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

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.