Class IA phosphatidylinositol 3-kinase (PI3K) catalytic subunits p110α and p110d are targets in cancer therapy expressed at high levels in T lymphocytes. The role of p110d PI3K in normal or pathological immune responses is well established, yet the importance of p110α subunits in T cell-dependent immune responses is not clear. To address this problem, mice with p110α conditionally deleted in CD4+ and CD8+ T lymphocytes (p110α-/-ΔT) were used. p110α-/-ΔT mice show normal development of T cell subsets, but slightly reduced numbers of CD4+ T cells in the spleen. "In vitro," TCR/CD3 plus CD28 activation of naive CD4+ and CD8+ p110α-/-ΔT T cells showed enhanced effector function, particularly IFN-γ secretion, T-bet induction, and Akt, Erk, or P38 activation. Tfh derived from p110α-/-ΔT cells also have enhanced responses when compared to normal mice, and IL-2 expanded p110α-/-ΔT CD8+ T cells had enhanced levels of LAMP-1 and Granzyme B. By contrast, the expansion of p110α-/-ΔT iTreg cells was diminished. Also, p110α-/-ΔT mice had enhanced anti-keyhole limpet hemocyanin (KLH) IFN-γ, or IL-4 responses and IgG1 and IgG2b anti-KLH antibodies, using CFA or Alum as adjuvant, respectively. When compared to WT mice, p110α-/-ΔT mice inoculated with B16.F10 melanoma showed delayed tumor progression. The percentage of CD8+ T lymphocytes was higher and the percentage of Treg cells lower in the spleen of tumor-bearing p110α-/-ΔT mice. Also, IFN-γ production in tumor antigen-activated spleen cells was enhanced. Thus, PI3K p110α plays a significant role in antigen activation and differentiation of CD4+ and CD8+ T lymphocytes modulating antitumor immunity.




L., A.-F., G., O., M., M.-C., Y., A.-A., U., D., P., P., & J.M., R. (2018). T-cell-specific loss of the PI-3-kinase p110α catalytic subunit results in enhanced cytokine production and antitumor response. Frontiers in Immunology, 9(FEB). https://doi.org/10.3389/fimmu.2018.00332 LK  - http://vb3lk7eb4t.search.serialssolutions.com?sid=EMBASE&issn=16643224&id=doi:10.3389%2Ffimmu.2018.00332&atitle=T-cell-specific+loss+of+the+PI-3-kinase+p110%CE%B1+catalytic+subunit+results+in+enhanced+cytokine+production+and+antitumor+response&stitle=Front.+Immunol.&title=Frontiers+in+Immunology&volume=9&issue=FEB&spage=&epage=&aulast=Aragoneses-Fenoll&aufirst=Laura&auinit=L.&aufull=Aragoneses-Fenoll+L.&coden=&isbn=&pages=-&date=2018&auinit1=L&auinitm=

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