Angiostrongylus cantonensis-infected rats were examined for the presence of antigen sensitive lymphocytes, as assessed by the in vitro uptake of tritiated thymidine by cells of various lymphoid organs (cervical, mediastinal and mesenteric lymph nodes, spleen and peripheral blood), following stimulation by adult worm antigen. The lymphoid cell response of rats to A. cantonensis appeared to be local in nature in that significant responses were noted only in the cervical lymph node cells during the first 4 weeks of infection. The responses of spleen cells to phytohemagglutinin gradually declined as the infection progressed and this reduced responsiveness was statistically significant during the period of 5 to 10 weeks of infection. Homocytotropic antibody, demonstrated by 72-hour homologous passive cutaneous anaphylaxis, was detected throughout 2 to 17 weeks postinfection with a peak response at the 5th week of infection. The antibody was heat labile and sensitive to reduction by 2-mercaptoethanol and alkylation. Hemagglutinating antibody was first observed 5 weeks after infection and high titers occurred throughout 6 to 17 weeks postinfection.
Present address: Department of Parasitology, Juntendo University School of Medicine, Hongo, Bunkyo-ku, Tokyo, Japan.