Passive immunity in rats infected with Angiostrongylus cantonensis: interactions between syngeneic immune serum and sensitized lymph node cells.

Immune serum injected into the peritoneum of rats passively protected them against Angiostrongylus cantonensis; this protection was greater than that conferred by passively transferred immune lymph node cells. When immune lymph node cells and serum were transferred together into the same rat, no enhanced protection was observed. The protective effect of serum was inhibited by the lymph node cells to levels commensurate with those conferred by immune lymph node cells alone. Normal lymph node cells also depressed the levels of immunity conferred by immune serum when they were transferred together with serum, but to a lesser extent than did sensitized lymph node cells. Transferred antibody acted to suppress antibody production against A. cantonensis in recipient rats.