Interleukin-12 can replace CD28-dependent T-cell costimulation during nonspecific cytotoxic T lymphocyte induction by anti-CD3 antibody.
Cytotoxic T lymphocyte (CTL) development is regulated closely by an intricate series of signals provided by the T-cell receptor/CD3 complex, cytokines, and costimulatory ligand/receptor systems. In this study, we have explored the role of interleukin (IL)-12 and CD28 in mouse CTL development. Activation of T cells with anti-CD3 monoclonal antibody (mAb) in the presence of anti-CD86 mAb, which prevents CD28-CD86 interaction, led to decreased production of type 1 (IL-2, interferon-gamma) and type 2 (IL-4, IL-6, IL-10) cytokines, as well as diminished expression of granzyme B (Gzm B) and reduced cytotoxic effector function. Cytolytic activity in T-cell cultures that were activated in the presence of anti-CD86-blocking mAb alone or in combination with anti-CD80 mAb could be restored by the addition of exogenous IL-12 at initiation of culture. The ability of IL-12 to substitute for CD28-costimulatory signaling during CTL development was found to be dependent on the presence of IL-2 rather than interferon-gamma. IL-2 is required for IL-12Rbeta2 expression by T cells activated in the presence of anti-CD86 mAb. Moreover, IL-12Rbeta2 expression by T cells activated in the presence of anti-CD86 mAb is enhanced by IL-12. We, therefore, conclude that the ability of IL-12 to substitute for CD28-costimulatory signaling during CTL development is a result of the interaction of IL-12 with IL-12Rbeta2 induced by low levels of IL-2 synthesized by T cells activated in a CD28-independent manner.
Makrigiannis
A P
AP
Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada.
Musgrave
B L
BL
Haeryfar
S M
SM
Hoskin
D W
DW
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D018106:CD28 Antigens / Q000276:immunology*; D017252:CD3 Complex / Q000276:immunology*; D003602:Cytotoxicity, Immunologic; D005260:Female; D018664:Interleukin-12 / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
D000911:Antibodies, Monoclonal; D018106:CD28 Antigens; D017252:CD3 Complex; D018664:Interleukin-12