Summary auto-generated
This study investigated tumor-associated antigens in X-ray-induced thymic lymphosarcomas (TLS) in C57BL/6 mice. Researchers established 17 permanent cell lines from radiation-induced tumors and generated monoclonal antibodies (MAbs) from splenocytes of tumor-bearing mice to identify tumor-specific antigens. The tumor cells were characterized as T lymphocytes and tested for retrovirus expression. Using ELISA, 12 MAbs were screened against tumor cell extracts and normal thymus tissue. Results revealed at least 10 distinct antibody specificities that fell into three categories: antibodies recognizing both tumor and normal thymic tissue; antibodies specific to the autologous tumor only; and antibodies specific to heterologous tumors but not autologous tumors. Notably, most detected antigens were present in normal thymus tissue with quantitative variations, and only two tumors exhibited additional antigenicities. No consistent relationship was observed between retrovirus expression and the pattern of antigen recognition, suggesting that tumor maintenance may not depend solely on viral expression. Each tumor displayed a unique antigen profile, with some showing selective loss of normal thymic antigens rather than gain of new ones.
Key findings
- Established 17 permanent cell lines from radiation-induced thymomas; 86% survival rate when cultured with thymic epithelial cell support
- Detected at least 10 distinct antibody specificities among monoclonal antibodies, classifying them into three categories based on tumor and normal tissue recognition patterns
- Most tumor-associated antigens were present in normal thymus tissue; only 2 of 13 tumors had additional antigenicities beyond normal tissue
- 65% of cultured tumor cell lines produced detectable retroviruses, but no correlation was found between viral expression and antigen recognition patterns
- Individual tumors were characterized by unique antigen profiles, with many showing selective loss of normal thymic antigens rather than novel antigen expression
This summary was generated automatically from the article PDF and is not part of the original publication. Refer to the PDF for the authoritative text.
Abstract
X-irradiation of C57BL/6 mice induces thymic lymphosarcomas which sometimes contain retroviruses which upon injection into normal mice mimic the effect of the irradiation. We examined whether specific antigenicities, viral or cellular, were expressed by tumour cells that could be recognized by antibodies from the irradiated animals. We developed monoclonal antibodies (MAbs) using splenocytes of the diseased animal. The reactivity of such MAbs towards thymoma cell lines established in vitro was investigated by means of an ELISA. At least 10 antibody specificities were detected on the 13 tumours investigated, allowing separation of the MAbs into three classes: (i) those recognizing the autologous tumour, heterologous tumours as well as normal thymic tissue, (ii) those specific for the autologous tumour, and (iii) those specific for one tumour, but not ones of autologous origin. The last two classes corresponded to specific tumour-associated antigens. Our panel of MAbs defined each tumour by the particular pattern of antigens harboured. It is striking that most of the antigens were present in the normal thymus and that only two tumours had additional antigenicities. Additionally, quantitative variations were observed in the levels of expression of these antigens.