VSV Amino Acids

The Homologous Relationship of Ophidian Amino Acids, as it Would Apply to a DNA-Based Vaccine in Humans

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Excerpt:

Part of my responsibility with this vaccine was to track down the complete DNA sequences of snake venom fractions that I was to use on myself, or humans in the field. This was a large task due to the plethora of deleterious fractions that venomous snake have. There are about 500 species of venomous snakes, and the biggest killers are Elapidae/Viperidae(3).Of those, only a handful are dangerous to humans due to human populations that encounter these snakes, venom toxicity, aggression, etc. Certain venomous snakes can have over 40-50 deleterious fractions that can be harmful to humans. How do you pick from this selection to chose the ones that we will use for a DNA-based vaccine protocol?

Two more very important goals I aimed at achieving where finding what other snake venom fractions had similar amino acid sequences, and what amino acids were involved in the epitope for IgG binding and possible cross-reactivity, that might be important with developing the DNA-based vaccine for humans. I felt a thorough epitope mapping mission was in order to reveal these critical IgG binding sites to maybe make a better vaccine.

This is where I turned to a super article by J.P. Chippaux on The Global Evaluation of Snakebites(1). His in depth article helped me focus in on the major culprits of snakebite death throughout the world. This gave me a great picture for the overall crisis of snakebite death. I couldn't start to build my theoretical case for a DNA-based vaccine without the appropriate fractions that would save the most amount of lives, fingers, hands, legs, etc.His study showed these results on snakebite death throughout the world. Europe(30 deaths), Middle East(100 deaths), USA/Canada(15 deaths), Central/South America(5,000 deaths), Africa(20,000 deaths), Asia(100,000 deaths), and Oceania(200)(1).

At this point I studied the major killers in these parts of the world and made a detailed list of them to further break down the schematic of death. South American deaths a year are due to Bothrops mainly(atrox, asper, jararaca,etc.). Crotalus durissus also comes into play, but Bothrops is the major killer.

Africa is next with many genera that can kill. Echis has 9 spp. that cause human deaths(coloratus, hughesi, jogeri, leucogaster, megalocephalus, ocellatus, omanensis, and pyramidum[3]). Bitis has 16 species that cause human deaths(albanica, arietans, armata, atropos, caudalis, cornuta, gabonica, heraldica, inornata,nasicornis, parviocula, peringueyi, rubida, schneideri, worthington, xeropaga[3]). Naja has 10 spp that cause human deaths( haje, melanoleuca, mossambica, katiensis, pallida, nigricollis, nivea, anchietae, annulifera, and nubiae[3]). The Dendroaspis genus has four species that cause human deaths (angusticeps, jamesoni, polylepis, and viridis[3]).

Asia has the biggest ratio of snakebite death due to the big four(plus others). Indian cobra, common krait, russell’s viper, and the saw-scaled viper. The cobras consist of Naja(atra, kaouthia, mandalayensis, naja, oxiana, philippinensis, sagittifera, samaras, siamensis, sputatrix, and sumatrana[3]). Bungarus has (andamanensis, bungaroides, caeruleus, candidus, ceylonicus, fasciatus, flaviceps, lividus, magnimaculatus, niger, sindanus, Lewinski[3]). Daboia russelii, and Echis carinatus also have very large roles in snakebite death in Asia.

At this time I focused on the major killers, with the major fractions that cause death or disability. I've chosen these genera, with these certain fractions that cause the most harm.

I broke it down into these major families that create the most trouble: SVMP(causes haemorrhage), PLA2(pro/anti coagulant), CTL(platelet/coagulation problems) alpha three-finger postsynaptic neurotoxins(inhibits nAChR and produces peripheral paralysis at the NMJ),PLA2 presynaptic beta neurotoxins(blocks acetylcholine release at the nerve terminal[2,4]). There are many more, but this is a strong representation of deleterious fractions from multiple genera as a comparison. The Harrisson paper also uses SVMP, PLA2 and CTL as a amino acid comparison(2).

There are many very positive features that can be drawn from these amino acid comparisons. The complete DNA sequences are already done for all these venom fractions, which makes it easier to develop a DNA-based vaccine for human use.

The structural similarity with these fractions means that IgG raised antibodies will cross with not just different species, but different genera, in different continents. There are many 50% amino acid similarities, but the 100% and 90% fractions show that cross- reactivity will happen. The alpha neurotoxins and CTL toxins are a very good example of how similar that group is. Truly, a partial multi-continental ophidian DNA -based vaccine.

My personal opinion would be having three continental DNA vaccines for humans(partial of course at this point). South America would have the DNA-jararhagin vaccine, Africa would have the DNA-ecarin/neuro-alpha(Naja), and Asia would have the DNA- ecarin/neuro-alpha(Naja)/RVV-X(Daboia)/bungarotoxin(Bungarus).

Obviously more fractions could be added, but I feel that's a good initial mix for partial coverage. At first though, I think just zeroing in on one fraction would be the key to see if IgG acceptable titers can be achieved.