AIM: To investigate the correlation between expression of calreticulin and infiltration of lymphocytes in stage ⅢB colon cancer. METHODS: Sixty-eight pathologically-confirmed speci-mens were obtained from stage ⅢB (...AIM: To investigate the correlation between expression of calreticulin and infiltration of lymphocytes in stage ⅢB colon cancer. METHODS: Sixty-eight pathologically-confirmed speci-mens were obtained from stage ⅢB (T3N1M0) colon cancer patients who underwent radical resection between January 1999 and May 2002 at the Cancer Center of Sun Yat-Sen University, Guangzhou, China. Immuno-histochemical analysis was performed to show infiltration of lymphocytes and expression of calreticulin in colon cancer. Association between calreticulin expression, infiltration of lymphocytes, and 5-year survival rate of patients was assessed. RESULTS: The expression level of calreticulin was lower in cancer nest than in its adjacent normal epithelium since 61.8% (42/68) of the samples were stained with calreticulin in colon cancer. The expression of calreticulin in colon cancer was associated with the infi ltration of CD45RO+ cells rather than with that of CD3+ cells. In addition, the stronger expression of calreticulin and the higher infiltration of CD3+ and CD45RO+ cells in colon cancer were associated with the higher 5-year survival rate of patients. CONCLUSION: Expression of calreticulin is associated with infiltration of T-cells, which implies that a low expression level of molecular marker may represent a new mechanism underlying immune escape in colon cancer.展开更多
AIM: To generate recombinant adenoviral vector con-taining calreticulin (CRT)-hepatitis B surface antigen (HBsAg) fusion gene for developing a safe, effective and HBsAg-specific therapeutic vaccine.METHODS: CRT and HB...AIM: To generate recombinant adenoviral vector con-taining calreticulin (CRT)-hepatitis B surface antigen (HBsAg) fusion gene for developing a safe, effective and HBsAg-specific therapeutic vaccine.METHODS: CRT and HBsAg gene were fused using polymerase chain reaction (PCR), endonuclease diges-tion and ligation methods. The fusion gene was cloned into pENTR/D-TOPO transfer vector after the base pairs of DNA (CACC) sequence was added to the 5′ end. Adenoviral expression vector containing CRT-HBsAg fusion gene was constructed by homologous recombinan-tion. The human embryo kidney (HEK) 293A cells were transfected with linearized DNA plasmid of the recombi-nant adenoviral vector to package and amplify recombi-nant adenovirus. The recombinant adenovirus titer was characterized using the end-dilution assay. The expres-sion of the CRT/HBsAg fusion protein in Ad-CRT/HBsAg infected 293A cells was detected by Western blotting.RESULTS: The CRT-HBsAg fusion gene was char-acterized by PCR and sequencing and its length and sequence were confirmed to be accurate. The CRT-HB-sAg fusion gene recombinant pENTR/D-TOPO transfer vector was constructed. The recombinant adenoviral vector, Ad-CRT/HBsAg, was generated successfully. The titer of Ad-CRT/HBsAg was characterized as 3.9 × 1011 pfu/mL. The CRT-HBsAg fusion protein was ex-pressed by HEK 293A cells correctly. CONCLUSION: CRT/HBsAg fusion gene recombinant replication-defective adenovirus expression vector is constructed successfully and this study has provided an experimental basis for further studies of Hepatitis B vi-rus gene therapy.展开更多
Objective： To investigate the recombinant calreticulin （rCRT） mediated antitumor immune response. Methods： Cell proliferation was determined by MTT method, apoptosis was evaluated by DNA fragmentation and CRT expr...Objective： To investigate the recombinant calreticulin （rCRT） mediated antitumor immune response. Methods： Cell proliferation was determined by MTT method, apoptosis was evaluated by DNA fragmentation and CRT expression and cell localization were assayed by western blotting, QT-RT-PCR and immunofluorescence assays. The mouse melanoma cell line B16-F1 was treated with polyamine analogue BENS to induce apoptosis and incubated with rCRT to get rCRT coated on the membrane, and then the cells were used to immune BALB/c mice as a cell-antigen. Immunized animals were rechallenged by live B16-F1 cells and then tumor generation ratio and the lactate dehydrogenase release assay were used to evaluate antitumor effects of rCRT-mediated immunity. Results： BENS induced apoptosis of B16-F1 cells without the redistribution of CRT within the cells. When B16-F1 cells coated with rCRT were used as cell-antigen to inoculate the animals, the mice obtained the ability in inhibiting proliferation of homologous tumor cells in vivo. Comparing with the positive control group, the splenocytes from those inoculated mice have an obvious enhancement on their cytolytic effects specifically against B16-F1 cells. Conclusion： rCRT coated on the cell surface can enhance immunogenicity of apoptotic tumor cells and mediated effective anti-tumor immunoresponse in mice.展开更多
Calreticulin(CRT)is a highly conserved Ca2+-binding protein and chaperone in the endoplasmic reticulum,which mainly participates in adjusting calcium level and directing proper conformation of proteins.Here,we cloned ...Calreticulin(CRT)is a highly conserved Ca2+-binding protein and chaperone in the endoplasmic reticulum,which mainly participates in adjusting calcium level and directing proper conformation of proteins.Here,we cloned the crt gene of the scleractinian coral Galaxea astreata,named Gacrt,and analysed its ability to drive bacterial agglutination.The full-length Gacrt cDNA consisted of 1792 nucleotides and contained a 77 bp 5’untranslated region(UTR),a 380 bp 3’UTR and a 1335 bp open reading frame(ORF)that encoded a 444 amino acid protein.The deduced peptide possessed a signal peptide domain,an endoplasmic reticulum retrieval signal sequence(KDEL),two potential calreticulin family signature motifs and a set of triplicate repeats.We also found that the recombinant GaCRT protein could promote agglutination of both the Gram-positive bacterium Micrococcus luteus and the Gram-negative bacterium Escherichia coli.These results show that the GaCRT protein can enhance bacterial agglutination,hinting that GaCRT is an immune-relevant molecule involved in host defense against bacterium.展开更多
基金Supported by National Nature Science Foundation of China, 30972882Key Projects of Science and Technology of Guang-dong Province, China, 2008B030301079
文摘AIM: To investigate the correlation between expression of calreticulin and infiltration of lymphocytes in stage ⅢB colon cancer. METHODS: Sixty-eight pathologically-confirmed speci-mens were obtained from stage ⅢB (T3N1M0) colon cancer patients who underwent radical resection between January 1999 and May 2002 at the Cancer Center of Sun Yat-Sen University, Guangzhou, China. Immuno-histochemical analysis was performed to show infiltration of lymphocytes and expression of calreticulin in colon cancer. Association between calreticulin expression, infiltration of lymphocytes, and 5-year survival rate of patients was assessed. RESULTS: The expression level of calreticulin was lower in cancer nest than in its adjacent normal epithelium since 61.8% (42/68) of the samples were stained with calreticulin in colon cancer. The expression of calreticulin in colon cancer was associated with the infi ltration of CD45RO+ cells rather than with that of CD3+ cells. In addition, the stronger expression of calreticulin and the higher infiltration of CD3+ and CD45RO+ cells in colon cancer were associated with the higher 5-year survival rate of patients. CONCLUSION: Expression of calreticulin is associated with infiltration of T-cells, which implies that a low expression level of molecular marker may represent a new mechanism underlying immune escape in colon cancer.
基金Supported by Grants from National Natural Science Foundation of China, No. 30901344
文摘AIM: To generate recombinant adenoviral vector con-taining calreticulin (CRT)-hepatitis B surface antigen (HBsAg) fusion gene for developing a safe, effective and HBsAg-specific therapeutic vaccine.METHODS: CRT and HBsAg gene were fused using polymerase chain reaction (PCR), endonuclease diges-tion and ligation methods. The fusion gene was cloned into pENTR/D-TOPO transfer vector after the base pairs of DNA (CACC) sequence was added to the 5′ end. Adenoviral expression vector containing CRT-HBsAg fusion gene was constructed by homologous recombinan-tion. The human embryo kidney (HEK) 293A cells were transfected with linearized DNA plasmid of the recombi-nant adenoviral vector to package and amplify recombi-nant adenovirus. The recombinant adenovirus titer was characterized using the end-dilution assay. The expres-sion of the CRT/HBsAg fusion protein in Ad-CRT/HBsAg infected 293A cells was detected by Western blotting.RESULTS: The CRT-HBsAg fusion gene was char-acterized by PCR and sequencing and its length and sequence were confirmed to be accurate. The CRT-HB-sAg fusion gene recombinant pENTR/D-TOPO transfer vector was constructed. The recombinant adenoviral vector, Ad-CRT/HBsAg, was generated successfully. The titer of Ad-CRT/HBsAg was characterized as 3.9 × 1011 pfu/mL. The CRT-HBsAg fusion protein was ex-pressed by HEK 293A cells correctly. CONCLUSION: CRT/HBsAg fusion gene recombinant replication-defective adenovirus expression vector is constructed successfully and this study has provided an experimental basis for further studies of Hepatitis B vi-rus gene therapy.
基金supported by a grant from the National Natural Science Foundation of China (No.30973445)
文摘Objective： To investigate the recombinant calreticulin （rCRT） mediated antitumor immune response. Methods： Cell proliferation was determined by MTT method, apoptosis was evaluated by DNA fragmentation and CRT expression and cell localization were assayed by western blotting, QT-RT-PCR and immunofluorescence assays. The mouse melanoma cell line B16-F1 was treated with polyamine analogue BENS to induce apoptosis and incubated with rCRT to get rCRT coated on the membrane, and then the cells were used to immune BALB/c mice as a cell-antigen. Immunized animals were rechallenged by live B16-F1 cells and then tumor generation ratio and the lactate dehydrogenase release assay were used to evaluate antitumor effects of rCRT-mediated immunity. Results： BENS induced apoptosis of B16-F1 cells without the redistribution of CRT within the cells. When B16-F1 cells coated with rCRT were used as cell-antigen to inoculate the animals, the mice obtained the ability in inhibiting proliferation of homologous tumor cells in vivo. Comparing with the positive control group, the splenocytes from those inoculated mice have an obvious enhancement on their cytolytic effects specifically against B16-F1 cells. Conclusion： rCRT coated on the cell surface can enhance immunogenicity of apoptotic tumor cells and mediated effective anti-tumor immunoresponse in mice.
基金The National Marine Welfare Industry Research Project under contract No.201105012the Guangdong Provincial Natural Science Foundation under contract No.S2011010000269+1 种基金the Guangdong Marine Fishery Science and Technology Extension Project under contract No.A201308E02the Guangdong Ocean University Scientific Research Start-up Fund for the Doctoral Program under contract No.R17066。
文摘Calreticulin(CRT)is a highly conserved Ca2+-binding protein and chaperone in the endoplasmic reticulum,which mainly participates in adjusting calcium level and directing proper conformation of proteins.Here,we cloned the crt gene of the scleractinian coral Galaxea astreata,named Gacrt,and analysed its ability to drive bacterial agglutination.The full-length Gacrt cDNA consisted of 1792 nucleotides and contained a 77 bp 5’untranslated region(UTR),a 380 bp 3’UTR and a 1335 bp open reading frame(ORF)that encoded a 444 amino acid protein.The deduced peptide possessed a signal peptide domain,an endoplasmic reticulum retrieval signal sequence(KDEL),two potential calreticulin family signature motifs and a set of triplicate repeats.We also found that the recombinant GaCRT protein could promote agglutination of both the Gram-positive bacterium Micrococcus luteus and the Gram-negative bacterium Escherichia coli.These results show that the GaCRT protein can enhance bacterial agglutination,hinting that GaCRT is an immune-relevant molecule involved in host defense against bacterium.
