The effects of alpha and beta adrenergic agents on spleen cell antigen binding in four amphibian species.
Adults of two urodele amphibian species (Triturus cristatus carnifex and Cynops hongkongensis) and two anuran species (Rana temporaria and Xenopus laevis laevis) were immunized with a 25% suspension of sheep or horse erythrocytes. After eight or 14 days, splenic lymphocytes were removed, and their specific red cell-binding capacities tested by immunocytoadherence. Antigen-binding cells were classified as high-dose nonsecretory (S-) or secretory (S+), according to whether they bound a single layer or several layers or erythrocytes. The stimulation of both alpha and beta adrenoreceptors reduced the numbers of S+ rosettes formed by Triturus and Cynops lymphocytes, whereas a beta agonist increased and an alpha agonist decreased S+ rosette formation by Rana and Xenopus splenic lymphocytes. These effects were blocked by alpha and beta adrenoreceptor antagonists. Low-dose immunization of Xenopus with a 0.0025% suspension of sheep erythrocytes gave a minimal number of S+ rosettes two and eight days after immunization, and beta adrenoreceptor stimulation had no effect on antigen binding. These results are discussed in terms of the distribution of alpha and beta adrenoreceptors in amphibians and possible relationships between S+ and high-dose S- antigen-binding cells, and support the view that functional lymphocyte heterogeneity exists in these lower vertebrates.