Enhancement of IgG production elicited in mice by treatment with anti-CD8 antibody.

Injection of an anti-CD8 monoclonal antibody into mice was followed by an increase in the production of immunoglobulins of the IgG1, IgG2a and IgG2b, but neither the IgG3 nor the IgM isotypes. A maximal effect was observed 6 days after administration of 100 micrograms antibody. However, no modification of spleen cell proliferation was elicited by the anti-CD8 treatment. Virally induced IgG2a and IgG2b secretion remained unchanged in mice infected with lactate dehydrogenase-elevating virus that received a concomitant injection of anti-CD8 antibody, whereas an enhancement of IgG1 was observed. Simultaneous treatment with an anti-CD4 antibody abrogated the immunoglobulin secretion triggered by anti-CD8. These results suggest that immunoglobulin production in unmanipulated mice is controlled by CD8+ lymphocytes.