ABILITY OF SPLEEN, PERITONEAL-CAVITY, AND LYMPH-NODE B-CELLS TO RECONSTITUTE SERUM IMMUNOGLOBULIN IN SCID MICE

The impact of intrinsic B lymphocyte heterogeneity and of microenviron mental influences on serum immunoglobulin production by B cells was ex amined by intravenous (i.v.) and intraperitoneal (i.p.) transfer of BA LB/c and BALB.xid (X-chromosome-linked immune-defective; XID) lymph no de (LN), splenic (SP) and peritoneal cavity (PerC) cells into severe-c ombined immune-defective (SCID) mice. The results indicate that each B -cell source restores all immunoglobulin classes within 5 weeks of tra nsfer, the rates for each isotype, however, differ between the B-cell sources. Serum IgM levels were restored most rapidly by PerC cell tran sfer, followed by SP and LN cell transfer. In addition, normal immunog lobulin levels were reached in the absence of complete lymphoid recons titution. Serum immunoglobulin phenotypes characteristic of the donor strain, e.g. reduced IgM and IgG3 production by XID B cells, were main tained after transfer into the SCID recipient. Microenvironmental infl uences were indicated by reduced immunoglobulin production after i.p. transfer and after i.v. transfer into irradiated SCID recipients. The data show that both B-cell type and microenvironment play significant roles in generating the heterogeneous pool of B cells required for hum oral immunity.