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Differentiation of lymphoid cells: the use of specific antisera to characterize the cells required for the induction of immunoglobulin M production in vitro.


 Anti-immunoglobulin as well as anti-thymocyte sera prevented the induction of immunoglobulin M production by rabbit popliteal lymph node cells that ordinarily occurs when such cells are cultured in vitro, in the absence of added antigen. Antibodies specific for the light chains and µ-chains of rabbit immunoglobulins were inhibitory whereas sera specific for α- and γ-chains were without effect. Univalent anti-µ-chain antibody and univalent anti-thymocyte antibody preparations were also inhibitory. All inhibitory antisera were without effect when added to cultures after the induction process was completed. Thymidine incorporation studies showed a lack of correspondence between the inhibitory activity and mitogenicity of anti-immunoglobulins.