| First Author | Cho SH | Year | 2019 |
| Journal | Proc Natl Acad Sci U S A | Volume | 116 |
| Issue | 18 | Pages | 8975-8984 |
| PubMed ID | 30988188 | Mgi Jnum | J:274662 |
| Mgi Id | MGI:6297166 | Doi | 10.1073/pnas.1811702116 |
| Citation | Cho SH, et al. (2019) Hypoxia-inducible factors in CD4(+) T cells promote metabolism, switch cytokine secretion, and T cell help in humoral immunity. Proc Natl Acad Sci U S A 116(18):8975-8984 |
| abstractText | T cell help in humoral immunity includes interactions of B cells with activated extrafollicular CD4(+) and follicular T helper (Tfh) cells. Each can promote antibody responses but Tfh cells play critical roles during germinal center (GC) reactions. After restimulation of their antigen receptor (TCR) by B cells, helper T cells act on B cells via CD40 ligand and secreted cytokines that guide Ig class switching. Hypoxia is a normal feature of GC, raising questions about molecular mechanisms governing the relationship between hypoxia response mechanisms and T cell help to antibody responses. Hypoxia-inducible factors (HIF) are prominent among mechanisms that mediate cellular responses to limited oxygen but also are induced by lymphocyte activation. We now show that loss of HIF-1alpha or of both HIF-1alpha and HIF-2alpha in CD4(+) T cells compromised essential functions in help during antibody responses. HIF-1alpha depletion from CD4(+) T cells reduced frequencies of antigen-specific GC B cells, Tfh cells, and overall antigen-specific Ab after immunization with sheep red blood cells. Compound deficiency of HIF-1alpha and HIF-2alpha led to humoral defects after hapten-carrier immunization. Further, HIF promoted CD40L expression while restraining the FoxP3-positive CD4(+) cells in the CXCR5(+) follicular regulatory population. Glycolysis increases T helper cytokine expression, and HIF promoted glycolysis in T helper cells via TCR or cytokine stimulation, as well as their production of cytokines that direct antibody class switching. Indeed, IFN-gamma elaboration by HIF-deficient in vivo-generated Tfh cells was impaired. Collectively, the results indicate that HIF transcription factors are vital components of the mechanisms of help during humoral responses. |
