HLA antigens expressed on human ervthroid burst forming cells

The human major histocompatibility antigens HLA, play an important role in transplantation. To ascertain the expression of the antigens of A and B loci on the surface of human hemopoietic progenitors, the cytotoxic effect of specific anti-HLA sera was examined. Anti-HLA A2 and B5 sera were used in the present experiments. Circulating blood mononuclear cells and nucleated marrow cells, pre-treated with appropriate specific anti-HLA sera and complement, formed fewer colonies from BFU-e and CFU-c in a culture medium than the controls which were treated with autologous serum. In our experiments, the HLA antisera also killed macrophages, monocytes and T cells which carry the surface antigen. Then, the influence of macrophages, monocytes, and T cells on colony formation from BFU-e and CFU-c was examined. These results indicated that BFU-e as well as CFU-c expressed HLA antigens on their surface.     

Genetically Appropriate Expression of HLA and DR (IA) Alloantigens on Human Melanoma Cell Lines

Studies of the expression of HLA and DR alloantigens on cultured human melanoma cells in comparison with those expressed on peripheral lymphocytes and B-cells derived from the same patients have shown that the HLA-A,B, and C locus antigens expressed on the cultured tumor cells were consistent with those expected from the typing of peripheral blood lymphocytes. One melanoma cell line failed to express all the HLA antigens expected from donor typing. All five of the lines tested also expressed DR antigens and in three instances these could be demonstrated to have genetically consistent allotypes. However, in preliminary studies stimulation of allogeneic lymphocytes by the DR positive melanoma cells could not be demonstrated.     

HLA class I alterations in laryngeal tumors

A series of 93 laryngeal tumors were evaluated in cryostatic sections with immunoperoxidase and immunophosphatase techniques for the expression of HLA class I antigens using a panel of mAbs defining HLA monomorphic, locus specific and allele specific determinants. PBL from patients were also typed for HLA alleles. We found 17 (18%) tumors presenting total HLA-ABC loss, 9 (9%) with selective loss of HLA-A antigens, 4 (4%) with absence of HLA-B antigens and 4 cases (4%) with loss of HLA-A and B. It has only been possible to study the HLA allelic expression in 12 cases which reacted positively with monomorphic and locus specific mAbs. We have found loss of some alleles in 7 of these 12 patients. These results show that 43 patients (46%) present some kind of HLA class I alterations. We can not exclude the existence of other allelic losses in these tumors since the appropriate mAbs were not available. The loss of expression of a single MHC restriction element could affect the immunosurveillance against tumors.     

The detection of human minor alloantigens following restriction determinant implantation

The recognition of minor alloantigens by cytotoxic T lymphocytes (CTL) serves as a model for the recognition of tumor and viral antigens. Progress in this area has been limited, however, since CTL recognize minor alloantigens only in association with self-class I antigens. Thus, experiments designed to study minor alloantigens are limited to target cells that share HLA determinants with the CTL. We raised CTL lines that recognized human minor alloantigens. In order to circumvent the problem that only target cells which expressed the appropriate restriction determinants could be tested for minor antigens. Sendai virus mediated fusion was used to integrate appropriate HLA antigens into cells that did not express them naturally. The target cells were then tested in CML for their expression of minor antigens. The results of experiments demonstrated that, following class I implantation, the detection of minor antigens on certain restriction determinant negative cells was possible. Furthermore, the restriction determinant was able to associate with the minor antigen in a manner appropriate for recognition by the T-cell receptor.     

Nonrandom association of cellular antigens with HTLV-III virions

Retroviruses are known to incorporate cellular antigens as they bud from infected cells. To identify the cellular antigens that associate with the AIDS-retrovirus, we evaluated a preparation of HTLV-III antigens with a panel of monoclonal antibodies reactive with a variety of antigens expressed on the H9 T-cell line used to produce the virus. Only monoclonal antibodies that identified HLA class-II antigens, beta-2 microglobulin, and a single anti-HLA class-I antibody were reactive in an ELISA of solubilized HTLV-III virus. No reactivity was seen with 11 monoclonal antibodies to T-cell antigens or with five antibodies to determinants on HLA class-I A or B molecules. These data suggest that on H9 cells the association of budding HTLV-III virions with cellular antigens may be a nonrandom process in which some HLA antigens, particularly class-II antigens, are selectively incorporated into the viral envelope. It is possible that a selective association of HLA class II antigens with budding HTLV-III virions may also occur for T cells infected in vivo, and could have relevance for the pathogenesis of this virus.     

Expression of normal and tumor-associated antigens in human breast carcinoma

The expression of six cytoplasmic/membrane antigens (beta 2-microglobulin, HLA, HLA-DR, carcinoembryonic antigen, and two breast tumor-associated antigens (TAAs), B6.2 and B72.3) was investigated in serial sections of 28 human breast carcinomas using monoclonal antibodies and the avidin-biotin complex immunoperoxidase technique. The frequency of expression and linkage between these antigens was determined, and antigenic expression was related to patient age, morphologic differentiation, cytologic grade, and estrogen receptor/progesterone receptor content of the tumor. The expression of beta 2-microglobulin and HLA correlated with morphologic differentiation, well-differentiated and moderately well-differentiated tumors expressing these antigens more often than poorly differentiated tumors. Expression of the TAAs, however, was not related to differentiation. There was no linkage between beta 2-microglobulin/HLA and the TAAs. Carcinoembryonic antigen was found to be linked to the TAA, B6.2. Expression of the TAA, B72.3, correlated with patient age. Eighty percent (23 of 28) of the tumors were positive for carcinoembryonic antigen or at least one of the TAAs. The estrogen receptor/progesterone receptor status of the tumor was not statistically related to the expression of any of the antigens studied. Analysis of tumor antigen profiles may provide important information relevant to prognosis, therapy, and early detection of cancer, as well as insights into the nature of the neoplastic process.     

Phenotypic heterogeneity of HLA products on human melanoma cells

The expression of class I and class II HLA antigens has been studied on primary and metastatic human melanomas, and on cell clones derived from the latter. A panel of monoclonal antibodies and flow cytofluorometric analysis were used to evaluate the presence of HLA-A, B, C and -DR, DQ antigens on freshly isolated tumour cells. HLA class I antigens were present on 91% and 93% of primary and metastatic tumours, respectively. Sixty per cent of primary and 50% of metastatic melanomas expressed HLA-DR antigens, whereas 38% and 21% of cases were positive for HLA-DQ. A marked heterogeneity was evident among primary and metastatic lesions for expression of class I and II antigens. Similar findings were obtained by analysing the phenotype of melanoma clones which indicates that a marked antigenic heterogeneity for class I and II HLA antigens occurs even among clones isolated from short-term cultures of metastatic melanomas.     

Antigens recognized on a melanoma cell line by autologous cytolytic T lymphocytes are also expressed on freshly collected tumor cells

Peripheral blood lymphocytes of a melanoma patient were stimulated in vitro with a permanent cell line derived from the autologous tumor. Stable cytolytic T lymphocyte (CTL) clones were obtained that lysed the melanoma cell line and did not lyse autologous Epstein-Barr virus-transformed B lymphocytes or K-562 cells. These CTL clones were directed against two distinct antigens on the melanoma line. In view of the possibility that these antigens could be culture artefacts, we tested the stimulatory ability of tumor cells that had been freshly collected from metastatic relapses on the CTL clones. A considerable CTL proliferation was observed and it appeared to be specific. We conclude that the antigens recognized by the autologous CTL clones on the permanent melanoma cell line were expressed by the tumor cells in the patient.     

HLA-A匹配的人胃癌细胞系诱生胃癌特异性T淋巴细胞

目的 用ＨＬＡ－Ａ匹配的人胃癌细胞系诱导对胃癌细胞具有特异性杀伤作用的Ｔ淋巴细胞。方法 分离胃癌患者及正常人外周血淋巴细胞（ＰＢＬ）,用ＨＬＡⅠ类型别已知、经照射的异体胃癌细胞系刺激,进行筛选性的混合淋巴细胞肿瘤细胞培养（ＭＬＴＣ）,初步获得ＨＬＡ－Ａ可能匹配的淋巴细胞供体,血清法测定其ＨＬＡ－Ａ、Ｂ分子确认匹配后,进一步进行ＭＬＴＣ,＾３Ｈ掺入法评估其增殖能力,直接免疫荧光法分析其细胞表型,＾５     

Evaluation of individual specificities of class I HLA on platelets by a newly developed monoclonal antibody

In order to quantify each specific HLA-A or-B antigen on platelets, a monoclonal antibody against HLA heavy chains was developed and designated as 2F2 monoclonal antibody. This monoclonal antibody reacted on Western blot with platelet HLA from each 10 individuals with different HLA phenotypes and precipitated all ³⁵S-methionine-labeled HLA-A and -B antigens from three different Epstein-Barr Virus-transformed lymphoblastoid cell lines. The results indicate that the 2F2 monoclonal antibody recognizes an epitope shared by different HLA-A and -B antigens. The quantitative variation of specific HLA antigens on platelets was then studied in nine different donors by isoelectric-focusing gel electrophoresis and immunoblot using the 2F2 monoclonal antibody. The results of our studies showed that the shared HLA antigens such as A2, B35, and B62, varied three- to fivefold among different individuals and individual HLA-A or -B antigen was not equally expressed on a person's platelets. The relative quantities of specific HLA-A and -B antigens on lymphocytes were also noted to be the same as those on platelets. The finding suggests that differential expression of HLA specificities may not be restricted to platelets but is a more general phenomenon including other nucleated cells.     

Expression of HLA class I antigens on hepatocytes in liver disease

Recent studies have demonstrated aberrant expression and topographical heterogeneity of HLA Class I and Class II antigens in tissues of patients with certain immunologic or neoplastic diseases. Current information about the expression of HLA antigens by normal and diseased hepatocytes is controversial. We analyzed the HLA antigenic profile of 4 normal fetal livers, 5 normal adult livers, 7 cases of chronic hepatitis B virus (HBV) infection, 14 cases of cirrhosis of various etiologies, 11 hepatic neoplasms, and 5 continuous cell lines derived from hepatic tumors. The specimens were tested by the indirect fluorescent antibody method with a panel of monoclonal antibodies to distinct monomorphic determinants of HLA Class I and Class II antigens and to beta 2-microglobulin. HLA Cells I antigens were not detected on normal fetal and adult hepatocytes, but were displayed on the plasma membrane of hepatocytes in the majority of all hepatic diseases tested and of the 5 hepatic tumor cell lines. There was a significant correlation between the expression of HLA Class I antigens on hepatocytes and the intensity of intralobular inflammation. Double immunofluorescent staining of livers infected with hepatitis B virus demonstrated simultaneous expression of HLA Class I antigens and HBsAg or HBcAg only in a small percentage of hepatocytes, suggesting lack of a specific association between HLA Class I and these viral antigens. HLA Class II antigens were not detected on hepatocytes from any of the liver diseases tested but were expressed by one of the 5 liver carcinoma cell lines analyzed. These findings confirm that HLA Class I antigens are not detectable within the limits of several immunohistochemical methods on normal hepatocytes and suggest that injury by a variety of factors directly or indirectly leads to induction of these antigens on the plasma membrane of hepatocytes.     

Differences in the antigens recognized by cytolytic T cells on two successive metastases of a melanoma patient are consistent with immune selection

We have studied the patterns of antigens recognized by autologous cytolytic T lymphocytes (CTL) on two melanoma cell lines derived from metastases that were removed from patient LB33 at several years distance. Cell line LB33-MEL. A was obtained after surgery in 1988. A large number of CTL clones directed against LB33-MEL. A was obtained with blood lymphocytes collected from the patient in 1990. In vitro selection of melanoma cells that were resistant to these CTL clones indicated that at least five different antigens were recognized on LB33-MEL. A by autologous CTL. Four of these antigens were found to be presented by HLA-A28, B13, B44 and Cw6, respectively. The patient remained disease-free until 1993 when a metastasis was detected and was used to obtain cell line LB33-MEL. B. This cell line proved resistant to lysis by all the CTL clones directed against the LB33-MEL. A cells and showed no expression of HLA class I molecules except for HLA-A24. Using LB33-MEL. B cells to stimulate blood lymphocytes collected from the patient in 1994 we derived CTL clones that lysed these cells. All these CTL clones recognized a new antigen presented by HLA-A24. These results suggest that in patient LB33 the melanoma cells may have lost the expression of several HLA molecules under the selective pressure of an anti-tumor CTL response.     

Modulation of MHC gene expression in human breast carcinoma cells by hormones

Products encoded by the class I Major Histocompatibility Complex (MHC) genes serve as restriction molecules which enable T cells to generate an immune response to specific antigens. Recently, many investigators have demonstrated the importance of class I antigens in enabling the host to regulate tumor growth in vivo. In this report, we have studied the regulation of HLA genes by hormones in human breast cancer cell lines. Eight lines were studied. Using HLA locus-specific DNA probes, the level of HLA-A and HLA-B specific mRNAs were found to be underrepresented in six of these cell lines when compared to an epithelial cell line derived from a normal lactating breast. Moreover, the expression of class I MHC mRNA in these cells correlated well with the level of chloramphenicol acetyltransferase (CAT) activity detected after the introduction of exogenous HLA-CAT DNA-constructs. It was also found that HLA expression in some of the breast carcinoma cell lines could be modulated by the addition of hormones. Hence, HLA mRNA expression in the cell line MCF-7 was enhanced by the addition of estrogen; but was down-regulated in the presence of dexamethasone. Conversely, for T-47D cells, HLA expression was suppressed by progesterone. These results indicate that hormones could have an influence on the expression of HLA genes and may therefore indirectly be involved in the regulation of tumor growth by the host's immune system.     

High frequency of altered HLA class I phenotypes in invasive breast carcinomas

We studied 105 tumor samples obtained from patients diagnosed as having breast carcinomas for HLA class I and II (DR) antigen expression, using a panel of mAbs defining HLA-monomorphic, locus-specific and allele-specific determinants. Peripheral blood lymphocytes from patients were also typed for HLA alleles. The results indicated total HLA class I losses in 55 patients (52.3%), HLA-A locus losses in four patients (3.8%), HLA-B locus losses in eight patients (7.6%), and A, B, locus losses in 10 patients (9.5%). The remaining 28 patients whose tissues reacted positively with monomorphic- and locus-specific mAbs were tested for HLA allelic losses using several anti-HLA mAbs defining A2, A3, A9, B8, B12, etc. Of these 28 patients, 16 (57%) showed one or more losses of HLA reactivity. These results indicated that in 88.5% of patients we detected a particular HLA-altered tumor phenotype. The downregulation of HLA class I antigens in breast carcinomas may thus be more frequent than previously reported, and patients without HLA class I downregulation may be the exception rather than the rule. It cannot be ruled out that HLA alterations are present in some of the 12 patients with an apparently normal HLA phenotype, as some HLA alleles could not be studied because of the lack of appropriate mAbs. These HLA alterations could represent an important step associated with tumor invasion, conferring to the tumor cells the ability to escape from T-lymphocyte recognition.     

Restoration of endogenous antigen processing in Burkitt's lymphoma cells by Epstein-Barr virus latent membrane protein-1: coordinate up-regulation of peptide transporters and HLA-class I antigen expression

Group I Burkitt lymphoma (BL) lines retaining the original BL tumor cell phenotype are unable to present endogenously expressed antigens to HLA class I-restricted cytotoxic T cells (CTL) but can be recognized if the relevant HLA class I/peptide epitope complex is reconstituted at the cell surface by exogenous addition of synthetic target peptide. Endogenous antigen-processing function is restored in BL lines that have undergone Epstein-Barr virus (EBV)-induced drift in culture to the group III phenotype typically displayed by EBV-transformed lymphoblastoid cell lines (LCL) of normal B cell origin. We compared group I versus group III cells for their expression of proteasome components, transporter proteins and HLA-class I antigens, all of which are thought to be involved in the endogenous antigen processing pathway. By Western blot analysis, there were not consistent differences in the low molecular mass protein subunits of proteasomes (lmp)-2, lmp-7 and δ, although the mb-1 proteasome subunit was regularly present at higher levels in group I BL lines relative to group III lines or LCL. By contrast there were marked differences in the expression of peptide transporter-associated proteins (Tap), with down-regulation of Tap-1 and Tap-2 in 8/8 and 7/8 group I BL lines, respectively. Surface levels of HLA class I antigens were also consistently lower in group I cells; this was not associated with an intracellular accumulation of free HLA heavy chains, such as is seen in the Tap-deficient T2 processing-mutant line, but instead reflected a reduced rate of HLA class I synthesis in group I cells. Analysis of EBV gene transfectants of the B lymphoma lines BJAB and BL41 showed that the virus-encoded latent membrane protein-1 (LMP1), which is one of several EBV antigens expressed in group III but not in group I cells, was uniquely able to up-regulate expression both of the Tap proteins and HLA class I. Furthermore, this was accompanied by a restoration of antigen-processing function as measured by the ability of these cells to present an endogenously expressed viral antigen to CTL. These effects of LMP1 were similar to those induced in the same cell lines by interferon-γ treatment. The results implicate both Tap and HLA class I expression as factors limiting the antigen-processing function of BL cells, and suggest that the accessibility of other EBV-associated malignancies to CTL surveillance may be critically dependent upon their LMP1 status.     

Expression of HLA class I/II antigens and T cell immune response in human neuroendocrine tumors of the pancreas

Peptide presentation by HLA class I and II antigens regulates specific antigen recognition by T cells. The present study aimed to investigate T cell infiltration and its relation to HLA antigen expression in pancreatic neuroendocrine tumors. Fresh tissue samples were collected from five insulinomas and six other neuroendocrine tumors (one gastrinoma, one glucagonoma, two carcinoid, and two neuroendocrine carcinomas). Normal pancreatic and splenic tissue samples were used as controls. Investigation of infiltrating lymphocyte populations, as well as staining of HLA class I and II antigens, were performed by standard immunohistochemistry. The majority of investigated tumors demonstrated an intratumoral infiltration by CD3+, CD4+ and CD8+ T cells that was significantly higher than in normal pancreatic islets. Only a minority of tumor-infiltrating T cells showed the CD45RO+ phenotype. The expression of HLA class I antigen was altered in 10 of 11 tumors. A loss of beta-2microglobulin represented the most frequent type of alteration to HLA class I expression, although the total loss of HLA class I was found in only one case of neuroendocrine carcinoma. HLA class II molecules were expressed by endothelial and lymphoid cells and not by tumor cells. In conclusion most neuroendocrine pancreatic tumors induce a T cell mediated immune response resulting in an intratumoral infiltration with CD3+, CD4+ and CD8+ T cells. Loss of beta-2microglobulin is a frequent alteration in these tumors, which may influence the normal function of the HLA class I antigen complex. In contrast to malignant tumors of the exocrine pancreas, expression of HLA class II was absent in neuendocrine pancreatic tumor cells.     

HLA-B27 in Rheumatoid Arthritis and Amyloidosis

To study the role of genetically determined immune responsiveness in the pathogenesis of systemic amyloidosis complicating rheumatoid arthritis the HLA antigens were identified in 26 patients with rheumatoid arthritis complicated by secondary amyloidosis, in 44 patients with rheumatoid arthritis, and in 11 patients with secondary amyloidosis of non-rheumatoid origin. Subjects with ankylosing spondylitis, sacroiliitis without peripheral polyarthritis, Reiter's disease, reactive arthritis, erosive osteoarthritis, psoriatic arthropathy, systemic lupus erythematosus or arthritis associated with a gastrointestinal involvement were excluded from the study. Patients with amyloidosis secondary to rheumatoid arthritis had a high frequency of the HLA specificity B27 and of the haplotype likely to bear A2, B27. The association with B27 was closest in the group of male patients with amyloidosis whose rheumatoid arthritis had begun at an early age and who lacked demonstrable rheumatoid factor in serum. These patients may represent a genetically determined subentity of rheumatoid arthritis.     

Effect of Tunicamycin on the Assembly and Antigenicity of HLA Antigens: Analysis with Monoclonal Antibodies

The effect of glycosylation on the assembly and antigenicity of HLA antigens was investigated by examining HLA antigens synthesized in the presence of the antibiotic tunicamycin, an inhibitor of asparagine-linked oligosaccharide addition, with monoclonal antibodies specific for a variety of antigenic determinants. The monoclonal antibody Q5/13 reactive with a determinant expressed on the beta chain of human Ia-like antigens immunoprecipitated alpha and beta subunits with reduced apparent molecular weights from tunicamycin-treated cells, indicating that glycosylation is not required for association of the Ia-like antigen alpha and beta subunits. Immunoprecipitation of HLA-A,B,C antigens from tunicamycin-treated cells with four monoclonal antibodies specific for the heavy chain and one specific for beta 2-microglobulin showed that the heavy-chain determinant detected by the antibody Q6/64 is absent from the non-glycosylated molecule. This is the first demonstration that carbohydrate addition during biosynthesis affects the protein conformation of the HLA-A,B,C heavy chain.     

Cellular localization of blood group antigens (including HLA markers) in human bladder urothelium

Expression of A, B, H, Lewis, I, i, HLA class I and class II antigens was studied on 81 urinary bladder samples. Striking variation in the expression of HLA class II and to a lesser extent of HLA class I determinants was observed. Expression of at least five distinct A (or B) determinants, the synthesis of which is controlled by H, A, B, secretor and Lewis genes, was demonstrated by using a panel of reagents directed against different A, B and H epitopes. These results suggest that evaluation of blood group changes during tumoral processes requires the precise determination of the specificity of reagents used and the knowledge of ABO, Lewis and secretor phenotypes for each patient. ABH and related antigens should now be regarded as tissue antigens with a complex genetic regulation and expression.