valeria turchi - Academia.edu (original) (raw)
Papers by valeria turchi
Acta Neuropathologica, 1994
The expression of the myogenic determination gene MyoD1 plays a primary role in the commitment of... more The expression of the myogenic determination gene MyoD1 plays a primary role in the commitment of primitive mesenchymal cells to a striated muscle lineage and is down-regulated during later stages of differentiation. To determine the potential role of this gene in myopathic conditions, we examined its expression by means of immunohistochemical analysis, using a series of muscle biopsies from 14
Int J Oncol, 1994
Integrin cc6ß4 plays an important role in the interaction of epithelia with basement membranes, a... more Integrin cc6ß4 plays an important role in the interaction of epithelia with basement membranes, and its expression appears to be profoundly altered during tumor progression. Using a quantitative immunochemical assay, we investigated the expression of the ß4 subunit associated with a6 in 25 primary carcinomas, and in matching normal mucosae. a6ß4 was expressed in all the carcinoma and mucosa samples. The highest ß4 levels were detected in tumors at high clinical stage (Dukes' stage C). Furthermore, ß4 reactivity inversely correlated with the degree of differentiation. By immunohistochemistry, ß4 expression was particularly strong in the epithelium lining the upper third of the crypts and the absorbing surface of normal mucosa. In villous adenomas, ß4 immunostaining tended to be enhanced in the epithelium lining the outer surfaces of neoplastic villi, but only 5 of 8 samples tested scored positive. In carcinomas, ß4 expression was detected in 18 of 21 samples tested, and was strongly influenced by the pattern of tumor growth and by the type and level of differentiation. Carcinomas, or areas of carcinomas, with cohesive and differentiated growth pattern demonstrated weak ß4 expression at the tumor-stroma interface. Carcinoma cells at the lumenal surface of the intestine, and carcinomas, or areas of carcinomas, composed of small clusters of cells surrounded by stroma, demonstrated strong ß4 expression. Altogether, our observations indicate that in colorectal tumors the expression of the ß4 subunit is strongly influenced by microenvironmental factors and tends to increase in high stage, poorly differentiated lesions.
The International Journal of Biological Markers, 1992
The purification of the IgM monoclonal antibody 436 against a breast tumor antigen from mouse asc... more The purification of the IgM monoclonal antibody 436 against a breast tumor antigen from mouse ascitic fluid is reported. The purified immunoglobulin was radioiodinated and the resulting product assessed for its binding capacity and binding specificity. Purified IgM-436 served for F(ab') 2μpreparation which was tested for its antigen binding capacity. Radioiodinated IgM-436 and its F(ab')2μ retained their immunological activity which was never lower than those of the corresponding cold products.
The International Journal of Biological Markers, 1992
Epithelial mucins have obtained increasing clinical relevance since they were found in the serum ... more Epithelial mucins have obtained increasing clinical relevance since they were found in the serum of cancer patients and were shown to be elevated in metastatic disease. We report here the characterization of the monoclonal antibody (MAb) 436 which recognises the protein core of the polymorphic epithelial mucin (PEM) of the human breast. MAb 436 was generated by immunizing Balb/c mice with membrane-enriched fractions prepared from metastatic lesions in the axillary lymph nodes. The antigenic determinant recognized by the MAb 436 is expressed on the surface of breast cancer cells and was measured by ELISA on all of 50 cytosol preparations of primary breast tumors. Immunohistochemistry showed 98% of primary and 100% of metastatic breast cancer lesions to be positive with the 436 antigenic determinant expressed both in the cytoplasm and at the plasma membrane level of the tumor cells. Moreover, the antigen was expressed in a homogeneous fashion (80-100% of the total number of tumor cell...
In vivo (Athens, Greece)
Human antibodies were generated by Epstein-Barr Virus (EBV) immortalization of B cells derived fr... more Human antibodies were generated by Epstein-Barr Virus (EBV) immortalization of B cells derived from tumor draining lymph nodes of cancer patients. Antibodies were screened for reactivity in ELISA against a synthetic peptide corresponding to the protein core of the Polymorphic Epithelial Mucin (PEM). Epitopes within this region are in fact considered to be tumor specific since they are selectively exposed on tumor cells due to aberrant glycosylation. Human antibodies thus selected react in ELISA and immunohistochemistry with PEM-expressing tumor cells. This is the first demonstration of the existence of B cell immune response against selected epitopes of PEM and, in association with the cytotoxic T cell (CTL) response already demonstrated, represents the basis for the use of synthetic peptides as vaccines in cancer patients.
Anticancer research
The antigenic phenotypic repertoire of MCF-7 human breast carcinoma cell line variants that displ... more The antigenic phenotypic repertoire of MCF-7 human breast carcinoma cell line variants that display different sensitivity to adriamycin (Adr) was analyzed using monoclonal antibodies (MoAbs) recognizing five different tumor associated antigens (TAAs) and the external domain of the epidermal growth factor receptor (EGF-R). ELISA and cytofluorimetry determinations were used and results indicate a diminished expression of one antigenic determinant of the carcinoembryonic antigen (CEA) molecule, the disappearance of all the other TAAs and the de novo expression of the EGF-R in the MCF-7 AdrR (IC50/Adr:10 uM). Treatment with recombinant alfa-Interferon (alfa-IFN) did not enhance antigenic expression in MCF-7 AdrR cells.
Hybridoma, 1987
The efficiency of various iirmunization protocols for the production of hybridomas secreting irrm... more The efficiency of various iirmunization protocols for the production of hybridomas secreting irrmunoglobulins specific to cell antigens was evaluated in 15 different fusion experiments. Some of these experiments were performed with splenic B-lymphocytes from mice at different stages of immunization. This approach allowed a dynamic analysis of immunocompetent splenic B-lymphocyte production during the immunization cycle.
Transplantation Proceedings, 2000
Transplantation Proceedings, 2000
Proceedings of the National Academy of Sciences, 2002
A large number of hDAF transgenic pigs to be used for xenotransplantation research were generated... more A large number of hDAF transgenic pigs to be used for xenotransplantation research were generated by using sperm-mediated gene transfer (SMGT). The efficiency of transgenesis obtained with SMGT was much greater than with any other method. In the experiments reported, up to 80% of pigs had the transgene integrated into the genome. Most of the pigs carrying the hDAF gene transcribed it in a stable manner (64%). The great majority of pigs that transcribed the gene expressed the protein (83%). The hDAF gene was transmitted to progeny. Expression was stable and found in caveolae as it is in human cells. The expressed gene was functional based on in vitro experiments performed on peripheral blood mononuclear cells. These results show that our SMGT approach to transgenesis provides an efficient procedure for studies involving large animal models.
European Journal of Cancer, 1996
The humoral immune response to the polymorphic epithelial mucin (PEM) was studied by characterisi... more The humoral immune response to the polymorphic epithelial mucin (PEM) was studied by characterising the reactivity of human antibodies generated by EBV-immortalised B-cells from tumourdraining lymph nodes of ovarian cancer patients. All the human antibodies, selected in ELISA for their reactivity to the protein core tandem repeat sequence, reacted with PEM-expressing tumour cells. Aberrant glycosylation of the peptide core of the PEM molecule in cancer cells leads to the exposure of peptide epitopes that can be considered tumour specific. The epitope mapping of six human antibodies revealed that only one of them contained the PDTR sequence, shown to be the immunodominant epitope in the mouse. Four of the six human antibodies recognised a novel common immunogenic sequence (APPAH) in the tandem repeats. The binding of these human antibodies did not appear to be modulated by the length of the carbohydrate side chains, as shown by 0-glycosylation inhibition studies. These results indicate that distinct sequences within the tandem repeat of PEM are target for a humoral immune response in humans. The presence of antibodies directed against different epitopes within the same antigenic region may modulate the antigen presentation process and the ongoing immune response. These data may help in clarifying the mechanisms of the immune response to PEM in cancer patients for the development of PEM-based immunotherapy.
Cell Proliferation, 1992
The effects of the differentiating agent N-methylformamide (NMF) on cell proliferation and antige... more The effects of the differentiating agent N-methylformamide (NMF) on cell proliferation and antigenic pattern of HT-29 colon carcinoma cells have been investigated. The cell line was cultured in the presence, or absence, of 1% NMF and tested for the above mentioned characteristics, both in vitro and after injection into nude mice. The percentage of cells in the various cell cycle compartments was estimated by flow cytometry. The presentation on the cell surface of molecules such as tumour associated antigens (TAAs), HLA class I molecules and epidermal growth factor receptor (EGF-R) was analysed by ELISA, flow cytometry and immunohistochemistry. Results demonstrate that NMF impairs HT-29 cell proliferation with a remarkable accumulation in the G0/G1 phases, as well as inducing a modification of the membrane antigenic pattern. The presence of NMF in the culture medium decreases the TAAs and EGF-R whereas HLA antigen maintains the same level of positivity in the two cell lines. These alterations are consistent with a different behaviour in vivo of the tumours originated from NMF treated and untreated cells. Tumours derived from NMF treated cells show a delay in the appearance and low levels of immunodetectable carcinoembryonic antigen (CEA) molecules.
Annals of the New York Academy of Sciences, 1993
Cancer research, 1993
Human antibodies generated by Epstein-Barr virus immortalized B-cells from tumor-draining lymph n... more Human antibodies generated by Epstein-Barr virus immortalized B-cells from tumor-draining lymph nodes of an ovarian cancer patient were screened for reactivity in enzyme-linked immunosorbent assay with a synthetic peptide corresponding to the protein core of the polymorphic epithelial mucin. Epitopes within this region are in fact considered tumor specific since they are selectively exposed in tumor cells due to aberrant glycosylation. Human antibody BB5, thus selected, reacts in enzyme-linked immunosorbent assay and immunohistochemistry with polymorphic epithelial mucin-expressing tumor cells. This is the first demonstration of the existence of a B-cell immune response to selected epitopes of polymorphic epithelial mucin and, together with the cytotoxic T-cell response already demonstrated, constitutes the basis for the use of synthetic peptides as a vaccine in cancer patients.
Acta Neuropathologica, 1994
The expression of the myogenic determination gene MyoD1 plays a primary role in the commitment of... more The expression of the myogenic determination gene MyoD1 plays a primary role in the commitment of primitive mesenchymal cells to a striated muscle lineage and is down-regulated during later stages of differentiation. To determine the potential role of this gene in myopathic conditions, we examined its expression by means of immunohistochemical analysis, using a series of muscle biopsies from 14
Int J Oncol, 1994
Integrin cc6ß4 plays an important role in the interaction of epithelia with basement membranes, a... more Integrin cc6ß4 plays an important role in the interaction of epithelia with basement membranes, and its expression appears to be profoundly altered during tumor progression. Using a quantitative immunochemical assay, we investigated the expression of the ß4 subunit associated with a6 in 25 primary carcinomas, and in matching normal mucosae. a6ß4 was expressed in all the carcinoma and mucosa samples. The highest ß4 levels were detected in tumors at high clinical stage (Dukes' stage C). Furthermore, ß4 reactivity inversely correlated with the degree of differentiation. By immunohistochemistry, ß4 expression was particularly strong in the epithelium lining the upper third of the crypts and the absorbing surface of normal mucosa. In villous adenomas, ß4 immunostaining tended to be enhanced in the epithelium lining the outer surfaces of neoplastic villi, but only 5 of 8 samples tested scored positive. In carcinomas, ß4 expression was detected in 18 of 21 samples tested, and was strongly influenced by the pattern of tumor growth and by the type and level of differentiation. Carcinomas, or areas of carcinomas, with cohesive and differentiated growth pattern demonstrated weak ß4 expression at the tumor-stroma interface. Carcinoma cells at the lumenal surface of the intestine, and carcinomas, or areas of carcinomas, composed of small clusters of cells surrounded by stroma, demonstrated strong ß4 expression. Altogether, our observations indicate that in colorectal tumors the expression of the ß4 subunit is strongly influenced by microenvironmental factors and tends to increase in high stage, poorly differentiated lesions.
The International Journal of Biological Markers, 1992
The purification of the IgM monoclonal antibody 436 against a breast tumor antigen from mouse asc... more The purification of the IgM monoclonal antibody 436 against a breast tumor antigen from mouse ascitic fluid is reported. The purified immunoglobulin was radioiodinated and the resulting product assessed for its binding capacity and binding specificity. Purified IgM-436 served for F(ab') 2μpreparation which was tested for its antigen binding capacity. Radioiodinated IgM-436 and its F(ab')2μ retained their immunological activity which was never lower than those of the corresponding cold products.
The International Journal of Biological Markers, 1992
Epithelial mucins have obtained increasing clinical relevance since they were found in the serum ... more Epithelial mucins have obtained increasing clinical relevance since they were found in the serum of cancer patients and were shown to be elevated in metastatic disease. We report here the characterization of the monoclonal antibody (MAb) 436 which recognises the protein core of the polymorphic epithelial mucin (PEM) of the human breast. MAb 436 was generated by immunizing Balb/c mice with membrane-enriched fractions prepared from metastatic lesions in the axillary lymph nodes. The antigenic determinant recognized by the MAb 436 is expressed on the surface of breast cancer cells and was measured by ELISA on all of 50 cytosol preparations of primary breast tumors. Immunohistochemistry showed 98% of primary and 100% of metastatic breast cancer lesions to be positive with the 436 antigenic determinant expressed both in the cytoplasm and at the plasma membrane level of the tumor cells. Moreover, the antigen was expressed in a homogeneous fashion (80-100% of the total number of tumor cell...
In vivo (Athens, Greece)
Human antibodies were generated by Epstein-Barr Virus (EBV) immortalization of B cells derived fr... more Human antibodies were generated by Epstein-Barr Virus (EBV) immortalization of B cells derived from tumor draining lymph nodes of cancer patients. Antibodies were screened for reactivity in ELISA against a synthetic peptide corresponding to the protein core of the Polymorphic Epithelial Mucin (PEM). Epitopes within this region are in fact considered to be tumor specific since they are selectively exposed on tumor cells due to aberrant glycosylation. Human antibodies thus selected react in ELISA and immunohistochemistry with PEM-expressing tumor cells. This is the first demonstration of the existence of B cell immune response against selected epitopes of PEM and, in association with the cytotoxic T cell (CTL) response already demonstrated, represents the basis for the use of synthetic peptides as vaccines in cancer patients.
Anticancer research
The antigenic phenotypic repertoire of MCF-7 human breast carcinoma cell line variants that displ... more The antigenic phenotypic repertoire of MCF-7 human breast carcinoma cell line variants that display different sensitivity to adriamycin (Adr) was analyzed using monoclonal antibodies (MoAbs) recognizing five different tumor associated antigens (TAAs) and the external domain of the epidermal growth factor receptor (EGF-R). ELISA and cytofluorimetry determinations were used and results indicate a diminished expression of one antigenic determinant of the carcinoembryonic antigen (CEA) molecule, the disappearance of all the other TAAs and the de novo expression of the EGF-R in the MCF-7 AdrR (IC50/Adr:10 uM). Treatment with recombinant alfa-Interferon (alfa-IFN) did not enhance antigenic expression in MCF-7 AdrR cells.
Hybridoma, 1987
The efficiency of various iirmunization protocols for the production of hybridomas secreting irrm... more The efficiency of various iirmunization protocols for the production of hybridomas secreting irrmunoglobulins specific to cell antigens was evaluated in 15 different fusion experiments. Some of these experiments were performed with splenic B-lymphocytes from mice at different stages of immunization. This approach allowed a dynamic analysis of immunocompetent splenic B-lymphocyte production during the immunization cycle.
Transplantation Proceedings, 2000
Transplantation Proceedings, 2000
Proceedings of the National Academy of Sciences, 2002
A large number of hDAF transgenic pigs to be used for xenotransplantation research were generated... more A large number of hDAF transgenic pigs to be used for xenotransplantation research were generated by using sperm-mediated gene transfer (SMGT). The efficiency of transgenesis obtained with SMGT was much greater than with any other method. In the experiments reported, up to 80% of pigs had the transgene integrated into the genome. Most of the pigs carrying the hDAF gene transcribed it in a stable manner (64%). The great majority of pigs that transcribed the gene expressed the protein (83%). The hDAF gene was transmitted to progeny. Expression was stable and found in caveolae as it is in human cells. The expressed gene was functional based on in vitro experiments performed on peripheral blood mononuclear cells. These results show that our SMGT approach to transgenesis provides an efficient procedure for studies involving large animal models.
European Journal of Cancer, 1996
The humoral immune response to the polymorphic epithelial mucin (PEM) was studied by characterisi... more The humoral immune response to the polymorphic epithelial mucin (PEM) was studied by characterising the reactivity of human antibodies generated by EBV-immortalised B-cells from tumourdraining lymph nodes of ovarian cancer patients. All the human antibodies, selected in ELISA for their reactivity to the protein core tandem repeat sequence, reacted with PEM-expressing tumour cells. Aberrant glycosylation of the peptide core of the PEM molecule in cancer cells leads to the exposure of peptide epitopes that can be considered tumour specific. The epitope mapping of six human antibodies revealed that only one of them contained the PDTR sequence, shown to be the immunodominant epitope in the mouse. Four of the six human antibodies recognised a novel common immunogenic sequence (APPAH) in the tandem repeats. The binding of these human antibodies did not appear to be modulated by the length of the carbohydrate side chains, as shown by 0-glycosylation inhibition studies. These results indicate that distinct sequences within the tandem repeat of PEM are target for a humoral immune response in humans. The presence of antibodies directed against different epitopes within the same antigenic region may modulate the antigen presentation process and the ongoing immune response. These data may help in clarifying the mechanisms of the immune response to PEM in cancer patients for the development of PEM-based immunotherapy.
Cell Proliferation, 1992
The effects of the differentiating agent N-methylformamide (NMF) on cell proliferation and antige... more The effects of the differentiating agent N-methylformamide (NMF) on cell proliferation and antigenic pattern of HT-29 colon carcinoma cells have been investigated. The cell line was cultured in the presence, or absence, of 1% NMF and tested for the above mentioned characteristics, both in vitro and after injection into nude mice. The percentage of cells in the various cell cycle compartments was estimated by flow cytometry. The presentation on the cell surface of molecules such as tumour associated antigens (TAAs), HLA class I molecules and epidermal growth factor receptor (EGF-R) was analysed by ELISA, flow cytometry and immunohistochemistry. Results demonstrate that NMF impairs HT-29 cell proliferation with a remarkable accumulation in the G0/G1 phases, as well as inducing a modification of the membrane antigenic pattern. The presence of NMF in the culture medium decreases the TAAs and EGF-R whereas HLA antigen maintains the same level of positivity in the two cell lines. These alterations are consistent with a different behaviour in vivo of the tumours originated from NMF treated and untreated cells. Tumours derived from NMF treated cells show a delay in the appearance and low levels of immunodetectable carcinoembryonic antigen (CEA) molecules.
Annals of the New York Academy of Sciences, 1993
Cancer research, 1993
Human antibodies generated by Epstein-Barr virus immortalized B-cells from tumor-draining lymph n... more Human antibodies generated by Epstein-Barr virus immortalized B-cells from tumor-draining lymph nodes of an ovarian cancer patient were screened for reactivity in enzyme-linked immunosorbent assay with a synthetic peptide corresponding to the protein core of the polymorphic epithelial mucin. Epitopes within this region are in fact considered tumor specific since they are selectively exposed in tumor cells due to aberrant glycosylation. Human antibody BB5, thus selected, reacts in enzyme-linked immunosorbent assay and immunohistochemistry with polymorphic epithelial mucin-expressing tumor cells. This is the first demonstration of the existence of a B-cell immune response to selected epitopes of polymorphic epithelial mucin and, together with the cytotoxic T-cell response already demonstrated, constitutes the basis for the use of synthetic peptides as a vaccine in cancer patients.