Bioinformatics analysis of HLA-A2 restricted neoantigen epitopes in breast cancer / 中国肿瘤生物治疗杂志

@#[Abstract] Objective: To screen candidate epitopes of breast cancer HLA-A2 restrictive neoantigen and to identify high frequency mutation sites in breast cancer neoantigen by using bioinformatics method. Methods: NCBI and GDC databases were used to search missense mutation sites formed by single nucleotide mutation in breast cancer among reported literatures and sequencing data. The new antigen epitopes were predicted by HLA-A2 antigen epitope prediction website BIMAS, SYFPEITHI and artificial neural networkbased NetMHC4.0, and the epitopes with TAP binding power less than Intermediate were eliminated. The candidate epitopes were prioritized by mutation frequency and prediction results. Results: A total of 17 high-frequency mutation genes, including BTLA, ERBB2 and NBPF12 etc, were screened by the above-mentioned methods, and a total of 26 neoantigen epitopes were identified. The binding power of epitopes predicted using BIMAS and SYFPEITHI showed great difference (P<0.05), epitopes in high priority as GSTP1 (A114V , mutation frequency of 5.94%) and BRCA2 (N991H, mutation frequency of 5.40%) etc, were expected to be candidate neo-antigen epitopes; however, their mutation frequency was relatively too low to achieve“universal use” . The possibility of these epitopes used as general breast cancer neo-antigen epitopes is less likely. Conclusion: The common mutation frequency of breast cancer is lower than that of other tumors; it ’s difficult to find“universal”new antigen epitopes of breast cancer; the individualized neoantigen vaccine may be of more promise, which needs further research.

In vivo immunogenic characteristics of cytotoxic T lymphocyte epitopes from pancreatic tumor antigen MUC4 / 中国病理生理杂志

AIM:Peptide vaccines have been conceived as promising therapies for tumor-inflicted patients due to their easy production and capability of inducing specific immune response required for defending the tumor.During our previous research,4 HLA-A2-restricted peptides had been identified as immunogenic in vivo.In this study, we aimed to testify the in vivo immunogenicity of the 4 peptides.METHODS: BALB/c mice were vaccinated with HLA-A2 restricted peptides emulsified in incomplete Freund's adjuvant(IFA)subcutaneously in combination with the epitope at the adjacent location.After the 3rd peptide vaccination for 10 d,the peptide-specific immune response was evaluated by ELISPOT and ELISA.The ability to induce T cell response was investigated by using cytotoxicity assay in vivo and the presence of pep-tide-specific CD8+T cells capable of recognizing the MHC-peptide was detected by flow cytometry.RESULTS: Among the 4 candidate HLA-A2 restricted peptides,the immune response elicited by P2004-1Y9V was superior to that of the other 3 peptides.The CTLs induced by P2004 and P2004-1Y9V lysed CAPAN-2 cells.P2004-1Y9V peptide-specific CTLs showed higher cytotoxicity against pancreatic tumor cell lines of CAPAN-2 than the native peptide-specific CTLs.Intracellu-lar cytokine staining assay indicated the presence of P 2004-1Y9V specific CD8 +T cells in the P2004-1Y9V vaccinated mice.CONCLUSION:P2004-1Y9V is the most immunogenic peptide in vivo, and can be explored as potential tumor peptide vaccine in the future clinical study.

Safety of the bone marrow derived mesenchymal stem cells after HLA A 2 gene silencing / 西安交通大学学报(医学版)

Objective To explore the safety of the human bone marrow‐derived mesenchymal stem cells (hBMSCs) after silencing of human leukocyte antigen A2 expression .Methods We divided the cells into three groups:normal cultured cells of the 8th passage served as control group , and hBMSCs after HLA A2 silencing expression of the 5th and 15th passage as experimental groups 1 and 2 ,respectively .The hBMSCs were recultured by sterile methods .The growth curve ,telomerase activation ,and expressions of P27 ,cyclin D2 and cyclin‐dependent kinase 4 (CDK4) were utilized to explore the safety of the hBMSCs induced by LV‐siRNA‐HLA A2 .The BMSCs were transplanted to the subcutaneous layer of nude mice .Tissue types were detected 24 weeks after transplantation . Results The cell curves had no obvious left or right shift in all the groups . The telomerease activation in experimental groups 1 and 2 did not significantly differ from those in control group . The expressions of anti‐oncogene P27 ,cyclin D2 and CDK4 had no obvious difference between the two experimental groups and control group , either . There was only ectopic osteogenesis 24 weeks after the BMSCs (HLA A2 gene silenced ) were transplanted to the subcutaneous layer of the nude mice .Conclusion There was no obvious evidence to support that hBMSCs had undergone change in safety after the silencing of HLA A 2 expression .

Relationship between Poor Immunogenicity of HLA-A2-Restricted Peptide Epitopes and Paucity of Naive CD8+ T-Cell Precursors in HLA-A2-Transgenic Mice

We examined the immunogenicity of H-2 class I-restricted and HLA-A2-restricted epitopes through peptide immunization of HLA-A2-transgenic mice that also express mouse H-2 class I molecules. All four of the tested epitopes restricted by H-2 class I robustly elicited T-cell responses, but four of seven epitopes restricted by HLA-A2 did not induce T-cell responses, showing that HLA-A2-restricted peptide epitopes tend to be poorly immunogenic in HLA-A2-transgenic mice. This finding was confirmed in HLA-A2-transgenic mice infected with a recombinant vaccinia virus expressing hepatitis C virus proteins. We examined the precursor frequency of epitope-specific naive CD8+ T cells in HLA-A2-transgenic and conventional C57BL/6 mice and found that the poor immunogenicity of HLA-A2-restricted peptide epitopes is related to the paucity of naive CD8+ T-cell precursors in HLA-A2-transgenic mice. These results provide direction for the improvement of mouse models to study epitope repertoires and the immunodominance of human T-cell responses.

Neonatal Alloimmune Thrombocytopenia Caused by Anti-HLA-A2 Alloantibodies Determined by Luminex Single Antigen Bead Assay

Neonatal alloimmune thrombocytopenia (NAIT) occurs when maternal alloantibodies react to antigens expressed on fetal platelets, which is mainly platelet-specific alloantigen or HLA, resulting in their immune destruction. Here, we described a patient who suffered from NAIT caused by anti-HLA-A2 antibody. Sera from the mother and the newborn were screened for human platelet antigen-specific antibodies and HLA antibodies by ELISA, and HLA antibodies were detected in both of them. The antibody specificity was identified as anti-HLA-A2 by Luminex single antigen bead assay. HLA typing results showed that patient's father descended HLA-A2 antigen on the patient and the mother was HLA-A2 negative. It is most conceivable that anti-HLA-A2 alloantibody in the mother's sera crossed the placenta and subsequently caused NAIT in the case presented. The patient received platelet concentrates, oral steroid and intravenous globulin and platelet count increased to 120x10(9)/L on the 90th day of life. The Luminex single antigen bead assay used in this case is highly sensitive and specific assay to determine antibody specificity and it is faster and more convenient for routine use in clinical laboratory so that this assay could be useful to diagnose NAIT caused by HLA antibodies and treat such NAIT patients with HLA matched platelet transfusion.

Expression of CD3+ CD8+ human leukocyte antigen-A2+ T lymphocytes with specificity to the different hepatitis B virus peptides in patients with hepatitis B associated hepatocellular carcinoma / 中华传染病杂志

ObjectiveTo explore the expression of CD3+ CD8+ human leukocyte antigen (HLA)-A2+T lymphocytes with specificity to the different hepatitis B virus (HBV) peptides in the peripheral blood mononuclear cells (PBMC)from the patients with hepatitis B associated hepatocellular carcinoma (HCC).MethodsThe HLA-A2+ PBMC from four patients with hepatitis B associated HCC were incubated with five HBV/HLA-A2 pentamers respectively,which were HBV sAg (FLLTRILTI),HBV sAg (GLSPTVWLSV),HBV sAg (WLSLLVPFV),HBV core (FLPSDFFPSV),and HBV pol (FLLSLGIHL),as well as anti-CD3-pacific blue and anti-CD8-fluorescein isothiocyanate (FITC).Then,HBV/HLA-A2-CD3-CD8 positive cells were detected by flow cytometry. The monoclonal HBV/HLA-A2-CD3-CD8+ cells were acquired by fluorescenceactivated cell sorter,and cultured and identified by flow cytometry.The anti-HBV specific T lymphocytes were then cultured with HepG2 (HLA-A2+ ) cells and the release of interferon γ (IFN-γ)were determined by enzyme-linked immunosorbent assay (ELISA),Res(a)ltsThe percentage of antiHBV T lymphoeytes with specificity to GLSPTVWLSV in total CD8+ T lymphoeytes from four patients with hepatitis B associated HCC was 1.44％±0.04％,which was higher than those to other four HBV antigen peptides (0.68％±0.08％ of FLLTRILTI,1.06％±0.09％ of FLPSDFFPSV,0.56％ ±0.04％ of FLLSLGIHL,and 0.46％ ±0.08％ of WLSLLVPFV) (t=0.001,P＜0.05).The two lines of monoclonal cell with specificity to GLSPTVWLSV both exhibited high level of IFN-γ expression after incubated with hepatic carcinoma cell line HepG2 (HLA-A2+)with HBV GLSPTVWLSV peptide.ConclusionsCD3+ CD8+ HLA-A2+ cells with specificity to the different HBV peptides exist in PBMC of patients with hepatitis B associated HCC.The expression level depends on HBV antigen peptide sequences and genomic sites.

HLA-A2-restricted point-mutated Survivin peptide elicited specific cytotoxic T lymphocyte reaction against hepatocarcinoma / 中华微生物学和免疫学杂志

Objective To investigate the anti-hepatocarcinoma(anti-HCC) function of HLA-A2-restricted point-mutated Survivin peptide induced CTLs.Methods The HLA-A2-restricted Survivin nonapeptides were evaluated using bioinformatics software.The binding affinity of Survivin peptide to HLA-A2 molecular was determined with flow cytometry analysis.After peptide-induced CTLs were generated in vitro,flow cytometry and ELISA were performed to detect the levels of IFN-γ,which were secreted by reactive CTLs.Peptide-induced CTLs were co-cultured with hepatoma cell lines HepG2 and BEL-7402.The rates of tumor cells lysis were assayed using CytoTox 96(R) and the morphological changes of tumor cells were observed with inverted phase contrast microscope.Results Point-mutated Survivin nonapeptide Sur79M2 (KMSSGCAFL) was filtered out,which was shown higher scores compared with the wild-type peptide Sur79.Consistent with the results of software analysis,Sur79M2 showed higher binding ability in T2 binding assays.At the same time,Sur79M2-induced CTLs could release a large number of IFN-γ after incubated with target cells rather than Sur79.When co-cultured with HCC cell lines HepG2 and BEL-7402,Sur79M2-induced CTLs effectively lysis HepG2 on HLA-A2-restricted manner without killing effect on BEL-7402 that do not express HLA-A2 molecules.Conclusion Sur79M2 could elicited specific cytotoxic T lymphocytes in vitro,which were able to specifically kill HCC cell lines on HLA-A2-restricted manner.

pMHC/scFv fusion protein mediates killing of tumor cells by viral specific cytotoxic T cells / 中华微生物学和免疫学杂志

Objective To study whether the HBC-A2/scFv fusion protein mediates killing of tumor cells by viral specific cytotoxic T cells. Methods The fusion protein was attached to the CD71-expressing, HLA class Ⅰ negative tumor cells. And then, cytolysis by viral peptide-specific CTLs which were generated by co-culture of peripheral blood lymphocytes from HLA-A2 positive donors with inactivated T2 cells pulsed with the viral peptide were tested by lactate dehydrogenase (LDH) releasing. Results The fusion protein can attach the active viral peptide/HLA-A2 complex to K562, HepG2 and U937 cells through binding of CD71 scFv to CD71 (37.30% ±8.25%, 27.20% ±3.88%, 21.80% ±6.49% ) and mediate cytotoxicity of viral peptide-specific CTLs against those cells in vitro ( K562: 42.08% ± 1.14% vs 8.07%± 1.39%; HepG2: 49.72% ± 1.59% vs 12.46% ± 1.26%; U937: 39.72% ± 3.26% vs 7.13% ±1.48% ). Conclusion This viral peptide/HLA-A2 complex targeted by CD71 scFv is able to redirect viral peptide-specific T-cell mediated immune responses against tumor cells.

The HLA-A2 restriction and immunogenicity of hepatitis C virus-spedfic cytotoxic T lymphocyte epitopes / 中华微生物学和免疫学杂志

Objective To explore the HLA-A2 restriction and immunogenicity of 5 previously identified HCV-speeific CTL epitopes. Methods Based on T2 cell, to explore the HLA-A2 restriction of previously identified HCV-specific CTL epitopes by MHC-peptide complex stabilization assay;To detect pep-tide-specific CTL in HLA-A2~+ PBMC stimulated by HLA-A2-restricted peptides by intracellular cytokine staining(ICS) and ELISPOT; To explore the cytotoxicity of peptide-specific CTL to same peptide-loaded T2 cells (target cells) by CTL cytotoxicity test. Results Among 5 previously identified CTL epitopes NS4b_78 (SMMAFSAAL) and NS5a_367 (TVSSALAEL) have high-affinity for HLA-A2 molecules(FI 1) ;ELISPOT results shown that NS4b_78(SMMAFSAAL) and NSSa_367(TVSSALAEL) induced high levels of IFN-γ-se-creting cells [(60±6) SFC/10~4 PBMC vs (4±1 ) SFC/10~4 PBMC, P < 0.01 ; (10 ± 3 ) SFC/10~4 PBMC vs (2±1 ) SFC/10~4 PBMC, P <0.01, respectively] ;ICS results indicated that there were high percentages of CD8~+ IFN-γ~+ T cells in total CD8~+T cells stimulated by these peptides [(2.33 ±0.22 ) % vs (0.05±0.01)%, P <0.001 ; (0.36±0.06)% vs (0.03±0.01)%, P <0.001, respectively]. Furthermore,peptide-specific CTL could effectively kill same peptide-loadcd T2 cells. Conclusion NS4b_78 (SMMAF-SAAL) and NSSa_367 (TVSSALAEL) were identified as HLA-A2-restricted CTL epitopes which could in-duce immune response in vitro.

Selection and identification of HLA-A2-restricted CTL epitopes within heparanase / 中华微生物学和免疫学杂志

Objective To select and identify human leukocyte antigen(HLA)-A2-restricted T-cell epitope within heparanase(Hpa),and to provide aeademic bases for peptide-based immunotherapy with malignant tumor.Methods The Hpa sequence was scanned for prediction of the immunogenic peptides-based CTL epitopes using the HLA-binding prediction software SYFPEITHI and BIMAS.Ten the affinity of candidate epitopes to HLA-A2 was evaluated by T2 binding test.Acfivation of T cell was assessed by ELIS-POT and cytotoxictiy by lactate dehydrogenase(LDH)release assay.Results of the six predicted nona-peptides,Hpa(310-318,FLNPDVLDI)showed high affinity of binding to HLA-A2 and led to IFN-γ secre-tion in vitro.Furthermore,Hpa(310-318) FLNPDVILDI could induce PBMC from a HLA-A2 positive healthy donor to lyse specifically HCC-LM6 and SW-480 cells which expressing both Hpa and HLA-A2.Conclusion The nona-peptide Hpa(310-318)FLNPDVLDI may be all HLA-A2-restricted CTL epitope.which is capable of inducing Hpa-specific CTL in vitro.

Prediction of HLA-A2.1 restricted CTL epitope of SSX gene family and affinity assay of these epitopes with MHC-Ⅰ molecule / 第三军医大学学报

Objective To explore the immunotherapeutic strategy based on SSX tumor gene family by the CTL epitope prediction of the members of SSX tumor gene family and affinity assay of the epitope combining with MHCⅠ molecule.Methods The CTL epitope in the members of SSX gene family were predicted with the predictive software of HLA-A2.1 restricted CTL epitope.The 4 predicted epitope peptides were synthesized: P1(AMTKLGFKA),P4 (AMTKLGFNV),P5(AMTKLGFKV) and P6(VMTKLGFKV).After the affinity between these peptides and MHC-Ⅰ molecule were examined respectively,the combining stability between these peptides and the MHC-Ⅰ molecule were investigated respectively.Results As compared with positive control peptide HBcAg18-27,all of the synthesized peptides except P1 showed high affinity with MHC-Ⅰ molecule.The combining stability assay indicated that dissociation complex 50(DC_(50)) for P1,P4 and the positive control HBcAg 18-27 was all above 8.0 h,but DC_(50) for P5 and P6 was between 2 h and 4 h.Conclusion Two ideal peptides were screened out from the predicted CTL epitope peptides by in vitro MHC-Ⅰ combining affinity and stability assay,which provided the experimental data for the further identification of these epitope peptides in vivo.

The Frequency of HLA Alleles in Korean Children with Aplastic Anemia and the Correlation with the Response to Immunosuppressive Treatment / 대한소아혈액종양학회지

PURPOSE: Immune pathophysiology of aplastic anemia (AA) has been indirectly inferred from responses to immunosuppressive agents. An association between AA and HLA-A2, or HLA-DR2 (its serologic split, HLA-DR15; or its molecular correspondents, DRB1*1501) has been implicated. The presence of HLA-DR15 (including DR2 or DRB1*15) has been closely associated with a favorable response to immunosuppression in AA. This study was aimed to characterize Korean patients with AA by determining the association with certain HLA alleles, such as HLA-DR2 or HLA-A2, and their implications in terms of the response to immunosuppression. METHODS: One-hundred eighteen children with AA from 10 university hospitals between 1990 and 2001 were enrolled in this multicenter, retrospective study. Among them, HLA data were available from 80 patients. Tests of proportions were used to compare allelic frequencies. RESULTS: The frequency of HLA-A2 (58.8%) or HLA-DR2 (24.7%) in AA was not significantly different from those of the controls. Analysis of the patients treated with immunosuppression (N=86) showed that, 50.0% of patients showed a response, including 16.0% of complete response at 6 months. The presence of DR2 allele did not portend a favorable response to immunosuppressive therapy. CONCLUSION: Unlike Western countries, the association of AA with certain HLA alleles was not documented in the Korean population. Moreover, the presence of HLA-DR2 did not predict a favorable response to immunosuppression. This peculiar characteristics of Korean AA needs to be investigated whether these findings reflect ethnic differences, different contribution of immune-mediated AA, different immune mechanisms, or mere limitation by number of study patients.

Direct Analysis of HBV-Specific CD8+ Lymphocyte By Tetrameric HLA-A2/core 18-27 Complex in Chronic Hepatitis B / 대한간학회지

BACKGROUNDS/AIMS: Hepatitis B virus(HBV) specific cytotoxic T lymphocyte (CTL) response is believed to play a major role in virus control and liver damage in chronic hepatitis B(CHB). We performed this study to evaluate whether HBV specific CTL could be visualized directly by tetrameric HLA-A2/core 18-27 complex(T c18-27) in the peripheral blood and liver of patients with CHB. On the basis of our results we clarified patients intrahepatic compartmentalization and correlation with HBV specific CTL and viral replication or liver damage. METHODS: We stained peripheral blood mononuclear cells of 33 HLA-A2 + and 8 HLA-A2 patients with CHB with cychrome conjugated anti-CD8 mAb and phycoerythrin conjugated T c18-27. Among these we analysed intrahepatic lymphocyte of 11 HLA-A2 + patients. We compared the frequency of T c18-27 specific CD8+ cells with serum HBV-DNA levels or alanine aminotransferase(ALT) levels. RESULTS: The frequency of circulating T c18-27 specific CD8+ cell was higher(9-101 cells per 50,000 CD8+ cells) than background level in 14 among 33 patients. The frequency of intrahepatic T c18-27 specific CD8+ cells was 12-2100 cells per 50,000 CD8+ cells in 8 out of 11 patients whose liver was obtained This was 17.4-150 times higher than circulating T c18-27 specific CD8+ cells. The frequency of circulating T c18-27 specific CD8+ cells was increased in 10 out of 18 patients with serum HBV DNA level 800 pg/mL and ALT >70 IU/L. The frequency of intrahepatic T c18-27 CTL tended to be lower in high levels of serum HBV DNA and was not correlated with liver inflammation. CONCLUSION: This study provess that if HBV-specific CTLs are barely detectable in the peripheral blood of CHB, much more HBV-specific CTLs are in the liver and most HBV-specific CTLs are infiltrated in the liver. Also, in the presence of an effective HBV specific CD8 response the inhibition of viral replication can be independent of liver damage.

Determination of circulating HBV specific CD8~+ cells by tetramer staining flow cytometry / 中华检验医学杂志

Objective To evaluate the clinical application of HLA-peptides tetramer staining flow cytometry for determining HBV specific CD8+ cells.Methods HBV specific CD8+ cells in whole blood samples of chronic hepatitis B patients were stained with tetramer complex of HLA-A2 and HBV core 18-27 peptide and counted by flow cytometry. Results The medians of percentages of HBV specific CD8+ cells of total CD8+ cells were 0.20%(0.02%～2.04%) in 11 acute hepatitis B patients and 0.05%(

A Case of Neonatal Alloimmune Thrombocytopenia dut to Anti-HLA A2

Neonatal alloimmune thrombocytopenia(NAIT) is a rare disease caused by maternal alloimmunization against fetal platelet surface antigen, which is mainly platelet specific alloantigen or human leukocyte antigen(HLA). During routine hemotology, we accidentally discovered thrombocytopenia in a female fullterm newborn admitted due to jaundice. We excluded NAIT due to human platelet alloantigen(HPA), because the HPA of the mother and baby were the same on PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism). Mother's serum was tested for lyrnphocytotoxity against 36 donor lymphocytes, and anti-HLA A2, A24 and B58 were found. HLA typing of the father and baby revealed A2 antigen which was not present on the mothers lymphocytes. The patient received concentrated platelet and intravenous globulin. Her platelet count increased to 222,000/mm from 3,000/mm on the 11th day of life. We described a case of NAIT due to anti-HLA A2 antibody with a detailed clinical feature. (J Korean Pediatr Soc 1999;43:861-865)

The study of human melanoma-specific antigen peptides by HLA-A2 restricted tumor-infiltrating lymphocytes / 中国免疫学杂志

Objective:To explore the characteristics of human melanoma-specific antigen peptides by HLA-A2 restricted tumor-infiltrating lymphocytes.Methods:The HLA-A2 protein and polypeptides molecules were purified from the three tumor cell lines(624-Mel, Chap-Mel and JY) by immunoaffinity chromatography, after the peptides bound to HLA-A2 protein solution were acidified with acetic acid and boiled by high temperature, and centrifuged through an Ultra-CL filter, then the peptides extracts were fractionated by revered phase high pressure liquid chromatography(RP-HPLC). Individual fractions were assessed for their ability to reconstitute melanoma-specific epitopes by adding to the HLA-A2 Ag-procceing mutant cell, T2. The biological feature of one of three active peptides from RT-HPLC samples was performed by mass spectrometric analysis. The synthetic peptides identical to active peptide sequences were determined in the reconstitute test.Results:Three prominent peaks(P19, P25 and P31) of the fraction from 624-Mel were observed in the reconstitute test, TIL killing rate was 67% for (P31) peptide fraction. The mass spectrometric analysis of one of active peptides (P31) showed that at mass-to-charge ratio(m/z) 948 has been usually nine residues. The sequence is H+ Ala Lue Trp Lue Phe Phe Gly Val Lue OH-. The peptide synthesized comprising epitopes were verified.Conclusion:These results showed the peptides derived from active fractions were related to human melanoma-specific tumor antigen peptides recognized by HLA-A2-restriced TIL. These peptides could develop novel peptide-based an anti-tumor vaccine for immunotherapy of CTL.

Expression of c-erbB2 and HLA-A2 in Breast Cancer Patients / 한국유방암학회지

PURPOSE: Oncogene c-erbB2 produces a transmembrane protein similar in structure to the tyrosine kinase family. Overexpression of c-erbB2 is known to lower the survival rate of breast cancer patients. c-erbB2 protein is an important antigen for tumor specific cytotoxic T lymphocytes induction that is dependent on its presentation as stably complexed with HLA-A2. In 1997, Nistico P reported low frequency of c-erbB2 proto-oncogene overexpression in HLA A2 positive breast cancer patients. And then in this study, correlation of HLA-A2 and the c-erbB2 expression was investigated in breast cancer patients. MATERIALS AND METHODS: HLA-A DNA typing by locus-specific generic PCR and by hybridization with sequence-specific oligonucleotide probes (SSOP) was performed on peripheral blood lymphocytes from 52 breast cancer patients (a PCR-SSOP typing method, involving a PCR amplification in conjunction with digoxigenin labelled sequence-specific oligonucleotide probes). To determine c-erbB2 expression, immunohistochemistry from paraffin-embedded tissues in a series of 47 patients with available tissue blocks was performed by use of rabbit anti-human c-erbB2 oncoprotein (DAKO, Glostrup, Denmark). And then we statistically analyzed the relation between the expressions of HLA-A2 and c-erbB2 in breast cancer patients. RESULTS: 29 out of 52 patients (55.8%) were HLA-A2 positive. 23.4% (11out of 47 patients) of breast cancer patients overexpressed c-erbB2. The patients with c-erbB2 overexpression showed lower estrogen receptor positivity compared to those without c-erbB2 overexpression (10.5%, vs 33.3%). HLA-A2 positive patients showed 18.5% (5/27) of overexpression and HLA-A2 negative patients showed 30.0% (6/20) of c-erbB2 overexpression (p=0.283). CONCLUSIONS: We observed no correlation between HLA-A2 and prognostic factors in breast cancer such as tumor size, axillary nodal status. However, our results showed a tendency without statistical significance between HLA-A2 and high frequency of c-erbB2 overexpression. More accumulation of patients will be needed for better conclusions.

Construction of mammalian cell expression vector for HLA-A~*0201 and EGFP fusion protein and its expression and localization in K562 cells / 中国病理生理杂志

AIM: To construct the mammalian cell expression vector for enhanced green fluorescent protein (EGFP) and HLA-A*0201 fusion protein and analyze its expression and subcellular localization in the transfected K562 cells. METHODS: The HLA-A*0201 cDNA was cloned by RT-PCR and the gene was inserted into pEGFP-N1 to construct a vector for the fusion protein. The expression of the fusion protein in K562 cells transfected with the vector was evaluated by flow cytometry and its subcellular localization was investigated by confocal microscopy. RESULTS: The full-length encoding region of HLA-A*0201 cDNA was cloned from two HLA-A2 positive donors and the expression vector for the HLA-A*0201-EGFP fusion protein was constructed by PCR using a primer pair to introduce a Kozak sequence before ATG and the stop codon was deleted. Five hours after K562 cells was transfected with the vector, the expression percentages of HLA-A*0201 and EGFP were 25.12?2.26 and 27.37?3.59, respectively and no significant increase was observed after 24 h. The fusion protein was predominantly located on the membrane with low level distribution within the cells. In contrast, no HLA-A*0201 but only EGFP was detected in the empty vector transfected K562 cells and the EGFP was dispersed within the cells. CONCLUSIONS: The expression vector for HLA-A*0201-EGFP fusion protein was constructed and the fusion protein expressed in K562 cells was primarily distributed on the membrane. The results suggest that the transfected K562 cells are potential antigen-presenting cells.