@article{HerrmannKarunakaran2014,
  author    = {Herrmann, Thomas and Karunakaran, Mohindar M.},
  title     = {The Vγ9Vδ2 T cell antigen receptor and butyrophilin-3 A1: models of interaction, the possibility of co-evolution, and the case of dendritic epidermal T cells},
  doi       = {10.3389/fimmu.2014.00648},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-111141},
  year      = {2014},
  abstract  = {Most circulating human gamma delta T cells are Vγ9Vδ2 T cells. Their hallmark is the expression of T cell antigen receptors (TCR) whose γ-chains show a Vγ9-JP (Vγ2-Jγ1.2) rearrangement and are paired with Vδ2-containing δ-chains, a dominantTCR configuration, which until recently seemed to occur in primates only. Vγ9Vδ2 T cells respond to phosphoantigens (PAg) such as (E)-4-Hydroxy-3-methyl-but-2-enyl pyrophosphate (HMBPP), which is produced by many pathogens and isopentenyl pyrophosphate (IPP), which accumulates in certain tumors or cells treated with aminobisphosphonates such as zoledronate. A prerequisite for PAg-induced activation is the contact of Vγ9Vδ2 T cells with cells expressing butyrophilin-3 A1 (BTN3A1). We will first critically review models of how BTN3 might act in PAg-mediated Vγ9Vδ2 T cell activation and then address putative co-evolution of Vγ9, Vδ2, and BTN3 genes. In those rodent and lagomorphs used as animal models, all three genes are lost but a data-base analysis showed that they emerged together with placental mammals. A strong concomitant conservation of functional Vγ9, Vδ2, and BTN3 genes in other species suggests co-evolution of these three genes. A detailed analysis was performed for the new world camelid alpaca (Vicugna pacos). It provides an excellent candidate for a non-primate species with presumably functional Vγ9Vδ2 T cells since TCR rearrangements share features characteristic for PAg-reactive primate Vγ9Vδ2 TCR and proposed PAg-binding sites of BTN3A1 have been conserved. Finally, we analyze the possible functional relationship between the butyrophilin-family member Skint1 and the γδTCR-V genes used by murine dendritic epithelialT cells (DETC). Among placental mammals, we identify five rodents, the cow, a bat, and the cape golden mole as the only species concomitantly possessing potentially functional homologs of murineVγ3,Vδ4 genes, and Skint1 gene and suggest to search for DETC like cells in these species.},
  language  = {en}
}
@article{HerrmannKarunakaran2022,
  author    = {Herrmann, Thomas and Karunakaran, Mohindar M.},
  title     = {Butyrophilins: γδ T cell receptor ligands, immunomodulators and more},
  series = {Frontiers in Immunology},
  volume    = {13},
  journal   = {Frontiers in Immunology},
  issn      = {1664-3224},
  doi       = {10.3389/fimmu.2022.876493},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-265944},
  year      = {2022},
  abstract  = {Butyrophilins (BTN) are relatives of the B7 family (e.g., CD80, PD-L1). They fulfill a wide range of functions including immunomodulation and bind to various receptors such as the γδ T cell receptor (γδTCR) and small molecules. One intensively studied molecule is BTN3A1, which binds via its cytoplasmic B30.2 domain, metabolites of isoprenoid synthesis, designated as phosphoantigen (PAg), The enrichment of PAgs in tumors or infected cells is sensed by Vγ9Vδ2 T cells, leading to the proliferation and execution of effector functions to remove these cells. This article discusses the contribution of BTNs, the related BTNL molecules and SKINT1 to the development, activation, and homeostasis of γδ T cells and their immunomodulatory potential, which makes them interesting targets for therapeutic intervention.},
  language  = {en}
}
@article{KarunakaranSubramanianJinetal.2023,
  author    = {Karunakaran, Mohindar M. and Subramanian, Hariharan and Jin, Yiming and Mohammed, Fiyaz and Kimmel, Brigitte and Juraske, Claudia and Starick, Lisa and N{\"o}hren, Anna and L{\"a}nder, Nora and Willcox, Carrie R. and Singh, Rohit and Schamel, Wolfgang W. and Nikolaev, Viacheslav O. and Kunzmann, Volker and Wiemer, Andrew J. and Willcox, Benjamin E. and Herrmann, Thomas},
  title     = {A distinct topology of BTN3A IgV and B30.2 domains controlled by juxtamembrane regions favors optimal human γδ T cell phosphoantigen sensing},
  series = {Nature Communications},
  volume    = {14},
  journal   = {Nature Communications},
  doi       = {10.1038/s41467-023-41938-8},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-358179},
  year      = {2023},
  abstract  = {Butyrophilin (BTN)-3A and BTN2A1 molecules control the activation of human Vγ9Vδ2 T cells during T cell receptor (TCR)-mediated sensing of phosphoantigens (PAg) derived from microbes and tumors. However, the molecular rules governing PAg sensing remain largely unknown. Here, we establish three mechanistic principles of PAg-mediated γδ T cell activation. First, in humans, following PAg binding to the intracellular BTN3A1-B30.2 domain, Vγ9Vδ2 TCR triggering involves the extracellular V-domain of BTN3A2/BTN3A3. Moreover, the localization of both protein domains on different chains of the BTN3A homo-or heteromers is essential for efficient PAg-mediated activation. Second, the formation of BTN3A homo-or heteromers, which differ in intracellular trafficking and conformation, is controlled by molecular interactions between the juxtamembrane regions of the BTN3A chains. Finally, the ability of PAg not simply to bind BTN3A-B30.2, but to promote its subsequent interaction with the BTN2A1-B30.2 domain, is essential for T-cell activation. Defining these determinants of cooperation and the division of labor in BTN proteins improves our understanding of PAg sensing and elucidates a mode of action that may apply to other BTN family members.},
  language  = {en}
}