In vitro differentiation of two surface markers for immature T cells by the synthetic pentapeptide, thymopoietin
Nash, L.; Good, R.A.; Hatzfeld, A.; Goldstein, G.; Incefy, G.S.
Journal of Immunology 126(1): 150-153
1981
ISSN/ISBN: 0022-1767 PMID: 6969740 Document Number: 175250
Immature T cell populations bearing receptors for peanut agglutinin (PNA) or having the ability to form autologous rosettes (A-RFC) were analyzed among splenocytes of aged C57BL/6 mice, adult thymectomized mice (ATx) and Swiss athymic nude mice and were compared to those of normal young adult animals. PNA-binding cells (PNA+) and A-RFC were present at a constant ratio (PNA+/A-RFC) between 3.3 and 3.6 among splenocytes of each of these animal groups. This ratio was observed even when marked increases in numbers of cells bearing these markers were detected in aging, nude and ATx animals. Reduction of A-RFC and PNA+ cells occurred rapidly in splenocytes of aged, ATx and nude mice after in vitro exposure to the synthetic pentapeptide, thymopoietin32-36 (TP-5). In the young adult animals, the ratio of PNA+/A-RFC did not change appreciably; in the nude, ATx and aged mice it rose to between 5.0 and 5.4 after treatment of the cells with TP-5. More splenocytes probably lose ability to form A-RFC than lose receptors for PNA after exposure to TP-5. A-RFC may represent a more mature population than the PNA+ cells since, under the influence of the thymic peptide, a higher proportion developed to a more advanced stage of differentiation. When A-rosette forming cells were separated by differential sedimentation, loss of the A-rosette marker occurred upon exposure to TP-5 on 91-96% of the cells from the A-RFC positive population, along with an increase in cells (11-20%) expressing Thy-1.2 marker. Some cells of the A-rosette negative population also differentiated to cells bearing the Thy-1.2 marker. TP-5 apparently can induce a differentiation process associated with loss or gain of cell surface characteristics.