In vitro leucocyte proliferative responses and lymphocyte sub-types in guinea pigs with genetically determined high- and low-level responsiveness to Trichostrongylus colubriformis

In vitro leucocyte proliferative responses to parasite antigens and to mitogens as well as lymphocyte sub-types were compared in guinea pigs with genetically determined differences in their ability to express protective immunity against Trichostronylus colubriformis infection. Proliferative responses to parasite antigens were greatest in high-responder (HR) animals, but cells from low-responder (LR) animals were generally more responsive to mitogens. However, HR circulating leucocytes were more responsive to the T-cell-dependent B-cell mitogen pokeweed mitogen (PWM), and the response of HR, but not LR, cells increased during primary infection with T. colubriformis. Flow cytometry revealed significantly greater numbers of circulating B-cells in HR animals and, as observed for responsiveness to PWM, the number of circulating B-cells increased in HR, but not LR, animals during primary infection with this parasite. These findings suggest a larger and more labile population of B-cells in HR guinea pigs. Received: 16 August 1999 / Accepted: 21 October 1999