Emergence of polyfunctional follicular CXCR5+CD8+ T cells in infectious
mononucleosis patients with EBV infection
Background. Epstein-Barr virus (EBV) infection elicit polyfunctional
CD8+ T cell response. Follicular CD8+ T cells with high C-X-C chemokine
receptor type 5 (CXCR5) expression have antiviral effects in chronic
viral infection. However, the role of follicular CXCR5+CD8+ T cells
during primary EBV infection remains unclear. Methods. Using multicolor
flow cytometry, we investigated the dynamic changes of circulating
follicular CXCR5+CD8+ T cells in EBV-infected infectious mononucleosis
(IM) patients. Evaluation of CXCR5+CD8+ response to EBV peptides was
performed. EBV DNA viral loads in PBMC were also determined. Results.
Circulating follicular CXCR5+CD8+ T cells emerged gradually but EBV DNA
viral loads steadily decreased over time after EBV infection.
Importantly, the upregulation of CXCR5+CD8+ T cells was correlated with
EBV DNA reduction. Programmed cell death 1 (PD-1) on CXCR5+CD8+ T cells
emerged over time. Furthermore, CXCR5+CD8+ T cells were demonstrated to
be polyfunctionality (IFN-γ and IL-2 secretion) with enhanced
cytotoxicity to EBV peptides. Conclusions. Polyfunctional CXCR5+CD8+ T
cells emerge during persistent EBV infection.