MEDIASTINAL LYMPH-NODE CELLS OF ANGIOSTRONGYLUS CANTONENSIS-INFECTED RATS RESPOND TO ANTIGENS AND RELEASE INTERLEUKIN-5 IN-VITRO

The kinetics of eosinophil growth and/or survival stimulating factor ( Eo-stimulating factor) production in Angiostrongylus cantonensis-infec ted rats was assessed by in vitro marrow cultures. When lymphocytes, o btained from cervical, mediastinal or mesenteric lymph nodes of infect ed WKAH rats, were cultured with A. cantonensis antigens, Eo-stimulati ng factor activity was detected in the conditioned media obtained only from mediastinal lymph node cells at and after 35 days p.i. Eo-stimul ating factor activity in the conditioned media,vas not detected before or at 20 days p.i. The kinetics of the factor was, therefore, almost identical to those of eosinophilia in bone marrow and peripheral blood . This Eo-stimulating factor activity was inhibited (maximum inhibitio n = 73%) by anti-mouse IL-5 monoclonal antibody in a dose-dependent fa shion, indicating that the factor would be, at least in part, identica l to IL-5. Similar Eo-stimulating factors were also detected in the co nditioned media which were obtained by stimulating spleen cells from W istar rats at 35-45 days p.i. with Con A. These data suggest that lymp hocytes in the mediastinal lymph nodes, local lymph nodes near the adu lt worm habitat, could play an essential role in induction of eosinoph ilia in A. cantonensis-infected rats. Copyright (C) 1996 Australian So ciety for Parasitology. Published by Elsevier Science Ltd.