Morphology of the antibody response to pneumococcal polysaccharide in mice.

In the course of an antibody immune response to pneumococcal polysaccharide - type III (S III) in mice a slight increase was observed in the proportion of plasma cells among the antibody-producing cells, reaching its peak at the time of decline of this reaction. On the basis of ultrastructural resemblance of these plasma cells to primitive reticular cells and in view of other specificities of the immunological response to S III antigen, the author presumes direct reticular origin of anti-S III antibody-producing plasma cells.