Effect of mouse antiserum against isologous aggregated immunoglobulins on accumulation of rosette-forming and antibody-forming cells in mice immunized with sheep's red blood cells

Data are given on the effect of mouse antiserum against isologous aggregated immunoglobulins (MAAS) on the kinetics of rosette-forming (RFC) and antibody-forming cells (AFC) in mice immunized with sheep's red blood cells (SRBC). The effect of MAAS in the experimentsin vivo was assessed by injecting this serum for 5 days into CBA mice, the first injecting being combined with injection of 5.107 SRBC. Injection of MAAS into mice immunized with SRBC was shown to cause a marked decrease in the number of RFC in the spleen on the 5th and 9th days after immunization. MAAS has no appreciable effect at these same times on proliferation of AFC producing IgM hemagglutinins. Meanwhile MAAS intensified proliferation of IgG-AFC during the period when the number of these cells of the spleen in the immunized mice was maximal. After adsorption of MAAS with immune complexes formed by mouse IgG antibodies this serum was shown to lose much of its ability to block RFCin vivo. It is postulated on the basis of these results that the property of MAAS of influencing the accumulation of RFC and AFC producing IgG hemagglutinins is due to a factor which reacts with the immune complex formed by mouse IgG antibodies. This factor may perhaps be antibodies against aggregated immunoglobulins of this class.