Postnatally-transmitted HIV-1 Envelope variants have similar neutralization-sensitivity and function to that of nontransmitted breast milk variants.

Abstract

BACKGROUND: Breastfeeding is a leading cause of infant HIV-1 infection in the developing world, yet only a minority of infants exposed to HIV-1 via breastfeeding become infected. As a genetic bottleneck severely restricts the number of postnatally-transmitted variants, genetic or phenotypic properties of the virus Envelope (Env) could be important for the establishment of infant infection. We examined the efficiency of virologic functions required for initiation of infection in the gastrointestinal tract and the neutralization sensitivity of HIV-1 Env variants isolated from milk of three postnatally-transmitting mothers (n = 13 viruses), five clinically-matched nontransmitting mothers (n = 16 viruses), and seven postnatally-infected infants (n = 7 postnatally-transmitted/founder (T/F) viruses). RESULTS: There was no difference in the efficiency of epithelial cell interactions between Env virus variants from the breast milk of transmitting and nontransmitting mothers. Moreover, there was similar efficiency of DC-mediated trans-infection, CCR5-usage, target cell fusion, and infectivity between HIV-1 Env-pseudoviruses from nontransmitting mothers and postnatal T/F viruses. Milk Env-pseudoviruses were generally sensitive to neutralization by autologous maternal plasma and resistant to breast milk neutralization. Infant T/F Env-pseudoviruses were equally sensitive to neutralization by broadly-neutralizing monoclonal and polyclonal antibodies as compared to nontransmitted breast milk Env variants. CONCLUSION: Postnatally-T/F Env variants do not appear to possess a superior ability to interact with and cross a mucosal barrier or an exceptional resistance to neutralization that define their capability to initiate infection across the infant gastrointestinal tract in the setting of preexisting maternal antibodies.

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Citation

Published Version (Please cite this version)

10.1186/1742-4690-10-3

Publication Info

Fouda, Genevieve G, Tatenda Mahlokozera, Jesus F Salazar-Gonzalez, Maria G Salazar, Gerald Learn, Surender B Kumar, S Moses Dennison, Elizabeth Russell, et al. (2013). Postnatally-transmitted HIV-1 Envelope variants have similar neutralization-sensitivity and function to that of nontransmitted breast milk variants. Retrovirology, 10. p. 3. 10.1186/1742-4690-10-3 Retrieved from https://hdl.handle.net/10161/10586.

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Scholars@Duke

Sekaran

Moses Sekaran

Assistant Professor in Surgery
Alam

S. Munir Alam

Professor in Medicine

Research Interests. 

The Alam laboratory’s primary research is focused on understanding the biophysical properties of antigen-antibody binding and the molecular events of early B cell activation using the HIV-1 broadly neutralizing antibody (bnAb) lineage models. We are studying how HIV-1 Envelope proteins of varying affinities are sensed by B cells expressing HIV-1 bnAbs or their germline antigen receptors and initiate early signaling events for their activation. In the long-term these studies will facilitate design and pre-selection of immunogens for testing in animal models and accelerate HIV-1 vaccine development.
Current research include the following NIAID-funded projects   

Antigen recognition and activation of B cell antigen receptors with the specificity of HIV-1 broadly neutralizing antibodies. This project involves elucidating the early events on the B cell surface following antigen (Ag) engagement of the B cell antigen receptor (BCR) and to provide an assessment of the in vivo potential of an Ag to drive B cell activation. We are performing biophysical interactions analyses and using high-resolution microscopy to define the physico-chemical properties of BCR-Ag interactions that govern signaling and activation thresholds for BCR triggering and the BCR endocytic function in antigen internalization. The overall objective of these studies is to bridge the quantitative biophysical and membrane dynamics measurements of Ag-BCR interactions to ex-vivo and in-vivo B cell activation. This NIAID-funded research is a collaboration with co-investigators Professor Michael Reth (University of Freiburg, Germany) and Dr. Laurent Verkoczy (San Diego Biomedical Research Institute, CA).  

Immunogen Design for Induction of HIV gp41 Broadly Neutralizing Antibodies. This research project addresses the critical problem of vaccine induction of disfavored HIV-1 antibody lineages, like those that target the membrane proximal external region (MPER) of HIV Env gp41. This program combines structure and lineage-based vaccine development strategies to design immunogens that will induce bnAb lineages that are not polyreactive and therefore easier to induce. The overall objective of this program grant is to develop and test sequential immunogens that will initiate and induce HIV-1 bnAb lineages like the potent MPER bnAb DH511. Using a germline-targeting (GT) epitope scaffold design and a prime/boost strategy, we are testing induction of DH511-like bnAbs in knock-in (KI) mice models expressing the DH511 germline receptors. This P01 research program is in collaboration with Dr. William Schief (The Scripps Research Institute, CA), who leads the team that are designing germline targeting (GT)-scaffold prime and boost immunogens and Dr. Ming Tian at Harvard University who developed relevant knock-mice models for the study.
Permar

Sallie Robey Permar

Adjunct Professor in the Department of Pathology

Dr. Permar's work focuses on the development of vaccines to prevent vertical transmission of neonatal viral pathogens. She has utilized the nonhuman primate model of HIV/AIDS to characterize the virus-specific immune responses and virus evolution in breast milk and develop a maternal vaccine regimen for protection against breast milk transmission of HIV. In addition, Dr. Permar's lab has advanced the understanding of HIV-specific immune responses and virus evolution in vertically-transmitting and nontransmitting HIV-infected women, defining maternal immune responses that may protect against neonatal transmission of HIV. Importantly, Dr. Permar has established a nonhuman primate model of congenital CMV infection adn is using this model to establish the maternal immune responses that are necessary for protection against placental virus transmission. Finally, Dr. Permar is studying the impact and prevention of postnatal CMV transmission in preterm infants.


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