摘要:

SUMMARYCancers are the result of somatic heritable changes in certain genes. The AKR leukaemia K36.16 has been extensively studied in our laboratory. When compared to normal AKR thymocytes, the K36.16 tumour cells do not express the H‐2Kkantigens and have an unexpected antigenic determinant that could be detected by anti‐H‐2Ddmonoclonal antibodies. To understand the molecular mechanisms that could be responsible for these changes, we have compared the genomic composition of the class I MHC genes in the K36.16 tumour cells to that of normal AKR lymphocytes. A unique polymorphic 2.6‐kb Hind III fragment was detected in DNA obtained from the K36.16 tumour cells after hybridization with a 3′‐gene‐coding H‐2 probe. This fragment is not present in DNA of normal AKR lymphocytes. In an effort to further understand the mechanism underlying the nature of this MHC gene polymorphism, we have cloned and sequenced this Hind III fragment. When compared with the reported sequences of a number of mouse class I MHC genes, the nucleotide sequence of this polymorphic Hind III fragment is similar to that of a re

ISSN:1744-3121    

DOI:10.1111/j.1744-313X.1989.tb00480.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARYMany human and mouse tumours do not express MHC class II antigens and have reduced levels of class I antigens. Because of the requirement for class I and/or class II antigen for antigen presentation to Thand Tccells, these phenotypes may enable tumour cells to ‘escape’ the host's immune response. Experiments presented here are designed to assess the role of MHC class I and class II antigens in tumour immunity, and to overcome the MHC class I‐ or class II‐negative phenotype. When transfected with the syngeneic H‐2Dbgene, the MHC antigen‐negative 402AX teratocarcinoma expresses high levels of H‐2Dbantigen. 402AX/Dbcells are rejected by MHC allogeneic and some WHC syngeneic 402AX‐susceptible mice, however the fully syngeneic strain of origin (129) remains tumour‐susceptible. Induction of MHC class I gene products on class I antigen‐negative embryonal carcinoma cells therefore increases tumour immunogenicity in some hosts, but not in the fully syngeneic mouse. In an attempt to enhance antigen presentation of tumour‐associated antigens to Thcells, MHC class I antigen‐positive SaI (KkDd) sarcoma cells were tranfected with syngeneicAαkandAβkgenes to generate Iak‐expressing tumour cells. SaI/Akcells are efficiently rejected by syngeneic A/J (KkDd) mice, while untransfected SaI cells are lethal. Induction of MHC class II antigen expression on the class I antigen‐positive SaI sarcoma therefore co

ISSN:1744-3121    

DOI:10.1111/j.1744-313X.1989.tb00481.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARYIn this report we demonstrate that lowered expression of the H‐2 antigens on RadLV‐induced tumour cells is a result of depressed levels of stable mRNA in these cells. Whether this observation is a result of lowered transcription or of mRNA instability is under investigation. In an effort to determine which viral sequences are essential for mediating both the H‐2 regulatory function and the transforming function of RadLV, we have begun to assemble newly integrated proviral genomes from tumours. The restriction enzyme cleavage sites of four isolates are presented; these isolates differ substantially from RadLV genomes previously presented. One of these molecular clones is shown to encode a non‐defective B‐tropic, ecotropic virus which when reinjected into resistant mouse strains can mediate the up‐regulation of H‐2Ddantigen expression. Finally, possible mechanisms of H‐2 regulatio

ISSN:1744-3121    

DOI:10.1111/j.1744-313X.1989.tb00482.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARYThe adenocarcinoma LT85 was chemically induced in a mouse from a C3Hf colony shown subsequently to be inbred for a gene conversion‐like mutation at theH‐2Klocus, characterized by a clustered four nucleotide substitution in exon 3. The H‐2K phenotype of LT85, however, more closely resembles that of C3H rather than the mutant strain now designated C3Hf H‐2km2. We cloned and sequenced theH‐2Kgene from this tumor to determine whether (i) LT85 might carry a tumor‐associated somatic reversion of theH‐2Kkm2germline mutation or (ii) the tumor was induced in a mouse that was geneticallyH‐2krather thanH‐2km2. Our analysis confirmed that the LT85H‐2Kallele is identical throughout the entire coding region to C3HH‐2Kk. To exclude the possibility of a somatic reversion by recombination, we used an oligonucleotide probe corresponding to the region altered inH‐2kto show that the C3Hf genome lacks the necessary coding information to reverse theH‐2Kkm2mutation through a sequence exchange with another class I locus. Since it is unlikely that multiple independent point mutations would account for restoration of this stretch ofH‐2Kksequences, the tumor was probably established in a mouse carrying a normalH‐2Kkallele, possibly at a point prior to the establishment of theH‐2Kkm2mutation as a homozygo

ISSN:1744-3121    

DOI:10.1111/j.1744-313X.1989.tb00483.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARYFollowing ‘in vivo’ treatment with 5‐(3–3′‐dimethyl‐l‐triazeno)imidazole‐4‐carbox‐amide (DTIC), murine leukemic cells acquire new antigenic specificities not detectable on parental cells and responsible for the rejection of the tumour by syngeneic hosts.‘In vivo’ and ‘in vitro’ experiments pointed out an immunological cross reactivity between DTIC treated and untreated lines. Furthermore, specific CTLs raised against DTIC treated L1210 tumour cells (H‐2d) were cytotoxic for H‐2ktarget cells. The aim of this study is to investigate whether the H‐2kcross reactivity displayed by L1210/DTIC is related to the drug treatment rather than due to an antigen already present in the parental line and maintained after treatment. Cloned cells from L1210, obtained by limiting dilution ‘in vitro’, were recloned ‘in vivo’ and then treated with DTIC. Syngeneic and allogeneic CTLs raised ‘in vitro’ against parental and treated clones showed lytic activity against H‐2ktarget cells. Treated and untreated clones were then checked for the presence of H‐2k‐like determinants using monoclonal antibodies. One of these, HB‐53 (IgG2bKkDkwas highly positive with all the clones tested in binding assay using iodinated Fab anti‐mouse Ig, fluorescence and FACS analysis. Others displayed a low reactivity against both treated and untreated clones without significant differences. After neuraminidase treatment of two clones (D and D/DTIC), the H‐100.5 (anti H‐2Kk)‐reactive epitope was dramatically exposed mi the DTIC tumour cells but not on the parental clones. These data suggest that the H‐2kcross reactivity is related to the presence of a TAA that is maintained after treatment. Nevertheless DTIC could enhance the expression of some H‐2k‐like determinants. So far it is not possible to rule out that this

ISSN:1744-3121    

DOI:10.1111/j.1744-313X.1989.tb00484.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARYExpression of beta human chorionic gonadotropin (βhCG) by bladder tumours has been shown to be associated with increased metastases and resistance to treatment with radiotherapy and chemotherapy. Preliminary results from typing frozen tumours using monoclonal antibodies against HLA determinants show reduced or lost expression of one or more antigens in two thirds of patients studied with a trend for more malignant behaviour and inability to generate tumour infiltrating lymphocyte expression using Interleukin‐2 in those patients whose tumours demonstrate loss. In this series βhCG expression was only seen in a subgroup of those demonstrating loss of HLA antigen expression. Studies of βhCG secreting bladder cancer cell lines showed that it was possible to induce class II HLA antigen expression with gamma Interferon, and that this treatment but not alpha Interferon reduced βhCG production by the cell

ISSN:1744-3121    

DOI:10.1111/j.1744-313X.1989.tb00485.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARYThe expression of HLA class I(‐like) genes was studied in two human developmental turnour cell lines representing embryonic (Tera‐2) and extra‐embryonic (Jeg‐3) origins. Neither cell line expresses polymorphic HLA‐A, ‐B, ‐C antigens as determined by standard serological typing. Tera‐2 cells express the HLA class I‐like T cell system A (TCA) determinants; Jeg‐3 cells are TCA negative. Northern blot analysis using an HLA class I α3 domain specific probe revealed markedly reduced levels of HLA class I(‐like) transcripts in both cell lines, which can be upregulated in Tera‐2 cells by incubation with gamma interferon (γIFN). Immunoprecipitation studies with a large panel of HLA class I/beta‐2 microglobulin (β2m) monoclonal antibodies (mAbs), detect low quantities of regular HLA class I heavy chains that are not associated with β2m on the surface of Tera‐2 cells. In contrast, Jeg‐3 cells express significant amounts of cell membrane β2m associated molecules of 41 and 45 kilodalton (kD). Screening of a Tera‐2 cDNA library, yielded 30 clones that hybridize to a full length HLA class I cDNA probe. Sixteen have been characterized and represent HLA class I sequences, consistent with the haplotype of Tera‐2. A similar screening of a Jeg‐3 cDNA library isolated clones representing a single novel HLA‐C‐like sequence; this probably codes for the 45 kD cell surface molecules of Jeg‐3. The 41 kD molecule may be encoded by the HLA‐6.0 gene since

ISSN:1744-3121    

DOI:10.1111/j.1744-313X.1989.tb00486.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARYProducts 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 growthin 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 under‐represented 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 hos

ISSN:1744-3121    

DOI:10.1111/j.1744-313X.1989.tb00487.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARYAlthough natural killer (NK) activity is not restricted by the major histocompati‐bility complex (MHC), it has been suggested that the level of expression of MHC antigens by target cells may influence their lysis by NK cells. We have studied the NK susceptibility of 20 cell lines obtained from primitive and metastatic human tumours and the K562 cell line treated with γ‐interferon, phorbol ester TPA and tumour factor NK‐RIF.When the levels of MHC class I antigen expression on the human tumour cell lines and their NK susceptibility were compared, no relationship between these two parameters was observed. Futhermore the treatment of K562 with either γ‐interferon, TPA or NK‐RIF decreased its NK susceptibility independently of MHC class I expression.These results indicate that the MHC class I antigen is not the only factor directly involved in NK susceptibility and suggest that other membrane structures modulated by γ‐interferon, TPA or NK‐RIF may also influence N

ISSN:1744-3121    

DOI:10.1111/j.1744-313X.1989.tb00488.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARYThe expression of HLA class I and II antigens was analysed in 30 primary gastric carcinomas, 27 autologous lymph node metastases and 25 autologous gastric mucosae. We used an immune alkaline phosphatase technique on cryostatic sections and mAbs directed against HLA class I monomorphic determinants, HLA‐B locus‐specific products and HLA‐DR, ‐DP and ‐DQ molecules. In addition HLA class I genes were analysed in tumour tissue and compared by Southern blots with the RFLP from autologous mucosa using locus‐specific HLA probes. Finally the infiltrating mononuclear cells were studied on gastric tumours and adjacent mucosa with mAbs defining CD4, CD8 and CD11b differentiation antigens.The results obtained showed that three out of 27 primary gastric carcinomas completely lack HLA‐ABC antigens (10%). In addition, two primary tumours presented a variable expression. The remaining 22 tumours presented a homogeneous positive HLA class I expression. Interestingly, when the autologous mucosa was analysed, only 12 out 25 specimens were homogeneously stained with mAbs against HLA class I antigens, suggesting that this tissue may lack the expression of HLA antigens before becoming malignant. Indeed, the majority of the gastric carcinomas studied presented a higher HLA‐ABC antigenic expression than autologous mucosa. Finally, the HLA expression observed in the primary tumour was similar to that observed in autologolous metastases.As a second part of the study we have found a direct relationship between the expression of HLA‐DR antigens in mucosa and the intensity of inflamatory infiltration. This relationship was not maintained in the tumour tissue. In the mucosa the CD4‐positive T cell was the predominant lymphocyte, while it was CD8 in the HLA

ISSN:1744-3121    

DOI:10.1111/j.1744-313X.1989.tb00489.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY