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Authors: Stergiou, Natascha
Title: Verwendung von Tumor-assoziiertem Mucin 1 zur Generierung von Anti-Tumor-Vakzinen und monoklonalen Antikörper-Derivaten als Basis für Therapie und Diagnostik von Brustkrebs
Online publication date: 27-May-2019
Year of first publication: 2019
Language: german
Abstract: Mucin1 (MUC1) is a very promising tumor antigen, because its tumor-associated (TA) form significantly differs from the glycoprotein form on healthy cells. Due to its aberrant glycosylation in tumor cells, specific MUC1 peptide epitopes are more or less accessible as neo-antigens in the protein backbone for antibodies. This enabled the working group of Prof. Dr. (Organic Chemistry, Johannes Gutenberg-University Mainz) to synthesize glycopeptide vaccines against the human (TA)MUC1 (anti-hu(TA)MUC1 glycopeptide vaccine) which were able to induce a brilliant humoral tumor-specific immune response. A special vaccine synthesized by Dr., in cooperation with the Institute of Immunology, led to the generation of a breast tumor-specific monoclonal antibody (mAb), GGSK-1/30. In the first part of this thesis, the immunological effects of different anti-hu(TA)MUC1 glycopeptide vaccines were compared. For this purpose, first wild-type mice were immunized with different hu(TA)MUC1 glycopeptides, which were each conjugated to the carrier protein tetanus toxoid (TTox). Compared to previous studies, it showed that the most accurate mapping possible of the (TA) glycosylation pattern, as it is believed to be on epithelial tumors, is required to generate high IgG antibody titers that can bind to breast cancer cells. Since TTox has a large number of T helper cell epitopes, the synthetic TTox vaccines proved to be very promising vaccines in this study as well as in previous studies which induced very strong and specific immune responses in mice. However, these TTox vaccines are difficult to characterize as the total molecule cannot be precisely analyzed because of its size. As an alternative, fully synthetic two-component vaccines were therefore produced by the working group of Prof. Dr. which carry peptide sequences of the tetanus toxoid (P30) or the polio virus (VP1103-115) as T helper cell epitopes. The immunological effect of these fully synthetic vaccines was compared to the TTox vaccines. Significantly weaker antigen-specific IgG titers were determined. This also resulted from the fact, that in this work the Complete Freund's Adjuvant(CFA) used in previous studies was omitted, since it is not allowed to use it in humans. Instead, the anti-hu(TA)MUC1 glycopeptide vaccines were combined with the human tolerated adjuvants CpG and poly(I:C). As a result, the immune responses of the two component vaccine could be significantly increased and the production of IgG2a and IgG2b antibodies could be induced, which play a crucial role in the antibody-dependent anti-tumor response. In addition, these adjuvants had the desired pro-inflammatory effect. Both proinflammatory (TNF-a, IL-1b) and anti-tumoral cytokines (IL-9, IFN-g), as well as CD8 T cells, which are crucial for the cellular tumor immune response, could be found. In another approach, the concept of targeting immune cells was used. The corresponding anti-hu(TA)MUC1 glycopeptide vaccine was covalently coupled to a divalent mannose. As a result, the uptake and presentation of the vaccine by accessory cells such as macrophages could be significantly increased, resulting in a stronger activation of T helper cells and comparatively high IgG antibody titers. In parallel to these investigations, a preclinical breast tumor model was developed. In contrast to other well-known breast cancer models, this model spontaneously developed autochthonous breast tumors expressing human MUC1. Immunization of these mice induced strong specific humoral immune responses, resulting in a marked slowing of tumor progression and increased survival of breast tumor-bearing mice. Finally, the mAb GGSK-1/30, which is able to completely differentiate between carcinogenic and normal epithelial cells, has been used as an important diagnostic tool ex vivo on human breast tumor tissue sections and in vivo in this preclinical breast tumor model. For this, the mAb GGSK-1/30 was labeled with the radioistop 89Zr in cooperation with the working group of Prof. Dr. (Nuclear Chemistry, Johannes Gutenberg-University Mainz) and administered intraperitoneally. By means of PET analyzes, a specific accumulation in the breast tumor tissue could be detected. Overall, both the immunization studies using anti-hu(TA)MUC1 glycopeptide vaccines and the analysis of the therapeutic and diagnostic potential of the hu(TA)MUC1-specific mAb GGSK-1/30 show that (TA)MUC1 represents an outstanding target molecule for tumor therapy. The generation of various antibody derivatives and the further improvement of the anti-hu(TA)MUC1 glycopeptide vaccine could enable first clinical trials in the foreseeable future.
DDC: 500 Naturwissenschaften
500 Natural sciences and mathematics
Institution: Johannes Gutenberg-Universität Mainz
Department: Externe Einrichtungen
FB 04 Medizin
FB 09 Chemie, Pharmazie u. Geowissensch.
Place: Mainz
URN: urn:nbn:de:hebis:77-diss-1000027985
Version: Original work
Publication type: Dissertation
License: In Copyright
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Extent: XIV, 222 Seiten
Annotation: ra
Appears in collections:JGU-Publikationen

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