Cytomegalovirus infection induces T-cell differentiation without impairing antigen-specific responses in Gambian infants

Cytomegalovirus (CMV) infection induces profound differentiation of T cells, and is associated with impaired responses to other immune challenges. We therefore considered whether CMV infection and the consequent T-cell differentiation in Gambian infants was associated with impaired specific responses to measles vaccination or polyclonal responses to the superantigen staphylococcal enterotoxin B (SEB). While the concentration of undifferentiated (CD27+ CD28+ CCR7+) T-cells in peripheral blood was unaffected by CMV, there was a large increase in differentiated (CD28 - CD57+) CD8 T-cells and a smaller increase in differentiated CD4 cells. One week post-vaccination, the CD4 cell interferon-γ (IFN-γ) response to measles was lower among CMV-infected infants, but there were no other differences between the cytokine responses, or between the cytokine or proliferative responses 4 months post-vaccination. However, the CD8 T cells of CMV-infected infants proliferated more in response to SEB and the antibody response to measles correlated with the IFN-γ response to CMV, indicating that CMV infection actually enhances some immune responses in infancy. © 2008 The Authors.