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Amin O, Powers J, Bricker KM, Chahroudi A. Understanding Viral and Immune Interplay During Vertical Transmission of HIV: Implications for Cure. Front Immunol 2021; 12:757400. [PMID: 34745130 PMCID: PMC8566974 DOI: 10.3389/fimmu.2021.757400] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 09/27/2021] [Indexed: 11/13/2022] Open
Abstract
Despite the significant progress that has been made to eliminate vertical HIV infection, more than 150,000 children were infected with HIV in 2019, emphasizing the continued need for sustainable HIV treatment strategies and ideally a cure for children. Mother-to-child-transmission (MTCT) remains the most important route of pediatric HIV acquisition and, in absence of prevention measures, transmission rates range from 15% to 45% via three distinct routes: in utero, intrapartum, and in the postnatal period through breastfeeding. The exact mechanisms and biological basis of these different routes of transmission are not yet fully understood. Some infants escape infection despite significant virus exposure, while others do not, suggesting possible maternal or fetal immune protective factors including the presence of HIV-specific antibodies. Here we summarize the unique aspects of HIV MTCT including the immunopathogenesis of the different routes of transmission, and how transmission in the antenatal or postnatal periods may affect early life immune responses and HIV persistence. A more refined understanding of the complex interaction between viral, maternal, and fetal/infant factors may enhance the pursuit of strategies to achieve an HIV cure for pediatric populations.
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Affiliation(s)
- Omayma Amin
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, United States
| | - Jenna Powers
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, United States
| | - Katherine M Bricker
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, United States
| | - Ann Chahroudi
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, United States.,Center for Childhood Infections and Vaccines of Children's Healthcare of Atlanta and Emory University, Atlanta, GA, United States
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Mangold JF, Goswami R, Nelson AN, Martinez DR, Fouda GG, Permar SR. Maternal Intervention to Prevent Mother-to-Child Transmission of HIV: Moving Beyond Antiretroviral Therapy. Pediatr Infect Dis J 2021; 40:S5-S10. [PMID: 34042904 PMCID: PMC9215267 DOI: 10.1097/inf.0000000000002774] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Widespread availability of antiretroviral therapy among pregnant women living with HIV has greatly reduced the rate of mother-to-child transmission (MTCT) of HIV across the globe. However, while Joint United Nations Programme on HIV/AIDS has set targets to reduce the annual number of new pediatric HIV infections to fewer than 40,000 in 2018 and fewer than 20,000 in 2020, progress towards these targets has plateaued at an unacceptably high global estimate of greater than 160,000 children newly infected with HIV in 2018. Moreover, it has become clear that expansion of maternal antiretroviral therapy alone will not be sufficient to close the remaining gap and eliminate MTCT of HIV. Additional strategies such as maternal or infant passive and/or active immunization that synergize with maternal antiretroviral therapy will be required to end the pediatric HIV epidemic. In this review, we outline the landscape of existing maternal interventions and emerging maternal immune-based approaches to prevent MTCT of HIV.
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Affiliation(s)
- Jesse F. Mangold
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - Ria Goswami
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - Ashley N. Nelson
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
| | - David R. Martinez
- Department of Epidemiology, University of North Carolina at Chapel Hill School of Global Public Health, Chapel Hill, NC, USA
| | - Genevieve G. Fouda
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
- Department of Pediatrics, Duke University Medical Center, Durham, NC, USA
| | - Sallie R. Permar
- Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA
- Department of Pediatrics, Duke University Medical Center, Durham, NC, USA
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Martinez DR, Tu JJ, Kumar A, Mangold JF, Mangan RJ, Goswami R, Giorgi EE, Chen J, Mengual M, Douglas AO, Heimsath H, Saunders KO, Nicely NI, Eudailey J, Hernandez G, Morgan-Asiedu PK, Wiehe K, Haynes BF, Moody MA, LaBranche C, Montefiori DC, Gao F, Permar SR. Maternal Broadly Neutralizing Antibodies Can Select for Neutralization-Resistant, Infant-Transmitted/Founder HIV Variants. mBio 2020; 11:e00176-20. [PMID: 32156815 PMCID: PMC7064758 DOI: 10.1128/mbio.00176-20] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 01/31/2020] [Indexed: 01/21/2023] Open
Abstract
Each year, >180,000 infants become infected via mother-to-child transmission (MTCT) of HIV despite the availability of effective maternal antiretroviral treatments, underlining the need for a maternal HIV vaccine. We characterized 224 maternal HIV envelope (Env)-specific IgG monoclonal antibodies (MAbs) from seven nontransmitting and transmitting HIV-infected U.S. and Malawian mothers and examined their neutralization activities against nontransmitted autologous circulating viruses and infant-transmitted founder (infant-T/F) viruses. Only a small subset of maternal viruses, 3 of 72 (4%), were weakly neutralized by maternal linear V3 epitope-specific IgG MAbs, whereas 6 out of 6 (100%) infant-T/F viruses were neutralization resistant to these V3-specific IgG MAbs. We also show that maternal-plasma broadly neutralizing antibody (bNAb) responses targeting the V3 glycan supersite in a transmitting woman may have selected for an N332 V3 glycan neutralization-resistant infant-T/F virus. These data have important implications for bNAb-eliciting vaccines and passively administered bNAbs in the setting of MTCT.IMPORTANCE Efforts to eliminate MTCT of HIV with antiretroviral therapy (ART) have met little success, with >180,000 infant infections each year worldwide. It is therefore likely that additional immunologic strategies that can synergize with ART will be required to eliminate MTCT of HIV. To this end, understanding the role of maternal HIV Env-specific IgG antibodies in the setting of MTCT is crucial. In this study, we found that maternal-plasma broadly neutralizing antibody (bNAb) responses can select for T/F viruses that initiate infection in infants. We propose that clinical trials testing the efficacy of single bNAb specificities should not include HIV-infected pregnant women, as a single bNAb might select for neutralization-resistant infant-T/F viruses.
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Affiliation(s)
- David R Martinez
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
- Duke Human Vaccine Institute, Durham, North Carolina, USA
| | - Joshua J Tu
- Duke Human Vaccine Institute, Durham, North Carolina, USA
| | - Amit Kumar
- Duke Human Vaccine Institute, Durham, North Carolina, USA
| | | | - Riley J Mangan
- Duke Human Vaccine Institute, Durham, North Carolina, USA
| | - Ria Goswami
- Duke Human Vaccine Institute, Durham, North Carolina, USA
| | - Elena E Giorgi
- Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - Juilin Chen
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
- Duke Human Vaccine Institute, Durham, North Carolina, USA
| | - Michael Mengual
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
| | | | - Holly Heimsath
- Duke Human Vaccine Institute, Durham, North Carolina, USA
| | - Kevin O Saunders
- Duke Human Vaccine Institute, Durham, North Carolina, USA
- Department of Surgery, Duke University Medical Center, Durham, North Carolina, USA
| | | | | | | | | | - Kevin Wiehe
- Duke Human Vaccine Institute, Durham, North Carolina, USA
| | - Barton F Haynes
- Duke Human Vaccine Institute, Durham, North Carolina, USA
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
| | - M Anthony Moody
- Duke Human Vaccine Institute, Durham, North Carolina, USA
- Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, USA
| | - Celia LaBranche
- Department of Surgery, Duke University Medical Center, Durham, North Carolina, USA
| | - David C Montefiori
- Duke Human Vaccine Institute, Durham, North Carolina, USA
- Department of Surgery, Duke University Medical Center, Durham, North Carolina, USA
| | - Feng Gao
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
| | - Sallie R Permar
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
- Duke Human Vaccine Institute, Durham, North Carolina, USA
- Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, USA
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Nelson CS, Fouda GG, Permar SR. Pediatric HIV-1 Acquisition and Lifelong Consequences of Infant Infection. CURRENT IMMUNOLOGY REVIEWS 2019; 15:131-138. [PMID: 33223981 PMCID: PMC7678020 DOI: 10.2174/1573395514666180531074047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 04/11/2018] [Accepted: 05/24/2018] [Indexed: 11/22/2022]
Abstract
Increased availability of antiretroviral therapy to pregnant and breastfeeding women in resource-limited areas has proven remarkably successful at reducing HIV vertical transmission rates over the past several decades. Yet, still more than 170,000 children are infected annually due to failures in therapy implementation, monitoring, and adherence. Mother-to-child transmission (MTCT) of HIV-1 can occur at one of several distinct stages of infant development - intrauterine, intrapartum, and postpartum. The heterogeneity of the maternal-fetal interface at each of these modes of transmission poses a challenge for the implementation of immune interventions to prevent all modes of HIV MTCT. However, using mother-infant human cohorts and nonhuman primate models of infant simian immunodeficiency virus (SIV) acquisition, investigators have made important observation about the biology of pediatric HIV infection and have identified unique protective immune factors for each mode of transmission. Knowledge of immune factors protective against HIV MTCT will be critical to the development of targeted immune therapies to prevent infant HIV acquisition and to bring an end to the pediatric AIDS epidemic.
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Affiliation(s)
- Cody S. Nelson
- Human Vaccine Institute, Duke University Medical Center, Durham, North Carolina, USA
| | - Genevieve G.A. Fouda
- Human Vaccine Institute, Duke University Medical Center, Durham, North Carolina, USA
| | - Sallie R. Permar
- Human Vaccine Institute, Duke University Medical Center, Durham, North Carolina, USA
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Maternal but Not Infant Anti-HIV-1 Neutralizing Antibody Response Associates with Enhanced Transmission and Infant Morbidity. mBio 2017; 8:mBio.01373-17. [PMID: 29066544 PMCID: PMC5654929 DOI: 10.1128/mbio.01373-17] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
A significant number of infants acquire HIV-1 through their infected mother’s breast milk, primarily due to limited access to antiretrovirals. Passive immunization with neutralizing antibodies (nAbs) may prevent this transmission. Previous studies, however, have generated conflicting results about the ability of nAbs to halt mother-to-child transmission (MTCT) and their impact on infant outcomes. This study compared plasma neutralizing activity in exposed infants and the infected mothers (n = 63) against heterologous HIV-1 variants and the quasispecies present in the mother. HIV-exposed uninfected infants (HEU) (n = 42), compared to those that eventually acquired infection (n = 21), did not possess higher nAb responses against heterologous envelopes (P = 0.46) or their mothers’ variants (P = 0.45). Transmitting compared to nontransmitting mothers, however, had significantly higher plasma neutralizing activity against heterologous envelopes (P = 0.03), although these two groups did not have significant differences in their ability to neutralize autologous strains (P = 0.39). Furthermore, infants born to mothers with greater neutralizing breadth and potency were significantly more likely to have a serious adverse event (P = 0.03). These results imply that preexisting anti-HIV-1 neutralizing activity does not prevent breast milk transmission. Additionally, high maternal neutralizing breadth and potency may adversely influence both the frequency of breast milk transmission and subsequent infant morbidity. Passive immunization trials are under way to understand if preexisting antibodies can decrease mother-to-child HIV-1 transmission and improve infant outcomes. We examined the influence of preexisting maternal and infant neutralizing activity on transmission and infant morbidity in a breastfeeding mother-infant cohort. Neutralization was examined against both the exposure strains circulating in the infected mothers and a standardized reference panel previously used to estimate breadth. HIV-exposed uninfected infants did not possess a broader and more potent response against both the exposure and heterologous strains compared to infants that acquired infection. Transmitting, compared to nontransmitting, mothers had significantly higher neutralization breadth and potency but similar responses against autologous variants. Infants born to mothers with higher neutralization responses were more likely to have a serious adverse event. Our results suggest that preexisting antibodies do not protect against breast milk HIV-1 acquisition and may have negative consequences for the baby.
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Abstract
PURPOSE OF REVIEW Although antiretroviral (ARV) prophylaxis can reduce mother-to-child transmission (MTCT) of HIV-1 to less than 2%, one-quarter of a million infants continue to be infected with HIV-1 annually. ARV prophylaxis alone will fail to eliminate infant HIV-1 infection because of issues of maternal adherence, toxicities, ARV-resistant virus strains, and acute maternal infection. Effective maternal and/or infant immunization will likely be required to achieve the goal of an HIV-free generation. RECENT FINDINGS This article describes recent studies of antibody responses that protect against vertical HIV-1 transmission. Studies have shown that maternal neutralization breadth is not a critical factor in MTCT, yet the ability of maternal plasma to neutralize autologous virus variants may be important in infant protection. There is also new evidence that infants mount robust and durable antibody responses to HIV-1 envelope following vaccination and can develop broad neutralization during infection. Finally, passive immunization of infants with highly potent and broad neutralizing antibodies may be an effective strategy to protect infants against infection with postnatally transmitted variants. SUMMARY Defining the characteristics of maternal and infant antibody responses that protect against MTCT will inform development of effective passive and active immunization strategies that will likely be required to eliminate pediatric HIV-1.
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Permar SR, Fong Y, Vandergrift N, Fouda GG, Gilbert P, Parks R, Jaeger FH, Pollara J, Martelli A, Liebl BE, Lloyd K, Yates NL, Overman RG, Shen X, Whitaker K, Chen H, Pritchett J, Solomon E, Friberg E, Marshall DJ, Whitesides JF, Gurley TC, Von Holle T, Martinez DR, Cai F, Kumar A, Xia SM, Lu X, Louzao R, Wilkes S, Datta S, Sarzotti-Kelsoe M, Liao HX, Ferrari G, Alam SM, Montefiori DC, Denny TN, Moody MA, Tomaras GD, Gao F, Haynes BF. Maternal HIV-1 envelope-specific antibody responses and reduced risk of perinatal transmission. J Clin Invest 2015; 125:2702-6. [PMID: 26053661 DOI: 10.1172/jci81593] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 04/30/2015] [Indexed: 12/16/2022] Open
Abstract
Despite the wide availability of antiretroviral drugs, more than 250,000 infants are vertically infected with HIV-1 annually, emphasizing the need for additional interventions to eliminate pediatric HIV-1 infections. Here, we aimed to define humoral immune correlates of risk of mother-to-child transmission (MTCT) of HIV-1, including responses associated with protection in the RV144 vaccine trial. Eighty-three untreated, HIV-1-transmitting mothers and 165 propensity score-matched nontransmitting mothers were selected from the Women and Infants Transmission Study (WITS) of US nonbreastfeeding, HIV-1-infected mothers. In a multivariable logistic regression model, the magnitude of the maternal IgG responses specific for the third variable loop (V3) of the HIV-1 envelope was predictive of a reduced risk of MTCT. Neutralizing Ab responses against easy-to-neutralize (tier 1) HIV-1 strains also predicted a reduced risk of peripartum transmission in secondary analyses. Moreover, recombinant maternal V3-specific IgG mAbs mediated neutralization of autologous HIV-1 isolates. Thus, common V3-specific Ab responses in maternal plasma predicted a reduced risk of MTCT and mediated autologous virus neutralization, suggesting that boosting these maternal Ab responses may further reduce HIV-1 MTCT.
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HIV-1 autologous antibody neutralization associates with mother to child transmission. PLoS One 2013; 8:e69274. [PMID: 23874931 PMCID: PMC3714266 DOI: 10.1371/journal.pone.0069274] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 06/06/2013] [Indexed: 01/07/2023] Open
Abstract
The HIV-1 characteristics associated with mother to child transmission (MTCT) are still poorly understood and if known would indicate where intervention strategies should be targeted. In contrast to horizontally infected individuals, exposed infants possess inherited antibodies (Abs) from their mother with the potential to protect against infection. We investigated the HIV-1 gp160 envelope proteins from seven transmitting mothers (TM) whose children were infected either during gestation or soon after delivery and from four non-transmitting mothers (NTM) with similar viral loads and CD4 counts. Using pseudo-typed viruses we tested gp160 envelope glycoproteins for TZM-bl infectivity, CD4 and CCR5 interactions, DC-SIGN capture and transfer and neutralization with an array of common neutralizing Abs (NAbs) (2F5, 2G12, 4E10 and b12) as well as mother and infant plasma. We found no viral correlates associated with HIV-1 MTCT nor did we find differences in neutralization with the panel of NAbs. We did, however, find that TM possessed significantly higher plasma neutralization capacities than NTM (P = 0.002). Furthermore, we found that in utero (IU) TM had a higher neutralization capacity than mothers transmitting either peri-partum (PP) or via breastfeeding (BF) (P = 0.002). Plasma from children infected IU neutralized viruses carrying autologous gp160 viral envelopes as well as those from their corresponding mothers whilst plasma from children infected PP and/or BF demonstrated poor neutralizing capacity. Our results demonstrate heightened autologous NAb responses against gp120/gp41 can associate with a greater risk of HIV-1 MTCT and more specifically in those infants infected IU. Although the number of HIV-1 transmitting pairs is low our results indicate that autologous NAb responses in mothers and infants do not protect against MTCT and may in fact be detrimental when considering IU HIV-1 transmissions.
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Passively transmitted gp41 antibodies in babies born from HIV-1 subtype C-seropositive women: correlation between fine specificity and protection. J Virol 2012; 86:4129-38. [PMID: 22301151 DOI: 10.1128/jvi.06359-11] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
HIV-exposed, uninfected (EUN) babies born to HIV-infected mothers are examples of natural resistance to HIV infection. In this study, we evaluated the titer and neutralizing potential of gp41-specific maternal antibodies and their correlation with HIV transmission in HIV-infected mother-child pairs. Specific gp41-binding and -neutralizing antibodies were determined in a cohort of 74 first-time mother-child pairs, of whom 40 mothers were infected with HIV subtype C. Within the infected mother cohort, 16 babies were born infected and 24 were PCR negative and uninfected at birth (i.e., exposed but uninfected). Thirty-four HIV-uninfected and HIV-unexposed mother-child pairs were included as controls. All HIV-positive mothers and their newborns showed high IgG titers to linear epitopes within the HR1 region and to the membrane-proximal (MPER) domain of gp41; most sera also recognized the disulfide loop immunodominant epitope (IDE). Antibody titers to the gp41 epitopes were significantly lower in nontransmitting mothers (P < 0.01) and in the EUN babies (P < 0.005) than in HIV-positive mother-child pairs. Three domains of gp41, HR1, IDE, and MPER, elicited antibodies that were effectively transmitted to EUN babies. Moreover, in EUN babies, epitopes overlapping the 2F5 epitope (ELDKWAS), but not the 4E10 epitope, were neutralization targets in two out of four viruses tested. Our findings highlight important epitopes in gp41 that appear to be associated with exposure without infection and would be important to consider for vaccine design.
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Kittinunvorakoon C, Morris MK, Neeyapun K, Jetsawang B, Buehring GC, Hanson CV. Mother to child transmission of HIV-1 in a Thai population: role of virus characteristics and maternal humoral immune response. J Med Virol 2009; 81:768-78. [PMID: 19319941 DOI: 10.1002/jmv.21465] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The objective of this study was to investigate factors influencing mother to child transmission of HIV-1 in Thailand, where HIV-1 CRF01_AE, the major subtype in Southeast Asia, predominates. Samples from 84 HIV-1 infected, anti-retroviral treatment-naïve, non-breast feeding mothers, 28 who transmitted HIV-1 to their babies (transmitters) and 56 who did not (non-transmitters), were studied for maternal humoral immune response and virus characteristics. Maternal humoral immune response was measured by lymphocyte phenotyping; neutralizing antibodies to laboratory HIV-1 MN strain and two clinical isolates; peptide binding antibody to gp41 and V3 from strains CRF01_AE, B, and MN; autologous antibodies; and quasispecies diversity. Virus characteristics studied were viral load, co-receptor usage, and viral replication capacity. No significant difference between transmitters and non-transmitters was found for any parameter of maternal humoral immune response. However, viral load and viral replication capacity were significantly higher in transmitters versus non-transmitters and were not correlated with each other. This suggests that viral replication capacity may be a transmission factor independent of viral load, which is already well established as a risk factor for transmission of HIV-1. All except four viral isolates used the CCR5 co-receptor. This is one of few studies of vertical transmission in a population where HIV-1 CRF01_AE predominates. The data suggest that in this population the maternal humoral immune response was not important in preventing transmission at parturition, but that virus characteristics were key factors, and that viral replication capacity may contribute to birth-associated mother to child transmission of HIV-1.
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Affiliation(s)
- Chonticha Kittinunvorakoon
- Division of Infectious Diseases, School of Public Health, University of California, Berkeley, CA 94720-7354, USA
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Lehman DA, Farquhar C. Biological mechanisms of vertical human immunodeficiency virus (HIV-1) transmission. Rev Med Virol 2007; 17:381-403. [PMID: 17542053 DOI: 10.1002/rmv.543] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In the absence of interventions, 30-45% of exposed infants acquire human immunodeficiency virus type 1 (HIV-1) through mother-to-child transmission. It remains unclear why some infants become infected while others do not, despite significant exposure to HIV-1 in utero, during delivery and while breastfeeding. Here we discuss the correlates of vertical transmission with an emphasis on factors that increase maternal HIV-1 levels, either systemically or locally in genital secretions and breast milk. Immune responses may influence maternal viral load, and data suggest that maternal neutralising antibodies reduce infection rates. In addition, infants may be capable of mounting HIV-specific cellular immune responses. We propose that both humoral and cellular responses are necessary to reduce infection because cell-free as well as cell-associated virus appears to play a role in vertical transmission. These distinct forms of the virus may be targeted most effectively by different components of the immune system. We also discuss the use of antiretrovirals to reduce transmission, focusing on the mechanisms of action of regimens currently used in developing country settings. We conclude that prevention relies not only on reducing maternal HIV-1 levels within blood, genital tract and breast milk, but also on pre- and/or post-exposure prophylaxis to the infant. However, HIV-1 has the capacity to mutate under drug pressure and rapidly acquires mutations conferring antiretroviral resistance. This review concludes with data on persistence of low-level resistance after delivery as well as recent guidelines for maternal and infant regimens designed to limit resistance.
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Affiliation(s)
- Dara A Lehman
- Department of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
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Kamara P, Melendez-Guerrero L, Arroyo M, Weiss H, Jolly P. Maternal plasma viral load and neutralizing/enhancing antibodies in vertical transmission of HIV: a non-randomized prospective study. Virol J 2005; 2:15. [PMID: 15730556 PMCID: PMC555584 DOI: 10.1186/1743-422x-2-15] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2004] [Accepted: 02/24/2005] [Indexed: 11/12/2022] Open
Abstract
Background We examined the association and interaction between maternal viral load and antibodies in vertical transmission of HIV in a non-randomized prospective study of 43 HIV-1 infected pregnant women who attended the San Juan City Hospital, Puerto Rico, and their 45 newborn infants. The women and infants received antiretroviral therapy. Methods A nested PCR assay of the HIV-1 envelope V3 region and infant PBMC culture were performed to determine HIV status of the infants. Maternal and infant plasma were tested for HIV neutralization or enhancement in monocyte-derived macrophages. Results Twelve (26.7%) infants were positive by the HIV V3 PCR assay and 3 of the 12 were also positive by culture. There was a trend of agreement between high maternal viral load and HIV transmission by multivariate analysis (OR = 2.5, CI = 0.92, p = 0.0681). Both maternal and infant plasma significantly (p = 0.001 for both) reduced HIV replication at 10-1 dilution compared with HIV negative plasma. Infant plasma neutralized HIV (p = 0.001) at 10-2 dilution but maternal plasma lost neutralizing effect at this dilution. At 10-3 dilution both maternal and infant plasma increased virus replication above that obtained with HIV negative plasma but only the increase by maternal plasma was statistically significant (p = 0.005). There were good agreements in enhancing activity in plasma between mother-infant pairs, but there was no significant association between HIV enhancement by maternal plasma and vertical transmission. Conclusion Although not statistically significant, the trend of association between maternal viral load and maternal-infant transmission of HIV supports the finding that viral load is a predictor of maternal-infant transmission. Both maternal and infant plasma neutralized HIV at low dilution and enhanced virus replication at high dilution. The antiretroviral treatments that the women received and the small sample size may have contributed to the lack of association between HIV enhancement by maternal plasma and vertical transmission.
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Affiliation(s)
- Paul Kamara
- Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, 1665 University Blvd., Ryals Building, Room 217, Birmingham AL 35294-0022, USA
| | - Loyda Melendez-Guerrero
- Department of Microbiology and Medical Zoology, University of Puerto Rico, Medical Sciences Campus, School of Medicine, San Juan, Puerto Rico
| | - Miguel Arroyo
- US Military HIV Research Program, Walter Reed Army Institute of Research, Division of Retrovirology, Silver Spring, MD 20910, USA
| | - Heidi Weiss
- Breast Center, Baylor College of Medicine, One Baylor Plaza, MS: BCM 600, 335A, Houston, TX 77030, USA
| | - Pauline Jolly
- Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, 1665 University Blvd., Ryals Building, Room 217, Birmingham AL 35294-0022, USA
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Farquhar C, John-Stewart G. The role of infant immune responses and genetic factors in preventing HIV-1 acquisition and disease progression. Clin Exp Immunol 2004; 134:367-77. [PMID: 14632739 PMCID: PMC1808883 DOI: 10.1111/j.1365-2249.2003.02292.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Affiliation(s)
- C Farquhar
- Department of Medicine, University of Washington, Seattle 98104-2499, USA.
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Ogundele MO, Coulter JBS. HIV transmission through breastfeeding: problems and prevention. ANNALS OF TROPICAL PAEDIATRICS 2003; 23:91-106. [PMID: 12803739 DOI: 10.1179/027249303235002161] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
The greatest burden of HIV infection in women and their children is disproportionately borne by the poorest countries, especially in sub-Saharan Africa. Breastfeeding is a major health-promoting factor for infants and children in developing countries but the risk of mother-to-child transmission (MTCT) of HIV by this route is challenging traditional practices and health policies in low-resource countries. Maternal and infant factors contributing to the risk of MTCT through breastfeeding are still poorly understood and not well researched. Factors identified include: advanced clinical stages of infection in the mother; high maternal plasma HIV-1 load; presence of mastitis; and infant oral thrush. In many developing countries, international agencies are providing support and recommendations for preventing MTCT of HIV-1 by breastfeeding. Preventive strategies supported by WHO/UNICEF and charitable agencies in some sentinel centres in sub-Saharan Africa include routine antenatal voluntary counselling and testing (VCT), PCR testing of infants of seropositive mothers at 6 weeks of age, various combinations of a shortened period (3-6 mths) of exclusive breastfeeding, perinatal administration of antiretrovirals (ARV) such as nevirapine and provision of affordable and safe infant replacement feeds (presently given free by UNICEF in some centres). Many problems, however, have hindered effective implementation of these interventions. In many poor communities, even where VCT facilities are available, acceptance of HIV testing is low because there is fear of stigmatisation by the spouse, family or community and compliance with complex drug regimens is therefore poor. Other problems include the exorbitant cost of antiretroviral drugs, inadequately resourced health care systems and unavailability or poor acceptance of safe breast-milk alternatives. The rate of mixed feeding is high and so the risk of MTCT is increased. Continued promotion of exclusive breastfeeding for at least 6 months, irrespective of HIV status, followed by a properly prepared, high energy, nutritious complementary diet, with the possibility of early weaning to an animal milk formula, still appears to be the most appropriate option for the poor in countries with high levels of MTCT not deriving any benefit from the above strategies. While a longer period of breastfeeding would probably increase the risk of MTCT in vulnerable communities, a shorter duration would certainly increase infant morbidity and mortality. Results of investigations of the efficacy of ARV for protecting the infants of HIV-infected mothers during the breastfeeding period are awaited.
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Affiliation(s)
- M O Ogundele
- Liverpool School of Tropical Medicine, Liverpool, UK
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Richardson J, Broche S, Baud S, Leste-Lasserre T, Féménia F, Levy D, Moraillon A, Pancino G, Sonigo P. Lymphoid activation: a confounding factor in AIDS vaccine development? J Gen Virol 2002; 83:2515-2521. [PMID: 12237435 DOI: 10.1099/0022-1317-83-10-2515] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In a previous vaccination trial, inoculation of env gene DNA failed to elicit a detectable antibody response, yet accelerated virus dissemination in most immunized cats following challenge with feline immunodeficiency virus. This result raised the possibility that cell-mediated immune responses had given rise to immune-mediated enhancement of infection. Since high-level replication of immunodeficiency viruses in lymphocytes requires cellular activation, antigen-specific responses or non-specific polyclonal activation may have increased the frequency of optimal target cells. In the present DNA vaccination trial, although designed so as to minimize non-specific polyclonal activation, immune-mediated enhancement was nonetheless observed in certain immunized cats. Moreover, rapid virus dissemination in vivo was associated with the presence of T-helper responses prior to challenge, and was linked to increased susceptibility of lymphocytes to ex vivo infection. Immune activation may thus be a confounding factor in vaccination against lentivirus infection, diminishing vaccine efficacy and giving rise to immune-mediated enhancement.
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Affiliation(s)
- Jennifer Richardson
- Génétique des Virus, Institut Cochin (INSERM U567 CNRS UMR 8104), 22 rue Méchain, 75014 Paris, France1
| | - Sophie Broche
- Génétique des Virus, Institut Cochin (INSERM U567 CNRS UMR 8104), 22 rue Méchain, 75014 Paris, France1
| | - Sandrine Baud
- Génétique des Virus, Institut Cochin (INSERM U567 CNRS UMR 8104), 22 rue Méchain, 75014 Paris, France1
| | - Thierry Leste-Lasserre
- Génétique des Virus, Institut Cochin (INSERM U567 CNRS UMR 8104), 22 rue Méchain, 75014 Paris, France1
| | - Françoise Féménia
- Génétique des Virus, Institut Cochin (INSERM U567 CNRS UMR 8104), 22 rue Méchain, 75014 Paris, France1
| | - Daniel Levy
- Génétique des Virus, Institut Cochin (INSERM U567 CNRS UMR 8104), 22 rue Méchain, 75014 Paris, France1
| | - Anne Moraillon
- Génétique des Virus, Institut Cochin (INSERM U567 CNRS UMR 8104), 22 rue Méchain, 75014 Paris, France1
| | - Gianfranco Pancino
- Génétique des Virus, Institut Cochin (INSERM U567 CNRS UMR 8104), 22 rue Méchain, 75014 Paris, France1
| | - Pierre Sonigo
- Génétique des Virus, Institut Cochin (INSERM U567 CNRS UMR 8104), 22 rue Méchain, 75014 Paris, France1
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Alfsen A, Iniguez P, Bouguyon E, Bomsel M. Secretory IgA specific for a conserved epitope on gp41 envelope glycoprotein inhibits epithelial transcytosis of HIV-1. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 166:6257-65. [PMID: 11342649 DOI: 10.4049/jimmunol.166.10.6257] [Citation(s) in RCA: 151] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
As one of the initial mucosal transmission pathways of HIV (HIV-1), epithelial cells translocate HIV-1 from apical to basolateral surface by nondegradative transcytosis. Transcytosis is initiated when HIV-1 envelope glycoproteins bind to the epithelial cell membrane. Here we show that the transmembrane gp41 subunit of the viral envelope binds to the epithelial glycosphingolipid galactosyl ceramide (Gal Cer), an alternative receptor for HIV-1, at a site involving the conserved ELDKWA epitope. Disrupting the raft organization of the Gal Cer-containing microdomains at the apical surface inhibited HIV-1 transcytosis. Immunological studies confirmed the critical role of the conserved ELDKWA hexapeptide in HIV-1 transcytosis. Mucosal IgA, but not IgG, from seropositive subjects targeted the conserved peptide, neutralized gp41 binding to Gal Cer, and blocked HIV-1 transcytosis. These results underscore the important role of secretory IgA in designing strategies for mucosal protection against HIV-1 infection.
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Affiliation(s)
- A Alfsen
- Institut National de la Santé et de la Recherche Médicale, Unité 332, Institut Cochin de Genetique Moleculaire, Paris, France
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Zachar V, Zacharova V, Fink T, Thomas RA, King BR, Ebbesen P, Jones TB, Goustin AS. Genetic analysis reveals ongoing HIV type 1 evolution in infected human placental trophoblast. AIDS Res Hum Retroviruses 1999; 15:1673-83. [PMID: 10606090 DOI: 10.1089/088922299309711] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
To provide a better understanding of the role of placenta in vertical human immunodeficiency virus (HIV) transmission, we have studied the infection of placental trophoblast in a group of 15 mother-neonate pairs. By nested PCR amplification of the C2V3 env gene region, HIV-1 has been found to infect the placenta in five cases (33%). Phylogenetic analysis of the cloned sequences showed that all recovered maternal variants were of the B subtype. Further investigation into the ancestral relationships at the nucleotide level revealed that the trophoblast sequences evolved into a quasispecies population clearly distant from that observed in the mother. As expected, the populations transmitted to the trophoblast were also found to be more homogeneous than those in the mothers when characterized on the basis of pairwise nucleotide sequence distances. With regard to the predicted biological properties, the primary amino acid structure of the V3 loop domain was consistent, with a macrophage-tropic, non-syncytium-inducing phenotype in all patients. We also attempted to determine if any of a number of selected maternal or viral factors was associated with trophoblast infection. However, none of the followed parameters, including maternal age, disease stage, antiretroviral therapy, CCR5delta32 deletion status of the infant, and viral genotype, could be associated with viral transmission. Moreover, in one pair with proven trophoblast infection, HIV was also detected in the cord blood. Taken together, our data suggest that the productive trophoblast infection by HIV-1 in vivo is a relatively frequent event that may bear direct implications for a further transplacental propagation of the virus.
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Affiliation(s)
- V Zachar
- Department of Virus and Cancer, Danish Cancer Society, Aarhus.
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Merat R, Raoul H, Leste-Lasserre T, Sonigo P, Pancino G. Variable constraints on the principal immunodominant domain of the transmembrane glycoprotein of human immunodeficiency virus type 1. J Virol 1999; 73:5698-706. [PMID: 10364320 PMCID: PMC112629 DOI: 10.1128/jvi.73.7.5698-5706.1999] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lentiviruses have in their transmembrane glycoprotein (TM) a highly immunogenic structure referred to as the principal immunodominant domain (PID). The PID forms a loop of 5 to 7 amino acids between two conserved cysteines. Previous studies showed that envelope (Env) glycoprotein functions of feline immunodeficiency virus (FIV) could be retained after extensive mutation of the PID loop sequence, in spite of its high conservation. In order to compare Env function in different lentiviruses, either random mutations were introduced in the PID loop sequence of human immunodeficiency virus type 1 (HIV-1) or the entire HIV-1 PID loop was replaced by the corresponding PID loop of FIV or simian immunodeficiency virus (SIV). In the macrophage-tropic HIV-1 ADA Env, mutations impaired the processing of the gp160 Env precursor, thereby abolishing viral infectivity. However, 6 of the 108 random Env mutants that were screened retained the capacity to induce cell membrane fusion. The SIV and FIV sequences and five random mutations were then introduced in the context of T-cell-line-adapted HIV-1 LAI which, although phenotypically distant from HIV-1 ADA, has an identical PID loop sequence. In contrast to the situation for HIV-1 ADA mutants, the cleavage of the Env precursor was unaffected in most HIV-1 LAI mutants. Such mutations, however, resulted in increased shedding of the gp120 surface glycoprotein (SU) from the gp41 TM. The HIV-1 LAI Env mutants showed high fusogenic efficiency. Three Env mutants retained the capacity to mediate virus entry in target cells, although less efficiently than the wild-type Env, and allowed the reconstitution of infectious molecular clones. These results indicated that in HIV-1, like FIV, the conserved PID sequence can be changed without impairing Env function. However, functional constraints on the PID of HIV-1 vary depending on the structural context of Env, presumably in relation to the role of the PID in the interaction of the SU and TM subunits and the stability of the Env complex.
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Affiliation(s)
- R Merat
- Génétique des Virus (ICGM-CNRS UPR0415), Institut Cochin de Génétique Moléculaire, 75014 Paris, France
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