A fetal wave of human type 3 effector γδ cells with restricted TCR diversity persists into adulthood

Abstract

Accumulating evidence suggests that the mouse embryonic thymus produces distinct waves of innate effector γδ T cells. However, it is unclear whether this process occurs similarly in humans and whether it comprises a dedicated subset of innate-like type 3 effector γδ T cells. Here, we present a protocol for high-throughput sequencing of TRG and TRD pairs that comprise the clonal γδTCR. In combination with single-cell RNA sequencing, multiparameter flow cytometry, and TCR sequencing, we reveal a high heterogeneity of γδ T cells sorted from neonatal and adult blood that correlated with TCR usage. Immature γδ T cell clusters displayed mixed and diverse TCRs, but effector cell types segregated according to the expression of either highly expanded individual Vδ1+ TCRs or moderately expanded semi-invariant Vγ9Vδ2+ TCRs. The Vγ9Vδ2+ T cells shared expression of genes that mark innate-like T cells, including ZBTB16 (encoding PLZF), KLRB1, and KLRC1, but consisted of distinct clusters with unrelated Vγ9Vδ2+ TCR clones characterized either by TBX21, FCGR3A, and cytotoxicity-associated gene expression (type 1) or by CCR6, RORC, IL23R, and DPP4 expression (type 3). Effector γδ T cells with type 1 and type 3 innate T cell signatures were detected in a public dataset of early embryonic thymus organogenesis. Together, this study suggests that functionally distinct waves of human innate-like effector γδ T cells with semi-invariant Vγ9Vδ2+ TCR develop in the early fetal thymus and persist into adulthood.

The Diverse Roles of γδ T Cells in Cancer: From Rapid Immunity to Aggressive Lymphoma

“…For example, it was shown that a subpopulation of CD28 + Vγ9Vδ2 cells produce IL-17, are positive for CD27 and CCR6 and express type-3 signature genes such as RORC and IL23R [ 56 ]. Notably, the recent identification of γδT17 Vδ2 cells in human embryonic thymus also suggests a potential pre-programing mechanism similar to mice [ 57 ].…”

Evidence for an Adult-Like Type 1-Immunity Phenotype of Vδ1, Vδ2 and Vδ3 T Cells in Ghanaian Children With Repeated Exposure to Malaria

“…In this sense, γδ T cells were subjected to flow cytometric analysis with antibodies specific for Vδ1 + , Vδ2 + , Vδ3 + and Vγ9 + T cell receptors (TCRs). At the same time, antibodies against CD27, CD45RA, CCR7, and CD127 were used to identify naïve and central memory cells; CCR4 for type 2-immunity γδ T cells; CCR6 and CD161 for innate type 3-immunity γδ T cells; and CD94, CD16, and PD1 for cytotoxic type 1 effector γδ T cells ( 5 ).…”

“…One subpopulation of T lymphocytes, gd T cells, could be essential to early neonatal and childhood protection. They start to develop during early fetal development, show a high functionality at birth and fast expansion upon microbial encounters (4)(5)(6)(7)(8)(9). Murine and human gd T cells are often grouped based on their surface gd T cell receptor and functionality.…”

“…Murine and human γδ T cells are often grouped based on their surface γδ T cell receptor and functionality. It is well received that type 1- and type3-immunity cells are the major functional γδ T cells subsets ( 10 ), albeit type 3 cells are less frequent in humans ( 5 ). Human type 1 immunity cells comprise Vγ9 + Vδ2 + and Vδ1 + T cells that are characterized by cytotoxicity-associated gene expression profiles by being for instance CD27 low , NK receptor CD94 + (mainly Vγ9 + Vδ2 + ) and CD16 + .…”

“…Human type 1 immunity cells comprise Vγ9 + Vδ2 + and Vδ1 + T cells that are characterized by cytotoxicity-associated gene expression profiles by being for instance CD27 low , NK receptor CD94 + (mainly Vγ9 + Vδ2 + ) and CD16 + . Human type 3 immunity cells express exclusively the Vγ9Vδ2 + TCR and genes like CCR6 and KLRB1 (encoding CD161) that relate to interleukin-17 production ( 5 ).…”