IgM and IgG plasma cells are found in most E/P^-/- lymphoid tissues. The density and total number of IgG (▪) and IgM (▦) plasma cells (ASC) in the cervical lymph nodes (LNs), spleen (SPL), and bone marrow (BM) of E/P^-/- mice was determined by ELISPOT. The data are represented as the mean ± SEM. For IgM, n = 8 mice, and for IgG, n = 10 to 12 mice. (A) ASC/10⁶ total cells. (B) Total ASC/tissue.