Benjamin Allsup (BRYSON LAB)

Proximity Labeling as an Approach to Study the Phagosome Proteome

Professional phagocytes must internalize and digest extracellular material in a variety of contexts: from clearing apoptotic cells to killing pathogens. The phagosome formed in this process is a highly dynamic organelle which interacts with many cellular compartments to transition from an initially innocuous environment to one capable of these differing functions. Thus phagosomes are highly diverse, giving rise to different outcomes from similar initial conditions. We posit that this heterogeneity derives from the molecular composition of the phagosome, but holistic characterization of the phagosome composition has historically been complicated by its dynamism. Here, we adapt proximity labeling techniques to circumvent these complications and enable facile proteome-level analysis of the phagosomal lumen.

Anna Romanov (BATHE & IRVINE LABS)

Programmable Display of Vaccine Immunogens on Inert DNA Origami Scaffolds

Multivalent display of vaccine antigens is a well-established method of enhancing humoral responses to vaccines. We present a proof-of-concept for a promising subunit vaccine platform using DNA origami virus-like particles (DNA-VLPs) with high programmability and low off-target anti-scaffold antibody responses. Using two different antigens, we found that prime-boost immunization with DNA-VLPs in mice lead to a valency-dependent elevation in antigen-specific titers but not scaffold-specific antibodies. Furthermore, we identified that optimized antigen spacing leads to more robust germinal center responses in vivo.