Abstract
The primary immune response in young adult mice to sheep red blood cells was studied by following the effects of anti-IgM or anti-Fc sera on the number of plaqueforming cells for IgM (dPFC) and IgG (iPFC) in the spleen. The number of dPFC in the case of administration of anti-IgM serum at 1 h before antigen injection was significantly decreased to 3.7±0.9/106 spleen cells in comparison with the value of control serum (69.0±15.7/106 spleen cells). However, the numbers of iPFC in the cases of both anti-IgM or control sera were similar. From these results, we suppose that progenitors of IgM-producing cells are different from progenitors of IgG-producing cells in adult mice.
