Prolonged Evolution of Virus-Specific Memory T Cell Immunity after Severe Avian Influenza A (H7N9) Virus Infection
Zhao M., Chen J., Tan S., Dong T., Jiang H., Zheng J., Quan C., Liao Q., Zhang H., Wang X., Wang Q., Bi Y., Liu F., Feng L., Horby PW., Klenerman P., Gao GF., Liu WJ., Yu H.
Avian influenza A H7N9 virus remains a major threat to public health. However, no previous studies have determined the characteristics and dynamics of virus-specific T cell immune memory in patients who have recovered from H7N9 infection. Our findings showed that establishment of H7N9-specific T cell memory after H7N9 infection was prolonged in older and severely affected patients. Severely ill patients mounted lower T cell responses in the first 4 months after infection, while T cell responses tended to increase over time in older and severely ill patients. Higher levels of antigen-specific CD8 + T cells expressing the lung-homing marker CD49a were detected at 6 to 8 months after infection. Our results indicated a long-term impact of H7N9 infection on virus-specific memory T cells. These findings advance our understanding of the dynamics of virus-specific memory T cell immunity after H7N9 infection, which is relevant to the development of T cell-based universal influenza vaccines.