The Antigenic Role of the Excretions and Secretions of Adult Trichinella spiralis in the Production of Immunity in Mice

Experimental evidence lends strong support to the generally accepted view that the excretions and secretions of parasitic worms elicit an immune response in the host. The major portion of this evidence is indirect, being concerned with demonstrations of precipitate formation around the body openings of worms incubated in homologous antiserum. The first direct evidence for this view was offered by Thorson (1951, 1953) who demonstrated that injection into rats of the excretions and secretions collected from infective larvae of Nippostrongylus muris gave partial protection against a challenging infection of the same parasite. Campbell (1955) added further proof by showing that injection of the excretions and secretions (ES antigen) of infective larvae of Trichinella spiralis elicits an immune response in white mice. This immunity was evidenced following infection by a more rapid loss of adult worms, a stunting of the adult females, and the presence of smaller numbers of larvae in the muscles of injected mice than in the control mice. On the basis of Campbell's results, using infective larvae, it seemed worthwhile to determine whether or not an ES antigen could be collected from the adults of T. spiralis, and, if so, how effective it would be in producing immunity.