The immune response to sheep erythrocytes in the lizard Calotes versicolor

Abstract

The immune response of the lizard, Calotes versicolor, to sheep red blood cells has been characterized in terms of the appearance of circulating antibodies as well as hemolysin-releasing plaque-forming cells (PFC). PFC appear in the spleen by the end of the 1st week after immunization and reach a maximum number at 14 days. The maximum level of serum antibody response is reached during the 3rd week. After a second immunization the rise in PFC and serum antibody is more rapid with a shorter latent period but without a concomitant increase in antibody level. PFC can be detected only in the spleen and blood of immunized lizards but not in other tissues such as the thymus, bone marrow, cloacal complex, lung, liver or kidney. Histologic changes occurring in the spleens of immunized lizards are also described. After immunization, there appear to be a greater abundance of mitotic figures, increased vascularity within the splenic pulp, and a reduction in the relative number of lymphocytes.