Biology subjects

Kaldine, H.

Publications and source records attributed to Kaldine, H..

3 recordsLinked to original sources

bioRxiv2022

Novavax NVX-COV2373 triggers potent neutralization of Omicron sub-lineages

The SARS-CoV-2 Omicron (B.1.1.529) Variant of Concern (VOC) and its sub-lineages (including BA.2, BA.4/5, BA.2.12.1) contain spike mutations that confer high level resistance to neutralizing antibodies. The NVX-CoV2373 vaccine, a protein nanoparticle vaccine, has value in countries with constrained cold-chain requirements. Here we report neutralizing titers following two or three doses of NVX-CoV2373. We show that after two doses, Omicron sub-lineages BA.1 and BA.4 were resistant to neutralization by 72% (21/29) and 59% (17/29) of samples. However, after a third dose of NVX-CoV2373, we observed high titers against Omicron BA.1 (GMT: 1,197) and BA.4 (GMT: 582), with responses similar in magnitude to those triggered by three doses of an mRNA vaccine. These data are of particular relevance as BA.4 is emerging to become the dominant strain in many locations, and highlight the potential utility of the NVX-CoV2373 vaccine as a booster in resource-limited environments.

immunology↗

bioRxiv2022

Fc effector activity and neutralization against SARS-CoV-2 BA.4 is compromised in convalescent sera, regardless of the infecting variant

The SARS-CoV-2 Omicron BA.1 variant, which exhibits high level neutralization resistance, has since evolved into several sub-lineages including BA.4 and BA.5, which have dominated the fifth wave of infection in South Africa. Here we assessed the sensitivity of BA.4 to neutralization and antibody dependent cellular cytotoxicity (ADCC) in convalescent donors infected with four previous variants of SARS-CoV-2, as well as in post-vaccination breakthrough infections (BTIs) caused by Delta or BA.1. We confirm that BA.4 shows high level resistance to neutralization, regardless of the infecting variant. However, breakthrough infections, which trigger potent neutralization, retained activity against BA.4, albeit at reduced titers. Fold reduction of neutralization in BTIs was lower than that seen in unvaccinated convalescent donors, suggesting maturation of neutralizing responses to become more resilient against VOCs in hybrid immunity. BA.4 sensitivity to ADCC was reduced but remained detectable in both convalescent donors and in BTIs. Overall, the high neutralization resistance of BA.4, even to antibodies from BA.1 infections, provides an immunological mechanism for the rapid spread of BA.4 immediately after a BA.1-dominated wave. Furthermore, although ADCC activity against BA.4 was reduced, residual activity may nonetheless contribute to the protection from disease.

immunology↗

bioRxiv2021

Sequence and functional characterization of a public HIV-specific antibody clonotype

Public antibody clonotypes shared among multiple individuals have been identified for several pathogens. However, little is known about the limits of what constitutes a public clonotype. Here, we characterize the sequence and functional properties of antibodies from a public HIV-specific clonotype comprising sequences from 3 individuals. Our results showed that antigen specificity for the public antibodies was modulated by the VH, but not VL, germline gene. Non-native pairing of public heavy and light chains from different donors resulted in antibodies with consistent antigen specificity, suggesting functional complementation of sequences within the public antibody clonotype. The strength of antigen recognition appeared to be dependent on the specific antibody light chain used, but not on other sequence features such as germline or native-antibody sequence identity. Understanding the determinants of antibody clonotype "publicness" can provide insights into the fundamental rules of host-pathogen interactions at the population level, with implications for clonotype-specific vaccine development.

immunology↗