Suppressor cells and T cell synergy in the primary MLR: interleukin-2 is required for the maintenance of rat CD8+ suppressor cells.
The requirements for maintenance of allospecific CD8+ Ts cells generated in the rat primary MLR were investigated. Allospecific CD8+ Ts cells rapidly lose their activity over 72 hr in secondary culture with media alone, whereas low concentrations of rIL-2 (less than 1 U/ml) are able to maintain potent CD8+ Ts cell activity. This Ts cell activity is maintained at rIL-2 concentrations which do not result in significant cell proliferation. Therefore, cell proliferation per se is not a requirement to maintain Ts cell activity, although the CD8+ Ts cells can proliferate to rIL2 in a concentration-dependent manner. An anti-IL-2 receptor monoclonal antibody significantly inhibited the maintenance of Ts cell activity. Two-color flow cytometric analysis demonstrated that Ts cells cultured in rIL-2 maintain upregulation of their high-affinity IL-2 receptor. Although allospecific Ts cells maintained in secondary culture with rIL-2 for 48 hr maintained antigen specificity, there is also the induction of an antigen-nonspecific population. After 168 hr in secondary culture the Ts cells have lost allospecificity, although Ts activity can be maintained with rIL2 in continuous culture for up to 4 weeks.
Van Sickler
J T
JT
Department of Medicine, University of Florida, Gainesville 32610.
Pickard
L L
LL
Salomon
D R
DR
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D002478:Cells, Cultured; D015536:Down-Regulation; D000939:Epitopes; D005434:Flow Cytometry; D007376:Interleukin-2 / Q000494:pharmacology*; D008213:Lymphocyte Activation / Q000187:drug effects; D007959:Lymphocyte Culture Test, Mixed; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D015375:Receptors, Interleukin-2 / Q000032:analysis; D011994:Recombinant Proteins / Q000494:pharmacology; D050378:T-Lymphocytes, Regulatory / Q000187:drug effects* / Q000276:immunology
D000911:Antibodies, Monoclonal; D000939:Epitopes; D007376:Interleukin-2; D015375:Receptors, Interleukin-2; D011994:Recombinant Proteins