The UC7-13D5 monoclonal antibody reacts with an epitope on the mouse γ/δ TCR (gamma delta T cell receptor) complex. The γ/δ TCR is expressed by a subset of T cells found in the thymus, peripheral lymphoid tissues, intestinal epithelium, epidermis, and peritoneum. The exact function, ligand, and specificity of γ/δ TCR-expressing T cells are not completely understood. Studies suggest that these cells recognize bacterial ligands and some tumor cells in the context of MHC class I-like gene products and play a role in regulating the immune response during bacterial infection. The UC7-13D5 antibody has been shown to activate γ/δ T cells in vitro and deplete γ/δ T cells when administered in vivo.

InVivoMAb anti-mouse TCR γ/δ (Clone: UC7-13D5)

Benevides, L., et al. (2015). "IL17 Promotes Mammary Tumor Progression by Changing the Behavior of Tumor Cells and Eliciting Tumorigenic Neutrophils Recruitment." Cancer Res 75(18): 3788-3799. PubMed

The aggressiveness of invasive ductal carcinoma (IDC) of the breast is associated with increased IL17 levels. Studying the role of IL17 in invasive breast tumor pathogenesis, we found that metastatic primary tumor-infiltrating T lymphocytes produced elevated levels of IL17, whereas IL17 neutralization inhibited tumor growth and prevented the migration of neutrophils and tumor cells to secondary disease sites. Tumorigenic neutrophils promote disease progression, producing CXCL1, MMP9, VEGF, and TNFalpha, and their depletion suppressed tumor growth. IL17A also induced IL6 and CCL20 production in metastatic tumor cells, favoring the recruitment and differentiation of Th17. In addition, IL17A changed the gene-expression profile and the behavior of nonmetastatic tumor cells, causing tumor growth in vivo, confirming the protumor role of IL17. Furthermore, high IL17 expression was associated with lower disease-free survival and worse prognosis in IDC patients. Thus, IL17 blockade represents an attractive approach for the control of invasive breast tumors. Cancer Res; 75(18); 3788-99. (c)2015 AACR.

Chu, D. K., et al. (2014). "T helper cell IL-4 drives intestinal Th2 priming to oral peanut antigen, under the control of OX40L and independent of innate-like lymphocytes." Mucosal Immunol 7(6): 1395-1404. PubMed

Intestinal T helper type 2 (Th2) immunity in food allergy results in IgG1 and IgE production, and antigen re-exposure elicits responses such as anaphylaxis and eosinophilic inflammation. Although interleukin-4 (IL-4) is critically required for allergic sensitization, the source and control of IL-4 during the initiation of Th2 immunity in vivo remains unclear. Non-intestinal and non-food allergy systems have suggested that natural killer-like T (NKT) or gammadelta T-cell innate lymphocytes can supply the IL-4 required to induce Th2 polarization. Group 2 innate lymphoid cells (ILCs) are a novel IL-4-competent population, but their contribution to initiating adaptive Th2 immunity is unclear. There are also reports of IL-4-independent Th2 responses. Here, we show that IL-4-dependent peanut allergic Th2 responses are completely intact in NKT-deficient, gammadelta T-deficient or ILC-deficient mice, including antigen-specific IgG1/IgE production, anaphylaxis, and cytokine production. Instead, IL-4 solely from CD4(+) Th cells induces full Th2 immunity. Further, CD4(+) Th cell production of IL-4 in vivo is dependent on OX40L, a costimulatory molecule on dendritic cells (DCs) required for intestinal allergic priming. However, both Th2 cells and ILCs orchestrated IL-13-dependent eosinophilic inflammation. Thus, intestinal Th2 priming is initiated by an autocrine/paracrine acting CD4(+) Th cell-intrinsic IL-4 program that is controlled by DC OX40L, and not by NKT, gammadelta T, or ILC cells.

Seedhom, M. O., et al. (2012). "Increased protection from vaccinia virus infection in mice genetically prone to lymphoproliferative disorders." J Virol 86(11): 6010-6022. PubMed

Mutations in the genes that encode Fas or Fas ligand (FasL) can result in poor restraints on lymphocyte activation and in increased susceptibility to autoimmune disorders. Because these mutations portend a continuously activated immune state, we hypothesized that they might in some cases confer resistance to infection. To examine this possibility, the immune response to, morbidity caused by, and clearance of vaccinia virus (VACV) Western Reserve was examined in 5- to 7-week-old Fas mutant (lpr) mice, before an overt lymphoproliferative disorder was observable. On day 6 after VACV infection, C57BL/6-lpr (B6-lpr) mice had decreased morbidity, decreased viral titers, and an increased percentage and number of CD4(+) and CD8(+) T cells. As early as day 2 after infection, B6-lpr mice had decreased liver and spleen viral titers and increased numbers of and increased gamma interferon (IFN-gamma) production by several different effector cell populations. Depletion of individual effector cell subsets did not inhibit the resistance of B6-lpr mice. Uninfected B6-lpr mice also had increased numbers of NK cells, gammadelta(+) T cells, and CD44(+) CD4(+) and CD44(+) CD8(+) T cells compared to uninfected B6 mice. Antibody to IFN-gamma resulted in increased virus load in both B6 and B6-lpr mice and eliminated the differences in viral titers between them. These results suggest that IFN-gamma produced by multiple activated leukocyte populations in Fas-deficient hosts enhances resistance to some viral infections.

Gillard, G. O., et al. (2011). "Thy1+ NK cells from vaccinia virus-primed mice confer protection against vaccinia virus challenge in the absence of adaptive lymphocytes." PLoS Pathog 7(8): e1002141. PubMed

While immunological memory has long been considered the province of T- and B-lymphocytes, it has recently been reported that innate cell populations are capable of mediating memory responses. We now show that an innate memory immune response is generated in mice following infection with vaccinia virus, a poxvirus for which no cognate germline-encoded receptor has been identified. This immune response results in viral clearance in the absence of classical adaptive T and B lymphocyte populations, and is mediated by a Thy1(+) subset of natural killer (NK) cells. We demonstrate that immune protection against infection from a lethal dose of virus can be adoptively transferred with memory hepatic Thy1(+) NK cells that were primed with live virus. Our results also indicate that, like classical immunological memory, stronger innate memory responses form in response to priming with live virus than a highly attenuated vector. These results demonstrate that a defined innate memory cell population alone can provide host protection against a lethal systemic infection through viral clearance.

Skyberg, J. A., et al. (2011). "Murine and bovine gammadelta T cells enhance innate immunity against Brucella abortus infections." PLoS One 6(7): e21978. PubMed

gammadelta T cells have been postulated to act as a first line of defense against infectious agents, particularly intracellular pathogens, representing an important link between the innate and adaptive immune responses. Human gammadelta T cells expand in the blood of brucellosis patients and are active against Brucella in vitro. However, the role of gammadelta T cells in vivo during experimental brucellosis has not been studied. Here we report TCRdelta(-/-) mice are more susceptible to B. abortus infection than C57BL/6 mice at one week post-infection as measured by splenic colonization and splenomegaly. An increase in TCRgammadelta cells was observed in the spleens of B. abortus-infected C57BL/6 mice, which peaked at two weeks post-infection and occurred concomitantly with diminished brucellae. gammadelta T cells were the major source of IL-17 following infection and also produced IFN-gamma. Depletion of gammadelta T cells from C57BL/6, IL-17Ralpha(-/-), and GMCSF(-/-) mice enhanced susceptibility to B. abortus infection although this susceptibility was unaltered in the mutant mice; however, when gammadelta T cells were depleted from IFN-gamma(-/-) mice, enhanced susceptibility was observed. Neutralization of gammadelta T cells in the absence of TNF-alpha did not further impair immunity. In the absence of TNF-alpha or gammadelta T cells, B. abortus-infected mice showed enhanced IFN-gamma, suggesting that they augmented production to compensate for the loss of gammadelta T cells and/or TNF-alpha. While the protective role of gammadelta T cells was TNF-alpha-dependent, gammadelta T cells were not the major source of TNF-alpha and activation of gammadelta T cells following B. abortus infection was TNF-alpha-independent. Additionally, bovine TCRgammadelta cells were found to respond rapidly to B. abortus infection upon co-culture with autologous macrophages and could impair the intramacrophage replication of B. abortus via IFN-gamma. Collectively, these results demonstrate gammadelta T cells are important for early protection to B. abortus infections.

Hayes, S. M. and P. E. Love (2002). "Distinct structure and signaling potential of the gamma delta TCR complex." Immunity 16(6): 827-838. PubMed

Alpha beta and gamma delta T cells are distinguished by the clonotypic subunits contained within their TCRs. Although the alpha beta TCR has been well characterized, much less is known about the gamma delta TCR. Here, we report that, unlike alpha beta T CRs, most gamma delta TCRs expressed on ex vivo gamma delta T cells lack CD3 delta. Despite this structural difference, signal transduction by the gamma delta TCR is superior to that of the alpha beta TCR, as measured by its ability to induce calcium mobilization, ERK activation, and cellular proliferation. Additionally, the TCR complexes expressed on primary gamma delta T cells contain only zeta zeta homodimers; however, following activation and expansion, Fc epsilon R1 gamma is expressed and is included in the gamma delta TCR complex. These results reveal fundamental differences in the primary structure and signaling potential of the alpha beta- and gamma delta TCR complexes.

Dieli, F., et al. (1997). "gamma delta cells involved in contact sensitivity preferentially rearrange the Vgamma3 region and require interleukin-7." Eur J Immunol 27(1): 206-214. PubMed

Ptak and Askenase showed that both alphabeta and gammadelta cells are required for transfer of contact sensitivity (CS). This study confirms that day 4 immune cells depleted of gammadelta cells fail to transfer CS to trinitrochlorobenzene (TNP-Cl) systemically and demonstrates that administration of anti-gammadelta monoclonal antibodies (mAb) in vivo abolishes the CS reaction. Moreover, gammadelta cells accumulate at the antigen challenge site: these cells have the unusual phenotype CD8alpha+, CD8beta-, IL-4 R+ which we suggest is due to their state of activation. Following immunization with contact sensitizer on the skin, the absolute number of gammadelta cells increases in the regional lymph nodes with a peak at 4 days. Of the gammadelta cells, 80 %, both in the lymph nodes of TNP-Cl-immune mice and accumulating at the antigen challenge site are Vgamma3+. The gammadelta cells expressing Vgamma3, which is characteristic of dendritic epithelial T cells (DETC), obtained 4 days after sensitization, proliferate in response to interleukin (IL)-7, but only poorly to IL-2 and IL-4. They also respond to concanavalin A and immobilized anti-gammadelta mAb, but not to haptens or heat-shocked syngeneic spleen cells. Furthermore, injection of mice with mAb to IL-7 inhibits accumulation of Vgamma3+ cells both in the lymph nodes after skin sensitization and at the antigen-challenge site. Altogether, these results strongly support the view that DETC are related to, or the original source of, the gammadelta cells found in the lymph node after skin sensitization and at the site of challenge, and that IL-7 is implicated in these phenomena.

Sperling, A. I., et al. (1993). "CD28-mediated costimulation is necessary for the activation of T cell receptor-gamma delta+ T lymphocytes." J Immunol 151(11): 6043-6050. PubMed

The role of costimulation in the activation of TCR-gamma delta cells in normal mice and mice transgenic (tg) for a TCR-gamma delta receptor was investigated. Activation of TCR-gamma delta cells required two signals. One signal was mediated by TCR occupancy, whereas a second signal was provided by accessory cells. The importance of the CD28/B7 interaction in the delivery of the second signal was demonstrated in multiple ways. First, addition of a soluble fusion protein homolog of CD28, CTLA4Ig, significantly inhibited the activation of G8 tg splenic TCR-gamma delta lymphocytes and intestinal epithelial TCR-gamma delta lymphocytes by Ag-bearing lymphocytes during primary stimulation. Similarly, both proliferation and IFN-gamma production were inhibited by addition of CTLA4Ig to secondary antigenic stimulation of G8 tg TCR-gamma delta cells. Second, an Ag-bearing thymoma, EL-4, was only able to stimulate expanded G8 tg TCR-gamma delta cells when the thymoma expressed B7. This stimulation was blocked by both CTLA4Ig and anti-B7 antibody. Third, antibodies to CD28 were able to mimic the costimulatory affect of APC. TCR-gamma delta cells cultured with either Ag-bearing fixed stimulator cells or submitogenic concentrations of immobilized anti-pan TCR-gamma delta mAb proliferated only in the presence of anti-CD28 mAb. Finally, G8 tg cells produced IL-2 only in the presence of APC costimulation or anti-CD28 antibodies, and the addition of exogenous rIL-2 overcame the need for costimulation. Thus, autocrine IL-2 production is one of the major consequences of TCR-gamma delta cell costimulation. Together these data demonstrate that costimulation is necessary for the activation of TCR-gamma delta cells and can occur through CD28 interaction.