CROI 2020 Abstract eBook

Abstract eBook

Poster Abstracts

end-stage, SIV-infected RM, cultured under aerobic and anaerobic conditions, and identified by MALDI-TOF or 16S rDNA sequencing. Bacterial growth was kinetically assayed by spectrophotometer. MV miRNA profiles were assessed by human miRNA Array cards and qRT-PCR. AMPs alpha defensin 1, beta defensin (bDEF) 1, bDEF2, bDEF4, Lysozyme C, PLA2G2a, and Reg3g were assayed by ELISA. Results: Utilizing a non-human primate model of AIDS, we observed that MV miRNA profiles differ significantly after SIV infection. Ninety-three of 100 differentially expressed miRNAs displayed upregulated expression, with miR-425 and -484 showing significant upregulation in MVs derived from SIV- infected RM. Among AMPs, bDEF1 showed a significant downregulation among MVs from SIV-infected RMs. Several bacterial species showed dose-dependent growth sensitivity upon MV co-culture. Notably, Lactobacillus salivarius showed significantly accelerated growth when co-cultured with MVs derived from SIV- infected animals while Klebsiella pneumoniae displayed stunted growth. Conclusion: Fecal MVs can differentially influence the growth of bacterial isolates known to translocate in SIV infection. This effect may be attributable to a shift in MV miRNA content and/or to a shift in AMP content. The identification of the precise mechanisms by which fecal MVs differentially regulate the behavior of translocating bacteria will inform the development of therapeutics aimed at impeding microbial translocation. 209 CHARACTERISATION OF POTENTIAL HIV TARGET MYELOID CELLS IN FORESKIN EPITHELIA Bokani Nleya 1 , Yamkela Qumbelo 1 , Nobomi Dontsa 1 , Christen Da Costa 1 , Kyle O'hagan 1 , Clive M. Gray 1 , Nyaradzo T. Chigorimbo-Tsikiwa 1 1 University of Cape Town, Cape Town, South Africa Background: The human foreskin is an immunologically active tissue containing both lymphoid and myeloid cells. The foreskin has been shown to play an important role in HIV infection as its complete removal during MMC has been shown to reduce the risk of HIV acquisition by up to 60%. CD4+/CCR5+ Langerhan’s cells (LCs) and macrophages are known to be resident in both inner and outer foreskin tissue and are potential HIV target cells. To better understand whether foreskin-derived myeloid cells are promiscuous to HIV-1, we exposed them to HIV in ex-vivochallenge assays. Methods: Foreskin cells were allowed to migrate out of isolated epidermal tissue from adult South African men undergoing vMMC. Briefly, epidermal sheets were obtained after dispase digestion of 1cm 2 foreskin tissue. Cells were collected after 48-hour incubation and remnant tissue resident cells were enzymatically isolated using liberase (5 mg/ml). Epidermal LCs and macrophages from the inner and outer foreskins were identified using a multiparameter flow panel: CD207, CD1a, CD80/86, HLA-DR, CD11c, CD209, CD206, CD14, CD4, CCR5, CD169 and zombie (live/dead). Ex-vivoHIV challenge assays were set up using migratory cells and HIV infection was detected using reporter genes, GFP and mCherry as well as p24 antibody. Results: Tissue resident LCs and macrophages were isolated. LCs (4.8 x 105) were more abundant than macrophages (9.4 x 101), with averages of 5% and 0.009% of the entire cell population respectively. Both migrating CD1a+, CD207+ LCs and CD209+, CD163+macrophages expressed higher levels of CD80/86 (p=0.006) and HLA-DR (p=0.02) relative to cells that remained in the tissue co-expressing these surface antigens (p=0.015). HIV exposed CD11c+ LCs and macrophages expressed 2%mCherry, 13% p24 and absolute CD4 downregulation. Conclusion: LCs and macrophages that migrate from foreskin epidermal sheets express high levels of maturation and activation markers CD40, CD80/86 and HLA-DR, they are therefore activated and susceptible to HIV infection as evidenced by reporter gene (mCherry) and p24 expression. CD4 downregulation also indicates HIV infection. 210 IMPACT OF CCL27 ON HIV-1 TARGET-CELL ABUNDANCE IN THE FORESKIN EPITHELIUM Shorok Sebaa 1 , Kyle O'Hagan 1 , Nyaradzo T. Chigorimbo-Tsikiwa 1 , Sylvie Amu 2 , Ramon Lorenzo-Redondo 3 , Ann M. Carias3, Francesca Chiodi 2 , Gianguido C. Cianci 3 , Thomas Hope 3 , Clive Gray 1 1 University of Cape Town, Cape Town, South Africa, 2 Karolinska Institute, Stockholm, Sweden, 3 Northwestern University, Chicago, IL, USA Background: Findings from our laboratory have shown that asymptomatic sexually transmitted infections (STIs) have a significant effect on foreskin immunity, by increasing the density of HIV target cells in the foreskin and

altering inflammatory markers in the tissue. Of particular importance, CCL27 transcript and protein were found to be significantly higher in the inner foreskin relative to the outer tissue. We hypothesized that CCL27, a skin-homing chemokine, might have an effect on recruiting HIV target cells to the foreskin epidermis, bringing target cells closer to where they might interact with HIV upon exposure. Methods: Inner foreskin tissue explants were cultured in either media alone or in the presence of TNFα (100ng/ml) or CCL27 (400ng/ml) for 48 hours. Tissue was embedded and frozen in OCT, sectioned and stained for HIV target cells (CD3+CD4+). A Delta Vision imaging systemwas used to acquire fluorescent images of the cells. Cell density was then calculated using Integrative Data Language (IDL), accounting for the size of the epidermis. Results: We observed an increase in the density of CD3+CD4+ T cells in the epithelium of the inner foreskin that was stimulated with CCL27. The data showed a 2- to 3-fold (q<0.001) increase in CD3+CD4+ T cell numbers in the epithelium after stimulation with TNFα (from 60 cells/mm 2 to 138 cells/mm 2 ) and CCL27 (from 60 cells/mm 2 to 147 cells/mm 2 ) compared to the unstimulated samples. Conclusion: In conclusion, exogenous stimulation of foreskin tissue with CCL27 was shown to significantly increase the population of CD3+CD4+ T cells in the inner foreskin. It is suggested that this increase is due to the migration of CD3+CD+ T cells from deeper layers of the tissue to the epithelium. Interestingly, CCR10 is the cognate receptor for CCL27 that is expressed on T helper 22 (Th22) cells. Th22 cells express CCR5, making them a possible target for HIV infection. Future work can explore how the interaction of CCL27 and Th22 cells in the foreskin affect HIV susceptibility in the male genital tract.

Poster Abstracts

211 IMPACT OF PENILE CIRCUMCISION ON HIV SUSCEPTIBILITY MARKERS IN THE URETHRA Ronald M. Galiwango 1 , Daniel Park 2 , Sanja Huibner 1 , Abigail Onos 2 , Maliha Aziz 2 , Kelsey Roach 2 , Aggrey Anok 3 , James Nnamutete 3 , Yahaya Isabirye 3 , Deo Male 3 , Godfrey Kigozi 3 , Aaron Tobian 4 , Jessica L.Prodger 5 , Cindy M. Liu 2 , Rupert Kaul 1 , for the Rakai Immuno Microbiome Research Group 1 University of Toronto, Toronto, ON, Canada, 2 George Washington University, Washington, DC, USA, 3 Rakai Health Sciences Program, Kalisizo, Uganda, 4 Johns Hopkins University School of Medicine, Baltimore, MD, USA, 5 Western University, London, ON, Canada Background: Penile circumcision (PC) reduces HIV risk by approximately 60%. This may relate to the stochastic reduction in susceptible foreskin tissue and/or alterations in the coronal sulcus (CS) microbiome and associated inflammatory cytokines/chemokines, particularly levels of IL8. However, it is also possible that circumcision mediates protection through effects on the urethral microbiome and immune milieu. Therefore we performed a prospective analysis of the impact of PC on the microbiome and immune milieu of both the urethra and CS. Methods: HIV-negative, STI symptom-free adult Ugandan men (n=51) undergoing elective PC were enrolled. Swabs were collected from the urethra and either the inner foreskin (pre-PC) or CS (post PC), at baseline and 12 months after PC. Multiplex ELISA quantified chemoattractant chemokines (IL-8, MIP-1b), proinflammatory cytokines (IL-1a, IL-1b) and an epithelial integrity biomarker (E-cadherin). Bacterial abundance was assessed by 16S rRNA qPCR and sequencing. The intra-individual impact of PC was assessed using the paired Wilcoxon test. Results: At baseline the urethra was enriched for IL-8, MIP-1b and E-cadherin, while the inner foreskin was enriched for IL-1a, IL-1b with a greater total

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CROI 2020