Jena D. French

Exacerbation of Collagen-Induced Arthritis by Oligoclonal, IL-17-Producing γδ T Cells

Murine γδ T cell subsets, defined by their Vγ chain usage, have been shown in various disease models to have distinct functional roles. In this study, we examined the responses of the two main peripheral γδ T cell subsets, Vγ1+ and Vγ4+ cells, during collagen-induced arthritis (CIA), a mouse model that shares many hallmarks with human rheumatoid arthritis. We found that whereas both subsets increased in number, only the Vγ4+ cells became activated. Surprisingly, these Vγ4+ cells appeared to be Ag selected, based on preferential Vγ4/Vδ4 pairing and very limited TCR junctions. Furthermore, in both the draining lymph node and the joints, the vast majority of the Vγ4/Vδ4+ cells produced IL-17, a cytokine that appears to be key in the development of CIA. In fact, the number of IL-17-producing Vγ4+ γδ T cells in the draining lymph nodes was found to be equivalent to the number of CD4+αβ+ Th-17 cells. When mice were depleted of Vγ4+ cells, clinical disease scores were significantly reduced and the incidence of disease was lowered. A decrease in total IgG and IgG2a anti-collagen Abs was also seen. These results suggest that Vγ4/Vδ4+ γδ T cells exacerbate CIA through their production of IL-17.

γδ T-cell receptors : functional correlations

Summary:  The γδ T‐cell receptors (TCRs) are limited in their diversity, suggesting that their natural ligands may be few in number. Ligands for γδTCRs that have thus far been determined are predominantly of host rather than foreign origin. Correlations have been noted between the Vγ and/or Vδ genes a γδ T cell expresses and its functional role. The reason for these correlations is not yet known, but several different mechanisms are conceivable. One possibility is that interactions between particular TCR‐V domains and ligands determine function or functional development. However, a recent study showed that at least for one ligand, receptor specificity is determined by the complementarity‐determining region 3 (CDR3) component of the TCR‐δ chain, regardless of the Vγ and/or Vδ. To determine what is required in the TCR for other specificities and to test whether recognition of certain ligands is connected to cell function, more γδTCR ligands must be defined. The use of recombinant soluble versions of γδTCRs appears to be a promising approach to finding new ligands, and recent results using this method are reviewed.

Tumor-Associated Lymphocytes and Increased FoxP3+ Regulatory T Cell Frequency Correlate with More Aggressive Papillary Thyroid Cancer

CONTEXT Ten to 30% of patients with papillary thyroid cancer (PTC) develop recurrent disease and may benefit from innovative adjuvant therapies. Immune-based therapies are under investigation to treat many types of cancer. The role of the immune system in PTC is poorly understood. OBJECTIVE We investigated whether tumor-associated lymphocytes (TAL), in the absence of background thyroiditis (LT), contribute to disease severity. We hypothesized that the type of lymphocytes associated with PTC would correlate with parameters of disease. DESIGN This retrospective study analyzed archived PTC samples for the presence of TAL and/or LT. A group of patients with TAL was evaluated for lymphocyte subsets by immunohistofluorescence. PATIENTS AND SETTING One hundred PTC patients were analyzed for LT and TAL, and 10 PTC patients with TAL were assessed for lymphocyte subsets at University of Colorado Hospital. MAIN OUTCOME We assessed correlations between disease and the presence of TAL, LT, and lymphocyte subset frequency. RESULTS Patients with TAL exhibited higher disease stage and increased incidence of invasion and lymph node metastasis compared with patients without lymphocytes or with LT. CD4(+) T cell frequency correlated with tumor size (r = 0.742; P = 0.017). FoxP3(+) regulatory T cell (Treg) frequency correlated with lymph node metastases (r = 0.858; P = 0.002), and CD8 to Treg ratio correlated inversely with tumor size (r = -0.804; P = 0.007). CONCLUSIONS TAL and high Treg frequency in primary thyroid tumors correlates with more aggressive disease. Future prospective studies may identify Treg frequency as a predictive factor in PTC, and the suppressive effects of Treg should be considered in the design of immune-based therapies.

Programmed Death-1+ T Cells and Regulatory T Cells Are Enriched in Tumor-Involved Lymph Nodes and Associated with Aggressive Features in Papillary Thyroid Cancer

CONTEXT Recurrent metastatic lymph node (LN) disease is common in patients with papillary thyroid cancer (PTC). Novel prognostic markers may be helpful in guiding a therapeutic approach. Our previous studies revealed that immune suppression is evident in PTC and associated with more severe disease. OBJECTIVE To characterize the immune response to metastatic PTC, we assessed CD4(+) T cell polarization in LN. In addition, we investigated the role of programmed death-1 (PD-1) and T cell exhaustion. DESIGN Uninvolved (UILN) and tumor-involved lymph nodes (TILN) were sampled ex vivo by fine-needle biopsy. T cell subsets were identified by flow cytometry. In parallel, archived TILN specimens were characterized by immunofluorescence. SETTING The study was conducted at the University of Colorado Hospital. PATIENTS Data were collected on 94 LN from 19 patients with PTC undergoing neck dissection. MAIN OUTCOME T cell subset frequencies were compared in UILN and TILN and assessed for correlation with recurrent disease and extranodal invasion. RESULTS Regulatory CD4(+) T cells (Treg) were enriched in TILN compared with UILN and further elevated in TILN from patients with recurrent disease. PD-1(+) T cells were present at high frequency in TILN and markedly enriched in TILN that showed evidence of extranodal invasion. In TILN, Treg frequency correlated with PD-1(+) T cell frequencies. Although PD-1(+) T cells produced interferon-γ, they failed to fully down-regulate CD27 and were not actively proliferating. CONCLUSIONS Increased Treg and PD-1(+) T cell frequencies in LN may be indicative of aggressive recurrent PTC. Future prospective studies are necessary to determine the prognostic and therapeutic value of these findings in PTC.

Airway hyperresponsiveness through synergy of γδ T cells and NKT cells

Mice sensitized and challenged with OVA were used to investigate the role of innate T cells in the development of allergic airway hyperresponsiveness (AHR). AHR, but not eosinophilic airway inflammation, was induced in T cell-deficient mice by small numbers of cotransferred γδ T cells and invariant NKT cells, whereas either cell type alone was not effective. Only Vγ1+Vδ5+ γδ T cells enhanced AHR. Surprisingly, OVA-specific αβ T cells were not required, revealing a pathway of AHR development mediated entirely by innate T cells. The data suggest that lymphocytic synergism, which is key to the Ag-specific adaptive immune response, is also intrinsic to T cell-dependent innate responses.

γδ T Lymphocytes—Selectable Cells Within the Innate System?

Lymphocytes expressing γδ T cell receptors (TCR) constitute an entire system of functionally specialized subsets that have been implicated in the regulation of immune responses, including responses to pathogens and allergens, and in tissue repair. The γδ TCRs share structural features with adaptive receptors and peripheral selection of γδ T cells occurs. Nevertheless, their specificities may be primarily directed at self-determinants, and the responses of γδ T cells exhibit innate characteristics. Continuous cross talk between γδ T cells and myeloid cells is evident in histological studies and in in vitro co-culture experiments, suggesting that γδ T cells play a functional role as an integral component of the innate immune system.

PD-1+Tim-3+ CD8+ T Lymphocytes Display Varied Degrees of Functional Exhaustion in Patients with Regionally Metastatic Differentiated Thyroid Cancer

Severson and colleagues show that exhaustion of PD-1+ T cells in tumor-involved lymph nodes from patients with metastatic differentiated thyroid cancer was not complete. While PD-1+CD8+ T cells were variably dysfunctional in their ability to produce cytokines, their proliferative capacity was maintained, and PD-1+CD4+ T cells remained functional. Regional metastatic differentiated thyroid cancer (mDTC) provides a unique model in which to study the tumor–immune interface. These lymph node metastases persist for years, generally without progression to distant metastases. Although the immune system likely impedes disease progression, it is unsuccessful in eliminating disease. Our previous studies revealed that programmed death-1 (PD-1)+ T cells were enriched in tumor-involved lymph nodes (TILN). Tumor-associated leukocytes and tumor cells were collected from grossly involved lymph nodes from 12 patients to further characterize the phenotype and functional potential of mDTC-associated PD-1+ T cells. PD-1+CD4+ and PD-1+CD8+ T cells were enriched in 8 of 12 TILN samples. PD-1+ T cells coexpressed Tim-3 and CD69 and failed to downregulate CD27. CD8+ T cells, but not CD4+ T cells, from these samples were variably deficient in their ability to produce effector cytokines when compared with control TILNs that lacked resident PD-1+ T cells. PD-1+CD8+ T cells were capable of exocytosis but lacked intracellular perforin. Surprisingly, T-cell proliferative capacity was largely maintained in all samples. Thus, although PD-1 expression by mDTC-associated CD8+ T cells was associated with dysfunction, exhaustion was not complete. Notably, molecular markers of exhaustion did not translate to dysfunction in all samples or in CD4+ T cells. Regulatory T cells (Treg), PD-L1, and galectin-9 were commonly found in mDTC and likely contributed to the initiation of T-cell exhaustion and disease progression. Therapies that release the effects of PD-1 and Tim-3 and reduce the suppressive effects of Tregs may encourage tumor elimination in patients with mDTC. Cancer Immunol Res; 3(6); 620–30. ©2015 AACR.

Tumor-Infiltrating T Cells and the PD-1 Checkpoint Pathway in Advanced Differentiated and Anaplastic Thyroid Cancer

CONTEXT Five to 10% of patients with differentiated thyroid cancers (DTC) develop invasive and/or distant metastatic disease that is marginally improved with standard therapies. Prognosis is poor for patients with anaplastic thyroid cancer, with a median survival of 3-5 months. We suggest that a paradigm shift is necessary in the treatment of advanced cases. OBJECTIVE We hypothesized that a T-cell response is generated in advanced thyroid cancer and may be a viable therapeutic target. DESIGN Primary DTCs were analyzed by quantitative RT-PCR (n = 92) for expression of CD3, CD8, forkhead box (Fox)-P3, programmed death (PD)-1, PD-1 ligand-1, and PD-1 ligand-2 and biopsied for cellular analysis by flow cytometry (n = 11). Advanced pT4 cases (n = 22) and metastases (n = 5) were analyzed by immunohistochemistry. SETTING The study was conducted at the University of Colorado Hospital. PATIENTS Thyroid cancer patients undergoing thyroidectomy or completion surgery for advanced disease between 2002 and 2013 participated in the study. INTERVENTION There were no interventions. MAIN OUTCOME MEASURE Immune markers were analyzed for association with disease severity. RESULTS Immune markers were commonly expressed at the RNA level. PD-L1 was higher (P = .0443) in patients with nodal metastases. FoxP3(+) (P < .0001), PD-1(+)CD8(+) (P = .0058), and PD-1(+)CD4(+) (P = .0104) T cells were enriched in DTC biopsies. CD8(+) and FoxP3(+) T cells were detected by immunohistochemistry in all pT4 tumors and a subset of metastases. PD-1(+) lymphocytes were found in 50% of DTCs. PD-L1 was expressed by tumor and associated leukocytes in 13 of 22 cases, and expression was more diffuse in anaplastic thyroid cancer (P = .0373). BRAF(V600E) mutation was associated with higher frequencies of tumor-associated lymphocytes (P = .0095) but not PD-L1 expression. CONCLUSIONS PD-1 checkpoint blockades may have therapeutic efficacy in patients with aggressive forms of thyroid cancer.

Atypical expression of ErbB3 in myeloma cells: cross-talk between ErbB3 and the interferon-alpha signaling complex.

We have previously demonstrated that the responsiveness of multiple myeloma (MM) cells to interferon-alpha (IFN-α) stimulation is variable, with an atypical growth response displayed by some cells. Here we report the ability of IFN-α to induce tyrosine phosphorylation of a 180 kDa band in the KAS-6/1 MM cell line, which is growth responsive to IFN-α. Further characterization demonstrated that this band corresponds to ErbB3. To our knowledge, this is the first report of ErbB3 expression in a cell type of the hematopoietic lineage. Although ErbB receptors have been shown to crosscommunicate with various other receptors, our results show for the first time that the IFN-α receptor can crosscommunicate with ErbB3. To address the significance of these observations, we transfected ErbB3-negative DP-6 MM cells with ErbB3 and used siRNA to silence ErbB3 in the KAS-6/1 cell line. Although IFN-α transactivated ErbB3 in the DP-6 transfectants, it did not confer growth responsiveness to IFN-α. Interestingly, silencing ErbB3 expression in the KAS-6/1 cells decreased the overall growth response to IFN-α and to interleukin-6. These results suggest that ErbB3 expression alone does not uniquely confer IFN-α growth responsiveness, but instead may amplify proliferation rates in MM cells that have acquired atypical expression of this receptor.

Analysis of il-6-mediated growth control of myeloma cells using a gp130 chimeric receptor approach

Interleukin 6 (IL-6) has been shown to be a key growth factor for myeloma cells. To study IL-6 signal transduction in multiple myeloma (MM), we employed chimeric receptors composed of the epidermal growth factor receptor (EGFR) extracellular domain, gp130 transmembrane domain, and full-length or truncated gp130 cytoplasmic domains lacking regions previously shown to be necessary for MAPK, STAT1, and STAT3 activation. The IL-6-dependent KAS-6/1 MM cell line was transfected with various chimeric receptor constructs and assayed for EGF responsiveness. EGF stimulation surprisingly stimulated DNA synthesis in all transfectants, regardless of receptor length. When cell proliferation was assayed instead, only transfectants capable of inducing high levels of STAT3 activation proliferated in response to EGF. Additional studies revealed that EGF stimulation resulted in tyrosine phosphorylation of endogenous gp130 in cells expressing the chimeric receptor. Replacing the gp130 transmembrane region with the EGFR transmembrane domain diminished but did not disrupt this interaction. This receptor interaction was also observed in the IL-6-dependent MM cell line ANBL-6. In summary, although our results suggest that STAT activation is crucial in gp130-mediated proliferation of myeloma cells, these results must be interpreted with caution given our demonstration of the interaction between chimeric and endogenous receptors in myeloma cells. Importantly, this interaction has not been noted in studies utilizing the same gp130 chimeric receptor system in non-MM cells.