Functional analysis of TCR gamma delta+ T cells in tumour-infiltrating lymphocytes (TIL) of human pancreatic cancer

The antitumor activity of hPRDX5 against pancreatic cancer and the possible mechanisms

Recombinant human peroxiredoxin-5 (hPRDX5), isolated from anti-cancer bioactive peptide (ACBPs), shows a homology of 89% with goat peroxiredoxin-5 (gPRDX5) and is reported to display anti-tumor activity in vivo. Herein, we explored the effect of hPRDX5 and the responsible mechanism in treating pancreatic cancer. Tumor-bearing mice were randomly divided into normal PBS group and treatment group (n=5; 10 mg/kg hPRDX5). Flow cytometry was employed to examine lymphocytes, myeloid-derived suppressor cell subsets, and the function proteins of natural killer (NK) cells in peripheral blood, spleen, and tumor tissues of mice. Western blot was used to measure the protein expressions of the key nodes in TLR4-MAPK-NF-κB signaling pathway. The rate of tumor suppression was 57.6% at a 10 mg/kg dose in orthotopic transplanted tumor mice. Moreover, the population of CD3+CD4+T cells, NK cells, and CD3+CD8+T cells was significantly increased in the tumor tissue of the hPRDX5 group, while the proportion of granulocytic-myeloid-derived suppressor cells decreased slightly. In addition, after treatment with hPRDX5, the percentage of NK cells in blood increased more than 4-fold. Our findings indicated that hPRDX5 effectively suppressed pancreatic cancer possibly via the TLR4-MAPK-NF-κB signaling cascade; hence hPRDX5 could be a prospective immunotherapy candidate for treating pancreatic cancer.

Prognostic and Therapeutic Significance of BTN3A Proteins in Tumors

The Butyrophilin 3A (BTN3A) family is a type I transmembrane protein belonging to the immunoglobulin (Ig) superfamily. The family contains three members: BTN3A1, BTN3A2 and BTN3A3, which share 95% homology in the extracellular domain. The expression of BTN3A family members is different in different types of tumors, which plays an important role in tumor prognosis. Among them, there are many studies on tumor immunity of BTN3A1, which shows that it is essential for the activation of Vγ9Vδ2 T cells, while BTN3A3 is expected to become a potential therapeutic target for breast cancer. Recent studies have shown that the BTN3A family is closely related to the occurrence and development of tumors. Now the BTN3A family has become one of the research hotspots and is expected to become new tumor prediction and treatment targets.

Diversity of Tumor-Infiltrating, γδ T-Cell Abundance in Solid Cancers

γδ T-cells contribute to the immune response against many tumor types through their direct cytolytic functions and their capacity to recruit and regulate the biological functions of other immune cells. As potent effectors of the anti-tumor immune response, they are considered an attractive therapeutic target for immunotherapies, but their presence and abundance in the tumor microenvironment are not routinely assessed in patients with cancer. Here, we validated an antibody for immunohistochemistry analysis that specifically detects all γδ T-cell subpopulations in healthy tissues and in the microenvironment of different cancer types. Tissue microarray analysis of breast, colon, ovarian, and pancreatic tumors showed that γδ T-cell density varies among cancer types. Moreover, the abundance of γδ tumor-infiltrating lymphocytes was variably associated with the outcome depending on the cancer type, suggesting that γδ T-cell recruitment is influenced by the context. These findings also suggest that γδ T-cell detection and analysis might represent a new and interesting diagnostic or prognostic marker.

Probiotic-Treated Super-Charged NK Cells Efficiently Clear Poorly Differentiated Pancreatic Tumors in Hu-BLT Mice

Abstract: Background and Aims: We have previously demonstrated that the stage of differentiation of tumors has profound effect on the function of NK cells, and that stem-like/poorly differentiated tumors were preferentially targeted by the NK cells. Therefore, in this study we determined the role of super-charged NK cells in immune mobilization, lysis, and differentiation of stem-like/undifferentiated tumors implanted in the pancreas of humanized-BLT (hu-BLT) mice fed with or without AJ2 probiotics. The phenotype, growth rate and metastatic potential of pancreatic tumors differentiated by the NK cells (NK-differentiated) or patient derived differentiated or stem-like/undifferentiated pancreatic tumors were investigated. Methods: Pancreatic tumor implantation was performed in NSG and hu-BLT mice. Stage of differentiation of tumors was determined using our published criteria for well-differentiated tumors exhibiting higher surface expression of MHC- class I, CD54, and PD-L1 (B7H1) and lower expression of CD44 receptors. The inverse was seen for poorly-differentiated tumors. Results: Stem-like/undifferentiated pancreatic tumors grew rapidly and formed large tumors and exhibited lower expression of above-mentioned differentiation antigens in the pancreas of NSG and hu-BLT mice. Unlike stem-like/undifferentiated tumors, NK-differentiated MP2 (MiaPaCa-2) tumors or patient-derived differentiated tumors were not able to grow or grew smaller tumors, and were unable to metastasize in NSG or hu-BLT mice, and they were susceptible to chemotherapeutic drugs. Stem-like/undifferentiated pancreatic tumors implanted in the pancreas of hu-BLT mice and injected with super-charged NK cells formed much smaller tumors, proliferated less, and exhibited differentiated phenotype. When differentiation of stem-like tumors by the NK cells was prevented by the addition of antibodies to IFN-γ and TNF-α, tumors grew rapidly and metastasized, and they remained resistant to chemotherapeutic drugs. Greater numbers of immune cells infiltrated the tumors of NK-injected and AJ2-probiotic bacteria-fed mice. Moreover, increased IFN-γ secretion in the presence of decreased IL-6 was seen in tumors resected and cultured from NK-injected and AJ2 fed mice. Tumor-induced decreases in NK cytotoxicity and IFN-γ secretion were restored/increased within PBMCs, spleen, and bone marrow when mice received NK cells and were fed with AJ2. Conclusion: NK cells prevent growth of pancreatic tumors through lysis and differentiation, thereby curtailing the growth and metastatic potential of stem-like/undifferentiated-tumors.

Tim-3 suppresses the killing effect of Vγ9Vδ2 T cells on colon cancer cells by reducing perforin and granzyme B expression

Gamma delta (γδ) T cell-based tumor immunotherapy has been one of the most promising cancer immunotherapeutic strategies. However, the key regulators of the Vγ9Vδ2 T cell-mediated antitumor response remain unclear. Recently, mounting reports have indicated that Tim-3 performs critical roles in the regulation of the activities of immune cells, including Vγ9Vδ2 T cells. However, the roles of Tim-3 in Vγ9Vδ2 T cell-mediated killing of colon cancer cells and the underlying mechanism remain largely unknown. Here, the proportion of Tim-3+ γδ T cells was significantly increased in both the peripheral blood and colon cancer tissue of patients and was significantly associated with TNM staging and tumor volume. Additionally, the activation of Tim-3 signaling significantly inhibited the killing efficiency of Vγ9Vδ2 T cells against colon cancer cells. In addition, Tim-3 signaling reduced the expression of perforin and granzyme B in Vγ9Vδ2 T cells. Blocking the perforin/granzyme B pathway also decreased the cytotoxicity of Vγ9Vδ2 T cells to colon cancer cells. Moreover, Tim-3 signaling reduced the perforin and granzyme B expression of Vγ9Vδ2 T cells in an ERK1/2 signaling pathway-dependent manner. This knowledge reveals that Tim-3 may be a promising therapeutic target to improve Vγ9Vδ2 T cell-based adoptive immunotherapy for colon cancer.

T cell receptor β-chain repertoire analysis of tumor-infiltrating lymphocytes in pancreatic cancer

Pancreatic cancer is lethal due to lack of perceptible symptoms and effective treatment methods. Immunotherapy may provide promising therapeutic choices for malignant tumors like pancreatic cancer. Tumor‐infiltrating lymphocytes (TIL) in tumor mesenchyme could recognize peptide antigens presented on the surface of tumor cells. The present study aimed to test the relationship between the T cell receptor (TCR) β repertoire of the tumor and peripheral blood, and also to investigate the intra‐tumor spatial heterogeneity of the TCR β repertoire in pancreatic cancer. To the best of our knowledge, this is the first study to evaluate the clonal composition of TCR β repertoire in TIL across the spatial extent of pancreatic cancer. In this study, we studied 5 patients who were diagnosed with primary pancreatic cancer. Ultra‐deep sequencing was used to assess the rearrangement of the TCR β‐chain (TCR β) gene. HE staining and immunohistochemistry of CD3, CD4, CD8 and HLA class I were used to show histopathology and immune conditions macroscopically. TIL repertoire showed that different regions of the same tumor showed a greater number of repertoire overlaps between each other than between peripheral blood, which suggested that T cell clones in pancreatic cancer might be quite different from those in peripheral blood. In contrast, intra‐tumoral TCR β repertoires were spatially homogeneous between different regions of a single tumor tissue. Based on these results, we speculated that the cellular adaptive immune response in pancreatic cancer was spatially homogeneous; this may pave the way for immunotherapy for the treatment of pancreatic cancer patients.

BTN3A is a prognosis marker and a promising target for Vγ9Vδ2 T cells based-immunotherapy in pancreatic ductal adenocarcinoma (PDAC)

Vγ9Vδ2 T cells are anti-tumor immune effectors of growing interest in cancer including Pancreatic Ductal Adenocarcinoma (PDAC), an especially aggressive cancer characterized by a hypoxic and nutrient-starved immunosuppressive microenvironment. Since Butyrophilin 3 A (BTN3A) isoforms are critical activating molecules of Vγ9Vδ2 T cells, we set out to study BTN3A expression under both basal and stress conditions in PDAC primary tumors, and in novel patient-derived xenograft and PDAC-derived cell lines. BTN3A2 was shown to be the most abundant isoform in PDAC and was stress-regulated. Vγ9Vδ2 T cells cytolytic functions against PDAC required BTN3A and this activity was strongly enhanced by the agonist anti-BTN3A 20.1 mAb even under conditions of hypoxia. In PDAC primary tumors, we established that BTN3A expression and high plasma levels of soluble BTN3A were strongly associated with a decreased survival. These findings may have important implications in the design of new immunotherapeutic strategies that target BTN3A for treating PDAC.

Human γδT-cell subsets and their involvement in tumor immunity

γδT cells are a conserved population of innate lymphocytes with diverse structural and functional heterogeneity that participate in various immune responses during tumor progression. γδT cells perform potent immunosurveillance by exerting direct cytotoxicity, strong cytokine production and indirect antitumor immune responses. However, certain γδT-cell subsets also contribute to tumor progression by facilitating cancer-related inflammation and immunosuppression. Here, we review recent observations regarding the antitumor and protumor roles of major structural and functional subsets of human γδT cells, describing how these subsets are activated and polarized, and how these events relate to subsequent function in tumor immunity. These studies provide insights into the manipulation of γδT-cell function to facilitate more targeted approaches for tumor therapy.

Phosphatidylinositol 3-Kinase: A Link Between Inflammation and Pancreatic Cancer

Even though a strong association between inflammation and cancer has been widely accepted, the underlying precise molecular mechanisms are still largely unknown. A complex signaling network between tumor and stromal cells is responsible for the infiltration of inflammatory cells into the cancer microenvironment. Tumor stromal cells such as pancreatic stellate cells (PSCs) and immune cells create a microenvironment that protects cancer cells through a complex interaction, ultimately facilitating their local proliferation and their migration to different sites. Furthermore, PSCs have multiple functions related to local immunity, angiogenesis, inflammation, and fibrosis. Recently, many studies have shown that members of the phosphoinositol-3-phosphate kinase (PI3K) family are activated in tumor cells, PSCs, and tumor-infiltrating inflammatory cells to promote cancer growth. Proinflammatory cytokines and chemokines secreted by immune cells and fibroblasts within the tumor environment can activate the PI3K pathway both in cancer and inflammatory cells. In this review, we focus on the central role of the PI3K pathway in regulating the cross talk between immune/stromal cells and cancer cells. Understanding the role of the PI3K pathway in the development of chronic pancreatitis and cancer is crucial for the discovery of novel and efficacious treatment options.

Tumor-Infiltrating γδ T Lymphocytes: Pathogenic Role, Clinical Significance, and Differential Programing in the Tumor Microenvironment

There is increasing clinical evidence indicating that the immune system may either promote or inhibit tumor progression. Several studies have demonstrated that tumors undergoing remission are largely infiltrated by T lymphocytes [tumor-infiltrating lymphocytes (TILs)], but on the other hand, several studies have shown that tumors may be infiltrated by TILs endowed with suppressive features, suggesting that TILs are rather associated with tumor progression and unfavorable prognosis. γδ T lymphocytes are an important component of TILs that may contribute to tumor immunosurveillance, as also suggested by promising reports from several small phase-I clinical trials. Typically, γδ T lymphocytes perform effector functions involved in anti-tumor immune responses (cytotoxicity, production of IFN-γ and TNF-α, and dendritic cell maturation), but under appropriate conditions they may divert from the typical Th1-like phenotype and polarize to Th2, Th17, and Treg cells thus acquiring the capability to inhibit anti-tumor immune responses and promote tumor growth. Recent studies have shown a high frequency of γδ T lymphocytes infiltrating different types of cancer, but the nature of this association and the exact mechanisms underlying it remain uncertain and whether or not the presence of tumor-infiltrating γδ T lymphocytes is a definite prognostic factor remains controversial. In this paper, we will review studies of tumor-infiltrating γδ T lymphocytes from patients with different types of cancer, and we will discuss their clinical relevance. Moreover, we will also discuss on the complex interplay between cancer, tumor stroma, and γδ T lymphocytes as a major determinant of the final outcome of the γδ T lymphocyte response. Finally, we propose that targeting γδ T lymphocyte polarization and skewing their phenotype to adapt to the microenvironment might hold great promise for the treatment of cancer.

Pancreatic ductal adenocarcinoma: a review of immunologic aspects

With the continued failures of both early diagnosis and treatment options for pancreatic cancer, it is now time to comprehensively evaluate the role of the immune system on the development and progression of pancreatic cancer. It is important to develop strategies that harness the molecules and cells of the immune system to treat this disease. This review will focus primarily on the role of immune cells in the development and progression of pancreatic ductal adenocarcinoma and to evaluate what is known about the interaction of immune cells with the tumor microenvironment and their role in tumor growth and metastasis. We will conclude with a brief discussion of therapy for pancreatic cancer and the potential role for immunotherapy. We hypothesize that the role of the immune system in tumor development and progression is tissue specific. Our hope is that better understanding of this process will lead to better treatments for this devastating disease.

Immunotherapy for gastrointestinal malignancies

BACKGROUND

Gastrointestinal (GI) cancers are the most common human tumors encountered worldwide. The majority of GI cancers are unresectable at the time of diagnosis, and in the subset of patients undergoing resection, few are cured. There is only a modest improvement in survival with the addition of modalities such as chemotherapy and radiation therapy. Due to an increasing global cancer burden, it is imperative to integrate alternative strategies to improve outcomes. It is well known that cancers possess diverse strategies to evade immune detection and destruction. This has led to the incorporation of various immunotherapeutic strategies, which enable reprogramming of the immune system to allow effective recognition and killing of GI tumors.

METHODS

A review was conducted of the results of published clinical trials employing immunotherapy for esophageal, gastroesophageal, gastric, hepatocellular, pancreatic, and colorectal cancers.

RESULTS

Monoclonal antibody therapy has come to the forefront in the past decade for the treatment of colorectal cancer. Immunotherapeutic successes in solid cancers such as melanoma and prostate cancer have led to the active investigation of immunotherapy for GI malignancies, with some promising results.

CONCLUSIONS

To date, monoclonal antibody therapy is the only immunotherapy approved by the US Food and Drug Administration for GI cancers. Initial trials validating new immunotherapeutic approaches, including vaccination-based and adoptive cell therapy strategies, for GI malignancies have demonstrated safety and the induction of antitumor immune responses. Therefore, immunotherapy is at the forefront of neoadjuvant as well as adjuvant therapies for the treatment and eradication of GI malignancies.

Pancreatic ductal adenocarcinoma: a review of immunologic aspects

With the continued failures of both early diagnosis and treatment options for pancreatic cancer, it is now time to comprehensively evaluate the role of the immune system on the development and progression of pancreatic cancer. It is important to develop strategies that harness the molecules and cells of the immune system to treat this disease. This review will focus primarily on the role of immune cells in the development and progression of pancreatic ductal adenocarcinoma and to evaluate what is known about the interaction of immune cells with the tumor microenvironment and their role in tumor growth and metastasis. We will conclude with a brief discussion of therapy for pancreatic cancer and the potential role for immunotherapy. We hypothesize that the role of the immune system in tumor development and progression is tissue specific. Our hope is that better understanding of this process will lead to better treatments for this devastating disease.

Lysis of a broad range of epithelial tumour cells by human gamma delta T cells: involvement of NKG2D ligands and T-cell receptor- versus NKG2D-dependent recognition

Human gammadelta T cells expressing a V gamma 9V delta 2 T-cell receptor (TCR) kill various tumour cells including autologous tumours. In addition to TCR-dependent recognition, activation of NKG2D-positive gammadelta T cells by tumour cell-expressed NKG2D ligands can also trigger cytotoxic effector function. In this study, we investigated the involvement of TCR versus NKG2D in tumour cell recognition as a prerequisite to identify tumour types suitable for gammadelta T-cell-based immunotherapy. We have characterized epithelial tumour cells of different origin with respect to cell surface expression of the known NKG2D ligands MHC class I-chain-related antigens (MIC) A/B and UL16-binding proteins (ULBP), and susceptibility to gammadelta T-cell killing. Most tumour cells expressed comparable levels of MICA and MICB as well as ULBP with the exception of ULBP-1 which was absent or only weakly expressed. Most epithelial tumours were susceptible to allogeneic gammadelta T-cell lysis and in the case of an established ovarian carcinoma to autologous gammadelta T-cell killing. Lysis of resistant cells was enhanced by pre-treatment of tumour cells with aminobisphosphonates or pre-activation of gammadelta T cells with phosphoantigens. A potential involvement of TCR and/or NKG2D was investigated by antibody blockade. These experiments revealed three patterns of inhibition, i.e. preferential inhibition by anti-TCR antibody, preferential inhibition by anti-NKG2D antibody, or additive blockade by anti-TCR plus anti-NKG2D antibodies. Our results indicate for the first time that the NKG2D pathway is involved in the lysis of different melanomas, pancreatic adenocarcinomas, squamous cell carcinomas of the head and neck, and lung carcinoma.

V gamma 9V delta 2 T cell response to colon carcinoma cells

During analysis of CD8 T cells derived from ascites of a colon cancer patient, we isolated a Vgamma9Vdelta2 T cell clone showing strong reactivity against autologous tumor cell lines. This clone killed a large fraction of allogeneic colon carcinoma and melanoma cell lines, but did not affect a normal colon cell line, colon fibroblasts, or melanocytes. Tumor cell recognition was TCR and NKG2D dependent and induced TNF-alpha and IFN-gamma secretion by the clone; accordingly, tumor targets expressed several NKG2D ligands, such as MHC class I chain-related gene A and UL16-binding protein molecules. Colon tumor recognition by Vgamma9Vdelta2 T cells was highly dependent on isopentenyl pyrophosphate production and ICAM-1 expression by target cells. Finally, similar reactivity patterns against colon carcinoma cell lines were observed using polyclonal Vgamma9Vdelta2 T cells of various origins, and Vgamma9Vdelta2 lymphocytes were present in the majority of colon tumor samples studied. Together, these results suggest that Vgamma9Vdelta2 T cells contribute to the natural immune surveillance against colon cancers. Therefore, this study provides a strong rationale for the use of Vgamma9Vdelta2 T cell agonists in immunotherapies targeting colon tumors.

Unique TCRDV1-positive lymphocytes that infiltrate colonic neoplasia originate from a selected cell population present in the intestinal mucosa and the peripheral blood

TCRDV1-positive lymphocytes, which infiltrate colon carcinomas, were recently shown to be cytolytic for tumour cells. However, the immune compartment from which these cells originate is unknown. The aim of the present studies was to determine the origin of TCRDV1-positive cells in colonic neoplasia. Biopsies were obtained from normal colon, polyps or carcinomas, concurrently with a sample from the peripheral blood. RNA was extracted and a TCRDV1-specific reverse transcriptase-polymerase chain reaction (RT-PCR) was performed. Amplification products were analysed by a CDR3 display and sequence analysis. In five out of six patients, the TCRDV1 CDR3 display of the whole cell population within the neoplastic tissue was distinct from that in the normal mucosa and the peripheral blood. The nucleotide sequences of CDR3 domains from the three compartments were distinct as well. In one patient, a pattern similar to the CDR3 display was detected in neoplastic and normal intestinal tissues. However, using junction-specific RT-PCR of CDR3 sequences derived from the neoplastic cells, such sequences could be detected in all three compartments. These findings suggest that in contrast to the current paradigm, a unique TCRDV1 cell population circulates in the peripheral blood and normal intestinal tissue and infiltrates colon neoplasia rather than being restricted to a single compartment as previously thought.

Distinct subpopulations of gamma delta T cells are present in normal and tumor-bearing human liver

Gamma delta T cells are thought to mediate immune responses at epithelial surfaces. We have quantified and characterized hepatic and peripheral blood gamma delta T cells from 11 normal and 13 unresolved tumor-bearing human liver specimens. gamma delta T cells are enriched in normal liver (6.6% of T cells) relative to matched blood (0.9%; P = 0.008). The majority express CD4(-)CD8(-) phenotypes and many express CD56 and/or CD161. In vitro, hepatic gamma delta T cells can be induced to kill tumor cell lines and release interferon-gamma, tumor necrosis factor-alpha, interleukin-2 and interleukin-4. Analysis of V gamma and V delta chain usage indicated that V delta 3(+) cells are expanded in normal livers (21.2% of gamma delta T cells) compared to blood (0.5%; P = 0.001). Tumor-bearing livers had significant expansions and depletions of gamma delta T cell subsets but normal cytolytic activity. This study identifies novel populations of liver T cells that may play a role in immunity against tumors.

Effector T lymphocyte subsets in human pancreatic cancer: detection of CD8+CD18+ cells and CD8+CD103+ cells by multi-epitope imaging

Pancreatic cancer is characterized by an increasing incidence and an extremely poor prognosis. It is resistant to most of the conventional treatment modalities. Histomorphologically, it presents with a strong desmoplastic reaction around cancer cells, and lymphocytes are typically localized as aggregates in the fibrotic interstitial tissue. Using the method of multi-epitope imaging with fluorochrome-tagged specific MoAbs which allows the simultaneous localization and characterization of T cells in tissues, we studied phenotypes and distribution of tumour-infiltrating lymphocytes (TIL) in pancreatic cancer. CD3+ T cells comprised up to 90% of the tumour-infiltrating cells which were either CD4+ or CD8+, most of them being memory cells (CD45RO+). In decreasing order of frequency, T lymphocytes carried the markers for CD45RO, CD18, CD103 and TCR gammadelta. Very few natural killer cells (CD56+) were observed. Twenty percent of CD8+ were labelled with CD103. These CD8+CD103+ T cells, analogous to the gut intraepithelial lymphocytes (IEL), were found in the fibrous interstitial tissue. Furthermore, an inverse correlation was found between the expression of CD18, the beta2-integrin, which mediates adhesion of activated lymphocytes, and CD45RO in the CD8+ subset of TIL (P = 0.046). In conclusion, phenotyping of T lymphocytes in pancreatic cancer raises the possibility that pancreatic cancer cells develop several strategies to escape the T cell-induced cytolysis by (i) the aggregation of cytotoxic CD8+CD103+ T cells in the fibrous tissue distant from the tumour cells, and (ii) the presence of CD18-bearing cells which lack the expression of the activation marker CD45RO.

Human intestinal Vdelta1+ lymphocytes recognize tumor cells of epithelial origin

gammadelta T cells can be grouped into discrete subsets based upon their expression of T cell receptor (TCR) variable (V) region families, their tissue distribution, and their specificity. Vdelta2+ T cells constitute the majority of gammadelta T cells in peripheral blood whereas Vdelta1+T cells reside preferentially in skin epithelium and in the intestine. gammadelta T cells are envisioned as first line host defense mechanisms capable of providing a source of immune effector T cells and immunomodulating cytokines such as interleukin (IL) 4 or interferon (IFN) gamma. We describe here the fine specificity of three distinct gammadelta+ tumor-infiltrating lymphocytes (TIL) obtained from patients with primary or metastatic colorectal cancer, that could be readily expanded in vitro in the presence of IL-1beta and IL-7. Irrespective of donor, these individual gammadelta T cells exhibited a similar pattern of reactivity defined by recognition of autologous and allogeneic colorectal cancer cells, renal cell cancer, pancreatic cancer, and a freshly isolated explant from human intestine as measured by cytolytic T cell responses and by IFN-gamma release. In contrast, tumors of alternate histologies were not lysed, including lung cancer, squamous cell cancer, as well as the natural/lymphocyte-activated killer cell-sensitive hematopoietic cell lines T2, C1R, or Daudi. The cell line K562 was only poorly lysed when compared with colorectal cancer targets. Target cell reactivity mediated by Vdelta1+ T cells was partially blocked with Abs directed against the TCR, the beta2 or beta7 integrin chains, or fibronectin receptor. Marker analysis using flow cytometry revealed that all three gammadelta T cell lines exhibit a similar phenotype. Analysis of the gammadelta TCR junctional suggested exclusive usage of the Vdelta1/Ddelta3/Jdelta1 TCR segments with extensive (< or = 29 bp) N/P region diversity. T cell recognition of target cells did not appear to be a major histocompatibility complex restricted or to be correlated with target cell expression of heat-shock proteins. Based on the ability of some epithelial tumors, including colorectal, pancreatic, and renal cell cancers to effectively cold target inhibit the lysis of colorectal cancer cell lines by these Vdelta1+ T cell lines, we suggest that intestinal Vdelta1+ T cell lines, we suggest that intestinal Vdelta1+ T cells are capable of recognizing cell surface Ag(s) shared by tumors of epithelial origin.

Localization of T cell receptor (TCR)-gamma delta + T cells into human colorectal cancer: flow cytometric analysis of TCR-gamma delta expression in tumour-infiltrating lymphocytes

We analysed TCR-gamma delta expression in tumour-infiltrating lymphocytes (TIL) obtained from 13 patients with colorectal cancer and simultaneously isolated the T lymphocytes from normal intestinal tissue (IL) to compare the frequencies of TCR-gamma delta expression in TIL, IL, and peripheral blood lymphocytes (PBL) in the same patient. Flow cytometric analysis showed that the frequency of TCR-gamma delta expression in TIL (2.75 +/- 1.84%) was significantly lower than that in IL (15.28 +/- 9.45%, P < 0.01). However, a larger quantity of TIL was separated than IL per unit weight of specimen, so the total number of gamma delta T cells obtained per unit weight was not different between tumour tissue and normal intestine. In addition, phenotypic analysis revealed that about half of the TCR-gamma delta + TIL were CD8+ (CD4+, 3.0 +/- 3.1%; CD8+, 54.7 +/- 19.9%, mean +/- s.d. of five patients), and a very similar result was obtained in TCR-gamma delta + IL (CD4+, 2.7 +/- 2.4%; CD8+, 53.1 +/- 17.4%). In contrast, most TCR-gamma delta + PBL were double-negative (CD4+, 3.2 +/- 3.0%; CD8+, 20.6 +/- 7.4%). These results indicated that TCR-gamma delta + CD8+ T cells selectively and consistently localized in colorectal tumour tissue, similarly to normal intestinal epithelium.

Genotype study of non-Hodgkin's lymphoma

DNA from 47 patients with non-Hodgkin's lymphoma (NHL) was studied for immunoglobulin and T-cell receptor (TCR) gene rearrangements with Southern blot hybridization. In 83% of the cases the genotypic changes were consistent with immunophenotypic and morphologic examination. Two cases showed mixed genotype and 9 cases of B-cell NHL (67% of centroblastic, 36% of follicular and 33% of large cell anaplastic) showed a population of cells with TCR gamma rearrangements in addition to immunoglobulin rearranged bands. We compared the TCR gamma variable region usage in these rearrangements in B-cell NHL with T-cell NHL and reactive hyperplasia. In T-cell NHL TCR gamma variable regions located at the 3' part of the variable locus were used more often, whilst in B-cell NHL regions of the 5' portion of the locus were preferentially used. Our results confirm the genotypic heterogeneity of histologically defined subtypes of NHL.

Suppression of cytotoxic T lymphocyte activity by gamma/delta T cells in tumor-bearing mice

Spleen cells derived from tumor-bearing mice prove useful for the elucidation of the mechanism determining how tumor cells evade cytotoxic T lymphocytes (CTL) in tumor-bearing hosts. Our data indicate that inactive CTL or precursor CTL specific for tumor antigens are present among lymphocytes of tumor-bearing mice. However, their activity is inhibited by a soluble factor produced by other cells present in the same source. Inhibition of the cytolytic reaction was also detected in the culture supernatant of spleen cells obtained from normal mice, precultured in the presence of tumor cell culture supernatant and interleukin-2 (IL-2). Cell-depletion and cell-purification studies let us conclude that cells that produced the CTL-inhibitory factor (CTL-IF) were gamma/delta T cells. The gamma/delta T cells that were activated in vivo in tumor bearers were able to produce CTL-IF after isolation and in vitro culture. Maximum activation of gamma/delta T cells was achieved by antigenic stimulation and by suppression of cells that interfered with the activation of gamma/delta T cells. CTL-IF, which was assayed by use of CTL clones, did not show antigen specificity. Inhibition depended on a relatively heat- and acid-stable, but alkali-labile molecule with a molecular mass of less than 10 kDa. The latter characteristics imply that CTL-IF does not resemble any of the known lymphokines produced by gamma/delta T cells. These observations emphasize the crucial role of the gamma/delta T cells in the escape of tumor cells from the attack of tumor-specific CTL.