three-finger toxins (3FTxs), appear nearly restricted to the Colubridae (sensu stricto). Some putative new toxins, such as snake venom matrix metalloproteinases, are in fact present in several colubrid Venoms, while others are only transcribed, at lower levels. This work provides insights into the evolution of these toxin classes, but because only a small number of species have been explored, generalizations are still rather limited. It is likely that new venom protein families await discovery, particularly among those species with highly specialized diets.
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Handbook of Venoms and Toxins of Reptiles - Handbook of Venoms and Toxins of Reptiles
2016Co-Authors: Stephen P MackessyAbstract:Field of Reptile Toxinology: Snakes, Lizards, and Their Venoms, S.P. Mackessy Recent Advances in Venomous Snake Systematics, A. Quijada-Mascarenas and W. Wuster Reptile Venom Glands: Form, Function, and Future, S.A. Weinstein, T.L. Smith, and K.V. Kardong Snake Venom Metalloproteinases, J.W. Fox and S.M.T. Serrano Snake Venom Metalloproteinases: Biological Roles and Participation in the Pathophysiology of Envenomation, J.M. Gutierrez, A. Rucavado, and T. Escalante Thrombin-like Snake Venom Serine Proteinases, D.J. Phillips, S.D. Swenson, and F.S. Markland, Jr. Snake Venom Nucleases, Nucleotidases, and Phosphomonoesterases, B.L. Dhananjaya, B.S. Vishwanath, and C.J.M. D'Souza Snake Venom Phospholipase A2 Enzymes, R. Doley, X. Zhou, and R.M. Kini Snake Venom Acetylcholinesterase, M. Ahmed, J.B.T. Rocha, V.M. Morsch, and M.R.C. Schetinger Snake Venom L-Amino Acid Oxidases, N.-H. Tan and S.-Y. Fung Hyaluronidases, a Neglected Class of Glycosidases from Snake Venom: Beyond a Spreading Factor, K. Kemparaju, K. S. Girish, and S. Nagaraju Enzyme Inhibitors in Reptile Venoms and Innate Immunity to Snake Venoms, A.G. da Costa Neves-Ferreira, R.H. Valente, J. Perales, and G.B. Domont Snake Venom Three-Finger Toxins, R.P. Hegde, N. Rajagopalan, R. Doley, and R.M. Kini Sarafotoxins, the Snake Venom Homologs of the Endothelins, A. Bdolah Fasciculins: Toxins from Mamba Venoms That Inhibit Acetylcholinesterase, A.L. Harvey Cysteine-rich Secretory Proteins in Reptile Venoms, W.H. Heyborne and S.P. Mackessy Snake Venomics and Disintegrins: Portrait and Evolution of a Family of Snake Venom Integrin Antagonists, J.J. Calvete, P. Juarez, and L. Sanz Reptile C-type Lectins, X.-Y. Du and K.J. Clemetson Snake Venom Nerve Growth Factors, M.F. Lavin, S. Earl, G. Birrell, L. St. Pierre, J. de Jersey, and P. Masci The Role of Purine and Pyrimidine Nucleosides in Snake Venoms, S.D. Aird Envenomation: Prevention and Treatment in Australia, J. White Snakebite in Africa: Current Situation and Urgent Needs, J.-P. Chippaux Envenomations by Reptiles in the United States, J. Smith and S. Bush Snakebite Envenomation in Central America, J.M. Gutierrez Index
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comparative venomics of the prairie rattlesnake crotalus viridis viridis from colorado identification of a novel pattern of ontogenetic changes in venom composition and assessment of the immunoreactivity of the commercial antivenom crofab
Journal of Proteomics, 2015Co-Authors: Libia Sanz, Juan J. Calvete, Anthony J Saviola, Todd A Castoe, Stephen P MackessyAbstract:Abstract Here we describe and compare the venomic and antivenomic characteristics of both neonate and adult Prairie Rattlesnake (Crotalus viridis viridis) Venoms. Although both neonate and adult Venoms contain unique components, similarities among protein family content were seen. Both neonate and adult Venoms consisted of myotoxin, bradykinin-potentiating peptide (BPP), phospholipase A2 (PLA2), Zn2 +-dependent metalloproteinase (SVMP), serine proteinase, L-amino acid oxidase (LAAO), cysteine-rich secretory protein (CRISP) and disintegrin families. Quantitative differences, however, were observed, with Venoms of adults containing significantly higher concentrations of the non-enzymatic toxic compounds and Venoms of neonates containing higher concentrations of pre-digestive enzymatic proteins such as SVMPs. To assess the relevance of this venom variation in the context of snakebite and snakebite treatment, we tested the efficacy of the common antivenom CroFab® for recognition of both adult and neonate Venoms in vitro. This comparison revealed that many of the major protein families (SVMPs, CRISP, PLA2, serine proteases, and LAAO) in both neonate and adult Venoms were immunodepleted by the antivenom, whereas myotoxins, one of the major toxic components of C. v. viridis venom, in addition to many of the small peptides, were not efficiently depleted by CroFab®. These results therefore provide a comprehensive catalog of the venom compounds present in C. v. viridis venom and new molecular insight into the potential efficacy of CroFab® against human envenomations by one of the most widely distributed rattlesnake species in North America. Biological significance Comparative proteomic analysis of Venoms of neonate and adult Prairie Rattlesnake (Crotalus viridis viridis) from a discrete population in Colorado revealed a novel pattern of ontogenetic shifts in toxin composition for viperid snakes. The observed stage-dependent decrease of the relative content of disintegrins, catalytically active D49-PLA2s, L-amino acid oxidase, and SVMPs, and the concomitant increase of the relative abundance of paralytic small basic myotoxins and ohanin-like toxin, and hemostasis-disrupting serine proteinases, may represent an age-dependent strategy for securing prey and avoiding injury as the snake switches from small ectothermic prey and newborn rodents to larger endothermic prey. Such age-dependent shifts in venom composition may be relevant for antivenom efficacy and treatment of snakebite. However, applying a second-generation antivenomics approach, we show that CroFab®, developed against venom of three Crotalus and one Agkistrodon species, efficiently immunodepleted many, but not all, of the major compounds present in neonate and adult C. v. viridis Venoms.
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handbook of Venoms and toxins of reptiles
Handbook of venoms and toxins of reptiles., 2009Co-Authors: Stephen P MackessyAbstract:Field of Reptile Toxinology: Snakes, Lizards, and Their Venoms, S.P. Mackessy Recent Advances in Venomous Snake Systematics, A. Quijada-Mascarenas and W. Wuster Reptile Venom Glands: Form, Function, and Future, S.A. Weinstein, T.L. Smith, and K.V. Kardong Snake Venom Metalloproteinases, J.W. Fox and S.M.T. Serrano Snake Venom Metalloproteinases: Biological Roles and Participation in the Pathophysiology of Envenomation, J.M. Gutierrez, A. Rucavado, and T. Escalante Thrombin-like Snake Venom Serine Proteinases, D.J. Phillips, S.D. Swenson, and F.S. Markland, Jr. Snake Venom Nucleases, Nucleotidases, and Phosphomonoesterases, B.L. Dhananjaya, B.S. Vishwanath, and C.J.M. D'Souza Snake Venom Phospholipase A2 Enzymes, R. Doley, X. Zhou, and R.M. Kini Snake Venom Acetylcholinesterase, M. Ahmed, J.B.T. Rocha, V.M. Morsch, and M.R.C. Schetinger Snake Venom L-Amino Acid Oxidases, N.-H. Tan and S.-Y. Fung Hyaluronidases, a Neglected Class of Glycosidases from Snake Venom: Beyond a Spreading Factor, K. Kemparaju, K. S. Girish, and S. Nagaraju Enzyme Inhibitors in Reptile Venoms and Innate Immunity to Snake Venoms, A.G. da Costa Neves-Ferreira, R.H. Valente, J. Perales, and G.B. Domont Snake Venom Three-Finger Toxins, R.P. Hegde, N. Rajagopalan, R. Doley, and R.M. Kini Sarafotoxins, the Snake Venom Homologs of the Endothelins, A. Bdolah Fasciculins: Toxins from Mamba Venoms That Inhibit Acetylcholinesterase, A.L. Harvey Cysteine-rich Secretory Proteins in Reptile Venoms, W.H. Heyborne and S.P. Mackessy Snake Venomics and Disintegrins: Portrait and Evolution of a Family of Snake Venom Integrin Antagonists, J.J. Calvete, P. Juarez, and L. Sanz Reptile C-type Lectins, X.-Y. Du and K.J. Clemetson Snake Venom Nerve Growth Factors, M.F. Lavin, S. Earl, G. Birrell, L. St. Pierre, J. de Jersey, and P. Masci The Role of Purine and Pyrimidine Nucleosides in Snake Venoms, S.D. Aird Envenomation: Prevention and Treatment in Australia, J. White Snakebite in Africa: Current Situation and Urgent Needs, J.-P. Chippaux Envenomations by Reptiles in the United States, J. Smith and S. Bush Snakebite Envenomation in Central America, J.M. Gutierrez Index
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venom of the brown treesnake boiga irregularis ontogenetic shifts and taxa specific toxicity
Toxicon, 2006Co-Authors: Stephen P Mackessy, Nicole M Sixberry, William H Heyborne, Thomas FrittsAbstract:The Brown Treesnake (Boiga irregularis), a rear-fanged member of the polyphyletic family Colubridae, is an introduced predator on Guam which has been responsible for numerous human envenomations. Because little is known about this species’ venom, we characterized venom proteins from B. irregularis using enzyme assays, one and 2D electrophoresis, Western blot analysis, mass spectrometry, HPLC and toxicity assays. Venom yields and protein content varied significantly with snake size, and large adult specimens averaged over 500 ml venom (19.2 mg, protein content w90%). Only two enzymes, azocaseinolytic metalloprotease and acetylcholinesterase, were detected in Venoms, and both activities increased with snake size/age. Western blot analysis demonstrated a 25 kDa CRiSP homolog in Venoms from both neonate and adult snakes. 2D electrophoresis showed variation between Venoms from neonate and adult snakes, especially with respect to metalloprotease and acetylcholinesterase. Analysis by MALDI-TOF mass spectrometry revealed the presence of numerous proteins with molecular masses of w8.5‐11 kDa. Adult B. irregularis venom was quite toxic to domestic chickens (Gallus domesticus; 1.75 mg/g) and lizards (Hemidactylus geckos: 2.5 mg/g and Carlia skinks: 4.5 mg/g), and intoxication was characterized by rapid paralysis of all species and neck droop in chickens. Toxicity of venom from neonates toward geckos was 1.1 mg/g, consistent with the presence of a greater diversity of 8‐11 kDa proteins (suspected neurotoxins) in these Venoms. All of these values were notably lower than murine LD50 values (neonate: 18 mg/g; adult: 31 mg/g). Like Venoms of several front-fanged species, B. irregularis venom showed an ontogenetic shift in enzyme activities and toxicity, and neonate snakes produced more toxic Venoms with lower protease and acetylcholinesterase activities. High toxicity toward non-mammalian prey demonstrated the presence of taxaspecific effects (and thus toxins) in B. irregularis venom, likely a characteristic of many colubrid snake Venoms. We hypothesize that the lack of significant envenomation effects in humans following most colubrid bites results from this taxaspecific action of colubrid venom components, not from a lack of toxins.
Wayne Clarence Hodgson - One of the best experts on this subject based on the ideXlab platform.
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proteomic characterization of two medically important malaysian snake Venoms calloselasma rhodostoma malayan pit viper and ophiophagus hannah king cobra
Toxins, 2018Co-Authors: Sugita Kunalan, Iekhsan Othman, Sharifah Syed Hassan, Wayne Clarence HodgsonAbstract:: Calloselasma rhodostoma (CR) and Ophiophagus hannah (OH) are two medically important snakes found in Malaysia. While some studies have described the biological properties of these Venoms, feeding and environmental conditions also influence the concentration and distribution of snake venom toxins, resulting in variations in venom composition. Therefore, a combined proteomic approach using shotgun and gel filtration chromatography, analyzed by tandem mass spectrometry, was used to examine the composition of Venoms from these Malaysian snakes. The analysis revealed 114 proteins (15 toxin families) and 176 proteins (20 toxin families) in Malaysian Calloselasma rhodostoma and Ophiophagus hannah species, respectively. Flavin monoamine oxidase, phospholipase A₂, phosphodiesterase, snake venom metalloproteinase, and serine protease toxin families were identified in both Venoms. Aminopeptidase, glutaminyl-peptide cyclotransferase along with ankyrin repeats were identified for the first time in CR venom, and insulin, c-type lectins/snaclecs, hepatocyte growth factor, and macrophage colony-stimulating factor together with tumor necrosis factor were identified in OH venom for the first time. Our combined proteomic approach has identified a comprehensive arsenal of toxins in CR and OH Venoms. These data may be utilized for improved antivenom production, understanding pathological effects of envenoming, and the discovery of biologically active peptides with medical and/or biotechnological value.
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comparative studies of the venom of a new taipan species oxyuranus temporalis with other members of its genus
Toxins, 2014Co-Authors: Carmel M Barber, Frank Madaras, Richard K Turnbull, Terry Morley, Nathan Dunstan, Luke Allen, Tim Kuchel, Peter Mirtschin, Wayne Clarence HodgsonAbstract:Taipans are highly venomous Australo-Papuan elapids. A new species of taipan, the Western Desert Taipan (Oxyuranus temporalis), has been discovered with two specimens housed in captivity at the Adelaide Zoo. This study is the first investigation of O. temporalis venom and seeks to characterise and compare the neurotoxicity, lethality and biochemical properties of O. temporalis venom with other taipan Venoms. Analysis of O. temporalis venom using size-exclusion and reverse-phase HPLC indicated a markedly simplified “profile” compared to other taipan Venoms. SDS-PAGE and agarose gel electrophoresis analysis also indicated a relatively simple composition. Murine LD50 studies showed that O. temporalis venom is less lethal than O. microlepidotus venom. Venoms were tested in vitro, using the chick biventer cervicis nerve-muscle preparation. Based on t90 values, O. temporalis venom is highly neurotoxic abolishing indirect twitches far more rapidly than other taipan Venoms. O. temporalis venom also abolished responses to exogenous acetylcholine and carbachol, indicating the presence of postsynaptic neurotoxins. Prior administration of CSL Taipan antivenom (CSL Limited) neutralised the inhibitory effects of all taipan Venoms. The results of this study suggest that the venom of the O. temporalis is highly neurotoxic in vitro and may contain procoagulant toxins, making this snake potentially dangerous to humans.
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differential myotoxic and cytotoxic activities of pre synaptic neurotoxins from papuan taipan oxyuranus scutellatus and irian jayan death adder acanthophis rugosus Venoms
Basic & Clinical Pharmacology & Toxicology, 2013Co-Authors: Janeyuth Chaisakul, Geoffrey K Isbister, Helena C Parkington, Nicki Konstantakopoulos, Wayne Clarence HodgsonAbstract:Pre-synaptic PLA(2) neurotoxins are important components of many Australasian elapid snake Venoms. These toxins disrupt neurotransmitter release. Taipoxin, a pre-synaptic neurotoxin isolated from the venom of the coastal taipan (Oxyuranus scutellatus), causes necrosis and muscle degeneration. The present study examined the myotoxic and cytotoxic activities of Venoms from Papuan taipan (O. scutellatus) and Irian Jayan death adder (Acanthophis rugosus), and also tested their pre-synaptic neurotoxins; cannitoxin and P-EPTX-Ar1a. Based on size-exclusion chromatography analysis, cannitoxin represents 16% of O. scutellatus venom, while P-EPTX-Ar1a represents 6% of A. rugosus venom. In the chick biventer cervicis nerve-muscle preparation, A. rugosus venom displayed significantly higher myotoxic activity than O. scutellatus venom as indicated by inhibition of direct twitches, and an increase in baseline tension. Both cannitoxin and P-EPTX-Ar1a, displayed marked myotoxic activity. A. rugosus venom (50-300 μg/ml) produced concentration-dependent inhibition of cell proliferation in rat skeletal muscle cell lines (L6), while 300 μg/ml of O. scutellatus venom was required to inhibit cell proliferation, following 24-hr incubation. P-EPTX-Ar1a had greater cytotoxicity than cannitoxin, inhibiting cell proliferation after 24-hr incubation in L6 cells. Lactate dehydrogenase levels were increased after 1-hr incubation with A. rugosus venom (100-250 μg/ml), O. scutellatus venom (200-250 μg/ml) and P-EPTX-Ar1a (1-2 μM), but not cannitoxin (1-2 μM), suggesting Venoms/toxin generated cell necrosis. Thus, A. rugosus and O. scutellatus Venoms possess different myotoxic and cytotoxic activities. The proportion of pre-synaptic neurotoxin in the Venoms and PLA(2) activity of the whole Venoms are unlikely to be responsible for these activities. Language: en
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cross neutralisation of australian brown snake taipan and death adder Venoms by monovalent antibodies
Vaccine, 2010Co-Authors: Geoffrey K Isbister, Margaret A Oleary, Wayne Clarence Hodgson, Jessica Hagan, Kearney Nichols, Tammy Jacoby, Kathleen Davern, Jennifer SchneiderAbstract:An understanding of the cross-neutralisation of snake Venoms by antibodies is important for snake antivenom development. We investigated the cross-neutralisation of brown snake (Pseudonaja textilis) venom, taipan (Oxyuranus scutellatus) venom and death adder (Acanthophis antarcticus) with commercial antiVenoms and monovalent anti-snake IgG, using enzyme immunoassays, in vitro clotting and neurotoxicity assays. Each commercial antivenom bound all three Venoms, and neutralised clotting activity of brown snake and taipan Venoms and neurotoxicity of death adder venom. The 'in-house' monovalent anti-snake venom IgG raised against procoagulant brown snake and taipan Venoms, did not neutralise the neurotoxic effects of death adder venom. However, they did cross-neutralise the procoagulant effects of both procoagulant Venoms. This supports the idea of developing antiVenoms against groups of snake toxins rather than individual snake Venoms.
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in vitro neuromuscular activity of colubrid Venoms clinical and evolutionary implications
Toxicon, 2004Co-Authors: Natalie G Lumsden, Manjunatha R Kini, Wayne Clarence HodgsonAbstract:Abstract In this study, Venoms from species in the Colubrinae, Homalopsinae, Natricinae, Pseudoxyrhophiinae and Psammophiinae snake families were assayed for activity in the chick biventer cervicis skeletal nerve muscle preparation. Boiga dendrophila , Boiga cynodon , Boiga dendrophila gemincincta , Boiga drapiezii , Boiga irregularis , Boiga nigriceps and Telescopus dhara Venoms (10 μg/ml) displayed postsynaptic neuromuscular activity as evidenced by inhibition of indirect (0.1 Hz, 0.2 ms, supramaximal V) twitches. Neostigmine (5 μM) reversed the inhibition caused by B. cynodon venom (10 μg/ml) while the inhibitory effects of Psammophis mossambicus venom (10 μg/ml) spontaneously reversed, indicating a reversible mode of action for both Venoms. Trimorphodon biscutatus (10 μg/ml) displayed irreversible presynaptic neurotoxic activity. Detectable levels of phospholipase A 2 activity were found only in T. biscutatus , T. dhara and P. mossambicus Venoms. The results demonstrate a hitherto unsuspected diversity of pharmacological actions in all lineages which may have implications ranging from clinical management of envenomings to venom evolution.
Gunter Allmaier - One of the best experts on this subject based on the ideXlab platform.
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intraspecies variability in vipera ammodytes ammodytes venom related to its toxicity and immunogenic potential
Comparative Biochemistry and Physiology, 2011Co-Authors: Beata Halassy, Marija Brgles, Lidija Habjanec, Maja Lang Balija, Tihana Kurtovic, Martina Marchettideschmann, Igor Križaj, Gunter AllmaierAbstract:Vipera ammodytes is the most venomous European snake, whose venom has been used as antigen for immunization of antivenom-producing animals. Same as venom of any other snake, it is a complex mixture of proteins, peptides and other compounds which biochemical and pharmacological variability has been demonstrated at interspecies and intraspecies level. In this work we demonstrated intraspecific variability between 8 venom production batches using both the conventional and the new methodology. Moreover, in contrast to the literature on different Venoms' variability, for the first time we were able to select those biochemical differences that are related to and give information on the venom's toxicity and immunogenicity. We have shown that methods quantifying ammodytoxin (the most toxic compound identified so far in the Vipera ammodytes ammodytes venom) content of the venom clearly distinguish between high and low immunogenic Venoms.
Beata Halassy - One of the best experts on this subject based on the ideXlab platform.
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intraspecies variability in vipera ammodytes ammodytes venom related to its toxicity and immunogenic potential
Comparative Biochemistry and Physiology, 2011Co-Authors: Beata Halassy, Marija Brgles, Lidija Habjanec, Maja Lang Balija, Tihana Kurtovic, Martina Marchettideschmann, Igor Križaj, Gunter AllmaierAbstract:Vipera ammodytes is the most venomous European snake, whose venom has been used as antigen for immunization of antivenom-producing animals. Same as venom of any other snake, it is a complex mixture of proteins, peptides and other compounds which biochemical and pharmacological variability has been demonstrated at interspecies and intraspecies level. In this work we demonstrated intraspecific variability between 8 venom production batches using both the conventional and the new methodology. Moreover, in contrast to the literature on different Venoms' variability, for the first time we were able to select those biochemical differences that are related to and give information on the venom's toxicity and immunogenicity. We have shown that methods quantifying ammodytoxin (the most toxic compound identified so far in the Vipera ammodytes ammodytes venom) content of the venom clearly distinguish between high and low immunogenic Venoms.
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Ammodytoxin content of Vipera ammodytes ammodytes venom as a prognostic factor for venom immunogenicity
Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology, 2010Co-Authors: Beata Halassy, Marija Brgles, Lidija Habjanec, Maja Lang Balija, Tihana Kurtović, Igor KrižajAbstract:Venoms are complex mixtures of proteins, peptides and other compounds whose biochemical and biological variability has been clearly demonstrated. These molecules have been used as antigens for immunization of anti-venom-producing animals (horses or sheep). Ammodytoxins (Atx) are potently neurotoxic compounds, and the most toxic compounds isolated so far from the Vipera ammodytes ammodytes (Vaa) venom. Recently we have shown that the level of antibodies specific to Vaa venom's most toxic component, ammodytoxin A (AtxA), (anti-AtxA IgG) in Vaa venom immunized rabbit sera highly correlated to the venom toxicity-neutralization potential of these sera. Here we investigated whether Atx content of Vaa venom could influence the outcome of immunization procedure. The novel ELISA was developed for precise determination of Atx content and Atx was quantified in venom samples used for immunization of rabbits. We clearly showed that animals immunized with the venom containing lower amount of Atx produced sera with significantly lower venom toxicity-neutralizing power and, vice versa, animals immunized with Venoms containing higher amount of Atx produced sera with higher venom toxicity-neutralizing ability. Thus, the content of Atx in Vaa venom is a relevant parameter of its suitability in the production of highly protective Vaa anti-venom.
Anthony J Saviola - One of the best experts on this subject based on the ideXlab platform.
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comparative venomics of the prairie rattlesnake crotalus viridis viridis from colorado identification of a novel pattern of ontogenetic changes in venom composition and assessment of the immunoreactivity of the commercial antivenom crofab
Journal of Proteomics, 2015Co-Authors: Libia Sanz, Juan J. Calvete, Anthony J Saviola, Todd A Castoe, Stephen P MackessyAbstract:Abstract Here we describe and compare the venomic and antivenomic characteristics of both neonate and adult Prairie Rattlesnake (Crotalus viridis viridis) Venoms. Although both neonate and adult Venoms contain unique components, similarities among protein family content were seen. Both neonate and adult Venoms consisted of myotoxin, bradykinin-potentiating peptide (BPP), phospholipase A2 (PLA2), Zn2 +-dependent metalloproteinase (SVMP), serine proteinase, L-amino acid oxidase (LAAO), cysteine-rich secretory protein (CRISP) and disintegrin families. Quantitative differences, however, were observed, with Venoms of adults containing significantly higher concentrations of the non-enzymatic toxic compounds and Venoms of neonates containing higher concentrations of pre-digestive enzymatic proteins such as SVMPs. To assess the relevance of this venom variation in the context of snakebite and snakebite treatment, we tested the efficacy of the common antivenom CroFab® for recognition of both adult and neonate Venoms in vitro. This comparison revealed that many of the major protein families (SVMPs, CRISP, PLA2, serine proteases, and LAAO) in both neonate and adult Venoms were immunodepleted by the antivenom, whereas myotoxins, one of the major toxic components of C. v. viridis venom, in addition to many of the small peptides, were not efficiently depleted by CroFab®. These results therefore provide a comprehensive catalog of the venom compounds present in C. v. viridis venom and new molecular insight into the potential efficacy of CroFab® against human envenomations by one of the most widely distributed rattlesnake species in North America. Biological significance Comparative proteomic analysis of Venoms of neonate and adult Prairie Rattlesnake (Crotalus viridis viridis) from a discrete population in Colorado revealed a novel pattern of ontogenetic shifts in toxin composition for viperid snakes. The observed stage-dependent decrease of the relative content of disintegrins, catalytically active D49-PLA2s, L-amino acid oxidase, and SVMPs, and the concomitant increase of the relative abundance of paralytic small basic myotoxins and ohanin-like toxin, and hemostasis-disrupting serine proteinases, may represent an age-dependent strategy for securing prey and avoiding injury as the snake switches from small ectothermic prey and newborn rodents to larger endothermic prey. Such age-dependent shifts in venom composition may be relevant for antivenom efficacy and treatment of snakebite. However, applying a second-generation antivenomics approach, we show that CroFab®, developed against venom of three Crotalus and one Agkistrodon species, efficiently immunodepleted many, but not all, of the major compounds present in neonate and adult C. v. viridis Venoms.