| First Author | Odegard JM | Year | 2008 |
| Journal | J Exp Med | Volume | 205 |
| Issue | 12 | Pages | 2873-86 |
| PubMed ID | 18981236 | Mgi Jnum | J:143221 |
| Mgi Id | MGI:3823182 | Doi | 10.1084/jem.20080840 |
| Citation | Odegard JM, et al. (2008) ICOS-dependent extrafollicular helper T cells elicit IgG production via IL-21 in systemic autoimmunity. J Exp Med 205(12):2873-86 |
| abstractText | The role of specialized follicular helper T (T(FH)) cells in the germinal center has become well recognized, but it is less clear how effector T cells govern the extrafollicular response, the dominant pathway of high-affinity, isotype-switched autoantibody production in the MRL/MpJ-Fas(lpr) (MRL(lpr)) mouse model of lupus. MRL(lpr) mice lacking the Icos gene have impaired extrafollicular differentiation of immunoglobulin (Ig) G(+) plasma cells accompanied by defects in CXC chemokine receptor (CXCR) 4 expression, interleukin (IL) 21 secretion, and B cell helper function in CD4 T cells. These phenotypes reflect the selective loss of a population of T cells marked by down-regulation of P-selectin glycoprotein ligand 1 (PSGL-1; also known as CD162). PSGL-1(lo) T cells from MRL(lpr) mice express CXCR4, localize to extrafollicular sites, and uniquely mediate IgG production through IL-21 and CD40L. In other autoimmune strains, PSGL-1(lo) T cells are also abundant but may exhibit either a follicular or extrafollicular phenotype. Our findings define an anatomically distinct extrafollicular population of cells that regulates plasma cell differentiation in chronic autoimmunity, indicating that specialized humoral effector T cells akin to T(FH) cells can occur outside the follicle. |
