title: Effective equine immunization protocol for production of potent poly-specific antisera against Calloselasma rhodostoma, Cryptelytrops albolabris and Daboia siamensis.
abstract: Snake envenomation has been estimated to affect 1.8 million people annually with about 94,000 deaths mostly in poor tropical countries. Specific antivenoms are the only rational and effective therapy for these cases. Efforts are being made to produce effective, affordable and sufficient antivenoms for these victims. The immunization process, which has rarely been described in detail, is one step that needs to be rigorously studied and improved especially with regard to the production of polyspecific antisera. The polyspecific nature of therapeutic antivenom could obviate the need to identify the culprit snake species. The aim of this study was to produce potent polyspecific antisera against 3 medically important vipers of Thailand and its neighboring countries, namely Cryptelytrops albolabris "White lipped pit viper" (CA), Calleoselasma rhodostoma "Malayan pit viper" (CR), and Daboia siamensis "Russell's viper" (DS). Four horses were immunized with a mixture of the 3 viper venoms using the 'low dose, low volume multi-site' immunization protocol. The antisera showed rapid rise in ELISA titers against the 3 venoms and reached plateau at about the 8th week post-immunization. The in vivo neutralization potency (P) of the antisera against CA, CR and DS venoms was 10.40, 2.42 and 0.76 mg/ml, respectively and was much higher than the minimal potency limits set by Queen Soavabha Memorial Institute (QSMI). The corresponding potency values for the QSMI monospecific antisera against CA, CR and DS venoms were 7.28, 3.12 and 1.50 mg/ml, respectively. The polyspecific antisera also effectively neutralized the procoagulant, hemorrhagic, necrotic and nephrotoxic activities of the viper venoms. This effective immunization protocol should be useful in the production of potent polyspecific antisera against snake venoms, and equine antisera against tetanus, diphtheria or rabies.
authors.affiliation: Department of Microbiology, Faculty of Science, Mahidol University, Bangkok, Thailand.
authors.forename: Sompong
authors.initials: S
authors.lastname: Sapsutthipas
authors.affiliation: Department of Pharmacology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Poh Kuan
authors.initials: PK
authors.lastname: Leong
authors.affiliation: Queen Saovabha Memorial Institute, Bangkok, Thailand.
authors.forename: Surasak
authors.initials: S
authors.lastname: Akesowan
authors.affiliation: Division of Biotechnology, Faculty of Agro-industry, Chiang Mai University, Chaing Mai, Thailand.
authors.forename: Ronachai
authors.initials: R
authors.lastname: Pratanaphon
authors.affiliation: Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Nget Hong
authors.initials: NH
authors.lastname: Tan
authors.affiliation: Department of Microbiology, Faculty of Science, Mahidol University, Bangkok, Thailand; Laboratory of Immunology, Chulabhorn Research Institute and Chulabhorn Graduate Institute, Thailand.
authors.forename: Kavi
authors.initials: K
authors.lastname: Ratanabanangkoon
mesh_terms: D000818:Animals; D000997:Antivenins / Q000096:biosynthesis*; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay; D006736:Horses; D007106:Immune Sera / Q000096:biosynthesis*; D007114:Immunization; D007928:Lethal Dose 50; D051379:Mice; D013785:Thailand; D014757:Viper Venoms / Q000276:immunology*
chemical_list: D000997:Antivenins; D007106:Immune Sera; D014757:Viper Venoms