Both CD62L⁺CD4⁺ and CD62L⁻CD4⁺ T cells proliferate in response to <i>Mmm</i>SC stimulation <i>in vitro</i>.

<p>Results of a typical four-color flow cytometric analysis are shown for one vaccinated animal. Cells were loaded with CFSE and incubated for 9 days with inactivated <i>Mmm</i>SC before cell surface staining and analysis by flow cytometry as follows: (a) a first gate (P1) was used to exclude dead cells (7AAD+) and cell debris (FSC<50); (b) a second gate (P2) was set, among P1 gated cells, to delineate viable and proliferating CD4⁺ T cells (CFSElow or CFSE<1×10³); and (c), histograms were opened on gate P2 to obtain the percentage of CD62L⁺ cells among proliferating CD4⁺ T cells (i.e., P3).