CROSS-REACTIVITY AND HETEROLOGOUS NEUTRALIZATION OF CROTALINE ANTIVENOMS USED IN ARGENTINA

The immunochemical cross-reactivity and neutralizing capacity of four crotalinae antivenoms consisting in equine F(ab')(2) fragments and ava ilable in Argentina (bothropic Bivalent, against Bothrops alternatus a nd B. neuwiedii venoms; bothropic Tetravalent against B. alternatus, B . neuwiedii, B. jararaca and B. jararacussu venoms; bothropic-crotalic Trivalent, against B. alternatus, B, neuwiedii and Crotalus (C.) duri ssus terrificus venoms and anticrotalic against C. d. terrificus venom ) were studied against B. alternatus, B, ammodytoides; B. jararaca, B, jararacussu; B. moojeni; B, neuwiedii and C, d. terrificus venoms. SD S-PAGE analysis of the Bothrops venoms showed protein bands of high (> 40 kDa) medium (20-40 kDa) and low (< 15 kDa) molecular weights, while that of C. d. terrificus exhibited a large amount of material with mo lecular weight of 15.0 kDa or lower. Immunoblotting showed a high cros sreactivity of all the major protein bands with all the antivenoms (ev en heterologous) tested. All the antivenoms were effective in neutrali zing the lethal activity of the venoms tested, and in some cases (B, j araraca and B. jararacussu) heterologous antivenoms exhibited similar neutralizing capacity than the homologous ones. In spite of the differ ences in biochemical composition and pharmacology, Bothropic antivenom s displayed a significant neutralizing capacity on lethal activity of C, d. terrificus venom. In addition, all the antivenoms (including the anticrotalic) were highly effective in neutralizing the hemorragic, n ecrotizing, procoagulant, and proteolytic activities. The antivenoms t ested produced different degrees of inhibition of phospholipase A2 act ivity, which exhibited a certain specificity but was also related to t he enzyme content in the venom. (C) 1998 Elsevier Science Ltd. All rig hts reserved.