Patterns of Leucocyte Common Antigen Expression in Peripheral Blood T Cell Populations

The restricted forms of CD45 are differentially expressed on lymphocyte subsets in different maturation stages and with different functional activities. The best-known examples are the expression of CD45RA on naive and CD45RO on memory T cells. Multicolor flow cytometry allows for the analysis of lymphocyte subsets with respect to the expression of the various CD45R isoforms (RA, RB, RO). Here we report on the distribution of these isoforms in normal peripheral blood T cells, including the CD4, CD8, and CD56 subsets. The results indicate the presence of a number of consistent patterns within these subsets, which can be linked to populations with well-defined functional activities, and also identify several transitional stages and hitherto undefined subsets.