Analysis by in situ hybridization of cells expressing mRNA for interleukin 4 in the developing thymus and in peripheral lymphocytes from mice.
We have made use of RNA.RNA in situ hybridization to study the presence of cells producing mRNA for interleukin 4 (IL-4) in the developing thymus, spleen, and T-cell line 2.19. Approximately 1 of 300-400 spleen cells expressed detectable IL-4 mRNA 24 hr after their stimulation by the lectin concanavalin A. Spleen cells were also induced to express mRNA for IL-4 by stimulation with alloantigens. Splenocytes producing mRNA for IL-4 were detected 4 hr after stimulation by concanavalin A; the response peaked at approximately equal to 24 hr and was undetectable by 72 hr. Cyclosporin A inhibited the synthesis of IL-4 mRNA in the T-cell line 2.19, which had been induced by concanavalin A. Approximately 1 of 10 fetal thymocytes at day 14 of gestation expressed mRNA for IL-4 after their stimulation by phorbol 12-myristate 13-acetate and ionomycin. Both the frequency of fetal thymocytes expressing IL-4 mRNA and the amount of mRNA for IL-4 synthesized per cell sharply decreased at day 16 of gestation, and less than 1 of 1800 fetal thymocytes at day 18 of gestation expressed detectable IL-4 mRNA. Our results define the relative frequency of cells capable of expressing IL-4 mRNA after stimulation in vitro in the spleen and in the developing thymus. The data strongly argue for an important role of IL-4 in growth and differentiation of lymphoid cells, notably during T-cell development within the thymus.
Sideras
P
P
Department of Immunology, University of Stockholm, Sweden.
Funa
K
K
Zalcberg-Quintana
I
I
Xanthopoulos
K G
KG
Kisielow
P
P
Palacios
R
R
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D015847:Interleukin-4; D007378:Interleukins / Q000235:genetics*; D051379:Mice; D008815:Mice, Inbred Strains; D009693:Nucleic Acid Hybridization; D012333:RNA, Messenger / Q000235:genetics*; D013601:T-Lymphocytes / Q000276:immunology*; D013950:Thymus Gland / Q000196:embryology / Q000276:immunology*
D007378:Interleukins; D012333:RNA, Messenger; D015847:Interleukin-4