Browsing by Author "Pickup, David J"
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Item Open Access Combined HIV-1 Envelope Systemic and Mucosal Immunization of Lactating Rhesus Monkeys Induces a Robust Immunoglobulin A Isotype B Cell Response in Breast Milk.(Journal of virology, 2016-05) Nelson, Cody S; Pollara, Justin; Kunz, Erika L; Jeffries, Thomas L; Duffy, Ryan; Beck, Charles; Stamper, Lisa; Wang, Minyue; Shen, Xiaoying; Pickup, David J; Staats, Herman F; Hudgens, Michael G; Kepler, Thomas B; Montefiori, David C; Moody, M Anthony; Tomaras, Georgia D; Liao, Hua-Xin; Haynes, Barton F; Ferrari, Guido; Fouda, Genevieve GA; Permar, Sallie RUnlabelled
Maternal vaccination to induce anti-HIV immune factors in breast milk is a potential intervention to prevent postnatal HIV-1 mother-to-child transmission (MTCT). We previously demonstrated that immunization of lactating rhesus monkeys with a modified vaccinia Ankara (MVA) prime/intramuscular (i.m.) protein boost regimen induced functional IgG responses in milk, while MVA prime/intranasal (i.n.) boost induced robust milk Env-specific IgA responses. Yet, recent studies have suggested that prevention of postnatal MTCT may require both Env-specific IgA and functional IgG responses in milk. Thus, to investigate whether both responses could be elicited by a combined systemic/mucosal immunization strategy, animals previously immunized with the MVA prime/i.n. boost regimen received an i.n./i.m. combined C.1086 gp120 boost. Remarkably, high-magnitude Env-specific IgA responses were observed in milk, surpassing those in plasma. Furthermore, 29% of vaccine-elicited Env-specific B cells isolated from breast milk were IgA isotype, in stark contrast to the overwhelming predominance of IgG isotype Env-specific B cells in breast milk of chronically HIV-infected women. A clonal relationship was identified between Env-specific blood and breast milk B cells, suggesting trafficking of that cell population between the two compartments. Furthermore, IgA and IgG monoclonal antibodies isolated from Env-specific breast milk B cells demonstrated diverse Env epitope specificities and multiple effector functions, including tier 1 neutralization, antibody-dependent cellular cytotoxicity (ADCC), infected cell binding, and inhibition of viral attachment to epithelial cells. Thus, maternal i.n./i.m. combined immunization is a novel strategy to enhance protective Env-specific IgA in milk, which is subsequently transferred to the infant via breastfeeding.Importance
Efforts to increase the availability of antiretroviral therapy to pregnant and breastfeeding women in resource-limited areas have proven remarkably successful at reducing HIV vertical transmission rates. However, more than 200,000 children are infected annually due to failures in therapy implementation, monitoring, and adherence, nearly half by postnatal HIV exposure via maternal breast milk. Intriguingly, in the absence of antiretroviral therapy, only 10% of breastfed infants born to HIV-infected mothers acquire the virus, suggesting the existence of naturally protective immune factors in milk. Enhancement of these protective immune factors through maternal vaccination will be a critical strategy to reduce the global pediatric AIDS epidemic. We have previously demonstrated that a high magnitude of HIV Env-specific IgA in milk correlates with reduced risk of infant HIV acquisition. In this study, we describe a novel HIV vaccine regimen that induces potent IgA responses in milk and therefore could potentially protect against breast milk HIV MTCT.Item Open Access Maternal HIV-1 Env Vaccination for Systemic and Breast Milk Immunity To Prevent Oral SHIV Acquisition in Infant Macaques.(mSphere, 2018-01) Eudailey, Joshua A; Dennis, Maria L; Parker, Morgan E; Phillips, Bonnie L; Huffman, Tori N; Bay, Camden P; Hudgens, Michael G; Wiseman, Roger W; Pollara, Justin J; Fouda, Genevieve G; Ferrari, Guido; Pickup, David J; Kozlowski, Pamela A; Van Rompay, Koen KA; De Paris, Kristina; Permar, Sallie RMother-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.Item Open Access Particulate allergens potentiate allergic asthma in mice through sustained IgE-mediated mast cell activation.(2010) Jin, CongIn recent years, the incidence of allergic asthma as well as the severity of disease has rapidly increased worldwide. Numerous epidemiological studies have related the exacerbation of allergic asthma with exposure to increased ambient particles from air pollutants. However, the mechanism by which particulate allergens (pAg) exacerbate allergic asthma remains undefined. To evaluate this, we modeled environmental pAg induced allergic asthma by exposing mice to polystyrene beads coated with natural allergen extracts. Compared to equal amounts of soluble allergen extracts (sAg), pAg triggered markedly enhanced airway hyper-responsiveness and pulmonary eosinophilia in allergen sensitized mice. The cellular basis for this effect was determined to be mast cells (MCs), as both airway allergic responses were attenuated in MC deficient KitWsh/KitW-sh mice compared to MC reconstituted KitW-sh/KitW-sh mice. The divergent responses of MCs to pAg versus sAg were due to differences in the termination rate of IgE/FcεRI initiated signaling. Following ligation of sAg, IgE/FcεRI rapidly shuttled into a degradative endosome/lysosome pathway. However, following ligation by pAg, IgE/FcεRI migrated into lipid raft enriched compartments and subsequently failed to follow a degradative pathway, which resulted in a prolonged signaling and heightened synthesis of proinflammatory mediators. These observations highlight the overlooked contributions of the particulate nature of allergens and mast cell endocytic circuitry to the aggravation of allergic asthma.Item Open Access Poxvirus Modulation of the Immune Response(2009) Spesock, AprilOrthopoxviruses encode many genes that are not essential for viral replication, which often account for differences in pathogenesis among otherwise closely related orthopoxviruses. Although dendritic cells (DCs) are essential to the generation of an effective anti-viral immune response, the effects of different orthopoxviruses on DC function is poorly understood. The objective of these studies was to determine the effect of different orthopoxviruses on DCs. Cowpox virus (CPXV) is ideally suited to this purpose because it encodes the largest and most representative set of accessory genes among orthopoxviruses, it is endemic in mouse populations, and can infect humans.
We hypothesized that CPXV would have novel mechanisms of evading the immune response that other orthopoxviruses lack, which may exert maximal effect in the context of antigen presenting cells such as DCs, allowing for discovery of novel viral strategies of immune evasion. To test this, CPXV was used to infected mouse bone marrow-derived DCs (BMDCs), and the effect of the virus on DC survival, expression of T-cell costimulatory molecules and cytokine production was determined. The effects of vaccinia virus strain Western Reserve (VV), the prototype of the species, and modified vaccinia virus strain Ankara (MVA), a promising vaccine vector, on mouse BMDCs were also determined. Confirming the hypothesis that CPXV would have different effects on mouse BMDCs from other orthopoxviruses, BMDCs infected with CPXV survived longer in culture than those infected with MVA or VV. In addition, CPXV specifically downregulated MHC I, MHC II, CD40, and CD86, and induced production of significant levels of IL-6 and IL-10.
Because IL-10 has many suppressive effects on the immune system, inducing IL-10 may provide a selective advantage to CPXV in vivo. To examine the role of IL-10 in a CPXV infection, wild type and IL-10 deficient mice were infected intranasally with CPXV. The effect of CPXV infection on disease morbidity, viral loads, inflammation and the protective immune response was determined. As expected, IL-10 was important in controlling inflammation during CPXV infection, but there was no effect on viral replication or clearance. Surprisingly, IL-10 was important in generation of a protective memory response to CPXV, which may reflect a novel role for IL-10 in the immune response.