Relationship between non-antigen-specific immunodepression and persisting immune complexes induced by pertussis in mice.

A temporal relationship has been demonstrated between persisting immune complexes and non-antigen-specific immunodepression. Mice were given intraperitoneal injections of Bordetella pertussis at weekly intervals. After 7 weeks they developed circulating immune complexes, the levels of which increased with continued administration of pertussis. The increase in immune complex levels was accompanied by a diminished primary immune response to intraperitoneally injected sheep erythrocytes (SRBC) as judged by a reduction in their direct and indirect plaque-forming cell response and serum agglutination titres. Spleen cells from immunodepressed pertussis-treated mice were transferred to irradiated normal recipients and displayed a normal response to SRBC. By contrast, spleen cells transferred from normal donors to irradiated pertussis-treated recipients had an impaired response to SRBC. Thus, the immunodepression caused by pertussis treatment is a property of the environment and not the lymphocytes themselves. It is considered that chronic circulating immune complexes induced by pertussis administration may cause non-antigen-specific immunodepression.