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J Virol. 2016 Jul 27;90(16):7285-7302. doi: 10.1128/JVI.00481-16. Print 2016 Aug 15.

Vaccine-Elicited Mucosal and Systemic Antibody Responses Are Associated with Reduced Simian Immunodeficiency Viremia in Infant Rhesus Macaques.

Author information

1
Department of Microbiology and Immunology and Center for AIDS Research, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
2
Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA.
3
California National Primate Research Center, University of California at Davis, Davis, California, USA.
4
AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory, Frederick, Maryland, USA.
5
Albert Einstein College of Medicine, New York, New York, USA.
6
Lineberger Cancer Center and Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
7
Gillings School of Public Health and Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
8
Department of Microbiology and Immunology and Center for AIDS Research, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA abelk@med.unc.edu.

Abstract

Despite significant progress in reducing peripartum mother-to-child transmission (MTCT) of human immunodeficiency virus (HIV) with antiretroviral therapy (ART), continued access to ART throughout the breastfeeding period is still a limiting factor, and breast milk exposure to HIV accounts for up to 44% of MTCT. As abstinence from breastfeeding is not recommended, alternative means are needed to prevent MTCT of HIV. We have previously shown that oral vaccination at birth with live attenuated Mycobacterium tuberculosis strains expressing simian immunodeficiency virus (SIV) genes safely induces persistent SIV-specific cellular and humoral immune responses both systemically and at the oral and intestinal mucosa. Here, we tested the ability of oral M. tuberculosis vaccine strains expressing SIV Env and Gag proteins, followed by systemic heterologous (MVA-SIV Env/Gag/Pol) boosting, to protect neonatal macaques against oral SIV challenge. While vaccination did not protect infant macaques against oral SIV acquisition, a subset of immunized animals had significantly lower peak viremia which inversely correlated with prechallenge SIV Env-specific salivary and intestinal IgA responses and higher-avidity SIV Env-specific IgG in plasma. These controller animals also maintained CD4(+) T cell populations better and showed reduced tissue pathology compared to noncontroller animals. We show that infants vaccinated at birth can develop vaccine-induced SIV-specific IgA and IgG antibodies and cellular immune responses within weeks of life. Our data further suggest that affinity maturation of vaccine-induced plasma antibodies and induction of mucosal IgA responses at potential SIV entry sites are associated with better control of viral replication, thereby likely reducing SIV morbidity.

IMPORTANCE:

Despite significant progress in reducing peripartum MTCT of HIV with ART, continued access to ART throughout the breastfeeding period is still a limiting factor. Breast milk exposure to HIV accounts for up to 44% of MTCT. Alternative measures, in addition to ART, are needed to achieve the goal of an AIDS-free generation. Pediatric HIV vaccines constitute a core component of such efforts. The results of our pediatric vaccine study highlight the potential importance of vaccine-elicited mucosal Env-specific IgA responses in combination with high-avidity systemic Env-specific IgG in protection against oral SIV transmission and control of viral replication in infant macaques. The induction of potent mucosal IgA antibodies by our vaccine is remarkable considering the age-dependent development of mucosal IgA responses postbirth. A deeper understanding of postnatal immune development may inform the design of improved vaccine strategies to enhance systemic and mucosal SIV/HIV antibody responses.

PMID:
27252535
PMCID:
PMC4984660
DOI:
10.1128/JVI.00481-16
[Indexed for MEDLINE]
Free PMC Article

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