Diminished primary CD8 T cell response to viral infection during protein energy malnutrition in mice is due to changes in microenvironment and low numbers of viral-specific CD8 T cell precursors.

Protein energy malnutrition (PEM) increases the incidence and severity of infection, causing morbidity and mortality in malnourished populations. Viral-specific cells are an important component of protective immunity. We hypothesized that reduction in the expansion of viral-specific cells and the microenvironment of the PEM host leads to increased incidence and severity of infections. We tested this hypothesis using a mouse model of lymphocytic choriomeningitis virus (LCMV) infection and an adoptive transfer system using P14 transgenic mice cells bearing T cell receptors specific for the D(b)-restricted LCMV glycoprotein 33-41 epitope. We transferred equal numbers of P14 cells from mice fed either an adequate, 18% protein or low, 0.6% protein diet into C57BL/6 mice that had been fed adequate-protein (AP) or low-protein (LP) diets for 2 wk, infected them with LCMV, and followed them 1 wk postinfection. During PEM, the expansion of primary viral-specific CD8 T cells diminished; in LP diet-fed mice, it was only 2-3% of that in the AP diet-fed mice. Furthermore, the diminished primary CD8 T cell response during PEM may in part have been due to low numbers of viral-specific CD8 T cells and an altered microenvironment.