A major goal for HIV-1 vaccine development is the production of an immunogen to mimic native, functional HIV-1 envelope trimeric spikes (Env) on the virion surface. We lack a reliable description of a native, functional trimer, however, because of inherent instability and heterogeneity in most preparations. We describe here two conformationally homogeneous Envs derived from difficult-to-neutralize primary isolates. All their non-neutralizing epitopes are fully concealed and independent of their proteolytic processing. Most broadly neutralizing antibodies (bnAbs) recognize these native trimers. Truncation of their cytoplasmic tail has little effect on membrane fusion, but it diminishes binding to trimer-specific bnAbs while exposing non-neutralizing epitopes. These results yield a more accurate antigenic picture than hitherto possible of a genuinely untriggered and functional HIV-1 Env; they can guide effective vaccine development.

Toxoplasmosis caused by the protozoan Toxoplasma gondii is a major public health problem, infecting one-third of the world human beings, and leads to abortion in domestic animals. A vaccine strategy would be an ideal tool for improving disease control. Many efforts have been made to develop vaccines against T. gondii to reduce oocyst shedding in cats and tissue cyst formation in mammals over the last 20 years, but only a live-attenuated vaccine based on the S48 strain has been licensed for veterinary use. Here, the authors review the recent development of T. gondii vaccines in cats, food-producing animals and mice, and present its future perspectives. However, a single or only a few antigen candidates revealed by various experimental studies are limited by only eliciting partial protective immunity against T. gondii. Future studies of T. gondii vaccines should include as many CTL epitopes as the live attenuated vaccines.

Although intestinal flora are crucial in maintaining immune homeostasis of the intestine, the role of intestinal flora in immune responses at other mucosal surfaces remains less clear. Here, we show that intestinal flora composition critically regulates the toll-like receptor 7 (TLR7) signaling pathway following respiratory influenza virus infection. TLR7 ligands rescued the immune impairment in antibiotic-treated mice. Intact microbiota provided signals leading to the expression of mRNA for TLR7, MyD88, IRAK4, TRAF6, and NF-κB at steady state. Significant changes in the composition of culturable commensal bacteria reduced the expression levels of components of the TLR7 signaling pathway. Our results reveal the importance of intestinal flora in regulating immunity in the respiratory mucosa through the upregulation of the TLR7 signaling pathway for the proper activation of inflammasomes.

Porous graphene membranes hold great promise for high-selectivity separation. Moreover, their practical application is limited by the lack of a simple and efficient method for the synthesis of porous graphene. Here, a rapid and scalable method is developed for the synthesis of porous graphene via partial combustion of graphene oxide imperfectly covered by hydrotalcite. This method is not only less energy-and time-intensive than existing ones, but also allows precise control of pore size. Remarkably, the resulting membrane of porous graphene exhibits high selectivity for K + and Na + (α = 3.84) separation. Hence, this facile route for preparing membranes of porous graphene oxide might direct application membranes in environmental, energy, desalination, and biomedical fields.