Biomedical subjects

V Apostolopoulos

Publications and source records attributed to V Apostolopoulos.

58 records · Page 4Linked to original sources

PubMed1994

Cellular mucins: targets for immunotherapy.

Mucins are attracting great interest as potential targets for immunotherapy in the development of vaccines for cancers expressing Mucin 1 (MUC1) (e.g., breast, pancreas, ovary, and others) as there is (1) a 10-fold increase in the amount in adenocarcinomas; (2) an alteration in expression where they become ubiquitous, and (3) due to altered glycosylation, new epitopes appear on the cell surface that are absent in normal tissues. These new epitopes can be carbohydrate; others are peptide in nature. The cloning of the cDNAs from mucins, particularly MUC1, has led to rapid advances being made, and it is clear that a highly immunogenic peptide exists within the variable number of tandem repeats (VNTR) found in all mucins. This peptide is immunogenic in mice, giving rise to strong antibody production, and most monoclonal antibodies made to breast cancer, which react with the protein core, react with the peptide APDTR. It is now also clear that humans with breast cancer have, in their draining lymph nodes, precursors of cytotoxic T cells that can be stimulated in vitro to react against breast cancer and indeed against the APDTR or a closely related peptide--shown from antibody-blocking studies. These CTLs are unique in that they are non-MHC restricted. The identification of suitable targets, coupled with the known immunogenicity of both the peptide and neo-carbohydrate epitopes, has led to the development of several different programs to immunize humans against breast cancer using either synthetic carbohydrates or peptides conjugated with adjuvants, and clinical trials are now in progress to evaluate their immunogenicity and anti-cancer effects.

Amino Acid Sequence↗

PubMed1993

Production of anti-breast cancer monoclonal antibodies using a glutathione-S-transferase-MUC1 bacterial fusion protein.

Two murine Mabs VA1(IgG1) and VA2(IgG1) were produced against a bacterial fusion protein comprising glutathione S-transferase and five tandem repeats of the MUC1 protein. Using the immunoperoxidase staining technique, VA1 detected 46/53 and VA2 detected 48/53 breast cancers and both also reacted with a range of other human epithelial carcinomas. In addition VA1 gave weak reactions with normal breast tissues whereas VA2 was non-reactive and could be a relatively tumour specific antibody for breast cancer. The antibodies were also tested by ELISA-VA1 reacted weakly with glycosylated HMFG but strongly with deglycosylated HMFG, whereas VA2 reacted strongly with both forms of HMFG. The reactivities of the two Mabs with synthetic peptides of the MUC1 tandem repeat were used to map the epitopes recognised by VA1 (amino acids RPAPGS) and VA2 (amino acids DTRPA). The use of fusion proteins provides another means of immunisation to produce anti-tumour antibodies.

Amino Acid Sequence↗

PubMed1993

Peptide binding sites recognized by anti-mucin (MUC2) monoclonal antibodies.

Multiple genes coding for human mucins have been identified (MUC 1-5) and here monoclonal antibodies (MoAb) to a gastrointestinal mucin--MUC2 are examined. The antibodies were made to a synthetic peptide representing a single repeat in the core protein of the variable number of tandem repeat region. Using the six-mer overlapping peptides synthesized on polyethylene pins, different binding sites were detected by five anti-MUC 2 MoAbs. These contained amino acids: STTT, PTT, GTQTP, TPTP and PTTT (one antibody), and TPTPT. The repeat region of MUC2 essentially is hydrophobic, but contain useful immunogenic sites. This information will be useful for studying the structure and function of MUC2.

Amino Acid Sequence↗

PubMedDate not supplied

Anti-peptide monoclonal antibodies to intestinal mucin 3.

Second generation anti-peptide monoclonal antibodies were produced using synthetic peptide SIB35 (C-HSTPSFTSSITTTETTSHSTPSFTSSITTTETTS) as an antigen which contains two of the MUC3 tandem repeats. Three monoclonal antibodies were produced (M3.1, M3.2 and M3.3) which reacted with the immunizing peptide, but also reacted strongly with colon tissues. Using the immunoperoxidase staining technique, two of the monoclonal antibodies, M3.1 and M3.2, reacted with both colon carcinoma and normal colon tissue whereas the antibody M3.3 reacted with normal colon tissues but very weakly, if not at all, with colon carcinoma. MUC3 was found to be distributed in colon and rectum, and was also present to a lesser extent in breast, lung and salivary gland tissues. Analysis of mucin molecules by Western blotting, revealed the antigen detected by the antibodies (M3.1 and M3.2) to be of a high relative molecular mass. M3.1 and M3.3 reacted with eptiopes SITTTE and PSFTSS, respectively. M3.2 did not react with any of the 6-mer peptides, even though it reacted with the full length VNTR (2 repeat peptide--SIB35). Anti-MUC3 peptide antibodies appear to react with colon, rectum, breast, salivary gland and lung tissues, and represent a new method of producing anti-tumour antibodies.

Amino Acid Sequence↗