Ex Vivo Phenotype and Frequency of Influenza Virus-Specific CD4 Memory T Cells
Lucas M., Day CL., Wyer JR., Cunliffe SL., Loughry A., McMichael AJ., Klenerman P.
<jats:title>ABSTRACT</jats:title> <jats:p>Recent advances in class II tetramer staining technology have allowed reliable direct ex vivo visualization of antigen-specific CD4 T cells. In order to define the frequency and phenotype of a prototype response to a nonpersistent pathogen, we have used such techniques to analyze influenza virus-specific memory CD4 T cells directly from blood. These responses are stably detectable ex vivo at low frequencies (range, 0.00012 to 0.0061% of CD4 T cells) and display a distinct “central memory” CD62L<jats:sup>+</jats:sup> phenotype.</jats:p>