Differential activation of cytokine genes in normal CD4‐bearing T cells is stimulus dependent

Abstract

Studies of cloned CD4+ T cell lines have shown that they can be separated into two distinct subsets with distinctions in their functional capabilities and by the differential release of either interleukin 2 (IL 2) (TH1/inflammatory type) or IL 4 (TH2/helper type) upon activation. To establish if in vivo-derived CD4+ T cells can exhibit distinct subsets we have investigated whether normal CD4+ T cells demonstrate differential expression of IL 2 and IL 4 mRNA, and secretion of IL 2 and IL 4 after primary stimulation in vitro. Utilizing the technique of in situ hybridization IL 2 and IL 4 gene expression in individual CD4+ T cells was readily detectable after concanavalin A (Con A) phytohemagglutinin (PHA) or pokeweed mitogen (PWM)-mediated activation. The frequencies of activated T cells producing IL 2 and IL 4 mRNA after Con A or PHA activation were approximately equivalent (30-40% of cells); however, after PWM activation the number of CD4+ T cells expressing IL 4 mRNA (78%) was more than twofold greater than the number of cells producing IL 2 mRNA (30%). Maximal levels of IL 2 gene expression occurred 24 h after mitogen activation whereas the highest levels of IL 4 mRNA were not detected until 48 h after mitogen activation. Similar distinctions in the kinetics of IL 2 and IL 4 secretion after mitogen activation were also found demonstrating good concordance in the observed expression of IL 2 and IL 4 mRNA and the levels of secreted lymphokines detected by bioassay. Most importantly, we have shown by in situ hybridization analysis that the majority of individual CD4+ T cells produce only IL 2 or IL 4 mRNA, and not both, after primary activation in vitro. By contrast, most CD4+ T cells activated in the presence of PMA and ionophore express both IL 2 and IL 4 mRNA. Our studies demonstrate that in normal, non-clonal populations of CD4+ T cells, the production of IL 2 and IL 4 is independently regulated in the majority of cells and appears to be stimulus dependent.

Regulation of murine lymphokine production in vivo. III. The lymphoid tissue microenvironment exerts regulatory influences over T helper cell function.

“…The results ( Fig. 1) demonstrate that IL-2 represents the major species of TCGF produced by anti-CD3-activated lymphocytes obtained from peripheral lymph nodes and spleen, a finding that is totally consistent with previously reported observations made by other investigators (24,25). Lymphocytes obtained from the mesenteric lymph nodes, which receive extravasating lymphocytes from both the blood and from the Peyer's patch drainage, produce approximately equal activities of IL-2 and IL-4 after in vitro activation .…”

“…24 h later, cell culture supernatants were assayed spectrophotometrically (see Materials and Methods) for the total TCGF (no blocking antibodies ; E), for the relative amount of IL-2 activity (anti-IL-4-blocking anti- Relative IL-2 and IL-4 bioactivity produced by lymphocytes isolated from the various lymphoid organs of (A) normal C3H mice, and (B) normal mice implanted with a biodegradable pellet containing the GC hormone corticosterone 2 d before death and lymphocyte isolation, or (C) normal mice implanted with a biodegradable pellet containing the potent GC antagonist RU486 . An analysis of IL-2 and IL-4 bioactivity in test supernatants was made 24 h after in vitro stimulation of lymphocytes with optimum amounts of anti-CD3 . The in vivo effects of corticosterone and RU486, on subsequent lymphokine production by activated lymphocytes isolated from treated animals, has been determined in at least three different experiments, and is found to be highly reproducible .…”

Altered production of tumour necrosis factors alpha and beta and interferon gamma by HIV-infected individuals

“…depletion. Cytokine production may also be stimulus dependent as has recently been shown for IL-2 and IFN-7 production (Cording et al, 1989;Francois-Jean et al. 1988).…”

Prevention of Diabetes in NOD Mice by Injection of Autoreactive T-Lymphocytes

“…CD4 T-lymphocytes can be further divided into T-inflammatory (T h1 ) and helper (T h2 ) T-lymphocytes by the pattern of lymphokines they produce (15,16). Lymphokine production by PR-3 on stimulation by NOD spleen cells or mitogens was determined from mRNA analysis and biological assays; PR-3 produces IL-2 and IFN-7 but not IL-4.…”

“…Supernatants were added at 25% to the lymphokine-dependent cell lines HT2, CTLL, and Wehi-3 with and without the addition of the anti-IL-2 (S4B6; 16), anti-IL-4 (11B11; 17), and anti-interferon-7 (INF-7) (H1; 18) antibodies. The cultures were pulsed 36 h later and harvested as described previously (15).…”