CROI 2016 Abstract eBook

Abstract Listing

Poster Abstracts

Conclusions: GLS is essential for EVs release in HIV-1-infected macrophages and microglia. Therefore, blocking EV release through GLS inhibitors may serve as a novel therapeutic strategy against the HIV-1 pathobiology and neurological complications. 398 HIV-1 Replication Dynamics in the CNS of TB-Coinfected Individuals Ikanyeng D. Seipone 1 ;Thumbi P. Ndungu 2 ; Ravesh Singh 1 ;Vinod Patel 3 1 HIV Pathogenesis Prog, Univ of Kwa-Zulu Natal, Durban, South Africa; 2 Univ of KwaZulu-Natal, Durban, South Africa; 3 Inkosi Albert Luthuli Hosp and the Nelson R Mandela Sch of Med, Univ of KwaZulu-Natal, Durban, South Africa Background: HIV-1-associated opportunistic infections of the central nervous system (CNS) are common but how they affect HIV replication dynamics at the site of infection is unknown. The most common opportunistic infection in sub-Saharan Africa is tuberculosis. HIV-1 and Mycobacterium tuberculosis co-infection of the central nervous systemmay alter the local microenvironment leading to independent viral evolution and clonal amplification or alternatively disrupt the blood-brain barrier resulting in loss of compartmentalization and virus influx from the periphery. In this study, we characterized viral load discordance and examined HIV-1 subtype C genetic diversity and compartmentalization between cerebrospinal fluid and plasma in patients with tuberculous meningitis (TBM) versus other meningitides. Methods: One hundred and three matched blood and cerebrospinal fluid (CSF) samples were obtained from patients presenting with suspected meningitis in Durban, South Africa. Patients were categorized as definite TBM (n=16), non-TBM (n=35), probable TBM (n=46) and 6 patients unclassified. The viral RNA for both plasma and CSF were quantified using the COBAS TaqMan HIV-Test. Genetic compartmentalization was assessed by single genome amplification (SGA) and sequencing of the env gene on eight of the patients. Phylogenetic analysis was done using sequencer software, Clustal W on Bioedit and maximum likehood trees were drawn using MEGA version 6. Intra-patient diversity, enumeration of glycosylation sites, and coreceptor usage prediction analysis were also done. Results: The plasma viral loads of the TBM and non-TBM groups did not differ but TBM participants CSF viral loads (median= (5.76 log 10 copies/ml, interquartile range [IQR] 4.85- 6.19) were higher than non-TBM CSF viral loads (4.40 log 10 copies/ml [3.46-4.78]) participants (p = 0.0005). Heterogeneous patterns of compartmentalization were observed, 1 TBM and 3 non-TBM patients had equilibration of CSF and plasma sequences, 1 TBM patient had partial intermixing and 2 TBM and 2 non-TBM patients had unique clusters within compartments. These patterns did not seem to depend on TBM versus non-TBM status of patients. TBM CSF viral sequences seem to be more diverse than plasma sequences. Irrespective of the compartment the viruses are R5, with 2 patients displaying some X4 virus. There was no difference in the number of glycosylation sites between compartments and groups.< Background: A humanized mouse brain was created in immune deficient mice. The molecular and biological complexity of this novel organ was subjected to robust cross species histopathologic and molecular analyses for studies of HIV-1 neuropathogenesis. Gene expression analysis of HIV-1 infected patients with co-morbid nervous system disorders was used for comparisons for molecular signatures in this mouse model which combines human hematolymphoid tissue with glial reconstitution. Methods: Human brain glial precursors (GP) were generated from human brain tissue neurospheres. GP were injected into lateral ventricle of animals reconstituted with human CD34+ hematopoietic stem cell. At 6 months of age animals were infected with the macrophage-tropic HIV-1 ADA. Brain tissues frommice were analyzed by immunohistochemistry; peripheral immune profiles and viral load were measured. Animals transplanted with the same donor cells, with near equivalent viral loads (> 10 5 copies/ ml) and glial distribution pattern were selected for gene expression analysis. Hippocampus and corpus collosum areas of control unmanipulated, humanized and HIV-1 infected animals were isolated. Deep sequencing was performed with the Illumina HiSeq 2500 analyzer. Results: Brain tissues were anatomically symmetric with both hemispheres showing similar numbers of human glial cells. Glial fibrillary acidic protein stains showed human astrocytes in corpus callosum and periventricular white matter. In comparison with uninfected mice, infected human astrocytes-containing brain samples exhibited unique expression of 45 and 56 human genes in the hippocampus and corpus collosum, respectively. These were linked to inflammatory response and antigen presentation, interferon responses and ubiquitin ligases pathways (PLSCR1, MHC I, IFIT1, IFI44, MX1, STAT1, IGS15, HERC5). The data set surprisingly overlapped with the disease profile in brains of HIV-1 infected humans. Conclusions: Dual reconstituted murine model can readily reflect molecular events in HIV-associated neurocognitive disorders with dysregulated transcriptions related to interferon response genes (IFRGs) and the interferon regulatory factor (IRF), canonical pathways for G protein receptors and cyclic adenosine monophosphate signaling. These results underscore the importance of the model as well as the role astrocytes play in mediating pathophysiological outcomes of human disease. 400 CNS Compartmentalization of HIV-1 and Sensitivity to Neutralizing Antibodies Karl Stefic 1 ; Antoine Chaillon 2 ; Mélanie Bouvin-Pley 3 ; Alain Moreau 3 ; Martine Braibant 3 ; Guillaume Gras 4 ; Frederic Bastides 4 ; Louis Bernard 4 ; Francis Barin 3 1 CHU de Tours, Tours, France; 2 Univ of California San Diego, San Diego, CA, USA; 3 François-Rabelais Univ, Tours, France, Tours, France; 4 CHU de Tours, Tours, France Background: Compartmentalization of HIV-1 has been observed in the cerebrospinal fluid (CSF) of patients with HIV-related neurocognitive disorders (HAND). Compartment specific modifications have been frequently described in the variable loops and the glycosylation sites of the envelope, a known mechanism to escape antibody neutralization. Considering the low permeability of the blood-brain barrier, we wondered if a lower selective pressure by neutralizing antibodies (NAb) could favor the evolution of NAb-sensitive viruses in the CSF. Methods: Single genome amplification (SGA) was used to sequence near full-length HIV-1 envelope variants (453 sequences) from paired CSF and blood plasma samples of 9 subjects with HAND infected by HIV variants of 5 different clades. Dynamics of viral evolution were evaluated with a bayesian coalescent approach for individuals with longitudinal samples (n=4). For 6 subjects, pseudotyped viruses expressing envelope glycoproteins variants representative of the quasi-species present in each compartment were generated, and their sensitivity to autologous neutralization, broadly neutralizing antibodies (bNAbs) and sCD4 was assessed. Results: In cross-sectional analyses, significant compartmentalization of HIV populations between blood and CSF were detected in 5 out of 9 subjects by all tests ( p < 0,001). Phylogenetic analysis confirmed the presence of monophyletic populations evolving independently within the CSF (aLRT > 0.9). Some of the previously described genetic determinants for neuroadaptation were observed regardless of the HIV-1 clade. There was no difference of sensitivity to autologous neutralization between blood- and CSF- variants, even using sera collected at different time-points. By contrast, in all cases, we observed major differences of sensitivity to sCD4 or to at least one bNAb targeting the N160-V1V2 site, the N332-V3 site or the CD4bs, between blood- and CSF-variants. Conclusions: Our data show that selective pressure by autologous NAb is not the main driver of HIV evolution in the CSF. Given that each of the conserved neutralizing epitopes is linked to a specific property for cell entry, our data suggest that some functional properties of the envelope are responsible for compartmentalization. Considering the possible migration from CSF to blood, CSF could be a reservoir of bNAb resistant viruses, an observation that should be considered for future studies of immunotherapy. Conclusions: TB co-infection of the CNS seems to enhance HIV-1 viral replication and evolution . 399 Glial Transcriptional Responses Follow HIV-1 Infection in a Humanized Mouse Brain Weizhe Li ; Li E.Wu; Jaclyn Knibbe-Hollinger; Santhi Gorantla; Howard E. Gendelman; LarisaY. Poluektova Univ of Nebraska Med Cntr, Omaha, NE, USA

Poster Abstracts

151

CROI 2016