Mechanism of immunosuppression by a murine non-specific suppressor T cell line, SB-1.
The mechanism of immunosuppression by a murine non-specific suppressor T cell clone (SB-1), which was established from concanavalin A (Con A)-activated murine spleen cells [Jpn. J. Exp. Med., 53, 139 (1983)], was investigated. SB-1-induced decrease of antigen non-specific plaque-forming cell (PFC) response was restored by the addition of 5 x 10(-6) M indomethacin, an inhibitor of cyclooxygenase. On the other hand, suppressive activity for antigen non-specific PFC response was found in the culture supernatant of SB-1 cells in the presence of proteose peptone-elicited macrophages. This induction of the suppressive activity was also inhibited by 5 x 10(-6) M indomethacin. Furthermore, 10(-5) M prostaglandine E2 (PGE2) was found to induce suppressive activity in the culture supernatant of SB-1 cells. 10(-5) M PGE2 did not suppress interleukin-2 (IL-2)-dependent proliferation of SB-1 cells, but increased a small quantity of protein synthesis and deoxyribonucleic acid (DNA) synthesis of SB-1 cells in the absence of IL-2. These results suggest that a cyclooxygenase product(s) such as PGE2 from macrophages may induce production of soluble suppressor factors in SB-1 cells. To characterize these suppressor factors, those in the culture supernatant of PGE2-stimulated SB-1 cells were partially purified by ammonium sulfate fractionation and sequential column chromatographies on diethylaminoethyl (DEAE)-cellulofine and Sephacryl S-200. Suppressor activities were eluted at the positions corresponding to the molecular masses of 10, 30, 70 and over 70 kilodalton (kDa) on Sephacryl S-200 column chromatography.(ABSTRACT TRUNCATED AT 250 WORDS)
Ezawa
K
K
Division of Chemical Toxicology and Immunochemistry, Faculty of Pharmaceutical Sciences, University of Tokyo, Japan.
Toyoshima
S
S
Osawa
T
T
D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism; D002460:Cell Line; D004247:DNA / Q000096:biosynthesis; D015232:Dinoprostone / Q000494:pharmacology; D005260:Female; D007213:Indomethacin / Q000494:pharmacology; D008264:Macrophages / Q000502:physiology; D051379:Mice; D008815:Mice, Inbred Strains; D014176:Protein Biosynthesis; D050378:T-Lymphocytes, Regulatory / Q000502:physiology*
D001095:Arachidonic Acids; D016718:Arachidonic Acid; D004247:DNA; D015232:Dinoprostone; D007213:Indomethacin