We have studied 51Cr-SRBC antigen clearance in two strains of mice differing in the capacity to react with IgG antibody formation. In the B10 strain which is a poor IgG anti SRBC producer, before immunization 80.3% of the injected radioactivity is taken up by liver, whereas after primary stimulation only 31.1%. This value decreases further to 22.8% after secondary stimulation. The well IgG antibody producing A/J strain accumulates in liver before immunization less antigen than the poorly responding strain (69.8%). On the 10th day after primary immunization there is a higher uptake of the radioactivity in liver than in the poor responder strain (53.8%) and this difference is even more pronounced after the secondary stimulation (49.6%). Interaction between peritoneal macrophages of the B10 and A/J strains before and after immunization with SRBC antigen was assessed from the formation of rosettes. Before immunization the low-responder strain B10 exhibited a three times higher level of rosette-forming macrophages, i.e. 6.1% than the high-responder strain A/J (2.0%). However, after immunization the RFM level in the A/J strain increased sevenfold (13.5%) whereas that in the low-responder strain B10 remained unaffected. These results suggested a role of macrophage population in regulation of IgG antibody response.

The effect of bilirubin on the Fc receptor expression and phagocytic activity of mouse peritoneal macrophages

Low IgG response of the mouse strain C57BL/10ScSn after immunization with protein antigens