The increase of $CD4^ +CD25^ +$ T cells in the peripheral blood of pigs persistently infected with porcine reproductive and respiratory syndrome virus

Abstract

Regulatory T lymphocytes (T-regs) may be involved in suppressing the host’s immunity, which is importantfor viral clearance, and may therefore contribute to persistent viral infection. However, nothing is known regardingthe situation of porcine T-regs during persistent infection with porcine reproductive and respiratory syndrome virus(PRRSV). This study, which used l ow cytometry and real-time PCR, determined that the frequencies of $CD4^ +CD25^ +$T-cells and porcine Forkhead/winged helix transcription factor (FoxP3) mRNA levels in peripheral blood signii cantlyincreased during PRRSV persistence, indicating that $CD4^ +CD25^ +$ T-regs might play an important role in PRRSVpersistent infection. This study contributes to a better understanding of the immunological basis of PRRSV persistence.