Uncleaved prefusion-optimized (UFO) design can stabilize diverse HIV-1 envelope glycoproteins (Envs). Single-component, self-assembling protein nanoparticles (1c-SApNP) can display 8 or 20 native-like Env trimers as vaccine candidates. We characterize the biophysical, structural, and antigenic properties of 1c-SApNPs that present the BG505 UFO trimer with wildtype and modified glycans. For 1c-SApNPs, glycan trimming improves recognition of the CD4 binding site without affecting broadly neutralizing antibodies (bNAbs) to major glycan epitopes. In mice, rabbits, and nonhuman primates, glycan trimming increases the frequency of vaccine responders (FVR) and steers antibody responses away from immunodominant glycan holes and glycan patches. The mechanism of vaccine-induced immunity is examined in mice. Compared with the UFO trimer, the multilayered E2p and I3-01v9 1c-SApNPs show 420 times longer retention in lymph node follicles, 20-32 times greater presentation on follicular dendritic cell dendrites, and up-to-4 times stronger germinal center reactions. These findings can inform future HIV-1 vaccine development.

The development of a cross-protective pan-influenza A vaccine remains a significant challenge. Here, we designed and characterized single-component, self-assembling protein nanoparticles (1c-SApNPs) presenting the conserved extracellular domain of matrix protein 2 (M2e) from influenza A viruses of human and other hosts. Vaccination with tandem repeats of M2e (M2ex3) displayed on 1c-SApNPs demonstrated higher survival and lower weight loss compared to the soluble M2ex3 antigen against lethal challenges of H1N1 and H3N2 in mice. The mechanism of vaccine-induced adaptive immunity was also investigated in mice. Compared with the soluble M2ex3 antigen, the M2ex3 I3-01v9a 1c-SApNP formulated with a squalene-based adjuvant showed 672 times longer follicular retention, 31 times greater exposure within follicular dendritic cell networks, and up to 2.5 times stronger germinal center reactions in lymph nodes. By inducing robust and durable M2e-specific functional antibody and T cell responses, the M2ex3-presenting I3-01v9a 1c-SApNP provides a promising pan-influenza A vaccine candidate.