IL-1 acts on antigen-presenting cells to enhance the in vivo proliferation of antigen-stimulated naive CD4 T cells via a CD28-dependent mechanism that does not involve increased expression of CD28 ligands.
The basis of the adjuvant effect of IL-1 on the clonal expansion of Ag-specific CD4 T cells was measured in vivo using the TCR transgenic T cell adoptive transfer method. Injection of Ag plus IL-1 caused naive CD4 T cells to proliferate to a greater extent than did injection of Ag alone. The T cells had to express CD28 to experience the beneficial effect of IL-1 whereas the host had to express the type I IL-1R, raising the possibility that IL-1's adjuvant properties were related to induction of CD28 ligands on APC. Surprisingly, however, expression of CD28 ligands on DC and B cells was not affected by IL-1. Therefore, the adjuvant properties of IL-1 depend on a basal level of CD28 signaling but cannot be explained by enhanced CD28 signaling due to CD28 ligand induction.
Khoruts
Alexander
A
Department of Medicine, Center for Immunology, University of Minnesota Medical School, Minneapolis, 55455, USA.
Osness
Richard E
RE
Jenkins
Marc K
MK
D019264:Adoptive Transfer; D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology*; D000941:Antigens / Q000276:immunology; D018106:CD28 Antigens / Q000235:genetics / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D005434:Flow Cytometry; D007375:Interleukin-1 / Q000276:immunology*; D008070:Lipopolysaccharides / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D008822:Mice, Transgenic; D011948:Receptors, Antigen, T-Cell / Q000276:immunology
D000941:Antigens; D018106:CD28 Antigens; D007375:Interleukin-1; D008070:Lipopolysaccharides; D011948:Receptors, Antigen, T-Cell