DIFFERENTIAL EXPRESSION OF THE ALTERNATIVELY SPLICED EXONS OF MURINE CD45 IN TH1 AND TH2 CELL CLONES

Antigen-specific murine CD4+ T cell clones can be divided into functionally distinct subsets known as T(h)1 and T(h)2. To date these cells have been indistinguishable by surface phenotype. This report identifies two anti-CD45R monoclonal antibodies (14.8 and C363.16A) that bind preferentially to T(h)2 cells. Further analysis of the CD45-specific mRNA in T(h)1 and T(h)2 cells shows clear differences between these two cell types. T(h)1 cell clones express mRNA for the two smallest forms of CD45 containing none or only one of the alternatively splices exons. In contrast, T(h)2 cell clones express predominantly the high molecular weight isoforms of CD45 containing two or three of the alternatively spliced exons.