Effector Memory Th1 CD4 T Cells Are Maintained in a Mouse Model of Chronic Malaria
Figure 5
Treatment of a chronic P. chabaudi infection changes the phenotype of memory cells and their cytokine profiles towards Th1 late effector profile.
CD4+ MSP1-specific B5 Tg T cells were seeded into Thy1.1 congenic mice to follow the antigen-specific response. Mice were infected with 105 Plasmodium chabaudi and treated with Chloroquine (CQ) during days 30–34 to clear the chronic infection. Splenocytes were analyzed by flow cytometry on day 60 post-infection, and the FACS plots were gated on Thy1.2+CD4+ cells. A) Differences in the proportions of Tmem, (CD44hi IL-7Rα+), and effector (Teff, CD44hi IL-7Rα−) cells at day 60 between mice treated and not treated with chloroquine (+CQ and −CQ respectively). The percentage of IL-7Rα+ Tmem or IL-7Rα− Teff within the CD44hi cell population is shown as a graph (right). These differences were observed in 4 independent experiments. B) IFN-γ and TNFα production in Thy1.2+CD4+ CD44hiCD62Llo B5 cells from chloroquine-treated and -untreated mice at day 60 post infection. C) Multiple cytokine producing B5 CD4 T cells from chloroquine-treated and untreated mice at day 60 post-infection. Percent double-producing TNFα+IFN-γ+IL-2− and triple-producing IFN-γ+TNFα+IL-2+ are shown. D) IFNγ+ TNFα+ (IL-2−) double producing cells within the Tem subset of B5 at 60 days post-infection. The graphs show means and SEM from 5 mice. ** p≤.01 and * p≤.05 by student's t-test.