In vitro stimulation with a non‐peptidic alkylphosphate expands cells expressing Vγ2‐Jγ1.2/Vδ2 T‐cell receptors

Abstract

SUMMARYThe majority of peripheral blood cd T cells in healthy adult humans express the Vc2/Vd2 T-cell receptor (TCR) and generate TCR-mediated, major histocompatibility complex (MHC)-unrestricted proliferative responses to low molecular weight alkylphosphates. Vc2/Vd2 populations after antigen proliferation maintained diversity in the CDR3s of Vc2 mRNA, indicating that the response was polyclonal or oligoclonal, and were enriched for Vc2 TCR chains containing the Jc1.2 segment. Alkylphosphate stimulation further skewed an already biased peripheral blood cd T-cell population and increased the abundance of Vc2-Jc1.2/Vd2 T cell receptors, suggesting similarities between the alkylphosphate response and peripheral selection mechanisms shaping this repertoire in human beings.

Individual Vγ2-Jγ1.2+ T cells respond to both isopentenyl pyrophosphate and Daudi cell stimulation: generating tumor effectors with low molecular weight phosphoantigens

“…Thus, selection for the Jγ1.2 segment is a common feature of the adult Vγ2 repertoire and occurs independently of ethnic or geographic background. Part of these data were reported previously [17,18].…”

“…Repertoire bias is a product of chronic positive selection for Vγ2-Jγ1.2 that is driven by self or ubiquitous antigens. The same bias is common to most human beings irrespective of haplotype [12,17] and is nearly identical in human and nonhuman primates [6,18,36]. In contrast, the highly diverse αβ TCR repertoire is shaped by MHC-dependent positive and negative selection mechanisms in the thymus and does not show an obvious bias in the absence of infection or immunization [33].…”

“…Primer extension reactions were performed as described previously [18]. Each reaction contained 1 μL PCR product, 3 mM MgCl 2 , 0.2 mM dNTP, 0.2 units Taq DNA polymerase (Promega, Madison, WI), 10 mM Tris-HCL pH 8.8, 50 mM KCl, and 0.1 μM -carboxyfluorescein (6-FAM)-labeled primer (Cγ6-FAM for Vγ2 chains: 5'-AATAGTGGGCTTGGGGGAAAC-3'; Cδ16-FAM for Vγ2 chains: 5'-ACGGATGGTTTGGTATGAGG-3').…”

“…We know that Vγ2Vδ2 T cells respond to stimulation with low molecular weight, non-peptidic antigens including intermediates of sterol biosynthesis (such as isopentenyl pyrophosphate) [9,16,18,35], aminobisphosphonate drugs [11,27] and alkylamines [3]. Vγ2Vδ2 T cells proliferate after stimulation with these agents and respond similarly to some tumor cell lines including the Daudi B cell lymphoma [4,22,25,30].…”

“…Tumor recognition is independent of classical MHC molecules, there is no defined requirement for antigen processing [13], and various tumor ligands have been implicated including HSP60 [28] and an F1 ATPase-related structure [37]. Cell lines expanded after stimulation with phosphoantigens or tumors are enriched for the Vγ2-Jγ1.2 rearrangement [18] and are potently cytotoxic for some tumors [10,38]. Stimulation also induces expression of Type 1 cytokines (IFN-γ, TNF-α, RANTES, MIP-1α, MIP-1β and Lymphotactin among others) [8,14,29,40] and can lead to surface expression of CD107a, a marker for cytotoxic effector cells [14].…”