Effects of early larval thymectomy on mitogen responses in leopard frog (Rana pipiens) tadpoles.

Two to 3-month old tadpoles (Rana pipiens), thymectomized 2-3 weeks postfertilization, exhibited: sharply reduced numbers of splenic and blood lymphocytes; no in vitro lymphocyte responsiveness to PHA; and normal in vitro lymphocyte reactivity to LPS. These results reveal lymphocyte heterogeneity in this anuran species.