Proteomics analysis to compare the venom composition between Naja naja and Naja kaouthia from the same geographical location of eastern India: Correlation with pathophysiology of envenomation and immunological cross-reactivity towards commercial polyantivenom.

BACKGROUND

Cobra bite is frequently reported across the Indian subcontinent and is associated with a high rate of death and morbidity. In eastern India (EI) Naja naja and Naja kaouthia are reported to be the two most abundant species of cobra.

RESEARCH DESIGN AND

METHODS

The venom proteome composition of N. naja (NnV) and N. kaouthia (NkV) from Burdwan districts of EI were compared by separation of venom proteins by 1D-SDS-PAGE followed by LC-MS/MS analysis of protein bands. The potency of commercial polyantivenom (PAV) was assessed by neutralization, ELISA, immuno-blot and venom-PAV immunoaffinity chromatography studies.

RESULTS

Proteomic analysis identified 52 and 55 proteins for NnV and NkV, respectively, when searched against the Elapidae database. A small quantitative difference in venom composition between these two species of cobra was observed. PAVs exhibited poor cross-reactivity against low molecular mass toxins (<20 kDa) of both cobra venoms, which was substantiated by a meager neutralization of their phospholipase A2 activity. Phospholipase A2 and 3FTx, the two major classes of nonenzymatic and enzymatic proteins, respectively, were partially recognized by PAVs.

CONCLUSIONS

Efforts must be made to improve immunization protocols and supplement existing antivenoms with antibodies raised against the major toxins of these venoms.