CROI 2015 Program and Abstracts

Abstract Listing

Poster Abstracts

TUESDAY, FEBRUARY 24, 2015 Session P-C5 Poster Session

Poster Hall

2:30 pm– 4:00 pm Studies of HIV-Exposed Uninfected Individuals 287 HIV-Exposed Seronegative MSM Have Increased Novel Antiviral Factors in Rectal Mucosa Laura Romas 1 ; Klara Hasselrot 2 ; Kristina Broliden 2 ; Carolina Herrera 3 ; GarrettWestmacott 4 ; Francis Plummer 4 ;Terry B. Ball 4 ; Adam Burgener 1

1 University of Manitoba, Winnipeg, Canada; 2 Karolinska Institutet, Stockholm, Sweden; 3 Imperial College London, London, United Kingdom; 4 Public Health Agency of Canada, Winnipeg, Canada Background: HIV-Exposed Seronegative (HESN) individuals have shown altered mucosal immune responses in cervical, salivary and foreskin secretions associated with reduced HIV-susceptibility; however, this has not been investigated in rectal mucosa. As the rectal compartment is a major portal of entry for HIV understanding site-specific immune responses is important for biomedical prevention research. Advances in proteomic tools, such as mass spectrometry, allow for a comprehensive evaluation of several hundreds of immune factors within mucosal secretions. Here we perform the first proteomic analysis of rectal mucosal from HESN MSM identifying unique antiviral factors in this population. Methods: Rectal lavage from HESN MSM (n=25) and non-exposed healthy controls (n=14) from the Venhälsan clinic, Sweden, were analysed by label-free tandemmass spectrometry. Identification of proteins, differential expression analysis and pathway analysis were performed. Several differentially expressed proteins that demonstrated innate expression were screened for HIV-neutralizing activity in PBMC and colorectal-explant culture and in the presence of R5- and X4-tropic HIV lab strains (HIV-Bal and HIV-3B, respectively) using p24 ELISA. Results: HESN MSM overexpressed 25 immune proteins, including 3 antiproteases (p<0.05). These proteins did not show a significant correlation (p>0.05) with clinical variables (frequency oral/anal sex, HIV-neutralizing IgA, and VL of HIV+ partner). Pathway analysis linked overabundant proteins to the canonical pathway. One antiprotease (AP1) overabundant in HESN MSM demonstrated antiviral activity in vitro . Preliminary neutralization assays showed that “AP1” reduced Bal infection by a maximum of 61% and reduced IIIB infection by 90% (20 μ g/ml) in PBMCs with negligible effect on cell viability (cell viability >60%, p<0.05); inhibition of HIV infection in rectal explants inhibited at a maximum of 75% (25 μ g/ml). Conclusions: HESN MSM overexpress an antiprotease with previously undescribed antiviral activity, which may contribute to reduced susceptibility to HIV at the rectal mucosa. This is likely a result of innate differences rather than HIV-exposure. Our findings overlap with previous studies of showing an overabundance of antiviral factors in the cervical secretions of HESN women, supporting further study into their roles in HIV infection. This knowledge is critical for the design of safe, effective HIV-prevention technologies for MSM. 288 PBMC FromHighly Exposed Seronegative Individuals Inhibit Transmitted Founder HIV Kevin C. Olivieri 1 ; Eunyoung Kim 3 ; Susan Little 5 ; MichaelTurchin 4 ;Vanessa Serrano 1 ; Amna Rasheed 2 ; Quy Nguyen 1 ; Paul Dejesus 1 ; StevenWolinsky 3 ; Sumit Chanda 1 1 Sanford-BurnhamMedical Research Institute, San Diego, CA, US; 2 University of California Los Angeles (UCLA), Los Angeles, CA, US; 3 Northwestern University, Feinberg School of Medicine, Chicago, IL, US; 4 University of Chicago, Chicago, IL, US; 5 University of California San Diego (UCSD), San Diego, CA, US Background: Highly-exposed Sero-Negative (HESN) individuals engage frequently in unprotected sexual activities, yet remain sero-negative. In order to avoid sero-conversion, these individuals likely restrict HIV infection soon after transmission. Transmission of HIV infection is established by an extremely small fraction of circulating virus. These Transmitted Founder viruses (TFV) likely arise from a single HIV clone. Recently, Parrish and Fenton-May have shown that TFV are type I interferon (IFN)-resistant compared to chronic viruses from the same individual. We hypothesize that HESN inhibit TFV more efficiently than normal donors after IFN-beta treatment. Methods: We examined the ability of PBMC from 23 normal donors and 32 HESN donors to inhibit 10 TFV or an R5-tropic NL4-3 derivative, JM1186 after IFN-beta treatment in 14 day in vitro assays. p24 concentration was determined by alpha-LISA. HESN PBMC genotypes for selected genes were performed by custom Nimblegen Array and 454 Sequencing. Results: After low dose IFN treatment, a significant proportion of HESN, but not normal, PBMC inhibited JM1186 infection >25% (p = 0.0017). In a separate assay, 12 HESN PBMC and 8 normal PBMC were infected with TF CH040, TF SUMA, TF CH058, 6 month chronic virus (6mo) CH058, and JM1186 and treated or not with 75 IU/ml IFN-beta. In untreated samples, only infection with TF CHO58 resulted in a significantly lower p24 in HESN (p = 0.0473). Interestingly, this virus does not trigger an IFN response in normal monocyte- derived dendritic cells. In normal PBMC, the TFV CHO40 and SUMA were more resistant to IFN-beta than JM1186 (p = 0.0031 and 0.0446, respectively). For HESN samples, the median level of IFN-beta inhibition for all viruses was lower than normal, significantly so for CH040 and SUMA, (p = 0.0027 and 0.0181, respectively). All samples were ranked for their ability to inhibit all viruses. 6 of 9 HESN donors with ranks above the distribution of normal donors had variations in genes that were reported to interact with HIV Protease, Vpr, Vpu, Integrase, and Env. Conclusions: PBMC from HESN respond to IFN in a manner that more efficiently inhibits some viruses, including two TFV. HESN appear able to also inhibit an IFN sensitive TFV without IFN treatment. Determining the mechanism of resistance, whether it is increased responsiveness to IFN,expression of variant genes which impede viral replication, or resistance to viral countermeasures, will uncover modes of HIV resistance relevant to in vivo transmission events. 289 HIV-1-Exposed Seronegative Persons Have Lower Mucosal Innate Immune Reactivity Jennifer A. Fulcher 1 ; Jennifer C. Hoffman 1 ; Laura M. Romas 2 ; KarenTanner 1 ;Terry Saunders 1 ; Julie Elliott 1 ; Adam D. Burgener 2 ; Peter A. Anton 1 ; Otto O.Yang 1 1 David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA, US; 2 University of Manitoba, Winnipeg, Canada Background: Mucosal transmission accounts for the majority of HIV infections, yet is a poorly understood event. Risk of HIV acquisition varies, and there are some individuals who appear to remain uninfected despite repeated high-risk sexual exposures, termed HIV-exposed seronegative (HESN). The immunologic factors contributing to this phenomenon are an area of intense interest. It is known that immune activation and inflammation can facilitate HIV disease progression and transmission. Therefore, we hypothesized that altered immune reactivity may contribute to differences in HIV susceptibility. Since innate immunity serves as the initial defense in mucosal HIV exposure, we have focused our studies on characterizing this response in rectal mucosa, a frequent site of HIV transmission. Methods: Sigmoid biopsies were obtained from healthy control men (N=12) and from HESN subjects (N=4) identified through the MACS cohort. The biopsies were used in an ex vivo mucosal explant model and stimulated with select innate immune ligands (TLR ligands, inactivated whole HIV, HSV-2 and Chlamydia) followed by cytokine expression assays, proteomic studies, gene expression analysis, immunohistochemistry, and HIV infection assays. Results: Gut mucosal explants from all 16 subjects were susceptible to HIV infection, although there was a trend toward lower replication in HESN subjects. Explants from all subjects produced similar amounts of the non-inflammatory cytokines IL-10, IL-4, and IL-5, both at baseline and in response to innate immune stimuli. As expected, control subject explants also produced large amounts of pro-inflammatory cytokines TNF- α , IL-6, and IL-12. In contrast, no HESN subjects produced detectable levels of these pro-inflammatory

Poster Abstracts

241

CROI 2015