Functional characteristics and differential expression of class II DR, DS, and SB antigens on human melanoma cell lines

Distribution of HLA-DR, HLA-DP, HLA-DQ antigens in liver tissue from patients with primary sclerosing cholangitis

This study describes the distribution of the major histocompatibility class II antigens HLA-DR, HLA-DP, and HLA-DQ in liver tissue from eight patients with primary sclerosing cholangitis, by means of the immunoperoxidase technique on cut cryostat sections. HLA-DR was expressed on the bile duct epithelium and vascular endothelium from all patients. HLA-DP showed an expression much like HLA-DR on the bile duct epithelium, but the vascular endothelium mostly did not stain for HLA-DP. HLA-DQ was generally more weakly expressed, and only three of the patients expressed HLA-DQ on the bile ducts. None of the hepatocytes expressed any of the MHC class II antigens.

Monoclonal antibody MAC 387 recognizes a myelomonocytic antigen shared by epithelial cells in inflammatory skin diseases

The monoclonal antibody MAC 387 recognizes an antigen expressed by human macrophages and granulocytes. Normal epidermis does not react with the antibody, but the inflamed epidermis may react. In this immunocytochemical study we have investigated the intracytoplasmic expression of the MAC 387 antigen in biopsies of a variety of skin disorders. In lichen planus the basal cells were usually negative, whilst suprabasal cells were positive. In the majority of other inflammatory dermatoses studied, there was positive staining of basal and suprabasal cells. A parallel frozen- and paraffin-section study of biopsies of cutaneous T-cell lymphomas and inflammatory conditions failed to demonstrate HLA Class II expression in the cytoplasm of keratinocytes. Expression of the MAC 387 antigen in the epidermis is directly associated with cell-mediated activity in the papillary dermis, but is not related to HLA Class II expression.

Langerhans cells expressing HLA-DQ, HLA-DR and T6 antigens in normal oral mucosa and lichen planus

We compared Langerhans cells (LC) expressing HLA-DQ, HLA-DR and T6 antigens in biopsies from the same oral mucosal site in 12 patients with oral lichen planus and eight healthy volunteers. LC expressing each antigen were observed in all the specimens, but in lichen planus the cells were located in higher levels of the epithelium than in controls. Compared with controls, lichen planus contained significantly more HLA-DQ-positive LC (P = 0.04) and fewer HLA-DR-positive LC (P = 0.05), but there was no such difference in T6-positive LC. In lichen planus specimens, there were significantly more LC expressing HLA-DQ and T6 than HLA-DR (P = 0.0001 and 0.02 respectively); no such differences were found in normal mucosa. Epithelial cells in lichen planus expressed HLA-DR antigen, but not HLA-DQ or T6 antigens. We conclude that in lichen planus there is modulation of HLA-DR and HLA-DQ antigen expression by LC, or differences in the number of LC expressing those antigens.

Accessory cell function of human melanoma cells in mitogen-induced T cell proliferation

Six out of eight human melanoma cell lines were found to be able to function as accessory cells in PHA-induced proliferation of autologous and allogeneic T cells. The accessory cell function of the melanoma cell lines appears to be similar to that of monocytes, requires the presence of viable cells, and does not correlate with the cell surface binding sites for PHA and with the level of expression of HMW-MAA and of HLA Class I antigens. HLA Class II antigens do not appear to play a major role in these phenomena, since there is no relationship between level of expression of HLA Class II antigens and accessory cell function of melanoma cells. Furthermore, addition of anti-HLA Class II monoclonal antibodies does not affect proliferation of T cells stimulated with PHA in the presence of melanoma cells with accessory cell function. Although melanoma cells exert accessory cell function, functional and immunological assays did not detect IL-1 in the spent medium of the melanoma cell lines. Furthermore, Northern blotting analysis with IL-1 alpha and IL-1 beta probes did not detect IL-1-specific mRNA in melanoma cell lines. These results suggest that PHA-induced proliferation of T cells in the presence of melanoma cells can bypass the requirement for IL-1 or utilizes factors other than IL-1.

DNA content and MHC class II antigen expression in malignant melanoma: clinical course

To assess the clinical value of two comparatively new properties (DNA content and MHC class II antigen expression (HLA-DR, DP, DQ) of melanoma cells) which have been independently reported to reflect the outlook for patients with malignant melanoma, we investigated retrospectively 50 stage I nodular melanomas in two comparably homogeneous groups of 23 and 27 patients, the course of whose disease differed at five years. Flow cytometry and immunohistology were used on paraffin wax embedded archival material for the analysis of DNA ploidy and detection of class II antigens, respectively. A close association was found between class II antigen expression, detected by monoclonal antibody CR3/43 (antimonomorphic DR, DP, DQ) present in 23 of 50 (46%) melanomas and unfavourable clinical course (p less than 0.005, by log rank test), but no such association was found for DNA ploidy. It is suggested that immunohistology for MHC class II antigen expression may help to predict the behaviour of nodular melanomas whereas the prognostic value of DNA ploidy is more limited. The finding that class II positive cells are found predominantly in melanomas with a substantially increased risk of metastases has implications both for concepts of tumour heterogeneity and host immunity.

HLA class II sublocus expression in benign and malignant breast epithelium

Using immunohistochemistry and a panel of five monoclonal antibodies, the epithelial expression of HLA class II sublocus products by benign and malignant breast has been studied. The magnitude of the stromal mononuclear inflammatory cell infiltrate was assessed. There was expression of HLA class II by 75 per cent of epithelial cells in the benign tissues, with little variation in intensity and between antibodies. There was coordinate expression of DR and DQW1. Epithelial expression by carcinomas was more complex and variable. Most (61 per cent) carcinomas exhibited variable loss of epithelial expression of class II products, as detected by three antibodies recognizing epitopes on DP, DQ, and DR together. Thirteen (28 per cent) carcinomas were completely negative or had very occasional positive cells. The extent of this loss was unrelated to the magnitude of the inflammatory infiltrate and axillary lymph node status. No well-differentiated carcinomas exhibited complete loss. Furthermore, non-coordinate expression of DR and DQW1 was present in 8 out of 40 carcinomas, with the proportion of DQW1 positive epithelium always being less than that of DR. Carcinomas exhibiting non-coordinate expression were never well differentiated; there was no relationship with the extent of the inflammatory infiltrate. This is the first study to detail HLA class II expression in breast, and our results suggest that alterations in expression of these products may modify or reflect tumour behaviour.

Differential expression of MHC class II subregion products on bile duct epithelial cells and hepatocytes in patients with primary biliary cirrhosis

To study the expression of MHC Class II subregion gene products on biliary epithelial cells in primary biliary cirrhosis, frozen sections from liver biopsies of 15 patients with primary biliary cirrhosis were studied immunohistochemically using HLA-D subregion specific monoclonal antibodies L243 (HLA-DR), Leu10 (HLA-DQ) and B7/21 (HLA-DP). Patients with early stages of primary biliary cirrhosis showed expression of HLA-DP, HLA-DR and HLA-DQ subregion gene products on bile duct epithelial cells. In advanced stages of disease, no MHC Class II antigens or only HLA-DR and HLA-DP were expressed on bile duct cells. While normal hepatocytes did not express detectable amounts of MHC Class II antigens, hepatocytes from liver biopsies of four patients with primary biliary cirrhosis showed a distinct staining exclusively with monoclonal antibodies specific for HLA-DR. The expression of MHC Class II antigens on parenchymal cells was independent of a lymphocytic infiltration into the tissue. This study demonstrates that bile ductular cells, but not hepatocytes, express a full set of MHC Class II molecules at least during the early stages of primary biliary cirrhosis. We propose, therefore, that the expression of both HLA-DR and HLA-DQ subregion products on bile duct epithelial cells may be a necessary, although not sufficient, condition for the initiation of an autoimmune process leading to the destruction of intrahepatic bile ducts in primary biliary cirrhosis.

Immunohistological evaluation of MHC class I and II antigen expression on nevi and melanoma: relation to biology of melanoma

MHC antigen expression on 20 nevi, and 35 primary and 95 metastatic melanomas was studied by immunoperoxidase techniques using monoclonal antibodies to identify the antigens on frozen tissue sections. DR antigens were not detected on nevi but were detected on 71% of primary melanomas and 56% of metastases, suggesting that this antigen may be a useful marker of malignant transformation of nevi. Expression of class II antigen could not be related to other prognostic histological features of primary melanoma such as tumour thickness, but comparison of the common phenotypes of primary and metastatic melanoma suggested that expression of DR antigens alone in the absence of DP, DQ and ABC antigens may be an indicator of metastatic potential. Class I (HLA-A,B,C) antigens were also expressed infrequently on nevi but were detected on 43% of primary melanomas and 34% of metastases. HLA-A,B,C expression was inversely related to thickness of the primary melanoma. This as well as the lower expression of class I antigens on metastases, may indicate that growth and spread of melanoma may be inhibited by MHC (class I) dependent cytotoxic T cell responses. Expression of class I MHC antigens was unrelated to class II antigens. Expression of DR was more common than DP or DQ, but the latter with one exception, were not expressed in the absence of DR antigens. Significant differences were not found in MHC antigen expression on metastases in lymph nodes compared to those in subcutaneous sites, but further studies are needed to determine whether such differences may exist between metastases in other visceral sites.

Differential expression of the HLA-DR genes in various melanoma cell lines treated with interferon-gamma: methylation of the HLA-DR alpha gene in these lines is not correlated with its expression

Melanoma cell lines treated with or without interferon-gamma were tested for the presence of DR alpha mRNA and protein. The six lines examined fell into three general categories: two that expressed high levels of DR alpha mRNA and protein before and after interferon-gamma treatment, one that expressed very low levels before treatment with interferon-gamma, but was induced to express high levels after interferon-gamma treatment, and three that expressed very low levels before treatment, and were only slightly inducible after treatment with interferon-gamma. The presence of DR-alpha protein on the melanoma cell surface was always positively correlated with the presence of DR alpha mRNA in the cells. Furthermore, in the cell line that was interferon-gamma-inducible, the time at which DR alpha mRNA and protein appeared and the doses of interferon-gamma needed to induce this appearance were directly correlated. Methylation patterns of the DR alpha gene in these cell lines were also studied in order to determine whether the degree of DR alpha gene methylation among the lines correlated with expression of the gene. Digestion of DNA with the restriction enzyme MspI, which recognizes the sequence 5'CCGG3' and 5'CmCGG3', led to the appearance of a 3.1 kb band from all lines tested. Hpa II digestion, which recognizes 5'CCGG3', but not 5'CmCGG3', led to the appearance of 3.1, 4.4, and 6.7 kb bands in all lines tested except for DUMEL 8, which showed only the 3.1 kb band. Interestingly, DUMEL 8 expressed very low levels of DR alpha mRNA and protein before and after interferon-gamma treatment. We conclude that interferon-gamma has a regulatory effect on DR alpha genes of various melanoma cell lines to varying degrees. This may reflect an effect of interferon-gamma on certain subpopulations of melanocytes in vivo. Our data also indicate that partial methylation of the DR alpha gene does not inhibit its expression. Furthermore, interferon-gamma does not appear to induce expression of the DR gene by altering methylation patterns within the region recognized by our probe.

Phenotypic profile of clones from early cultures of human metastatic melanomas and its modulation by recombinant interferon gamma

Fifty-six tumor clones isolated by cloning in soft agar from early cultures (before the 10th in vitro passage) of two different human metastatic melanomas (Me9229 and Me28) were characterized by FACS analysis for surface expression of class-I and class-II HLA antigens and of melanoma-associated antigens (MAA) with a panel of 15 monoclonal antibodies (MAbs). A marked phenotypic heterogeneity involving MAA and/or HLA markers was observed among the clones derived from both tumors. The differences among the tumor clones and between them and the uncloned melanoma were qualitative and quantitative for each antigen considered. Clones derived from Me9229 expressed the same HLA profile as the parental culture (class I+, class II-) while strong heterogeneity was observed for MAA expression. Clones from Me28 presented a marked heterogeneity for class-I and class-II HLA antigens but were more homogeneous for MAA. The phenotype of the clones was repeatedly checked over the first month in culture and found to remain generally unchanged and not linked to the cell cycle. However, major changes in antigenic expression of the clones could be observed upon treatment with recombinant interferon-gamma (rIFN-gamma): class-I and -II HLA antigens could be induced or augmented while a moderate inhibition was seen on MAA expression. Furthermore, an apparent hierarchy in expression and/or induction of class-II antigens by rIFN-gamma was observed among the tumor clones. DR antigens were more frequently expressed (Me28 clones) and upon treatment with rIFN-gamma reached higher levels than DP and DQ products. Taken together these results indicate that antigenic heterogeneity for MAA and HLA antigens can be detected in cells isolated from early cultures of human metastatic melanomas and suggest that the original uncloned tumor might be considered as a complex mixed population made up of a number of neoplastic cells each expressing a distinct phenotype which can be modulated by lymphokines such as IFN-gamma.

Expression of HLA-D sub-region products on human colorectal carcinoma

The major histocompatibility complex (MHC) status of normal, inflamed, pre-malignant and malignant epithelia of the human gastrointestinal tract was investigated by immunocytochemical methods using monoclonal antibodies (MAbs) directed against heavy (alpha)- and light (beta 2m)-chain Class-I molecules and sub-locus products (DP, DQ, DR) of the HLA-D region. Class-I expression on epithelial cells appeared to vary little with pathological status except in the case of 4/32 (13%) colorectal carcinomas in which the antigens were undetectable or scanty. The pattern of Class-II expression was more complex. The antigens were readily detectable on normal stomach epithelium, in villous adenomas and in inflammatory bowel mucosa. In each of these situations DR was the predominant specificity, followed by DP and DQ. Expression on normal colonic epithelium was usually negative but, in the vicinity of a neoplasm or an area of marked leukocyte infiltration, Class-II molecules (DR greater than DP much greater than DQ) were detectable. A similar pattern of non-coordinate expression was found on 23/32 (72%) colorectal carcinomas, but on the remaining 28% no Class-II products were detectable, under conditions wherein stromal leukocytes were strongly stained. The data suggest that in a significant proportion (nearly 30%) of primary colorectal carcinomas, the capacity for Class-II induction, a constitutive or acquired feature of normal colorectal epithelium, is either diminished or lost. Also, tumor Class-II status is not correlated to Dukes' stage or differentiation.

Expression of MHC class II products on human colorectal cancer. An immunohistological and flow cytometric study

The MHC status of epithelial cells from 32 primary colorectal neoplasms, villous adenomata (VA; 2) and inflammatory bowel disease (IBD; 3) were evaluated using a panel of monoclonal antibodies (mAbs). Class I antigens and beta 2 microglobulin (beta 2m) were expressed on all normal, benign, inflammatory and malignant epithelia with the exception of two carcinomas. A more complex pattern of reactivity was encountered with anti-class II mAbs. Some expression was detected on normal glandular and luminal epithelium, particularly adjacent to the tumour. Inflammatory tissues, VA and 23/32 carcinomas were also antigen-positive, the proportion of stained epithelial cells ranging from 5% to 90%. Expression was usually non-coordinate, DR being the predominant specificity followed by DP and DQ, which is suggestive of independent D region gene regulation. The hypothesis that class II expression is induced in vivo by locally generated IFN gamma was not confirmed by in vitro treatment with this agent of epithelial colorectal carcinoma-derived cell lines. These provisional data suggest that although IFN gamma may be a necessary stimulus for class II expression it is insufficient and that other factors also influence the responsiveness of tumour cells in this respect.

Gene products of the HLA-D region in normal and malignant tissues of nonlymphoid origin

Indirect immunofluorescence staining with monoclonal antibodies has shown a differential distribution of HLA-DR, DQ, and DP antigens in normal tissues of nonlymphoid origin. The distribution of HLA-DP antigens is similar to that of HLA-DR antigens, while that of HLA-DQ antigens is more restricted. Malignant transformation of cells of nonlymphoid origin may be associated with the appearance of the gene products of the HLA-D region. HLA-DR antigens appear more frequently than the other two types of HLA class II antigens and HLA-DP antigens more frequently than HLA-DQ antigens. Differential expression of the gene products of the HLA-D region was also found in autologous metastases removed from different anatomic sites from patients with melanoma. The HLA class II phenotype of surgically removed malignant lesions did not correlate with the degree of differentiation of tumor cells and/or with the expression and/or cellular distribution of HLA class I antigens. Furthermore, in melanoma lesions, no relationship was found between the HLA class II phenotype and the expression of 3 membrane bound and 1 cytoplasmic melanoma associated antigen recognized by monoclonal antibodies. The functional significance and the practical implications of the differential expression of the gene products of the HLA-D region by tumor cells are discussed.

Class II positive human dermal fibroblasts restimulate cloned allospecific T cells but fail to stimulate primary allogeneic lymphoproliferation

Recently, a number of laboratories have shown that gamma interferon (IFN-gamma) is a potent modulator of HLA class II antigen expression in a variety of cell types ranging from classical antigen presenting cells to those not expected to participate in physiological antigen presentation such as fibroblasts. In order to examine the role of HLA class II expressing fibroblasts in antigen presentation, we established dermal fibroblast (FIB) strains from five HLA typed donors. After optimal preculture with IFN-gamma, class II positive FIB were fully competent to restimulate proliferative responses of two DR specific T cell clones and one DP specific T cell line. However, they failed to elicit strong primary allogeneic proliferation from fully DR mismatched fresh PBMC. This failure was not due to a direct suppressive effect of FIB and could not be corrected by exogenous IL1 or by factors contained in conventional mixed leukocyte culture supernatants.

Divergent expression of HLA-DC/MB, -DR, and -SB region products on normal and pathological tissues as detected by monoclonal antibodies

A group of eight monoclonal antibodies directed against different monomorphic determinants of HLA-class II molecules was used to investigate the distribution of HLA-DC/DS/MB, -DR and -SB-like antigens on normal and pathological lymphoid and nonlymphoid tissues of human adult and fetal donors. HLA-MB/DC/DS-like molecules, as defined by the antibody TU 22, showed the most limited distribution as they were detected on B-lymphocytes, monocyte/macrophage subpopulations and distinct interstitial cells of various organs. HLA-DR and -SB-like antigens characterized by the other anti-HLA-class II reagents (TU34, TU35, TU37, TU39, TU43, TU58) were also present on these cell types. However, selective expression of HLA-DR and/or -SB like molecules was demonstrated with these antibodies on certain vascular endothelia, as well as different B-cell lymphomas and distinct epithelial cells in adults. Exclusive reactivity of the antibody TU39 shown on endothelial cells of fetal liver and kidney suggested specific functions of HLA-SB antigens during ontogeny. Furthermore, HLA-DR and/or -SB like molecules but not TU22+ HLA-DC/MB antigens were found to be inducible on normally Ia-like antigen negative epithelial cells of various diseased organs. Implications of this differential tissue distribution of HLA-DC/MB/DS, -DR and -SB like products in relation to organ transplantation, regulation of immune responses and cell differentiation are discussed.

Autologous cellular immune response to primary and metastatic human melanomas and its regulation by DR antigens expressed on tumor cells

Evidence for heterogeneity of several biological features of human malignant melanoma (Me) like morphology, cytogenetics, oncogenes activation, antigenic expression, metastatizing capacity and procoagulant activity are briefly reviewed in an attempt to distinguish findings related to primary vs. metastatic lesions. In our own studies monoclonal antibodies were used to study expression of MHC class I, class II products and of Me-associated antigens (MAA) on primary and metastatic Me cells. High expression of class I antigens was found in a high percentage of both primary and metastatic tumors, whereas DR and MAA showed a significant variation (from 3 to 90% of cells) in expression both in primary and in metastatic Me. When autologous cell-mediated immune responses were evaluated, it was found that Me cells from primary tumors but not those from lymph node metastases were able to stimulate autologous lymphocytes to proliferate and become cytotoxic for autologous Me. Clonal analysis of cytotoxic lymphocytes was then carried out in order to see whether the lack of lymphocytes reactivity to metastatic cells was due to the absence or to a low frequency of cytotoxic cells in the unstimulated PBL. CTL clones cytotoxic for autologous Me (Auto-Me) cells were indeed isolated. Three classes of CTL clones were identified: 1) one which is cytotoxic for Auto-Me; 2) a second one which lyse Auto-Me and allogeneic Me; and 3) a third one which is cytotoxic for Auto-Me and allogeneic normal and neoplastic cells. Metastatic Me cells, however, had the ability to suppress the stimulation of autologous PBL by alloantigens or IL-2. This effect was dose-dependent and was not due to absorption of IL-2 by Me cells. Since it has been reported that Me cells express class II MHC antigens, we investigated whether there was any correlation between autologous immune responses and DR expression on Me cells. Autologous lymphocytes stimulation was found to occur only with DR+ Me cells from primary lesions, whereas metastatic cells, either DR+ or DR-, did not stimulate autologous PBL. Moreover, the suppressive effect of metastatic Me cells was associated with their expression of DR antigens. The modulation of DR antigens on Me cells by Interferon-gamma correlated positively with their suppressive capacity. Thus, it appears that primary Me can behave differently from the metastatic one in their interactions with the immune system of autologous host. These findings suggest that DR antigens on Me cells may have an important role in the regulation of autologous immune responses.

The inhibition of lymphocyte stimulation by autologous human metastatic melanoma cells correlates with the expression of HLA-DR antigens on the tumor cells

Previous studies indicated that peripheral blood lymphocytes from patients (Pt-PBL) with lymph node metastatic melanomas proliferated in vitro and developed into tumor-restricted cytotoxic lymphocytes in response to alloantigens or interleukin 2 (IL-2). However, Pt-PBL were not stimulated by irradiated autologous metastatic melanoma (Auto-Me) cells. In the present study we report that the lack of stimulatory activity of Auto-Me cells may be due to a suppressive effect exerted by Auto-Me cells on the responder lymphocytes. In fact, we found that in 62% of cases examined, the addition of 5-10% Auto-Me cells to Pt-PBL cultures strongly inhibited both proliferation and the generation of tumor cytotoxic lymphocytes induced by alloantigens or IL-2. The inhibition was dose-dependent and tumor-restricted, and was not due either to toxicity, medium depletion or IL-2 absorption by Auto-Me cells. Normal fibroblasts, K562 cells and autologous E-lymphocytes were not suppressive. Auto-Me cells were able to inhibit Pt-PBL responses only when added during the first 24 h of culture and not later. Phenotypic analysis of Auto-Me cells using monoclonal antibodies directed against HLA-A,B,C, HLA-DR and melanoma-associated antigens revealed that the expression of high levels of DR antigens on Auto-Me cells was associated with an elevated suppressive activity. Conversely, Auto-Me cells with low or undetectable levels of DR antigens were not inhibitory. Furthermore, the increased expression of DR antigens on Auto-Me cells obtained by in vitro treatment with human interferon gamma (IFN-gamma) also resulted in an increased suppressive activity. We conclude that HLA-DR+ metastatic melanoma cells can interfere with the generation of an anti-tumor immune response, thus potentially favoring the escape of the tumor from the host's control mechanism.