Biology subjects

Leaman, D. P.

Publications and source records attributed to Leaman, D. P..

2 recordsLinked to original sources

bioRxiv2021

Cryo-ET of HIV reveals Env positioning on Gag lattice and structural variation among Env trimers

HIV-1 Env mediates viral entry into host cells and is the sole target for neutralizing antibodies. However, Env structure and organization in its native virion context has eluded detailed characterization. Here we used cryo-electron tomography to analyze Env in mature and immature HIV-1 particles. Immature particles showed distinct Env positioning relative to the underlying Gag lattice, providing insights into long-standing questions about Env incorporation. A 9.1[A] sub-tomogram averaged reconstruction of virion-bound Env in conjunction with structural mass spectrometry revealed unexpected features, including a variable central core of the gp41 subunit, heterogeneous glycosylation between protomers plus a flexible stalk that allows Env tilting and variable exposure of neutralizing epitopes. Together, our results provide an integrative understanding of HIV assembly and structural variation in Env antigen presentation.

biophysics↗

bioRxiv2020

Membrane Env liposomes for immunization with HIV spikes

A key goal in HIV vaccine design remains to elicit broadly neutralizing antibodies (bnAbs) against the membrane-embedded envelope glycoprotein spike (mEnv). However, mEnv has lagged behind engineered soluble Envs in vaccine development due to low expression yields and the presence of extraneous proteins on particles. Here, we describe a mEnv vaccine platform that requires no extra proteins or protein engineering. MEnv trimers were fixed, purified and combined with liposomes in mild detergent. On removal of detergent, mEnvs were observed embedded in particles, designated mEnv liposomes (MELs), which were recognized by HIV bnAbs but not non-nAbs. Following sequential immunization in rabbits, MEL antisera neutralized select tier 2 HIV isolates. Variations between the Env immunogens, including a missing N-glycosylation site at position 197 near the CD4 binding site, provide insights into the specificities elicited and possible ways to improve immunogens. MELs can facilitate vaccine design to elicit HIV bnAbs using biochemically defined and multimerized mEnv.

immunology↗