RAT THYMIC DENDRITIC CELLS - CELL-SURFACE MARKER VARIATIONS IN CULTURE

Rat thymic dendritic cells (DC) have been analyzed by flow cytometry i n order to study the variations on the cell surface marker expression upon culture at 37-degrees-C. Our results demonstrate that whereas exp ression of major histocompatability complex (MHC) molecules, CD45, Mac -1, LFA-1, B-cell markers, macrophage markers and some T-cell markers (as CD2, CD4 and CD8) did not undergo changes in culture, the level of expression of the adhesion molecules VLA-4 and ICAM-1, and the T-cell markers CD5, CD25 and Thy-1 increased after 14 h incubation at 37-deg rees-C. VLA-4, ICAM-1 and Thy-1 expression was upregulated from interm ediate to high levels, the percentage of CD5+ cells increased from 20% to 50%, and the interleukin-2 (IL-2) receptor alpha chain (CD25) was induced in 50% of DC after the culture period. These results are discu ssed with regard to the functional significance of DC phenotypic varia tions, and their implications concerning the development of in vitro s ystems designed for T-cell differentiation studies involving purified DC.