title: CD4 ligation promotes the IL-4-independent development of IL-4-producing clones from naive CD4(+) T cells.
abstract: The signals that trigger IL-4-independent IL-4 synthesis by conventional CD4(+) T cells are not yet defined. In this study, we show that coactivation with anti-CD4 mAb can stimulate single naive CD4(+) T cells to form IL-4-producing clones in the absence of APC and exogenous IL-4, independently of effects on proliferation. When single CD4(+) lymph node cells from C57BL/6 mice were cultured with immobilized anti-CD3epsilon mAb and IL-2, 65-85% formed clones over 12-14 days. Coimmobilization of mAb to CD4, CD11a, and/or CD28 increased the size of these clones but each exerted different effects on their cytokine profiles. Most clones produced IFN-gamma and/or IL-3 regardless of the coactivating mAb. However, whereas 0-6% of clones obtained with mAb to CD11a or CD28 produced IL-4, 10-40% of those coactivated with anti-CD4 mAb were IL-4 producers. A similar response was observed among CD4(+) cells from BALB/c mice. Most IL-4-producing clones were derived from CD4(+) cells of naive (CD44(low) or CD62L(high)) phenotype and the great majority coproduced IFN-gamma and IL-3. The effect of anti-CD4 mAb on IL-4 synthesis could be dissociated from effects on clone size since anti-CD4 and anti-CD11a mAb stimulated formation of clones of similar size which differed markedly in IL-4 production. Engagement of CD3 and CD4 in the presence of IL-2 is therefore sufficient to induce a substantial proportion of naive CD4(+) T cells to form IL-4-producing clones in the absence of other exogenous signals, including IL-4 itself.
authors.affiliation: Queensland Institute of Medical Research, Joint Transplantation Biology Program, University of Queensland, Australia.
authors.forename: S B
authors.initials: SB
authors.lastname: Campbell
authors.forename: T
authors.initials: T
authors.lastname: Komata
authors.forename: A
authors.initials: A
authors.lastname: Kelso
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D015704:CD4 Antigens / Q000276:immunology / Q000502:physiology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D048429:Cell Size; D002478:Cells, Cultured; D002999:Clone Cells; D005260:Female; D016130:Immunophenotyping; D007371:Interferon-gamma / Q000096:biosynthesis; D007377:Interleukin-3 / Q000096:biosynthesis; D015847:Interleukin-4 / Q000096:biosynthesis* / Q000494:pharmacology / Q000502:physiology*; D007700:Kinetics; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL
chemical_list: D000911:Antibodies, Monoclonal; D015704:CD4 Antigens; D007377:Interleukin-3; D015847:Interleukin-4; D007371:Interferon-gamma