TCR delta repertoire from peripheral blood of infants followed longitudinally for herpesvirus infections.

Gamma-delta T cells are unconventional T cells that help control cytomegalovirus (CMV) infection in adults. Gamma-delta T cells develop early in gestation, and a fetal public T cell receptor (TCR) clonotype is detected in congenital CMV infections (Vermijlen et al. 2010). In the associated study (Tuengel et al. 2021) age-dependent gamma-delta T cell responses to primary CMV infection were studied in a cohort of 32 infants followed prospectively from birth. The EBV and HHV6 status of the infants and the HIV status of the mother were monitored alongside CMV. The TCR sequencing detected the public TCR delta clonotype only in CMV-infected infants <120 days old and at lower frequencies than previously described in fetal infections. The results on the TCR sequencing of the peripheral blood of the infants together with flow cytometry data showed that CMV infection drives age-dependent expansions of specific gamma-delta T cell populations.