Immunotoxicology of brown recluse spider (Loxosceles reclusa) venom.

A purified toxic protein from Loxosceles reclusa venom was assayed for its in vitro effects on the human immunological and blood clotting systems. The toxin caused inhibition of neutrophil chemotaxis, depletion of serum hemolytic complement, prolongation of the activated partial thromboplastin time and depletion of clotting factors XII, XI, IX and VIII by an average of 44% in human plasma. The prothrombin time of human plasma was also prolonged by 1.5-2.0 sec. No effect of the purified toxin was observed on microbicidal ability of neutrophils, the release of enzymes from neutrophils or the adherence of neutrophils to glass beads.