Maternal HIV-1 Env Vaccination for Systemic and Breast Milk Immunity To Prevent Oral SHIV Acquisition in Infant Macaques.

Abstract

Mother-to-child transmission (MTCT) of human immunodeficiency virus type 1 (HIV-1) contributes to an estimated 150,000 new infections annually. Maternal vaccination has proven safe and effective at mitigating the impact of other neonatal pathogens and is one avenue toward generating the potentially protective immune responses necessary to inhibit HIV-1 infection of infants through breastfeeding. In the present study, we tested the efficacy of a maternal vaccine regimen consisting of a modified vaccinia virus Ankara (MVA) 1086.C gp120 prime-combined intramuscular-intranasal gp120 boost administered during pregnancy and postpartum to confer passive protection on infant rhesus macaques against weekly oral exposure to subtype C simian-human immunodeficiency virus 1157ipd3N4 (SHIV1157ipd3N4) starting 6 weeks after birth. Despite eliciting a robust systemic envelope (Env)-specific IgG response, as well as durable milk IgA responses, the maternal vaccine did not have a discernible impact on infant oral SHIV acquisition. This study revealed considerable variation in vaccine-elicited IgG placental transfer and a swift decline of both Env-specific antibodies (Abs) and functional Ab responses in the infants prior to the first challenge, illustrating the importance of pregnancy immunization timing to elicit optimal systemic Ab levels at birth. Interestingly, the strongest correlation to the number of challenges required to infect the infants was the percentage of activated CD4+ T cells in the infant peripheral blood at the time of the first challenge. These findings suggest that, in addition to maternal immunization, interventions that limit the activation of target cells that contribute to susceptibility to oral HIV-1 acquisition independently of vaccination may be required to reduce infant HIV-1 acquisition via breastfeeding. IMPORTANCE Without novel strategies to prevent mother-to-child HIV-1 transmission, more than 5% of HIV-1-exposed infants will continue to acquire HIV-1, most through breastfeeding. This study of rhesus macaque dam-and-infant pairs is the first preclinical study to investigate the protective role of transplacentally transferred HIV-1 vaccine-elicited antibodies and HIV-1 vaccine-elicited breast milk antibody responses in infant oral virus acquisition. It revealed highly variable placental transfer of potentially protective antibodies and emphasized the importance of pregnancy immunization timing to reach peak antibody levels prior to delivery. While there was no discernible impact of maternal immunization on late infant oral virus acquisition, we observed a strong correlation between the percentage of activated CD4+ T cells in infant peripheral blood and a reduced number of challenges to infection. This finding highlights an important consideration for future studies evaluating alternative strategies to further reduce the vertical HIV-1 transmission risk.

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Published Version (Please cite this version)

10.1128/mSphere.00505-17

Publication Info

Eudailey, Joshua A, Maria L Dennis, Morgan E Parker, Bonnie L Phillips, Tori N Huffman, Camden P Bay, Michael G Hudgens, Roger W Wiseman, et al. (2018). Maternal HIV-1 Env Vaccination for Systemic and Breast Milk Immunity To Prevent Oral SHIV Acquisition in Infant Macaques. mSphere, 3(1). 10.1128/mSphere.00505-17 Retrieved from https://hdl.handle.net/10161/16037.

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Scholars@Duke

Pollara

Justin Joseph Pollara

Associate Professor in Surgery

Dr. Justin Pollara is a member of the Duke Human Vaccine Institute and the Duke Center for Human Systems Immunology, and is Associate Director of the Duke Center for AIDS Research (CFAR) Developmental Core. He received his PhD from North Carolina State University and completed his postdoctoral training as a recipient of the Duke NIH Interdisciplinary Research Training Program in AIDS (IRTPA) T32 award in the laboratory of Dr. Guido Ferrari. He joined the faculty of the Duke Department of Surgery in 2016.

A common theme of research performed in Dr. Pollara’s laboratory is a focus on interactions between innate and adaptive immunity. Dr. Pollara’s work has contributed significantly to the understanding of the roles played by non-neutralizing antibodies in limiting HIV-1 disease progression, and in prevention of infection or control of virus replication in preclinical and clinical HIV-1 vaccine trials. Dr. Pollara’s research has also identified specific components of the immune response that reduce the risk of vertical transmission of both HIV-1 and human cytomegalovirus. The Pollara lab characterizes the phenotype and functionality of antibody-interacting innate immune cells and explores how natural genetic variation in antibodies and antibody receptors may contribute to vaccine responsiveness and immune competence. Further, with a strong interdisciplinary and collaborative approach, the Pollara Lab has broadened its scope beyond infectious diseases and is now actively leading studies aimed at understanding how inflammation, antibodies, innate immune cells, and newly described populations of T cells promote allograft injury that underlies rejection of transplanted organs.

Ferrari

Guido Ferrari

Professor in Surgery

The activities of the Ferrari Laboratory are based on both independent basic research and immune monitoring studies. The research revolves around three main areas of interest: class I-mediated cytotoxic CD8+ T cell responses, antibody-dependent cellular cytotoxicity (ADCC), gene expression in NK and T cellular subsets upon infection with HIV-1. With continuous funding over the last 11 years from the NIH and Bill & Melinda Gates Foundation along with many other productive collaborations within and outside of Duke, the Ferrari Lab has expanded its focus of research to include the ontogeny of HIV-1 specific immune responses that work by eliminating HIV-1 infected cells and how these can be induced by AIDS vaccine candidates.

Pickup

David James Pickup

Associate Professor Emeritus of Molecular Genetics and Microbiology

Viral inhibition of host immune defenses
Many viruses have evolved mechanisms to protect themselves from host immune defenses. Among this group are the orthopoxviruses, whose members include smallpox virus, one of the deadliest of human viruses, and cowpox virus, the virus that Edward Jenner used to begin the eradication of smallpox.

One of the especially interesting features of theses viruses is their ability to interfere with a wide range of innate and adaptive immune responses to infection. For example, we have found that cowpox virus inhibits inflammation by suppressing the actions of cytokines controlling inflammatory processes. Moreover, the virus does this in several ways: by preventing the synthesis of cytokines; by interfering with normal cytokine-receptor interactions; and by inhibiting cytokine-signaling pathways.

Our main research objectives are to identify mechanisms of virus-host interaction leading to the modification or alteration of host functions. Our working model is that such interactions are amongst the most important factors in viral pathogenesis. In addition, knowledge of these virus-host interactions should help in the development of new vaccines and therapies for a variety of conditions associated with infectious diseases, inflammatory diseases, autoimmune diseases, cancers, and organ transplantation.

Development of improved viral vaccines
Several excellent vaccine platforms exist, but among these vaccinia virus vaccines have unusual potential for targeting multiple different pathogens because of the extraordinary capacity of these vectors to encode multiple foreign proteins. Replication-defective vaccinia vectors are extremely safe. However, this safety comes at a cost. Because only a small amount of antigen can be produced during the single cycle of viral replication, vectors of this type typically require high doses and multiple boosts to induce protective immune responses.  We are interested in finding ways to enhance the immunogenicity of these replication-defective vaccine viruses without compromising on safety.


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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