Late dominance of the inflammatory process in murine influenza by γ/δ+ T cells

Abstract

The inflammatory response in the lungs of mice infected with an influenza A virus consists largely of macrophages and CD3+ T cells. Most T lymphocytes recovered before day 7 after infection express mRNA for the T cell receptor α/β (TCR-α/β), while TCR-γ/δ mRNA+ cells are found at much higher frequency over the next 7 d. The predominant surface phenotype for the TCR-γ/δ mRNA+ population is CD3+4-8- TCR-α/β-. Some lymphocytes expressing all the known Vγ genes are found in the inflammatory exudate, but Vγ2+/Vγ1+ and Vγ4+ T cells are present at highest frequency. The response is staged, with maximal numbers of Vγ4+ cells occurring on day 10 after infection, while the predominant phenotype on day 13 is Vγ2/Vγ1+. The emerging peak in numbers of Vγ4+ lymphocytes is paralleled by increasing numbers of macrophages expressing hsp mRNA. The later maxima found for the Vγ2+/Vγ1+ T cells is consistent with the possibility that at least some of these lymphocytes are responding to the hsp+ cells and are functioning to resolve the inflammatory process.