Impaired trafficking of Gnai2+/- and Gnai2-/- T lymphocytes: implications for T cell movement within lymph nodes.
Signals generated by the engagement of chemoattractants with their cognate receptors orchestrate lymphocyte movements into and out of lymphoid organs and sites of inflammation. Yet, the role of chemokines in organizing lymphocyte movements in lymphoid organs is controversial. Recent evidence suggests that the extensive network of fibroblastic reticular cells within the T cell areas helps guide T cells. The expression of adhesion molecules and chemokines by fibroblastic reticular cells most likely facilitates their influence on T cell movements. Consistent with this hypothesis, CD4 T cells with defective chemokine receptor signaling move very differently within lymph nodes than do normal cells. For the imaging studies, we used CD4 T cells prepared from Gnai2(-/-) mice, which lack G(alphai2) expression. We first demonstrate that CD4 as well as CD8 T cells from these mice are markedly defective in chemokine receptor signaling. Gnai2(-/-) T cells have profound defects in chemokine-induced intracellular calcium mobilization, chemotaxis, and homing, whereas Gnai2(+/-) T cells exhibit modest defects. Intravital imaging revealed that within the inguinal lymph nodes Gnai2(-/-) CD4 T accumulate at the cortical ridge, poorly accessing the lymph node paracortex. They also lack the customary amoeboid-like cell movements and active membrane projections observed with normal CD4 T cells. These results demonstrate the importance of G(alphai2) for T lymphocyte chemokine receptor signaling and argue that local chemoattractants regulate the movement of CD4 T cells in lymph nodes.
Hwang
Il-Young
IY
Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 10 Center Drive, Bethesda, MD 20892, USA.
Park
Chung
C
Kehrl
John H
JH
D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D020013:Calcium Signaling / Q000235:genetics / Q000276:immunology; D002464:Cell Migration Inhibition; D002634:Chemotaxis, Leukocyte / Q000235:genetics / Q000276:immunology*; D015536:Down-Regulation / Q000235:genetics / Q000276:immunology; D051960:GTP-Binding Protein alpha Subunit, Gi2 / Q000096:biosynthesis* / Q000172:deficiency* / Q000235:genetics / Q000502:physiology; D005786:Gene Expression Regulation / Q000276:immunology; D008198:Lymph Nodes / Q000276:immunology* / Q000378:metabolism* / Q000473:pathology; D008213:Lymphocyte Activation / Q000235:genetics / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D020033:Protein Isoforms / Q000096:biosynthesis / Q000172:deficiency / Q000502:physiology; D019707:Receptors, Chemokine / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000502:physiology; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism* / Q000473:pathology
D020033:Protein Isoforms; D019707:Receptors, Chemokine; D051960:GTP-Binding Protein alpha Subunit, Gi2; C498016:Gnai2 protein, mouse