title: IL-4-based helper activity of CD4+ T cells is radiation sensitive.
abstract: The capacity of CD4+ T cells to induce IgG synthesis in B cells has been known to be radioresistant for more than 20 years. However, the radiation sensitivity of helper T cells with regard to their ability to induce the synthesis of isotypes other than IgG has not been studied. We therefore irradiated KLH-primed lymph node T cells and examined their capacity to induce IgG, IgM, and IgE synthesis in hapten-primed B cells. We demonstrated that while the capacity of KLH-primed lymph node cells to induce IgG synthesis was not affected by irradiation, the capacity of such T cells to induce IgE synthesis was greatly reduced by gamma-irradiation. This was consistent with our observations that IL-4 and IL-5 synthesis in such cells was greatly diminished by irradiation, whereas IL-2 synthesis was only minimally affected. A similar differential sensitivity to irradiation of the helper activity of Th1 and Th2 clones was observed with regard to their ability to induce IgE and IgG synthesis under cognate conditions. Irradiation greatly inhibited the capacity of Th2 clones to induce IgE synthesis, but only minimally affected the capacity of Th1 clones to induce IgG synthesis in primed B cells. The capacity of irradiated Th2 clones to induce IgE synthesis was restored by the addition of IL-4 and IL-5. These results taken together indicated that the sensitivity to irradiation of T helper cells with regard to the induction of IgE but not IgG synthesis was due to the sensitivity to irradiation of the production of IL-4 but not of IL-2.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Pediatrics, Stanford University, California 94305, USA.
authors.forename: R H
authors.initials: RH
authors.lastname: DeKruyff
authors.forename: Y
authors.initials: Y
authors.lastname: Fang
authors.forename: D T
authors.initials: DT
authors.lastname: Umetsu
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000528:radiation effects*; D003207:Conalbumin / Q000276:immunology; D005720:Gamma Rays; D005786:Gene Expression Regulation; D006241:Haptens; D006433:Hemocyanins / Q000276:immunology; D007073:Immunoglobulin E / Q000096:biosynthesis* / Q000235:genetics; D007074:Immunoglobulin G / Q000096:biosynthesis / Q000235:genetics; D007376:Interleukin-2 / Q000096:biosynthesis / Q000235:genetics / Q000494:pharmacology; D015847:Interleukin-4 / Q000096:biosynthesis / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D015848:Interleukin-5 / Q000096:biosynthesis / Q000235:genetics / Q000494:pharmacology; D008211:Lymphocyte Cooperation / Q000528:radiation effects*; D016131:Lymphocyte Subsets / Q000276:immunology / Q000528:radiation effects*; D051379:Mice; D008807:Mice, Inbred BALB C; D008811:Mice, Inbred DBA; D011836:Radiation Tolerance; D011994:Recombinant Proteins / Q000494:pharmacology; D018417:Th1 Cells / Q000276:immunology / Q000528:radiation effects; D018418:Th2 Cells / Q000276:immunology / Q000528:radiation effects; D014301:Trinitrobenzenes / Q000276:immunology
chemical_list: D006241:Haptens; D007074:Immunoglobulin G; D007376:Interleukin-2; D015848:Interleukin-5; D011994:Recombinant Proteins; D014301:Trinitrobenzenes; D003207:Conalbumin; D015847:Interleukin-4; D007073:Immunoglobulin E; D006433:Hemocyanins; C032808:keyhole-limpet hemocyanin