Identification of Relevant Conformational Epitopes on the HER2 Oncoprotein by Using Large Fragment Phage Display (LFPD)

We developed a new phage-display based approach, the Large Fragment Phage Display (LFPD), that can be used for mapping conformational epitopes on target molecules of immunological interest. LFPD uses a simplified and more effective phage-display approach in which only a limited set of larger fragments (about 100 aa in length) are expressed on the phage surface. Using the human HER2 oncoprotein as a target, we identified novel B-cell conformational epitopes. The same homologous epitopes were also detected in rat HER2 and all corresponded to the epitopes predicted by computational analysis (PEPITO software), showing that LFPD gives reproducible and accurate results. Interestingly, these newly identified HER2 epitopes seem to be crucial for an effective immune response against HER2-overexpressing breast cancers and might help discriminating between metastatic breast cancer and early breast cancer patients. Overall, the results obtained in this study demonstrated the utility of LFPD and its potential application to the detection of conformational epitopes on many other molecules of interest, as well as, the development of new and potentially more effective B-cell conformational epitopes based vaccines

Multiple roles of perforin in hampering ERBB-2 (Her-2/neu) carcinogenesis in transgenic male mice.

Perforin (pfp)-mediated cytotoxicity is one of the principal immunosurveillance mechanisms involved in the fight against cancer. However, its importance in spontaneous epithelial cancer is still poorly defined. In this study, we use a realistic mouse model that displays many features that are equivalent to human pathology to evaluate the role of pfp-dependent immunosurveillance by comparing tumor progression in rat ERBB-2 (neu) transgenic, pfp-proficient (neu+/pfp+) or pfp-deficient (neu+/pfp2) BALB/c male mice. Adult neu+/pfp+ males developed poorly differentiated salivary carcinomas, whereas neu+/pfp2 males displayed their salivary carcinomas noticeably earlier and showed zones of more highly differentiated tumor, indicating that pfp-mediated immunosurveillance is able not only to delay the growth kinetic of an aggressive epithelial tumor, but also to shape its histology. The role of pfp-mediated immunosurveillance appeared to be of even more dramatic importance against the less aggressive male mammary carcinomas. In neu+/pfp+ males, the incidence of mammary carcinomas was a sporadic and late event. In contrast, in neu+/pfp2 males their incidence was four-fold higher. This higher cancer incidence was associated with a 2-fold higher occurrence of persisting mammary remnants, a major risk factor for mammary cancer in male mice, and one that would appear to be due to pfp\u2019s previously unidentified involvement in male mammary gland rejection during embryogenesis. This work thus provides further proof of the complex role that the immune system plays in the body and gives new insight into the pathogenesis of epithelial tumors, demonstrating that the penetrance and malignancy of a tumor may be dramatically affected by pfp-dependent mechanisms

Human responses against HER-2-positive cancer cells in human immune system-engrafted mice.

none17De Giovanni C;Nicoletti G;Landuzzi L;Romani F;Croci S;Palladini A;Murgo A;Antognoli A;Ianzano ML;Stivani V;Grosso V;Iezzi M;Stramucci L;Barbieri E;Lemoli RM;Nanni P;Lollini PLDe Giovanni, C; Nicoletti, G; Landuzzi, L; Romani, F; Croci, S; Palladini, A; Murgo, A; Antognoli, A; Ianzano, Ml; Stivani, V; Grosso, V; Iezzi, M; Stramucci, L; Barbieri, E; Lemoli, ROBERTO MASSIMO; Nanni, P; Lollini, P