Low protease activity in B cell follicles promotes retention of intact antigens after immunization.

The structural integrity of vaccine antigens is critical to the generation of protective antibody responses, but the impact of protease activity on vaccination in vivo is poorly understood. We characterized protease activity in lymph nodes and found that antigens were rapidly degraded in the subcapsular sinus, paracortex, and interfollicular regions, whereas low protease activity and antigen degradation rates were detected in the vicinity of follicular dendritic cells (FDCs). Correlated with these findings, immunization regimens designed to target antigen to FDCs led to germinal centers dominantly targeting intact antigen, whereas traditional immunizations led to much weaker responses that equally targeted the intact immunogen and antigen breakdown products. Thus, spatially compartmentalized antigen proteolysis affects humoral immunity and can be exploited.

Reprogramming NK cells and macrophages via combined antibody and cytokine therapy primes tumors for elimination by checkpoint blockade.

Treatments aiming to augment immune checkpoint blockade (ICB) in cancer often focus on T cell immunity, but innate immune cells may have important roles to play. Here, we demonstrate a single-dose combination treatment (termed AIP) using a pan-tumor-targeting antibody surrogate, half-life-extended interleukin-2 (IL-2), and anti-programmed cell death 1 (PD-1), which primes tumors to respond to subsequent ICB and promotes rejection of large established tumors in mice. Natural killer (NK) cells and macrophages activated by AIP treatment underwent transcriptional reprogramming; rapidly killed cancer cells; governed the recruitment of cross-presenting dendritic cells (DCs) and other leukocytes; and induced normalization of the tumor vasculature, facilitating further immune infiltration. Thus, innate cell-activating therapies can initiate critical steps leading to a self-sustaining cycle of T cell priming driven by ICB.

A Robust Fabrication Technique for Hydrogel Films Containing Micropatterned Opal Structures via Micromolding and an Integrated Evaporative Deposition-Photopolymerization Approach.

Opal-structured thin-film hydrogel materials with micropatterns hold great potential for utility in a wide range of sensing applications. Micropatterning offers key advantages such as ready addressability, high throughput assay, and multiplexing. However, controlled fabrication of such films in a rapid, inexpensive, and reliable manner remains a challenge. Existing techniques suffer from long opal deposition times and often involve complex and arduous steps. In this report, we examined a simple micromolding-based evaporation-polymerization method for the fabrication of poly(ethylene glycol)-based hydrogel films containing micropatterned opal structures. Specifically, intense and uniform opalescent colors were achieved by evaporative deposition of polystyrene bead solution in patterned micromolds. These opal micropatterns were then captured in hydrogel films by simple photopolymerization of a UV-curable PEG diacrylate solution. The as-prepared films show high tunability as well as responsiveness to various environmental cues readily manifested via shifts in color. Combined with UV-vis reflectance spectroscopy and scanning electron microscopy results, these findings illustrate the robust, simple, and reliable nature of our integrated deposition-polymerization approach for controlled fabrication of optically active and stimuli-responsive functional materials. We thus envision that the results and the facile approach reported here can be extended to many application areas including environmental monitoring, diagnostics, and biosensing applications.