PRO-INFLAMMATORY ACTIVITIES IN ELAPID SNAKE-VENOMS

1 Snake venoms from the genera Micrurus (M. ibiboboca and M. spixii) and Naja (N. naja, N. melanoleuca and N. nigricollis) were analysed, using biological and immunochemical methods, to detect pro-inflammatory activities, cobra venom factor (COF), proteolytic enzymes, thrombin-like substances, haemorrhagic and oedema-producing substances. 2 The venoms of the five snake species activate the complement system (C) in normal human serum (NHS) in a dose-related fashion, at concentrations ranging from 5 mu g to 200 mu g ml(-1) serum. Electrophoretic conversion of C3 was observed with all venoms in NHS containing normal concentrations of Ca2+ and Mg2+, but only by venoms from N. naja and N. melanoleuca when Ca2+ was chelated by adding Mg2+-EGTA. 3 Purified human C3 was electrophoretically converted, in the absence of other C components, by the venoms from N. naja, N. nigricollis and M. ibiboboca. However, only the venoms from N. naja and N. melanoleuca contained a 144 kDa protein revealed in Western blot with sera against COF or human C3. 4 All venoms, at minimum concentrations of 30 ng ml(-1), were capable of lysing sheep red blood cells, also in a dose-related fashion, when incubated with these cells in presence of egg yolk as a source of lecithin. Although the venoms from M. spixii and N. nigricollis showed detectable thrombin-like activity, these and the other venoms were free of proteolytic activity when fibrin, gelatin and casein, were used as substrates. 5 When tested on mice skin, all five venoms were capable of inducing an increase in vascular permeability and oedema, but were devoid of haemorrhagic producing substances (haemorrhagins). 6 These data provide evidence indicating that Elapidae venoms contain various pro-inflammatory factors which may be important in the spreading of neurotoxins throughout the tissues of the prey or human victim.