Expression of HLA-DR antigens in nasopharyngeal carcinoma: an immunohistological analysis of the tumour cells and infiltrating lymphocytes

Potent human monoclonal antibodies targeting Epstein-Barr virus gp42 reveal vulnerable sites for virus infection

Epstein-Barr virus (EBV) is linked to various malignancies and autoimmune diseases, posing a significant global health challenge due to the lack of specific treatments or vaccines. Despite its crucial role in EBV infection in B cells, the mechanisms of the glycoprotein gp42 remain elusive. In this study, we construct an antibody phage library from 100 EBV-positive individuals, leading to the identification of two human monoclonal antibodies, 2B7 and 2C1. These antibodies effectively neutralize EBV infection in vitro and in vivo while preserving gp42's interaction with the human leukocyte antigen class II (HLA-II) receptor. Structural analysis unveils their distinct binding epitopes on gp42, different from the HLA-II binding site. Furthermore, both 2B7 and 2C1 demonstrate potent neutralization of EBV infection in HLA-II-positive epithelial cells, expanding our understanding of gp42's role. Overall, this study introduces two human anti-gp42 antibodies with potential implications for developing EBV vaccines targeting gp42 epitopes, addressing a critical gap in EBV research.

Immune Phenotypes of Nasopharyngeal Cancer

Simple Summary

As for many solid cancers, nasopharyngeal cancer (NPC) interacts with the immune system. In this retrospective study, immune features of NPC were explored and assessed against Epstein-Barr virus status, clinical stage, and survival. Specific immune phenotypes were identified based on presence and distribution of CD8+ T-cells: i.e., “inflamed”, “excluded”, and “deserted” NPC, which carried important prognostic information. Presence and distribution of CD207+ cells, likely representing antigen-presenting dendritic cells, were demonstrated, suggesting a potential for immune cell targeting. Gene expression revealed differences in immune profiles between NPC and control tissue as well as between subgroups of NPC based on CD8 expression (high vs. low). Taken together, the observations may be of relevance to prognostication of NPC as well as for explorations into the field of immunotherapy.

Abstract

Nasopharyngeal cancer (NPC) features intralesional immune cells, but data are lacking on presence/distribution of T-cells and dendritic cells (DCs). Based on intralesional distribution of lymphocytes, a series of NPC biopsies (n = 48) were classified into “inflamed”, “excluded”, and “deserted” phenotypes. In addition, CD8+ T-cells and CD207+ DCs were quantified. The data were analyzed in relation to Epstein–Barr virus-encoded small RNA (EBER), Epstein-Barr virus (EBV) DNA, and survival. Separately, data on gene expression from a public database were analyzed. 61.7% of NPC lesions were “inflamed”, 29.8% were “excluded”, and 8.5% were “deserted”. While CD8+ cells were present in cancer cell areas and in surrounding stroma, CD207+ cells were observed largely in cancer cell areas. High CD8+ T-cell presence was associated with EBV+ disease, but no such pattern was observed for CD207+ DCs. There was a difference in disease-free survival in favor of “inflamed” over “excluded” NPC. Gene expression analysis revealed differences between NPC and control tissue (e.g., with regard to interferon activity) as well as between subgroups of NPC based on CD8 expression (high vs. low). In conclusion, NPC lesions are heterogeneous with regard to distribution of CD8+ T-cells and CD207+ DCs. NPC can be classified into immune phenotypes that carry prognostic information. CD207+ DCs may represent a target for immunotherapy with potential to facilitate the antigen cross-presentation necessary to execute cytotoxic T-lymphocyte responses.

The small molecule antibody mimic SH7139 targets a family of HLA-DRs expressed by B-cell lymphomas and other solid cancers

Selective high-affinity ligands (SHALs) belong to a novel class of small-molecule cancer therapeutics that function as targeted prodrugs. SH7139, the most advanced of the SHAL drugs designed to bind to a unique β-subunit structural epitope located on HLA-DR10, has exhibited exceptional preclinical efficacy and safety profiles. A comparison of SH7139 and SH7129, a biotin derivative of the drug developed for use as a diagnostic, showed the incorporation of a biotin tag did not alter the SHALs ability to target or kill HLA-DR10 expressing Raji cells. The use of SH7129 in an immuno-histochemical type assay to stain peripheral blood mononuclear cells (PBMCs) obtained from individuals expressing specific HLA-DRB1 alleles has also revealed that in addition to HLA-DR10, seven other more commonly expressed HLA-DRs are targeted by the drug. Computational dockings of the SHAL's recognition ligands to a number of HLA-DR structures explain, in part, why the targeting domains of SH7129 and SH7139 bind to some HLA-DRs but not others. The results also substantiate the selectivity of SH7129 and suggest it may prove useful as a companion diagnostic for pre-screening biopsy samples to identify those patients whose tumours should respond to SH7139 therapy.

An Unusual Presentation of Nasopharyngeal Carcinoma as Lemierre Syndrome

BACKGROUND Clinical presentation of nasopharyngeal carcinoma (NPC) is correlated with the extent of primary and nodal disease. Hence, depending on the anatomical structures affected, the clinical presentation varies accordingly, ranging from non-specific symptoms of epistaxis, unilateral nasal obstruction, and auditory complaints, to cranial nerve palsies. Nodal metastasis in the neck is a frequent clinical finding in nasopharyngeal carcinoma. CASE REPORT A female was admitted to the hospital because of fever and trismus with painful swelling in the right neck. Computed tomography (CT) revealed a mass in the nasopharynx with heterogeneous enhancement and multiple swollen lymph nodes in the corresponding neck. Initial biopsies of nasopharyngeal mass and lymph node of the neck revealed nonspecific lymphoid hyperplasia; we administered antibiotics with the provisional diagnosis of bacterial infection, including Lemierre syndrome that is typically defined by the constellation of septic internal jugular vein thrombophlebitis, pulmonary and other septic emboli, and sterile site bacterial infection. However, the patient was refractory to antibiotics over a month of treatments. The third biopsy of the throat lesion revealed NPC and bacterial cultures using the biopsy specimen were negative. She received intensity-modulated radiation therapy and chemotherapy for NPC stage II (TNM staging: T2N1M0). She never developed Lemierre syndrome-like symptoms after chemoradiotherapy. CONCLUSIONS We report a unique case of NPC presenting with Lemierre syndrome-like symptoms, including prior sore throat, trismus, painful swollen neck, and high fever. Since these symptoms have not been reported in NPC, we included NPC as a differential diagnosis.

Dendritic cell subpopulations in nasopharyngeal cancer

Nasopharyngeal cancer (NPC) is associated with Epstein-Barr virus (EBV) and EBV antigen may be utilized for therapeutic purposes, including targeting of dendritic cells (DCs). Although DCs may be present in NPC, the information is limited and not up-to-date with current knowledge on DC subsets. In the present study, biopsies from untreated NPC were obtained and subjected to multicolor flow-cytometry focusing on DC subtype markers: CD123 for plasmacytoid DCs (pDCs); and CD1c and CD141 for myeloid DCs (mDCs). Furthermore, subset-specific expression of the C-lectin receptor (CLR) CD207 (also termed langerin) was assessed. pDCs and mDCs were detected in the NPC lesions, contributing to a frequency mean average of 0.78% of CD45⁺ leukocytes in situ. Different subpopulations, previously not described in NPC, were observed, including: CD123⁺ pDCs; CD1c⁺ mDCs; CD141⁺ mDCs; and CD1c^-CD141^- mDCs. A high frequency of CD1c⁺ mDCs expressing CD207 was observed, compared with other subsets. In conclusion, different DC subsets are present in NPC lesions. The CLR CD207, a selective endocytic marker on CD1c⁺ mDCs, may be targeted for therapeutic purposes to facilitate cross-presentation of antigens and aid cell-mediated antitumor effects.

Genetic factors leading to chronic Epstein-Barr virus infection and nasopharyngeal carcinoma in South East China: study design, methods and feasibility

Nasopharyngeal carcinoma (NPC) is a complex disease caused by a combination of Epstein-Barr virus chronic infection, the environment and host genes in a multi-step process of carcinogenesis. The identity of genetic factors involved in the development of chronic Epstein-Barr virus infection and NPC remains elusive, however. Here, we describe a two-phase, population-based, case-control study of Han Chinese from Guangxi province, where the NPC incidence rate rises to a high of 25-50 per 100,000 individuals. Phase I, powered to detect single gene associations, enrolled 984 subjects to determine feasibility, to develop infrastructure and logistics and to determine error rates in sample handling. A microsatellite screen of Phase I study participants, genotyped for 319 alleles from 34 microsatellites spanning an 18-megabase region of chromosome 4 (4p15.1-q12), previously implicated by a linkage analysis of familial NPC, found 14 alleles marginally associated with developing NPC or chronic immunoglobulin A production (p = 0.001-0.03). These associations lost significance after applying a correction for multiple tests. Although the present results await confirmation, the Phase II study population has tripled patient enrolment and has included environmental covariates, offering the potential to validate this and other genomic regions that influence the onset of NPC.

CD4+ T-cell responses to Epstein-Barr virus nuclear antigen EBNA1 in Chinese populations are highly focused on novel C-terminal domain-derived epitopes

Epstein-Barr virus nuclear antigen EBNA1, the one viral protein uniformly expressed in nasopharyngeal carcinoma (NPC), represents a prime target for T-cell-based immunotherapy. However, little is known about the EBNA1 epitopes, particularly CD4 epitopes, presented by HLA alleles in Chinese people, the group at highest risk for NPC. We analyzed the CD4+ T-cell responses to EBNA1 in 78 healthy Chinese donors and found marked focusing on a small number of epitopes in the EBNA1 C-terminal region, including a DP5-restricted epitope that was recognized by almost half of the donors tested and elicited responses able to recognize EBNA1-expressing, DP5-positive target cells.

Hypericin-mediated photodynamic therapy elicits differential interleukin-6 response in nasopharyngeal cancer

Cytokines induce inflammatory and immune responses in tumors after photodynamic therapy (PDT). Since there are no reports of IL-6 in nasopharyngeal cancer (NPC) cells following PDT, we evaluated IL-6 expression in two different NPC tumors after hypericin mediated PDT. Interleukin-6 transcription was significantly upregulated in PDT-treated CNE-2 poorly differentiated cells but not in HK1 well differentiated cells. In vivo, IL-6 mRNA expression was elevated in PDT-treated CNE-2 tumors but not in HK1 tumors. In conclusion, the study elucidated that the cell type, degree of histological differentiation and the basal expression of the cytokine influence the cytokine response following PDT.

Pulmonary lymphoepithelioma-like carcinoma: predominant infiltration of tumor-associated cytotoxic T lymphocytes might represent the enhanced tumor immunity

Lymphoepithelioma-like carcinoma (LELC) of the lung is an undifferentiated carcinoma with prominent lymphoid stroma. We encountered a case of synchronous primary lung cancers of LELC and papillary adenocarcinoma in a 67-year-old Japanese woman. By in situ hybridization, Epstein-Barr virus (EBV) genome was detected in malignant epithelial cells of LELC but not in the papillary adenocarcinoma. Tumor-infiltrating lymphocytes in LELC were predominantly CD8+ and T cell intracytoplasmic antigen (TIA-1)+ cytotoxic T cells with closely associated with HLA-DR-positive LELC cells by double immunostaining. These data indicate that the exaggerated lymphoid infiltration in and around the EBV-infected carcinoma cells may represent the enhanced tumor immunity, suggesting a better prognostic indicator.

Potential selection of LMP1 variants in nasopharyngeal carcinoma

Seven distinct sequence variants of the Epstein-Barr virus latent membrane protein 1 (LMP1) have been identified by distinguishing amino acid changes in the carboxy-terminal domain. In this study the transmembrane domains are shown to segregate identically with the distinct carboxy-terminal amino acid sequences. Since strains of LMP1 have been shown to differ in abundance between blood and throat washes, nasopharyngeal carcinomas (NPCs) from areas of endemicity and nonendemicity with matching blood were analyzed by using a heteroduplex tracking assay to distinguish LMP1 variants. Striking differences were found between the compartments with the Ch1 strain prevalent in the NPCs from areas of endemicity and nonendemicity and the B958 strain prevalent in the blood of the endemic samples, whereas multiple strains of LMP1 were prevalent in the blood of the nonendemic samples. The possible selection against the B958 strain appearing in the tumor was highly significant (P < 0.0001). Sequence analysis of the full-length LMP1 variants revealed changes in many of the known and computer-predicted HLA-restricted epitopes with changes in key positions in multiple, potential epitopes for the specific HLA of the patients. These amino acid substitutions at key positions in the LMP1 epitopes may result in a reduced cytotoxic-T-lymphocyte response. These data indicate that strains with specific variants of LMP1 are more likely to be found in NPC. The predominance of specific LMP1 variants in NPC could reflect differences in the biologic or molecular properties of the distinct forms of LMP1 or possible immune selection.

Nasopharyngeal carcinoma and the EBV-specific T cell response: prospects for immunotherapy

T cells specific for Epstein-Barr virus (EBV) can effectively target the virus-transformed B lymphoproliferative lesions that arise in immunosuppressed transplant patients. This review explores the possibility of developing similar T cell-based strategies to treat an EBV-positive epithelial tumour, nasopharyngeal carcinoma (NPC), which arises in relatively immunocompetent individuals and where EBV antigen expression in the tumour is more limited.

CTL control of EBV in nasopharyngeal carcinoma (NPC): EBV-specific CTL responses in the blood and tumors of NPC patients and the antigen-processing function of the tumor cells

Undifferentiated nasopharyngeal carcinoma (NPC) is latently infected with EBV and expresses a restricted number of viral proteins. Studies in healthy virus carriers have demonstrated that at least some of these proteins can act as targets for HLA class I-restricted CTLs. Therefore we have explored the possibility of a CTL-based therapy for NPC by characterizing EBV-specific CTL responses in 10 newly diagnosed NPC cases and 21 healthy virus carriers from Southeast Asia. Using the autologous EBV-transformed lymphoblastoid cell line, virus-specific CTL were reactivated in vitro from PBMC, cloned, and screened for cytotoxicity against target cells expressing individual EBV proteins from recombinant vaccinia vectors. EBV-specific CTLs were identified in 6 of 10 patients and 14 of 21 controls and mainly targeted the EBV nuclear Ag 3 (EBNA3) family of viral latent proteins. However, in 3 of 10 patients and 11 of 21 controls, CTLs specific for the NPC-associated protein LMP2 were also detected, albeit at low frequency. EBV-specific CTLs were detected in tumor biopsy material obtained from 3 of 6 of the patients, indicating that functional CTL are present at the tumor site, but none was specific for tumor-associated viral proteins. To assess the Ag-presenting function in NPC we studied two NPC-derived cell lines (C15 and c666.1) and demonstrated that both were capable of processing and presenting endogenously synthesized protein to HLA class I-restricted CTL clones. Overall, our data provide a sound theoretical basis for therapeutic strategies that aim to boost or elicit LMP2-specific CTL responses in NPC patients.

Undifferentiated nasopharyngeal cancer (UCNT): current diagnostic and therapeutic aspects

Undifferentiated carcinoma of the nasopharynx (UCNT) is a particular head and neck epidermoid lineage tumor related to the Epstein Barr Virus (EBV). It has geographically selective endemic epidemiologic features, without relation to external carcinogens. Its systemic agressiveness is the source of most disease-related demises, because radiotherapy achieves excellent local control and a significant percentage of cure in patients with exclusive locoregional disease. Difference in the staying systems currently in use, the recent changes in imaging and radiotherapy technology, and the lack of distinction between UCNT and squamous cell carcinoma (SCC) of the nasopharynx in Western literature reports make for some difficulty in therapeutic results evaluation when analyzing available literature. Its chemosensitivity is a relatively recent acknowledged fact, and its use in metastatic patients results in a high percentage of objective responses, many of long duration. Neoadjuvant cisplatin-based chemotherapy seems to be of benefit, but outstanding controversies in this regard will be soon answered through ongoing phase III trials. After a review of the current literature of all the above-mentioned aspects of this fascinating nosologic entity, our own experience, both in metastatic and locoregional disease patients is analyzed.

Selective induction of allostimulatory capacity after 5-azaC treatment of EBV carrying but not EBV negative Burkitt lymphoma cell lines

Epstein-Barr virus (EBV) negative and EBV carrying Burkitt lymphoma (BL) lines that remain phenotypically similar to the in vivo tumor cells (operationally defined group I BLs) express high levels of CD10 and CD77, and lack immunoblastic markers such as CD23 and CD39, and the cell adhesion molecules CD11a, CD18, CD54 and CD58. This cell phenotype is associated with poor stimulatory capacity in allogeneic mixed lymphocytes cultures (MLC) [Avila-Carino et al. Int. J. Cancer 40, 691-697 (1987)] EBV carrying BL lines tend to drift spontaneously towards an immunoblastic phenotype in parallel with up-regulation of six EBV-encoded nuclear antigens (EBNA-2 to -6) and two membrane proteins (LMP-1 and -2). These viral antigens are characteristically expressed in all EBV transformed lymphoblastoid cell lines (LCLs) of normal B cell origin and can be induced in group I BL lines by treatment with the DNA demethylating agent 5-azacytidine (5-azaC) [Masucci et al. J. Virol. 65, 1558-1567 (1989)]. We have now studied the effect of 5-azaC on the induction of allogenic T cell proliferation by three EBV negative (Ramos, BL28 and BL41) and four EBV carrying BL lines (Rael, Eli, Chep and Mutu) which stably express a group I phenotype. Pre-treatment with 4-15 microM 5-azaC had no effect on the EBV negative cells but increased the stimulatory capacity of all four EBV carrying lines. LMP-1 was the only viral antigen regularly induced suggesting that its expression may be required for the increase of allostimulation. This was corroborated by the observation that LMP-1 transfection increased 35-70-fold the stimulatory capacity of Rael cells. The cell adhesion molecule CD54 was the only cellular marker selectively up-regulated in all cell lines with increased stimulatory capacity.

Expression of the Epstein-Barr virus latent membrane protein in nasopharyngeal carcinoma biopsy specimens

It has been known for some time that the Epstein-Barr virus (EBV) is associated with nasopharyngeal carcinoma (NPC). The tumor cells are known to harbor EBV in a latent state. Latently-infected B cells that have become growth transformed by EBV in vitro express some 10 antigens, two of which (Epstein-Barr nuclear antigen 2 [EBNA2] and the latent membrane protein [LMP]) are associated with cellular transformation. We evaluated the expression of these two EBV antigens in NPC by probing tissue sections with monoclonal antibodies. We found that EBNA2 was not expressed and that LMP was expressed in seven of nine biopsy specimens. It is therefore postulated that either there are subsets of NPC or that LMP may be involved only in certain stages of tumor formation.

Phase II trial of recombinant interferon gamma in refractory undifferentiated carcinoma of the nasopharynx

The presence of Epstein-Barr virus (EBV) genomes in the DNA of tumor cells of undifferentiated carcinoma of nasopharyngeal type (UCNT), associated with significant lymphocytic infiltration of tumor led to therapeutic trials with interferon (IFN) because of its antiviral, antiproliferative, and immunomodulatory properties. Fourteen patients with histologically proven UCNT (2 had locoregional disease alone and 12 metastatic disease) who were refractory to conventional chemotherapy, were treated with IFN gamma 20 x 10(6) U twice a week. Treatment was well tolerated. No objective response were achieved in the 13 evaluated patients, and all patients progressed after a median treatment duration of 10 weeks (6-32). IFN gamma seems unable to induce antitumor activity alone in such heavily pretreated patients. Its possible place in the management of UCNT is probably earlier in the natural history of this disease.

Selective homing of phenotypically lytic cells within nasopharyngeal carcinoma biopsies: numerous CD8- and CD16-positive cells in the tumor

We present a comparative analysis of cell-mediated immunity between circulating lymphocytes and tumor-infiltrating lymphocytes (TIL) from patients with nasopharyngeal carcinoma (NPC). Phenotypic analysis using a panel of monoclonal antibodies (MAbs) to define lymphocytic subsets has revealed a selective homing of phenotypically lytic cells such as CD8- and CD16-positive cells, but a low percentage of macrophages when compared to PBL of NPC patients. Also, PBL and TIL contain an equivalent percentage of activated T-lymphocytes expressing HLA-DR molecules and IL-2 receptors. Functionally, TIL exhibit an abolished NK-cell activity and concomitant decrease of proliferative response to phytohemagglutinin (PHA) and concanavalin A (ConA) stimulation when compared with PBL.

Soluble interleukin-2 receptors in patients with nasopharyngeal carcinoma

The authors performed a retrospective analysis of serum soluble interleukin-2 receptor (sIL-2R) levels in 72 patients with nasopharyngeal carcinoma (NPC) using an enzyme immunoassay. Their objectives were to determine the value of serum sIL-2R in estimating the tumor burden, and its predictive value in response to therapy and prognosis. The data showed that serum sIL-2R levels in patients were significantly higher than that of healthy controls. The serum levels correlated with clinical staging and hence the tumor burden of NPC. Serial measurement of serum sIL-2R provided an accurate prognostic index of the clinical response to radiotherapy in at least 89% of patients with raised serum sIL-2R at initial diagnosis (defined as mean + 2 SD of healthy controls) and a reliable predictive index in all patients who subsequently developed distant metastasis despite initial radiotherapy. Simultaneous measurement of Epstein-Barr virus-related serology (IgA-VCA and IgG-EA) failed to demonstrate predictive value comparable with that of serum sIL-2R. The authors conclude that monitoring serum sIL-2R levels has clinical and prognostic significance in patients with NPC and that prospective studies are indicated.

Direct ultrastructural evidence of lymphocyte-mediated cancer cell lysis in the microenvironment of Chinese nasopharyngeal carcinoma

We observed 101 cases of Chinese nasopharyngeal carcinoma (NPC) with light and electron microscopy, focusing on the relationship between lymphocytes and cancer cells and their alterations during interaction. Cancer cells conjugated by lymphocytes showed injuries to varying degrees in 60% of cases with World Health Organization classification 2 + 3 NPC, but not in those cases with World Health Organization classification 1 NPC. The alterations of cancer cells conjugated by lymphocytes included loss of cell membrane and cytoplasm, degeneration of cell organelles, and even cell necrosis. Initial lesions of the cancer cell frequently occurred in the region infiltrated by lymphocytes. The lymphocytes could penetrate deeply into the cytoplasm, even into the nucleus of the cancer cell. At the same time, lymphocytes were themselves intact. The lymphocytes were classified into three groups: small lymphocytes, medium-sized lymphocytes, and blastoid type or transformed lymphocytes. The current study provided the direct ultrastructural evidence that lymphocyte-mediated cancer cell lysis might occur in the microenvironment of NPC and enabled us to summarize ultrastructural features of this phenomenon.

Cytotoxic potential despite impaired activation pathways in T lymphocytes infiltrating nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is an epithelial tumor consistently associated with EBV. The histological picture is characterized by a strikingly abundant lymphocytic infiltrate. Furthermore, the epithelial tumor cells present several immunological characteristics which suggest an important role for tumor-infiltrating lymphocytes (TIL) in the biology of this tumor. The present study reports the phenotypic and functional characterization of TIL from NPC obtained after enzymatic digestion of 15 NPC biopsies. Flow cytometric analysis of TIL suspensions indicated that most TIL were mature CD3+ T lymphocytes (mean = 60%) with a variable CD4/CD8 ratio. Most TIL were TCR alpha/beta-positive (mean = 55%) and only a few TCR gamma-delta-positive cells could be identified. A small percentage (mean = 9%) displayed an activated phenotype (CD25+, HLA class II+). Using limiting dilution analysis, we found that the average frequency of proliferative T-lymphocyte precursors (PTL-P) is lower among TIL (1/40) than in autologous (1/7) or normal PBL (1/1.4). Moreover, sorting experiments have shown that this defect is significantly more pronounced in the CD8+ than in the CD4+ TIL subset. Accordingly, the TCR and the CD2-mediated antigen-independent pathways of activation were impaired. Different types of cytotoxic precursor could be detected. These included lectin-dependent cell cytotoxicity (LDCC) and NK-like or lymphokine-activated killer (LAK) activity. Interestingly, some TIL from NPC were able to lyse an NPC tumor (C15) maintained in nude mice. Thus, despite impaired activation pathways, the cytolytic potential of proliferating TIL in NPC is preserved.

Immunohistological characteristics of the infiltrating lymphoid cells and expression of HLA class I and II antigens in nasopharyngeal carcinoma

The immunohistological characteristics of infiltrating lymphoid cells and the expression of human leucocyte antigens class I and II (HLA-ABC and HLA-DR, respectively) were studied in 50 pre-treatment nasopharyngeal carcinomas. The majority of lymphoid cells were activated lymphocytes expressing thymocyte OKT10 marker. CD4+ cells (T-helper/inducer) out-numbered CD8+ cells (T-suppressor/cytotoxic) by at least two- to four-fold. CD22+ cells (pan-B lymphocytes) were scanty in the peri-tumoral areas and were absent in 29 out of 50 biopsies. A moderate number of cells expressing CD15 (monocytes/macrophages) were also detected. CD16+ cells (natural killer cells) were found to be sparse or absent. Expression of HLA class I and II antigens on the tumor cells in 35 biopsies was variable. HLA-ABC staining was intense in 6, reduced in 13 and partially lost in 16, whereas staining of HLA DR was intense in 7, reduced in 11 and partially lost in 17. Full expression of both antigens was demonstrable in only 2 biopsy samples. The expression of HLA antigens in the tumour had no relationship to the type or degree of lymphocytic infiltration or staging of the tumour.

What's new in the local immune response in cancer?

Malignant tumors in humans are commonly associated with an inflammatory infiltrate. The mechanisms that account for the accumulation of T-lymphocytes and macrophages--these cells comprise the major components of tumor infiltrates--in the vicinity of a growing tumor are not fully understood. Tumor specific and immunogenic antigens could not be demonstrated in most solid tumors of humans, in contrast to several experimental tumor models. Thus it is not proven in human malignancies that neoantigens expressed on malignant cells are the signal which initiates an inflammatory response that, immunohistologically, is comparable to mononuclear infiltrates present in allograft rejection. A variety of nonspecific factors including lymphokines released by tumor cells may also account for the accumulation of inflammatory cells at the tumor site. The difficulties to evaluate the functional role of the "local immune response" for tumor and host are even greater. Most tumors progress in the presence of mononuclear infiltrates. Do they progress in spite of or because of the action of the local immune response? Clinical, immunopathological, and experimental data suggest that both is right, and that at least four distinct properties of tumor-associated immune reactions exist: Regression, Selection, Modulation and Progression. These distinct properties will be discussed below, using mainly the malignant melanoma of the skin as a model for a malignant tumor in humans.

Establishment and characterization of three transplantable EBV-containing nasopharyngeal carcinomas

Three transplantable nasopharyngeal carcinoma (NPC) tumors, designated C15, C17 and C18, have been obtained and characterized. C15, derived from a primary NPC tumor, has been propagated in nude mice for 30 passages. C17 and C18, derived from metastatic NPC tissue, have been passaged 10 times. Desmosomes, present in every case, provided confirmation of the epithelial origin of all 3 tumors. The Epstein-Barr virus (EBV) genome is contained in C15, C18 and C17 tumor cells with 30, 12 and 3 copies, respectively. The Epstein-Barr virus nuclear antigen (EBNA) was stained by the classical anti-complement immunofluorescence (ACIF) technique. Fluorescence intensity was strong in C15, moderate in C18, and hardly detectable in C17 cells. No expression of the EA and VCA antigens was detected. Flow cytometry analysis performed on monocellular suspensions showed the absence of detectable CR2 molecules (the EBV receptor on B lymphocytes) in all 3 tumors, and the constitutive expression of HLA class-II antigens in C15 and C17 cells. IL-1 activity was demonstrated in the supernatant of C15 and C17 cells cultivated in vitro for 3 days. These data confirm that the constitutive synthesis of MHC class-II molecules and the release of IL-1-like activities are frequent features of NPC cells. These characteristics could be of importance in relation with the T-cell infiltrate found in NPC primary tumors.

Expression of endothelial cell markers PAL-E and EN-4 and Ia-antigens in Kaposi's sarcoma

Eleven biopsy specimens of Kaposi's sarcoma (KS) removed from the skin and oral mucosa were examined immunohistochemically with monoclonal antibodies PAL-E and EN-4, specific for human vascular endothelial cells, and with LN-3 monoclonal antibody reactive with immune-associated (Ia) antigens in the HLA-DR locus. The early lesions of KS, corresponding to the patch phase, contained hyperplastic venules and an increased number of lymphatic capillaries. The lymphatic capillary endothelium was reactive with EN-4, whereas, PAL-E reacted only with blood vessel endothelial cells. The spindle cells, like lymphatic endothelial cells, were non-reactive with PAL-E but showed positive reaction with EN-4 antibodies. The observed morphologic pattern of vasculogenesis and the demonstrated immune-reactivity in KS support an origin from the venule-lymphatic junction. This is an aberrant pattern but reminiscent of normal embryonal lymphatic channel development. The lymphatic capillaries and vascular slits were nonreactive with LN-3 antibody, but it was positive on cell membranes in a number of spindle cells, suggesting the focal expression of Ia-antigens.

Expression of the c-fgr related transcripts in Epstein-Barr virus-associated malignancies

The proto-oncogene c-fgr is expressed at high levels in cell lines derived from lymphomas which are infected with Epstein-Barr virus (EBV) (Cheah et al., 1986). mRNA extracted directly from biopsies of EBV-infected tissues was analyzed on Northern blots to determine if c-fgr is expressed during lympho-proliferations induced in vivo by EBV and in nasopharyngeal carcinoma (NPC), the epithelial malignancy associated with the virus. Elevated levels of c-fgr expression were detected in all EBV-positive lympho-proliferations in vivo but not in cell lines established by EBV infection in vitro. This indicates that the induction of the c-fgr proto-oncogene is not an essential component of EBV-induced transformation. Although no c-fgr expression was detected in EBV-positive or -negative epithelial cell lines, the 3.0-kb c-fgr mRNA was detected at low levels in mRNA obtained from NPC biopsy specimens. However, NPC tissue, after passage in nude mice (which eliminates infiltrating lymphoid and myeloid cells) did not contain the 3.0-kb c-fgr mRNA. The absence of expression of c-fgr in the malignant epithelial cells infected with EBV contrasts with the elevated level of the proto-oncogene in EBV-infected lymphoma tissue and cell lines established from lymphomas. This suggests differences in the expression of cellular functions in EBV-induced malignancies of these 2 distinct cell types.

Lymphocyte subsets in tumour of patients with undifferentiated nasopharyngeal carcinoma: presence of lymphocytes with the phenotype of activated T cells

We have analyzed lymphocytes infiltrating nasopharyngeal carcinomas, using a combination of immunoperoxidase staining of frozen and paraffin-embedded sections, and immunofluorescence on lymphocyte suspensions recovered from teased tumours. A panel of monoclonal antibodies was used to define lymphocytic subsets on frozen sections of 14 different tumours. The vast majority of peri- and intra-tumoral lymphocytes were stained by OKT3 antibody. In 8 sections, T4 positive cells were largely predominant, while T8 positive cells were the majority in three sections. Twenty-nine paraffin-embedded sections from other NPC patients stained with HNK-1 antibody showed a variable percentage of positive cells reaching 6 to 15% in nine patients. Most HNK-1 positive cells had the morphology of large granular lymphocytes typical of natural killer cells. Double staining experiments on lymphocytes isolated from 7 tumours revealed a constant presence of T3 positive, HLA-DR positive lymphocytes (from 6 to 29% of mononuclear cells), and of lymphocytes coexpressing the T3 and the Tac (IL-2 receptor) antigens (from 5 to 12% of mononuclear cells). Lymphocytes with a phenotype of activated T-cells are thus constantly found in NPC tumours.

S-100 protein positive cells in nasopharyngeal carcinoma (NPC): absence of prognostic significance. A clinicopathological and immunohistochemical study of 40 cases

An immunohistochemical study of S-100 protein in 43 nasopharyngeal carcinomas (NPC) of known clinical evolution (33 primary and 10 metastatic) is presented. Sixty per cent of primary site cases as well as all metastatic forms showed S-100 protein positive cells intermingled with tumour cells. These S-100 positive elements were identified as Langerhans cells. No significant differences were found when correlating S-100 protein positivity and histological NPC variants, neither in age nor in sex of patients. Statistical analysis failed to demonstrate any positive correlation between S-100 protein reactivity and clinical survival.

Epstein-Barr virus-associated malignancies

The infectious aspects of cancer in humans were epidemiologically pioneered by Dr. David Burkitt through his observations of lymphomatous tumors seen in children in equatorial Africa. Years, later, the Epstein-Barr virus (EBV) was shown to be intimately associated with such tumors and is now recognized as a component of some B-cell lymphomas and nasopharyngeal carcinoma. Still the questions of an active, passive, or accessory role persist. The ability of this virus to cause immunosuppressive hemopoietic disturbances in individuals infected with EBV but not developing cancer raise questions about host susceptibility, host immune response, and possible coconspiring, infectious, oncogenic agents. Recent associations of EBV antibody found in diseases, such as squamous cell carcinoma of the head and neck and acquired immunodeficiency syndromes, point to its possible accessory role as an immunosuppressive agent. The ability of EBV to spread by extracellular and intracellular mechanisms demonstrates its variable infectious potential. Numerous EBV-transformed human cell lines attest to its ability to confer "immortality" with uncontrolled growth patterns. This review critically examines the association of EBV with various malignancies, the type of evidence which links it there, and the implications for further investigations and therapy.

Immunohistological studies of lymphoproliferative lesions in a fatal case of Epstein-Barr virus infection

A fatal case of infectious mononucleosis occurred in a young adult. Abnormal serological features were noted in his mother, although there was no other family history suggesting an inherited defect of immune response to Epstein-Barr virus (EBV). The cellular infiltrate observed in tissues obtained at necropsy was analysed with a range of specific monoclonal and polyclonal antibodies. Polyclonal plasmacytoid B cell proliferation had occurred in many tissues. These cells were positive for EBV nuclear antigen, but viral particles were not seen on ultrastructural examination, and the virus was not isolated, suggesting a non-permissive infection.