Minimal role for the spleen in antibody responses of C57BR/cdj mice to pneumococcal polysaccharide antigens.

The role of the spleen in antibody production and in susceptibility to pneumococcal infections remains poorly understood. Recently we showed that in A/J mice high antibody responses to polysaccharide antigens depend upon dosage, antigenic structure, interval between immunization and assay and the presence of the spleen. To investigate the possibility of alternative patterns of response, intact and splenectomized (Sx) C57BR/cdj mice were assayed for antibody responses to two structurally different pneumococcal polysaccharides, type 3 (SIII) and type 14 (SXIV). After 50 or 100 ng of SIII, intact C57BR/cdj mice produced uniformly low antibody responses that were further suppressed by splenectomy, but after 1,000 ng of SIII, C57BR/cdj mice, regardless of whether they were intact or Sx, produced antibody responses as high as those of intact A/J mice. Following SXIV, a spleen-dependent antigen, C57BR/cdj mice produced consistently lower antibody responses than A/J mice. Antibody responses to 500 or 5,000 ng of SXIV were totally obliterated in Sx C57BR/cdj mice; but unlike A/J mice, responses to 10,000 ng were similar regardless of whether C57BR/cdj mice were intact or Sx. The inability of intact C57BR/cdj mice to produce elevated responses to SIII or SXIV suggests that C57BR/cdj mice may lack the subset of spleen cells necessary for a vigorous response to these antigens. The data suggest that these mice could provide useful animal models for studying host variability in antibody responses to pneumococcal polysaccharides.