title: In vivo application of mAb directed against the gammadelta TCR does not deplete but generates "invisible" gammadelta T cells.
abstract: mAb targeting the gammadelta TCR have been used for gammadelta T-cell depletion with varying success. Although the depletion-capacity of the anti-gammadelta TCR mAb clone GL3 has been disputed repeatedly, many groups continue to use gammadelta T-cell depletion protocols involving the mAb clone UC7-13D5 and find significant biological effects. We show here that treatment with both GL3 and UC7-13D5 antibodies does not deplete gammadelta T cells in vivo, but rather leads to TCR internalization and thereby generates "invisible" gammadelta T cells. We addressed this issue using anti-gammadelta TCR mAb injections into WT mice as well as into reporter TCR delta locus-histone 2B enhanced GFP knock-in mice, in which gammadelta T cells can be detected based on an intrinsic green fluorescence. Importantly, the use of TCR delta locus-histone 2B enhanced GFP mice provided here for the first time direct evidence that the "depleted" gammadelta T cells were actually still present. Our results show further that GL3 and UC7-13D5 mAb are in part cross-competing for the same epitope. Assessed by activation markers, we observed in vitro and in vivo activation of gammadelta T cells through mAb. We conclude that gammadelta T-cell depletion experiments must be evaluated with caution and discuss the implications for future studies on the physiological functions of gammadelta T cells.
authors.affiliation: Institute of Immunology, Hannover Medical School, Hannover, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Koenecke
authors.forename: Vijaykumar
authors.initials: V
authors.lastname: Chennupati
authors.forename: Susanne
authors.initials: S
authors.lastname: Schmitz
authors.forename: Bernard
authors.initials: B
authors.lastname: Malissen
authors.forename: Reinhold
authors.initials: R
authors.lastname: Förster
authors.forename: Immo
authors.initials: I
authors.lastname: Prinz
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D055879:Gene Knock-In Techniques; D049452:Green Fluorescent Proteins / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology*; D008212:Lymphocyte Depletion; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000037:antagonists & inhibitors* / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D016692:Receptors, Antigen, T-Cell, gamma-delta; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins