Abstract A11: The function of B cells in non-small cell lung cancer patients.

Abstract

Abstract Lung cancer is the leading cause of cancer death in both men and women. Although novel therapies are emerging, we are interested in boosting tumor-specific immune responses in infiltrating lymphocytes. In a flow cytometric analysis of the immune infiltrate in non-small cell lung cancer (NSCLC) tumors (n=25), we found that the total number of infiltrating B cells (TIL-Bs) in the tumor versus the matched tumor-adjacent tissue was increased compared to other immune subsets, specifically T cells. Most NSCLC TIL-Bs were activated (CD69+ and CD86+) and had a memory phenotype (CD27+). Proliferation, antigen presentation, and antibody production studies were done to assess the range of function in TIL-Bs. Positively isolated TIL-Bs that were stimulated for three days through the antigen receptor had varied proliferation when compared to B cells from the tumor adjacent tissue, which suggests a spectrum of function in TIL-Bs at the site of the tumor. For antigen presentation, TIL-Bs stimulated CD4 tumor infiltrating lymphocytes (CD4 TILs) to proliferate without the addition of tumor lysate compared to the negative and positive controls (T cells alone and T cells activated through the T cell receptor, respectively). This suggests that TIL-Bs can present endogenous tumor antigens to CD4 TILs; however, antigen presentation is not as robust with TIL-Bs from other patient tumors, which is another example of a spectrum in TIL-B function. Finally, we assayed total antibody production (IgG) by TIL-Bs to determine if this is a function at the site of the tumor. Tumor and tumor adjacent B cells produce antibody in comparison to B cells from the periphery of a normal donor; this function is uniform unlike proliferation and antigen presentation. We predict that TIL-Bs have a range of function in their response against tumors. Our overall hypothesis is that tumor immunity in NSCLC is influenced by the molecular signature of TIL-Bs, which directs proliferation, presentation of tumor antigens to T cells, and production of anti-tumor antibodies. We are determining if proliferation, antigen presentation, and antibody production are tumor antigen-specific, particularly for the lung cancer-testis antigen XAGE-1b. This antigen was the most highly expressed in our patient tumor cells when analyzed by real time PCR and has been shown to play a role in NSCLC. We are performing experiments with TIL-Bs to test XAGE-1b specific proliferation and antigen presentation. Further, we generated a XAGE-1b ELISA to test the specificity of the antibodies generated by the TIL-Bs. Three out of twelve patient sera were positive for XAGE-1b-specific antibodies indicating that the XAGE-1b ELISA is working for the detection of XAGE-1b antibodies. Further, we are isolating cells from tumor, tumor adjacent, and normal (cancer-free) lung tissue to analyze the molecular signature of TIL-Bs to identify a pathway upstream of B cell signaling that may be altered and influencing TIL-B function. Results from this study will advance the understanding of the function of TIL-Bs in solid tumors, and which functions can be targeted. Ultimately, this project will provide a platform for a therapeutic vaccine for lung cancer patients, and more importantly, will help us understand why some patients do not respond well to immunotherapy. Such results may lead to the development of a prognostic tool to screen patients that will respond to vaccine. Citation Format: Tullia C. Bruno, Daniel Munson, Brandon Moore, Katherine Waugh, Jeffrey Kern, Jill E. Slansky. The function of B cells in non-small cell lung cancer patients. [abstract]. In: Proceedings of the AACR-IASLC Joint Conference on Molecular Origins of Lung Cancer; 2014 Jan 6-9; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2014;20(2Suppl):Abstract nr A11.