NEO ANTIGEN AND IMMUNOBIOLOGY OF MEDULLARY BREAST CANCER

拟议的研究旨在确定和表征新表达的蛋白质（新抗原），导致浆细胞反应在乳腺髓样癌（MC）。 我们的主要假设是，浆细胞和淋巴样成分的显著浸润反映了针对肿瘤的局部免疫应答，这是导致仅手术治疗后MIC肿瘤的自然病程更有利的印象的原因。 我们将应用分子克隆技术从肿瘤浸润的浆细胞中获得抗体，然后使用这些抗体来检索在肿瘤中新表达的蛋白质引起的反应。 我们从浆细胞浸润的MC肿瘤制备了组合噬菌体Fab文库。 我们证明这些组织表达高度集中的IgG抗体库，支持我们对肿瘤中表达的新抗原的特异性免疫反应的前提。 此外，肿瘤中占优势的类别转换的IgG同种型和高程度的CDR突变表明T依赖性抗原，即，蛋白质。 研究还表明，新抗原既不是p53也不是Her 2/neu，这两种主要的乳腺癌相关抗原，这使得新抗原更有可能（但尚未证明）是以前未描述的蛋白质或以前未识别为肿瘤相关的蛋白质。新抗原可以是外来的（即，病毒）蛋白或存在于肿瘤中的异常表达或突变的正常蛋白。 这些重要的初步数据证明了继续克隆引发抗原的努力是正确的。 将通过用患者抗体筛选肿瘤特异性表达文库来克隆抗原，同时采用平行生物化学方法以确保克隆成功。 然后研究和评估克隆和表达的新抗原在恶性增殖中的可能作用。

The proposed research seeks to identify and characterize newly expressed proteins (neo-antigens) that cause plasma cell reactions in medullary carcinomas (MC) of breast. It is our principal hypothesis that the marked infiltration of plasma cells and lymphoid elements reflects a local immune response against tumor that is responsible for the impression of a more favorable natural course of MIC tumors after surgery-only therapy. We will apply molecular cloning techniques to derive antibodies from tumor-infiltrating plasma cells, and then use these antibodies to retrieve the proteins whose new expression in the tumors caused the response. We prepared combinatorial phage Fab libraries from plasma cell-infiltrated MC tumors. We proved these tissues express highly focussed IgG antibody repertoires, supporting our premise of a specific immune reaction against a neo-antigen expressed in the tumor. Further, the dominant class-switched IgG isotype in the tumor and the high degree of CDR mutations suggest a T-dependent antigen, i.e., a protein. It was also shown that the neo-antigen is neither p53 nor Her2/neu, two dominant breast carcinoma-associated antigens, making it more likely (but not yet proving) that the neo-antigen is a previously undescribed protein or a protein not previously recognized to be tumor-associated. The neo-antigen could be a foreign (i.e., viral) protein or an aberrantly expressed or mutated normal protein that is present in the tumor. These important preliminary data justify the pursuit of the remaining effort to clone the eliciting antigen. Antigen will be cloned by screening of tumor-specific expression libraries with patient antibodies, while pursuing a parallel biochemical approach to ensure success in the cloning. The cloned and expressed neoantigen(s) is(are) then studied and assessed for possible roles in the malignant proliferation.