Negative Selection by an Endogenous Retrovirus Promotes a Higher-Avidity CD4+ T Cell Response to Retroviral Infection
Figure 1
Detection of env-specific CD4+ T cells by Ab-env123-141 tetramer eclipsed by antigen-induced TCR downregulation.
(A) Ab-hCLIP (control) or Ab-env123-141 tetramer staining in total CD4+ T cells isolated from the spleen of wild-type B6 mice 7 days post FV infection. Plots are representative of 7 mice. (B) Frequency of Vα2 cells in either bulk naïve (CD44lo), bulk memory (CD44hi) or Ab- env123-141 tetramer+ CD4+ T cells from the same FV infected mice. Horizontal short lines in naïve and memory subsets denote the mean frequency of Vα2 cells in the same populations from uninfected mice. Each symbol represents an individual mouse. (C–F) CD45.1+ EF4.1 CD4+ T cells were adoptively transferred into wild-type B6 recipients that were infected with FV the same day. (C) Ab-env123-141 tetramer staining in host (CD45.1−) or donor (CD45.1+) CD4+ T cells according to TCRα or TCRβ staining. Gates in donor CD4+ T cells are set around the median TCRα and TCRβ staining, respectively. (D) Percentage of Ab-env123-141 tetramer+ cells in donor CD4+ T cells with TCRβ (left) or TCRα (right) staining below or above the median. (E) Ab-hCLIP or Ab-env123-141 tetramer staining in host or donor CD4+ T cells from the same recipients assessed directly ex vivo (top) or following 3-day in vitro culture in the absence of antigenic stimulation (bottom). (F) Percentage of Ab-env123-141 tetramer+ cells in donor CD4+ T cells before and after in vitro culture. In (D) and (F) each symbol represents an individual mouse from one of two experiments.