AN INVESTIGATION INTO THE ANTIGENIC CROSS-REACTIVITY OF OPHIOPHAGUS-HANNAH (KING COBRA) VENOM NEUROTOXIN, PHOSPHOLIPASE-A(2), HEMORRHAGIN AND L-AMINO-ACID OXIDASE USING ENZYME-LINKED-IMMUNOSORBENT-ASSAY

The antigenic cross-reactivity of four Ophiophagus hannah (king cobra) venom components, the neurotoxin (OH-NTX), phospholipase A2 (OH-PLA2) , hemorrhagin (OH-HMG) and L-amino acid oxidase (OH-LAAO) were examine d by indirect and double sandwich ELISAs. The indirect ELISAs for OH-N TX, OH-PLA2 and OH-HMG were very specific when assayed against the var ious heterologous snake venoms and O. hannah venom components, at 25 n g/ml antigen level. At higher antigen concentrations (100-400 ng/ml), there were moderate to strong indirect ELISA cross-reactions between a nti-O. hannah neurotoxin and venoms from various species of cobra as w ell as two short neurotoxins. However, anti-O. hannah hemorrhagin did not cross-react with any of the venoms tested, even at these high anti gen concentrations, indicating that O. hannah hemorrhagin is antigenic ally very different from other venom hemorrhagins. Examination of the indirect ELISA cross-reactions between anti-O. hannah PLA2 and several elapid PLA2 enzymes suggests that the elapid PLA2 antigenic class has more than two subgroups. The antibodies to O. hannah L-amino acid oxi dase, however, yielded indirect ELISA cross-reactions with many venoms as well as with OH-NTX, OH-PLA2 and OH-HMG, indicating that OH-LAAO s hares common epitopes even with unrelated proteins. The double sandwic h ELISAs for the four anti-O. hannah venom components, on the other ha nd, generally exhibited a higher degree of selectivity than the indire ct ELISA procedure.