Objective: HIV-1 has been classified into four groups: M, N, O and P. The aim of this study was to revisit the cross-group neutralization using a highly diverse panel of primary isolates.
Design: The panel of viruses included nine HIV-1 group O primary isolates, one recombinant M/O primary isolate, one group N primary isolates, one group P primary isolate, two group M (subtype B) primary isolates and the HIV-1 group M adapted strain MN.
Methods: All the viruses were tested for neutralization in TZM-bl cells, using sera issued from patients infected by viruses of group M (n = 11), O (n = 12) and P (n = 1), and a panel of nine human monoclonal broadly neutralizing antibodies (HuMo bNAbs).
Results: Although the primary isolates displayed a wide spectrum of sensitivity to neutralization by the human sera, cross-group neutralization was clearly observed. In contrast, the bNAbs did not show any cross-group neutralization, except PG9 and PG16. Interestingly, the group N prototype strain YBF30 was highly sensitive to neutralization by PG9 (IC50: 0.28 μg/ml) and PG16 (IC50: < 0.12 μg/ml). The interaction between PG9 and key residues of YBF30 was confirmed by molecular modeling.
Conclusion: The conservation of the PG9 and PG16 epitopes within groups M and N provides an argument for their relevance as components of a potentially efficient HIV vaccine immunogen.
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http://dx.doi.org/10.1097/QAD.0b013e32835ecb42 | DOI Listing |
Cell Rep
December 2024
Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA. Electronic address:
Antibodies targeting epitopes through germline-encoded motifs can be found in different individuals. While these public antibodies are often beneficial, they also pose hurdles for subdominant antibodies to emerge. Here, we use transgenic mice that reproduce the human IGHV1-6901 germline-encoded antibody response to the conserved stem epitope on group 1 hemagglutinin (HA) of influenza A virus to show that this germline-endowed response can be overridden by a subdominant yet cross-group reactive public antibody response.
View Article and Find Full Text PDFVaccines (Basel)
June 2024
HSF Pharmaceuticals SA, 1814 La Tour-de-Peilz, Switzerland.
Vaccination with transiently activated replication-competent controlled herpesviruses (RCCVs) expressing influenza A virus hemagglutinins broadly protects mice against lethal influenza virus challenges. The non-replicating RCCVs can be activated to transiently replicate with high efficiency. Activation involves a brief heat treatment to the epidermal administration site in the presence of a drug.
View Article and Find Full Text PDFVaccines (Basel)
May 2024
HSF Pharmaceuticals SA, 1814 La Tour-de-Peilz, Switzerland.
A universal vaccine that generally prevents influenza virus infection and/or illness remains elusive. We have been exploring a novel approach to vaccination involving replication-competent controlled herpesviruses (RCCVs) that can be deliberately activated to replicate efficiently but only transiently in an administration site in the skin of a subject. The RCCVs are derived from a virulent wild-type herpesvirus strain that has been engineered to contain a heat shock promoter-based gene switch that controls the expression of, typically, two replication-essential viral genes.
View Article and Find Full Text PDFImmunity
May 2024
The Ragon Institute of Mass General, The Massachusetts Institute of Technology and Harvard University, 400 Technology Square, Cambridge, MA 02139, USA. Electronic address:
Broadly neutralizing antibodies (bnAbs) targeting the hemagglutinin (HA) stem of influenza A viruses (IAVs) tend to be effective against either group 1 or group 2 viral diversity. In rarer cases, intergroup protective bnAbs can be generated by human antibody paratopes that accommodate the conserved glycan differences between the group 1 and group 2 stems. We applied germline-engaging nanoparticle immunogens to elicit a class of cross-group bnAbs from physiological precursor frequency within a humanized mouse model.
View Article and Find Full Text PDFPLoS Biol
December 2023
Center for Vaccine Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America.
Antibody titers that inhibit the influenza virus hemagglutinin (HA) from engaging its receptor are the accepted correlate of protection from infection. Many potent antibodies with broad, intra-subtype specificity bind HA at the receptor binding site (RBS). One barrier to broad H1-H3 cross-subtype neutralization is an insertion (133a) between positions 133 and 134 on the rim of the H1 HA RBS.
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