The semen microbiome and its relationship with local immunology and viral load in HIV infection

Liu, Cindy M. and Osborne, Brendan J. W. and Hungate, Bruce A. and Shahabi, Kamnoosh and Huibner, Sanja and Lester, Richard and Dwan, Michael G. and Kovacs, Colin and Contente-Cuomo, Tania L. and Benko, Erika and Aziz, Maliha and Price, Lance B. and Kaul, Rupert (2014) The semen microbiome and its relationship with local immunology and viral load in HIV infection. PLoS Pathogens, 10 (7). e1004262. ISSN 1553-7366

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Abstract

Semen is a major vector for HIV transmission, but the semen HIV RNA viral load (VL) only correlates moderately with the blood VL. Viral shedding can be enhanced by genital infections and associated inflammation, but it can also occur in the absence of classical pathogens. Thus, we hypothesized that a dysregulated semen microbiome correlates with local HIV shedding. We analyzed semen samples from 49 men who have sex with men (MSM), including 22 HIV-uninfected and 27 HIV-infected men, at baseline and after starting antiretroviral therapy (ART) using 16S rRNA gene-based pyrosequencing and quantitative PCR. We studied the relationship of semen bacteria with HIV infection, semen cytokine levels, and semen VL by linear regression, non-metric multidimensional scaling, and goodness-of-fit test. Streptococcus, Corynebacterium, and Staphylococcus were common semen bacteria, irrespective of HIV status. While Ureaplasma was the more abundant Mollicutes in HIV-uninfected men, Mycoplasma dominated after HIV infection. HIV infection was associated with decreased semen microbiome diversity and richness, which were restored after six months of ART. In HIV-infected men, semen bacterial load correlated with seven pro-inflammatory semen cytokines, including IL-6 (p = 0.024), TNF-α (p = 0.009), and IL-1b (p = 0.002). IL-1b in particular was associated with semen VL (r(2)  = 0.18, p = 0.02). Semen bacterial load was also directly linked to the semen HIV VL (r(2) = 0.15, p = 0.02). HIV infection reshapes the relationship between semen bacteria and pro-inflammatory cytokines, and both are linked to semen VL, which supports a role of the semen microbiome in HIV sexual transmission.

Item Type:	Article
ID number or DOI:	10.1371/journal.ppat.1004262
Keywords:	Anti-HIV agents; Biology and life sciences; Blood; Clinical immunology; Diagnostic medicine; Disease; Ecology; effective antiretroviral therapy; Genitourinary infections; HIV; HIV clinical manifestations; HIV infections -- Transmission; HIV-positive men; Host-pathogen interactions; human-immunodeficiency-virus; Immunodeficiency viruses; Immunology; Immunopathology; Infectious diseases; infertile couples; male genital-tract; Medical microbiology; Medicine and health sciences; Men; Men who have sex with men; microbial ecology; Microbial pathogens; Microbiology; mycoplasma-hominis; Pathogenesis; Pathology and laboratory medicine; research; Research Article; RNA; Semen; seminal plasma; Sexually transmitted diseases; Therapeutic use; ureaplasma-urealyticum; Urologic infections; Urology; Viral diseases; Viral load; Viral pathogens
Subjects:	Q Science > QR Microbiology > QR355 Virology
NAU Depositing Author Academic Status:	Faculty/Staff
Department/Unit:	College of Engineering, Forestry, and Natural Science > Biological Sciences Research Centers > Center for Microbial Genetics and Genomics
Date Deposited:	18 Oct 2015 19:50
URI:	http://openknowledge.nau.edu/id/eprint/1685

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