Mosaic HIV-1 vaccine and SHIV challenge strain V2 loop sequence identity and protection in primates.

The failure of human vaccine efficacy trials assessing a mosaic HIV-1 vaccine calls into question the translatability of preclinical SHIV challenge studies that demonstrated high efficacy of this vaccine in primates. Here we present a post hoc immune correlates analysis of HIV-1 Env peptide-binding antibody responses from the NHP13-19 study identifying the V2 loop as the principal correlate of protection in primates. Moreover, we found high V2 loop sequence identity between the Mos1 vaccine component and the SHIV challenge strain, while the vaccine showed considerably lower V2 identity to globally circulating HIV-1 sequences.

The Biodistribution of the Spike Protein after Ad26.COV2.S Vaccination Is Unlikely to Play a Role in Vaccine-Induced Immune Thrombotic Thrombocytopenia.

Ad26.COV2.S vaccination can lead to vaccine-induced immune thrombotic thrombocytopenia (VITT), a rare but severe adverse effect, characterized by thrombocytopenia and thrombosis.

CoPoP liposomes displaying stabilized clade C HIV-1 Env elicit tier 2 multiclade neutralization in rabbits.

One of the strategies towards an effective HIV-1 vaccine is to elicit broadly neutralizing antibody responses that target the high HIV-1 Env diversity. Here, we present an HIV-1 vaccine candidate that consists of cobalt porphyrin-phospholipid (CoPoP) liposomes decorated with repaired and stabilized clade C HIV-1 Env trimers in a prefusion conformation. These particles exhibit high HIV-1 Env trimer decoration, serum stability and bind broadly neutralizing antibodies.

Intravenous Administration of Ad26.COV2.S Does Not Induce Thrombocytopenia or Thrombotic Events or Affect SARS-CoV-2 Spike Protein Bioavailability in Blood Compared with Intramuscular Vaccination in Rabbits.

Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a very rare but serious adverse reaction that can occur after Ad26.COV2.S vaccination in humans, leading to thrombosis at unusual anatomic sites.