T-CELL REGENERATION AFTER BONE-MARROW TRANSPLANTATION - DIFFERENTIAL CD45 ISOFORM EXPRESSION ON THYMIC-DERIVED VERSUS THYMIC-INDEPENDENT PROGENY BLOOD Mackall, C. L., Granger, L., Sheard, M. A., Cepeda, R., Gress, R. E. 1993; 82 (8): 2585-2594

Abstract

To study the source of regenerated T cells after bone marrow transplantation (BMT), lethally irradiated thymectomized and thymus-bearing C57BL/6 (Thy 1.2+) mice were injected with syngeneic T-cell depleted bone marrow (TCD BM) cells and graded numbers of congenic B6/Thy 1.1+ lymph node (LN) cells. LN cell expansion was the predominant source for T-cell regeneration in thymectomized hosts but was minimal in thymus-bearing hosts. Analysis of T-cell receptor (TCR) expression on LN progeny showed a diverse V beta repertoire. Therefore, peripheral T-cell progenitors exist within V beta families, but expansion of these progenitors after BMT is downregulated in the presence of a functional thymus. CD4+ cells derived from BM versus LN in thymus-bearing hosts displayed differential CD44 and CD45 isoform expression. BM-derived cells were primarily CD45RB+CD44lo and LN derived cells were nearly exclusively CD45RB- CD44hi. In thymectomized hosts, BM, host, and LN CD4+ progeny were CD45RB- CD44hi. We conclude that T-cell regeneration via peripheral T-cell progenitors predominates in hosts lacking thymic function and gives rise to T cells that display a "memory" phenotype. In contrast, the ability to generate sizable populations of "naive" type T cells after BMT appears limited to the prethymic progenitor pool and could serve as a marker for thymic regenerative capacity.

View details for Web of Science ID A1993MC27600041

View details for PubMedID 7691265