Diminished Primary and Secondary Influenza Virus-Specific CD8 + T-Cell Responses in CD4-Depleted Ig −/− Mice

Abstract

ABSTRACT Optimal expansion of influenza virus nucleoprotein (D b NP 366 )-specific CD8 + T cells following respiratory challenge of naive Ig −/− μMT mice was found to require CD4 + T-cell help, and this effect was also observed in primed animals. Absence of the CD4 + population was consistently correlated with diminished recruitment of virus-specific CD8 + T cells to the infected lung, delayed virus clearance, and increased morbidity. The splenic CD8 + set generated during the recall response in Ig −/− mice primed at least 6 months previously showed a normal profile of gamma interferon production subsequent to short-term, in vitro stimulation with viral peptide, irrespective of a concurrent CD4 + T-cell response. Both the magnitude and the localization profiles of virus-specific CD8 + T cells, though perhaps not their functional characteristics, are thus modified in mice lacking CD4 + T cells.