Anti-immunoglobulin M induces both B-lymphocyte proliferation and differentiation in Xenopus laevis.
Anti-IgM induced the proliferation of spleen lymphocytes of the amphibian Xenopus laevis as determined by 3H-thymidine uptake. The responding cells were B lymphocytes, since lymphocyte populations enriched in surface-Ig-positive cells exhibited an increased proliferative response, and spleen cells from larvally thymectomized animals still responded to anti-IgM. Immunofluorescence analysis and gel electrophoresis of biosynthetically labeled Ig polypeptides revealed that lymphoblasts induced by anti-IgM differentiated into plasmablasts that synthesized and secreted mainly IgM and small amounts of IgY. The in vitro differentiation of B lymphocytes also occurred in spleen cells obtained from thymectomized animals. These findings are in contrast with those obtained in mammals and suggest that the differentiation of B lymphocytes in X. laevis is subject to different regulatory mechanisms.
D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000502:physiology*; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D002454:Cell Differentiation; D002455:Cell Division; D002478:Cells, Cultured; D005260:Female; D007075:Immunoglobulin M / Q000502:physiology*; D007814:Larva / Q000166:cytology / Q000276:immunology; D008213:Lymphocyte Activation; D008297:Male; D013154:Spleen / Q000166:cytology; D013934:Thymectomy; D013936:Thymidine; D014982:Xenopus laevis
D000888:Antibodies, Anti-Idiotypic; D007075:Immunoglobulin M; C044203:anti-IgM; D013936:Thymidine