Fig 4.

Priming with LVS ΔcapB and boosting with rLm/iglC enhance IglC-specific multifunctional CD4⁺ T cells. Splenic lymphocytes from sham-immunized mice and mice immunized with various vaccines (n = 4 mice/group) were stimulated with F. tularensis IglC protein (a and d), IglC peptide (b and e), or HI-LVS (c and f) and analyzed for cytokine-producing CD4⁺ T cells by multiparameter flow cytometry. (a to c) Total frequencies of CD4⁺ T cells expressing IFN-γ, IL-2, or TNF (i.e., all T cell subsets producing a given cytokine either alone or with other cytokines). (d to f) Multiparameter analysis of CD4⁺ T cells. Data shown are the frequencies of the 7 subpopulations of CD4⁺ T cells expressing one, two, or three cytokines among IFN-γ, IL-2, and TNF. Values are means and standard errors for 4 mice. The experiment was repeated once, with similar results.