Differential Effect of CD4+Foxp3+ T-regulatory Cells on the B and T Helper Cell Responses to Influenza Virus Vaccination

The T-regulatory (T-reg) cells restrict the T-cell functions in various viral infections including influenza infection. However little is known about the effect of T-regs in influenza vaccination. Herein, we found that immunization of BALB/c mice with a prototype of UV-inactivated influenza PRS/A/34 virus vaccine expanded the CD4+Foxp3+ T-reg pool and fostered the development of virus-specific CD4+Foxp3+ T-reg cells. Increasing the size of Foxp3+ T-reg pool did not alter the primary PR8-specific B-cell response. but it did suppress the primary and memory PR8-specific T helper responses induced by vaccination. In contrast, the vaccination-induced T helper cell response was augmented in the absence of CD4+Foxp3+ T-reg cells. Since CD4 T helper cells contribute to anti-influenza protection, therapeutic quenching of T-reg function prior to vaccination may enhance the efficacy of influenza vaccination. Published in Vaccine, v28 p7319-7330, 2010.