Casein-induced experimental amyloidosis. III. Response to mitogens, allogeneic cells, and graft-versus-host reactions in the murine model.

The functional capacity of lymphoid cells has been determined in amyloid-susceptible CBA/J and amyloid-resistant A/J mice. Following multiple casein injections mitogen responses to phytohaemagglutinin (PHA), concanavalin A (Con-A), pokeweed mitogen (PKW) and lipopolysaccharide (LPS) were significantly depressed in spleen cell suspensions of the A/J strain. Mitogen responses to PHA, Con-A and PKW were also reduced in casein-treated CBA/J animals, but improved during the active phase of amyloid deposition. The response to LPS was not affected in pre-amyloid and amyloid CBA/J animals. Spleen cells from caseintreated CBA/J mice responded normally to allogeneic cells from BALB/c and A/J mice; on the other hand graft-versus-host reactions in BALB/c mice receiving spleen cells from pre-amyloid and amyloid CBA/J mice were markedly impaired. The marked depression of certain T-cell populations, plus the maintenance of normal B-cell function in the CBA/J mice, suggest that disturbances of immunoregulatory mechanisms may be a critical step in the pathogenesis of experimental amyloid disease.