CCR5/CCR6 Chemokine Receptor Profiles Differ in γδTCR Intensity-Defined Subsets but Remain Conserved Across...

During pregnancy, immune tolerance toward the semi-allogeneic fetus must be established. γδT cells constitute a distinct T-cell lineage characterized by expression of the γδT-cell receptor (γδTCR). They combine rapid innate-like responses with adaptive immune functions and contribute to feto-maternal immune regulation; however, their peripheral phenotypic characteristics, including chemokine receptor (ChR) profiles potentially relevant to decidual recruitment, remain incompletely characterized. Peripheral blood from healthy non-pregnant and first-trimester pregnant women was analyzed by flow cytometry to assess γδT-cell phenotypes and CCR5/CCR6 ChR expression. Analysis of γδT-cell subsets defined by lower (γδTCR^dim) or higher (γδTCR^bright) surface γδTCR expression showed that CCR5^-/CCR6^- cells were more frequent in γδTCR^bright cells, whereas CCR5⁺ phenotypes were more prominent in γδTCR^dim cells; CD4/CD8 and CD56/CD8 distributions were comparable. Resting γδT cells were mainly CD4^-/CD8^-, whereas recently activated CD69⁺ γδT cells had increased CD4⁺ or CD8⁺ single-positive frequencies. Compared with non-γδT cells, γδT cells showed distinct CD4/CD8-linked CCR5/CCR6 organization, including a CCR5⁺/CCR6^- preference. Unlike non-γδT cells, conventional CD56^- and NK-like CD56⁺ γδT cells retained similar CCR5/CCR6 profiles across CD4/CD8-defined subsets. PMA/ionomycin-stimulated samples generally exhibited lower CCR5⁺ and higher CCR5^- frequencies across CD4^- conventional and NK-like γδT cell subsets. Pregnancy-related circulating γδT-cell phenotype changes were negligible, possibly reflecting decidual immune adaptation. Overall, the study highlights γδTCR intensity-linked ChR heterogeneity and, in contrast to non-γδT cells, conserved CCR5/CCR6 organization across CD56-defined γδT-cell subsets. Broader ChR phenotyping and functional migration analyses could clarify the biological relevance of these subset-specific differences.