Regulation of the immune response by antibody II. IGM-MEDIATED ENHANCEMENT: DEPENDENCY ON ANTIGEN DOSE, T-CELL REQUIREMENT AND LACK OF EVIDENCE FOR AN IDIOTYPE-RELATED MECHANISM.

Passive administration of monoclonal IgM anti-sheep red blood cell antibody 2 hr prior to a low dose of sheep red blood cells (SR BC) markedly enhances the specific antibody response. This IgM enhancement of the response to SRBC is highly reproducible and can furthermore be demonstrated in vitro. The time course and dose dependency of the response indicate that a critical antibody: antigen ratio is necessary for enhancement to occur. The IgM enhancement phenomenon has been demonstrated in several strains of mice, providing strong evidence against an idiotype-related mechanism. [ABSTRACT FROM AUTHOR]