Previous studies using anti‐CD45R monoclonal antibodies (mAb) have shown that normal CD4+ T cells can be separated into virgin and memory cells basedon their level of expression of CD45R. CD45Rhi (virgin)T cells secrete interleukin (IL)‐2 whereas CD45Rlo (memory) T cells secrete both IL‐2 and IL‐4. In contrast to these results, studies using cultured T cell lines haveshown that IL‐2‐secreting T helper cell type 1 (Th1) cells are CD45Rlo and IL‐4‐secreting Th2 cells are CD45Rhi. To resolve this discrepancy, and to determine how the Th1 and Th2 cell lines relate to memory CD45Rlo and virgin CD45Rhi CD4+ T cells, we have isolated CD45Rlo cells from alloantigen‐primed mice and developed allospecific Th1 and Th2 cell lines. The lymphokinessecreted by these lines were then evaluated. Our results show that as CD45Rlo T cells develop into in vitro cell lines which secrete IL‐4, they become CD45Rhi. In contrast, CD45Rlo cells that develop into lines which secrete IL‐2 maintain their CD45Rlo phenotype. Thus, although both Th1 and Th2 cells arise initially from CD45Rlo cells, Th2 cells become CD45Rhi during prolonged in vitro culture but, Th1 cells do not.
ASJC Scopus subject areas
- Immunology and Allergy