title: Different competitive capacities of Stat4- and Stat6-deficient CD4+ T cells during lymphophenia-driven proliferation.
abstract: The outcome of an immune response relies on the competitive capacities acquired through differentiation of CD4(+) T cells into Th1 or Th2 effector cells. Because Stat4 and Stat6 proteins are implicated in the Th1 vs Th2 generation and maintenance, respectively, we compare in this study the kinetics of Stat4(-/-) and Stat6(-/-) CD4(+) T cells during competitive bone marrow reconstitution and lymphopenia-driven proliferation. After bone marrow transplantation, both populations reconstitute the peripheral T cell pools equally well. After transfer into lymphopenic hosts, wild-type and Stat6(-/-) CD4(+) T cells show a proliferation advantage, which is early associated with the expression of an active phospho-Stat4 and the down-regulation of Stat6. Despite these differences, Stat4- and Stat6-deficient T cells reach similar steady state numbers. However, when both Stat4(-/-) and Stat6(-/-) CD4(+) T cells are coinjected into the same hosts, the Stat6(-/-) cells become dominant and out-compete Stat4(-/-) cells. These findings suggest that cell activation, through the Stat4 pathway and the down-regulation of Stat6, confers to pro-Th1 T cells a slight proliferation advantage that in a competitive situation has major late repercussions, because it modifies the final homeostatic equilibrium of the populations and favors the establishment of Th1 CD4(+) T cell dominance.
authors.affiliation: Lymphocyte Population Biology Unit, Institute Pasteur, France.
authors.forename: Vanesa
authors.initials: V
authors.lastname: Sanchez-Guajardo
authors.forename: José A M
authors.initials: JA
authors.lastname: Borghans
authors.forename: Maria-Elena
authors.initials: ME
authors.lastname: Marquez
authors.forename: Sylvie
authors.initials: S
authors.lastname: Garcia
authors.forename: Antonio A
authors.initials: AA
authors.lastname: Freitas
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D016026:Bone Marrow Transplantation / Q000276:immunology / Q000473:pathology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism / Q000637:transplantation; D002455:Cell Division / Q000235:genetics / Q000276:immunology; D049109:Cell Proliferation; D004268:DNA-Binding Proteins / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation / Q000235:genetics / Q000276:immunology; D006706:Homeostasis / Q000235:genetics / Q000276:immunology; D008198:Lymph Nodes / Q000276:immunology / Q000378:metabolism / Q000637:transplantation; D008213:Lymphocyte Activation / Q000235:genetics; D008231:Lymphopenia / Q000235:genetics* / Q000276:immunology* / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D010766:Phosphorylation; D050797:STAT4 Transcription Factor; D050800:STAT6 Transcription Factor; D018417:Th1 Cells / Q000276:immunology / Q000378:metabolism; D013997:Time Factors; D015534:Trans-Activators / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D050797:STAT4 Transcription Factor; D050800:STAT6 Transcription Factor; C494091:Stat4 protein, mouse; C494100:Stat6 protein, mouse; D015534:Trans-Activators