Subsets of thymopoietic rat thymocytes defined by expression of the CD2 antigen and the MRC OX‐22 determinant of the leukocyte‐common an

Publisher Website
Google Scholar
Abstract
The MRC OX‐22 monoclonal antibody recognizes a restricted determinant of the rat leukocyte‐common antigen (L‐CA, CD45), which is expressed on most peripheral T cells and all B cells. In contrast only 2%–3% of thymocytes are OX‐22+ and these are now shown to be mostly of the immature CD4−CD8− (double‐negative, DN), phenotype with very few of the mature phenotype cells being OX‐22+. Analysis of immunoperoxidase sections suggests that the DN OX‐22+ cells are located in the cortex. Among the DN cells about 60% are OX‐22+ and a similar percentage are positive for CD2 antigen. Double staining showed that OX‐22+CD2−, OX‐22+CD2+, and OX‐22−CD2+ populations can be defined and that these three sets account for ∼95% of the DN cells. Measurement of the thymopoietic activity of DN subsets showed that OX‐22+CD2− and OX‐22+CD2+ cells have regenerative capacity whilst OX‐22−CD2+cells do not.