Moderate Malnutrition Decrease Malaria-Specific Effector CD4+ T Cells

Malnutrition is known to predispose people to infections by affecting immune cell populations, but it is not known how moderate malnutrition affects the survival of effector CD4+ T cells that could be protective against chronic infections such as malaria. In our current study, we hypothesized that moderate malnutrition leads to a reduction of malaria-specific CD4+ T cells resulting in lower numbers of activated effector CD4+ T cells that have poor survival potential due to decreased Bcl-2/Bcl-xL expression. Using flow cytometry, we observed that moderate malnutrition does not decrease the total number of lymphocytes and polyclonal CD4+ T cells, but the moderate malnourished mice had lower spleen weights compared to well-nourished mice. Using adoptive transfer technique, we found that moderate malnutrition decreases malaria-specific CD4+ T cells that express Thy1.2 molecule, along with reduced numbers of activated malaria-specific effector CD4+ T cells. The decrease in activated malaria-specific effector cells was accompanied by reduced cytokine production. We also found that Bcl-2 expression is downregulated, but Bcl-xL may play a compensatory role in the infected malnourished group. These findings suggest that moderate malnutrition does impair pathogen specific CD4+ T cell populations during chronic infection, which may have a significant effect on other immune cells.