Pankaj Kumar

TLR5 Signaling Causes Dendritic Cell Dysfunction and Orchestrates Failure of Immune Checkpoint Therapy against Ovarian Cancer

Abstract Ovarian cancer accounts for more deaths than any other cancer of the female reproductive system. Patients who have ovarian tumors infiltrated with high frequencies of T cells are associated with a greater survival probability. However, therapies to revitalize tumor-associated T cells, such as PD-L1/PD-1 or CTLA4 blockade, are ineffective for the treatment of ovarian cancer. In this study, we demonstrate that for ovarian cancer, Toll-like receptor 5 (TLR5) signaling, for which the only known ligand is bacterial flagellin, governed failure of PD-L1 and CTLA4 blockade. Mechanistically, chronic TLR5 signaling on CD11c+ cells in vivo and in vitro impaired the differentiation of functional IL-12–producing XCR1+CD103+ conventional type 1 dendritic cells, biasing CD11c+ precursor cells toward myeloid subsets expressing high levels of PD-L1. This culminated in impaired activation of CD8+ T cells, reducing CD8+ T-cell function and ability to persist within the ovarian tumor microenvironment. Expansion of XCR1+CD103+ conventional type 1 dendritic cells in situ using Flt3L-Ig in combination with PD-L1 blockade achieved significant survival benefit in TLR5 knockout mice bearing ovarian tumors, whereas no benefit was observed in the presence of TLR5 signaling. Thus, we have identified a host-intrinsic mechanism leading to the failure of PD-L1 blockade for ovarian cancer, demonstrating that chronic TLR5 signaling on CD11c+ cells is a barrier limiting the efficacy of checkpoint therapy.

Diagnostic Translational Considerations for Global Health Settings: Portable Detection of Human Papillomavirus for Cervical Cancer Screening in India

PURPOSE Translation of diagnostic technology developed at the laboratory bench involves iterations of user feedback and design modifications. Learning about translational requirements early in the design process facilitates the development of feasible prototypes that have a better likelihood of implementation in global health settings. During our development of a portable system to detect human papillomavirus (HPV) for cervical cancer screening in India, we encountered and solved issues related to research translation. We report our findings to help others deploying diagnostic technology for global health. MATERIALS AND METHODS We designed a point-of-care system to process patient samples and diagnose HPV infection in the cervix. We continually shipped components of the system from the United States to our collaborating team in India to assess component condition and usability at the local site. We simultaneously developed HPV isothermal amplification assays that were fit for purpose. Cervical brush samples were used in our portable system for functional validation. RESULTS We found ideal transport methods to ensure component quality and reagent stability through the international shipment chain. Portable systems should be designed as simple as possible for correct usage at the local testing site. Usability tests drove our design improvements from 28% to 93% success rates. We demonstrated proof-of-concept functionality of our portable system for 13 cervical brush samples on-site, with a sensitivity of 100% and specificity of 88.9%. CONCLUSION Issues related to technology transfer for global health settings manifest during distribution and deployment of prototypes. We identified several issues during our synergistic design process and report recommendations on the basis of our experience.