Induction of peripheral blood eosinophilia in mice by excretory and secretory antigen of Toxocara canis larvae.

Medium in which T. canis larvae had been cultured was applied to a Sephadex G-25 gel column and four fractions (Fr. 1-Fr. 4) were isolated. Each fraction was administered to mice by implanting a mini-osmotic pump into the peritoneal cavity and the subsequent peripheral blood eosinophilic counts were recorded. Mice given Fr. 1 showed a markedly greater eosinophilic response than did those given the other fractions. Complement activation by each fraction was investigated using normal human serum. Fr. 1 and Fr. 3 had a capacity to activate complement. The results suggest that Fr. 1 may be not only antigenetic and allergenic but also could induce eosinophilia and activate complement.