Clearance of persistent respiratory syncytial virus infections in immunodeficient mice following transfer of primed T cells.

Little is known of the role of T-cell mediated immune responses in the clearance and pathogenesis of respiratory syncytial virus (RSV) infection. In this study, we established persistent pulmonary RSV infections in athymic nu/nu BALB/c mice or immunodeficient irradiated BALB/c mice, and examined the patterns of virus clearance following adoptive transfer of splenic memory T cells. Primed T cells transferred between Day 5 and Day 8 of infection will clear lung RSV from both nu/nu mice and irradiated mice within 10 days of transfer. Partially purified Lyt 2+ T cells are more effective than L3T4+-selected T cells. No RSV-specific serum antibody could be detected, suggesting that clearance is by an antibody-independent mechanism. In contrast, delayed (Day 14) transfer of primed L3T4+-selected cells clears lung RSV from nu/nu mice, and this correlates with RSV-specific serum antibody production. Clearance is not seen following Day 14 transfer of total primed T cells or T cells selected for the Lyt 2+ subset.