| IntroductionThe major histocompatibility complex ( MHC) , which are called human leukocyte antigens (HLA) in humans, locate on chromosome 6p21 and encode several sets of immunoregulatory molecules. HLA class I antigens are polymorphic transmemberane glycoproteins composed of two polypeptide chains. The heavy chain is highly polymorphic HLA - A, B and C, the other chain isp2 - m . HLA class I antigens are widely distributed on most nucleated cells, with the exception of neurons, sperm and trophoblast. Presentatation of endogenous anti-genie peptides to cytotocic T lymphocytes( CTL) is their major function. HLA - A, B and C antigens play key roles in the course of CTL mediated immune elimination of tumor cells.At present, the generation, development and metastasis of tumors were considered the result of tumor cell escape immune surveillance from T and NK cells. The expression of HLA class I antigens have been measured by immunohistochemistry (IHC ) in various tumors and the result demonstrated the deficient expression, furthermore correlated with clinicopathologic characteristics of tumors. Overall or selective loss of expression of HLA - A, B and C antigens in human tumors help tumor cells escape immune surveillance from CTL and NK celland make tumors developed. Reduced expression of HLA class I antigens has been observed in melanoma, cervical carcinoma, colon and gastric cancer, and has been associated with tumor invasiveness and aggressiveness. Study on expression of HLA - A, B and C antigens in lung cancer were little, and opinions of different scholar were different. In our study, using the monoclonal antibody against HLA - A, B and C antigens (W6/32) , we detected the expression of human leucocytes antigen in primary and their metastatic lymph nodes, and discuss the relation between the expression of HLA - A, B and C antigens and clinicopathologic factors of lung carcinomas.Materials and methodsPatients and specimen;We study 67 patients with primary lung cancer who had definitive pulmonary resection with complete ipsilateral mediastinal lymph nodes resection at the department of thoracic surgery of the first clinical hospital of china medical university between March 2001 and December 2001. All patients underwent potentially curative surgery without pre-operative adjuvant therapy. There were 48 men and 19 women, with a mean age of 58. 3 years ( s. d6. 6, range32 ~ 78). The histological typing was performed according to the revised WHO classification. Six patients were SCLC, 27 patients were SQC and 34 patients were AC. Tumor tissue, normal lung tissue which distanced tumor 5cm and part of resected lymph nodes were snap frozen in liquid nitrogen after resection and stored at a temperature of - 80 Tl.Monoclonal antibodies;Mouse anti-human MAbs W6/32 ( Dako) were used to directed a-gainst a monomorphic antigenic epitope of HLA class I heavy chains (HLA - A, B and C antigens).Immunohistochemistry;From each specimen, 4μm thickness cryostat sections were made and stored at -80℃ until use. The sections were fixed with acetone for 10 minutes and air dried. All subsequent. steps were performed at room temperature. The sections were incubated with methanol containing 0.3% hydrogen peroxide for 20 minutes to block endogenous per-oxidase activity. After treatment with PBS containing 5% normal rabbit serum for 20 minutes, the sections were incubated with mouse monoclonal anti-human HLA- A,B and C antibody(W6/32) at a dilution of 1:200 for 2 hours in a moist chamber. After treated with bioti-nylatede rabbit and-mouse immunoglobulin dilution of 1: 100 for 30 minutes , the sections were incubated with S-P for 20 minutes, and followed by DAB and hydrogen peroxide mixture. The sections were counterstained with hematoxylin, dehydrated in graded ethanol , cleared in xylene and mounted. Negative controls were established by replacing the primary antibody ( W6/32) with PBS .Evaluation of the specimens;If membrane of cell was stained brown-color, the cell would be called positive cell . We...
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