STRUCTURAL FACTORS AFFECT THE INTERACTIONS OF ANTICARDIOTOXIN ANTIBODIES AND COBRA VENOM CARDIOTOXINS

Two antibody preparations against cardiotoxins were raised by immunizi ng rabbits with cardiotoxin 1 and cardiotoxin 3, respectively. The two antibody preparations showed precipitin reactions with cardiotoxins 1 , 2, 3 and 5 respectively. However, the results of competitive enzyme- linked immunoassay revealed that the respective cardiotoxin molecules exhibited different reactivity toward anticardiotoxin antibodies. More over, the order of reactivity with antibodies was not in line with the degree of their sequence identity. This suggest that the anticardioto xin antibodies may recognize conformational epitopes rather than seque ntial ones in the toxin molecules. Alternatively, the four cardiotoxin s reacted well with the antibodies in the absence of competitor, sugge sting that sequence variations with cardiotoxin molecules may not excl usively influence the potential use of the anticardiotoxin antibodies for the neutralization of the activity of cardiotoxin variants.