Conditional IL-2 Gene Deletion: Consequences for T Cell Proliferation

Abstract

To explore the role of interleukin-2 (IL-2) in T cell proliferation, and to circumvent the IL-2 deficiency autoimmune syndrome of conventional il2 gene deletion, mice were created to allow conditional il2 gene deletion when treated with the estrogen analog, tamoxifen (TAM) as adults. Splenocytes from four different mouse strains, C57Bl/6 wild type (WT), conventional IL-2(−/−), TAM-treated Cre recombinase-negative (Cre−)/IL2fl/fl, and Cre recombinase-positive (Cre+)/IL2fl/fl, were activated with anti-CD3 and anti-CD28, and monitored for CD4+ and CD8+ T cell lymphocyte blastogenesis, aerobic glycolysis, BrdU incorporation into newly synthesized DNA, and CFSE dye dilution to monitor cell division. IL-2 production was monitored by quantitative ELISA and multiple additional cytokines were monitored by quantitative protein-bead arrays. Splenocytes from conventional IL-2(−/−) and TAM-treated Cre+ mice resulted in undetectable IL-2 production by ELISA, so that both strains were IL-2-deficient. As monitored by flow cytometry, activated CD4+ and CD8+ T cells from WT, Cre+, and Cre− mice all underwent blastogenesis, whereas far fewer cells from conventional IL-2(−/−) mice did so. By comparison, only cells from IL-2 sufficient WT and Cre− mice switched to aerobic glycolysis as evidenced by a drop in media pH. Blastogenesis was mirrored by BrdU incorporation and CFSE dye dilution by CD4+ and CD8+ T cells from WT, Cre+, and Cre− mice, which were all equivalent, while proliferation of cells from conventional IL-2(−/−) mice was compromised. Splenocytes from IL-2 deficient conventional IL-2(−/−) mice produced low or undetectable other γc-chain cytokines (IL-4, IL-7, IL-9, IL-13, IL-15, and IL-21), whereas production of these γc-chain cytokines from IL-2-deficient conditional IL-2(−/−) Cre+ mice were comparable with WT and Cre− mice. These results indicate that CD4+ and CD8+ T cell blastogenesis cannot be attributable to IL-2 alone, but a switch to aerobic glycolysis was attributable to IL-2, and proliferation after CD3/CD28 activation is dependent on γc-chain cytokines, and not CD3/28 triggering per se.

Anti-CD3 Antibody Treatment Induces Hypoglycemia and Super Tolerance to Glucose Challenge in Mice through Enhancing Glucose Consumption by Activated Lymphocytes

“…Given that the serum T cell cytokine levels are elevated after anti-CD3 therapy, it is possible that anti-CD3 antibodies activate T cells in vivo resulting in increased consumption or intracellular transportation of glucose. Previous reports have demonstrated that there were elevated levels of glycolysis in activated T cells [17–19]. It is reported recently that glucose transportation is significantly increased upon T cell activation [13], which is consistent with our in vitro experimental data in the current study showing that spleen cells activated by anti-CD3 antibodies significantly reduce the glucose levels in the culture media and promote the glucose uptake by activated T and B cells.…”

The T‐cell fingerprint of MALT1 paracaspase revealed by selective inhibition

“…Beside its effect on cell survival, BCL‐x L was previously reported to control various aspects of bioenergetic metabolism, including mitochondrial ATP production . Moreover, the switch to aerobic glycolysis, a characteristic of effector T‐cells, is known to rely on IL‐2 . Therefore, we analyzed the metabolic activity of stimulated isolated human naïve T‐cells in the absence or presence of MLT‐827.…”

Cdk5 controls IL-2 gene expression via repression of the mSin3a-HDAC complex

“…For example, the suppressed proliferative response of T cells deficient in either the expression or activity of Cdk5 may reflect a defect in the expression of autocrine factors, 4 such as IL-2, that are known to be essential for an optimal mitogenic response following TCR activation. 12 Indeed, the autocrine expression of IL-2 following T cell activation is important for both T-cell differentiation and survival. 13,14 Several studies have recently highlighted a role for the classical zinc-dependent histone deacetylases (HDACs) in repressing IL-2 gene expression.…”