Distinct mitogens reveal different mechanisms of suppressor activity in human cord blood.
We have studied the suppressive ability of human cord blood lymphoid cells in a three-days mixed lymphocyte culture proliferation assay stimulated by mitogen. Sex chromosomes served as markers for dividing cord (male) or maternal cells. Three distinct mitogenic agents were used in the co-cultures: the mitogenic lectin PHA, the anti-CD3 monoclonal antibody OKT3, and 12-0-tetradecanoyl-13-acetate (TPA), a direct activator of protein kinase C. With all mitogens we observed significant, non-specific suppression of maternal/adult cell division. However, three separate levels of suppression were evident. PHA-stimulated co-cultures always showed the highest amount of cold suppressor activity (mean +/- SEM: 64.9 +/- 3.9). The mean suppression in OKT3- and TPA-stimulated co-cultures was 34.7 +/- 6.0 and 22.0 +/- 4.1%, respectively. Furthermore, indomethacin, a prostaglandin (PG) synthetase inhibitor, reduced by 41% the suppression in PHA-driven co-cultures, whereas having no significant effect on the corresponding OKT3-driven co-cultures. Our results indicate the existence of an indomethacine-sensitive, PG-dependent mechanism and a separate, indomethacine-resistant, mechanism of cord cell suppression.
Papadogiannakis
N
N
Department of Pathology, Gothenburg University, Sweden.
Johnsen
S A
SA
D015232:Dinoprostone / Q000494:pharmacology; D005260:Female; D005312:Fetal Blood / Q000166:cytology / Q000276:immunology*; D006801:Humans; D007108:Immune Tolerance; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D007231:Infant, Newborn; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D008297:Male; D008934:Mitogens / Q000494:pharmacology*; D011247:Pregnancy; D050378:T-Lymphocytes, Regulatory / Q000187:drug effects / Q000276:immunology*
D008934:Mitogens; D015232:Dinoprostone; D007213:Indomethacin