title: Immunochemical cross-reactivity of neurotoxic phospholipase A2 enzymes from Indian cobra (Naja naja naja) venom using polyclonal antibodies.
abstract: Rabbit antibodies were prepared against purified phospholipase A2 (NN-XIa-PLA2) from Indian cobra (Naja naja naja) venom. The PLA2 has haemolytic, neurotoxic, myotoxic, cytotoxic and oedema-inducing activities apart from the catalytic activity. The immunological cross-reactivity of structurally similar neurotoxic PLA2s was investigated using enzyme-linked immunosorbent assay (ELISA) and immunodiffusion. Anti-NN-XIa-PLA2 IgG cross-reacted with other purified neurotoxic PLA2s from the same venom. Immunochemical cross-reactions of anti-NN-XIa-PLA2 IgG with NN-XIa-PLA2, NN-XIb-PLA2, NN-XIII-PLA2, NN-IVb1-PLA2 and NN-Vb-PLA2 were shown by a very high ELISA titre and a single precipitin band on double immunodiffusion agarose plates. The catalytic activity of these PLA2s was inhibited dose-dependently by anti-NN-XIa-PLA2 IgG but was unable to neutralize lethality and neurotoxic symptoms in experimental animals injected with neurotoxic PLA2. Anti-NN-XIa-PLA2 IgG fails to neutralize myotoxicity and oedema-inducing activities of NN-XIa-PLA2 and NN-XIII-PLA2. Anti-NN-XIa-PLA2 IgG inhibited cytotoxic effects of NN-XIa-PLA2 dose-dependently, but failed to inhibit NN-XIII-PLA2-induced cytotoxicity. Direct haemolytic activity of NN-XIa-PLA2 and NN-XIII-PLA2 was inhibited dose-dependently by these antibodies. The results indicate the presence of separate catalytic and pharmacologic site(s).
authors.affiliation: Department of Studies in Biochemistry, University of Mysore, Manasagangotri, India.
authors.forename: B S
authors.initials: BS
authors.lastname: Basavarajappa
authors.forename: S C
authors.initials: SC
authors.lastname: Guru
authors.forename: T V
authors.initials: TV
authors.lastname: Gowda
mesh_terms: D000818:Animals; D000906:Antibodies / Q000032:analysis; D000918:Antibody Specificity; D002470:Cell Survival / Q000187:drug effects; D003429:Cross Reactions; D004487:Edema / Q000139:chemically induced / Q000473:pathology; D004546:Elapid Venoms / Q000201:enzymology* / Q000276:immunology / Q000633:toxicity; D004797:Enzyme-Linked Immunosorbent Assay; D006461:Hemolysis / Q000187:drug effects; D007120:Immunochemistry; D008297:Male; D051379:Mice; D009135:Muscular Diseases / Q000139:chemically induced / Q000473:pathology; D009498:Neurotoxins / Q000633:toxicity; D010741:Phospholipases A / Q000032:analysis / Q000276:immunology* / Q000633:toxicity; D054467:Phospholipases A2; D005719:gamma-Globulins / Q000032:analysis / Q000276:immunology
chemical_list: D000906:Antibodies; D004546:Elapid Venoms; D009498:Neurotoxins; D005719:gamma-Globulins; D010741:Phospholipases A; D054467:Phospholipases A2