Processing of normal antibody-coated sheep erythrocytes by mouse peritoneal macrophages.

The processing by mouse peritoneal macrophages of normal sheep red blood cells (SRBC) or SRBC coated with 19S or 7S antibody was investigated by measuring (a) total uptake of SRBC, (b) changes in subcellular distribution of antigen during culture, and (c) immunogenicity of SRBC-containing macrophages. Most of the ingested antigen was found to be bound to lysosomal membranes. Its concentration decreased rapidly during the first 5 hours of culture. Although SRBC uptake was increased by the addition of either class of antibody, 7S antibody suppressed and 19S antibody enhanced the immunogenicity of SRBC-containing macrophages. Rate of intracellular antigen degradation and production of low-density antigen did not correlate with macrophage immunogenicity. While the enhancing effect of 19S antibody probably was due to an increase in the percentage of SRBC-ingesting cells, suppression by 7S antibody may have been related to the creation of a distinct class of heavily laden macrophages with reduced immunogenic efficiency.