CROI 2024 Abstract eBook

Abstract eBook

Poster Abstracts

537

Potent Indoline CD4 Mimetics Enable Anti-Coreceptor Binding Site Antibodies to Mediate ADCC Jonathan Richard 1 , Li Zhu 2 , Lorie Marchitto 1 , Catherine Bourassa 1 , William D. Tolbert 3 , Sri Lakshmi T. Boodapati 2 , Derek Yang 4 , Hongil Kim 2 , Guillaume Beaudoin-Bussieres 5 , Mehdi Benlarbi 5 , Joseph Sodroski 6 , Amos B. Smith III 4 , Marzena Pazgier 3 , Priti Kumar 2 , Andrés Finzi 1 1 Centre de Recherche du CHUM, Montreal, Canada, 2 Yale University, New Haven, CT, USA, 3 Uniformed Services University of the Health Sciences, Bethesda, MD, USA, 4 University of Pennsylvania, Philadelphia, PA, USA, 5 Centre de Recherche du CHUM, Université de Montreal, Montreal, Canada, 6 Harvard Medical School, Boston, MA, USA Background: Antiretroviral therapy efficiently supresses HIV-1 replication but does not eradicate the virus. New approaches aimed at eliminating infected cells represent an appealing avenue to achieve this goal. Non-neutralizing antibodies (nnAbs) naturally present in the plasma of people living with HIV-1 (PLWH) have the potential to eliminate HIV-1-infected cells via antibody dependent cellular cytotoxicity (ADCC). However, these nnAbs largely recognize epitopes only accessible upon interaction of the envelope glycoproteins (Env) with CD4. HIV-1 limits surface Env-CD4 interaction by downregulating CD4, thus protecting infected cells from CD4-induced (CD4i) nnAb-mediated ADCC responses. CD4-mimetic compounds (CD4mcs) can "open-up" Env and sensitize HIV-1-infected cells to ADCC mediated by HIV+ plasma. We have shown that two families of CD4i nnAbs contribute to eliminate infected cells in the presence of CD4mc: the anti-cluster A and the anti-coreceptor binding site (CoRBS) Abs. Of note, while indane CD4mcs significantly enhance the recognition of infected cells by anti-CoRBS Abs, these nnAbs mediate ADCC poorly. The combination of anti-CoRBS Abs together with CD4mc and anti-Cluster A is required to mediate ADCC. This combination reduces the size of the HIV-1 reservoir and delays viral rebound after ART interruption in humanized mice. The development of new indoline CD4mc with improved neutralization potency and breath enabled us to revisit the capacity of anti-CoRBS Abs to mediate ADCC. Methods: The capacity of anti-CoRBS Abs to mediate ADCC against HIV-1 infected cells in the presence of indane and indoline CD4mcs was assessed in vitro, while their capacity to delay viral rebound in vivo was evaluated in infected humanized mice. Results: Contrary to indane CD4mcs, we found that the lead indoline CD4mc, CJF-III-288, sensitizes HIV-1-infected cells to ADCC mediated by anti-CoRBS Abs. This was observed with multiple HIV-1 primary strains and using various anti-CoRBS Abs. Accordingly, treatment of humanized mice with CJF-III-288 and an CoRBS Ab alone was sufficient to delay viral rebound after ART interruption, and notably, for much longer when administered prior to ART initiation. These results suggest that the indoline CD4mc "open" the Env trimer in such a way that favors Fc gamma receptor engagement on effector cells. Conclusion: More potent indoline CD4mc have the ability to sensitize HIV-1 infected cells to CoRBS Abs-mediated ADCC responses, thereby improving their therapeutic potential. Lipid Composition and CXCR4 Decoration Facilitate HIV-1 CRISPR Delivery and Viral Excision Sudipta Panja, Lubaba A Zaman , Milankumar Patel, Howard E. Gendelman University of Nebraska Medical Center, Omaha, NE, USA Background: A principal limitation in achieving HIV cure rests, first, in locating and then eliminating integrated proviral DNA from viral target cells (CD4+ T and myeloid cells). In recent reports, the development of viral vector to deliver clustered regularly interspaced short palindromic repeats (CRISPR) guide RNAs (gRNAs) provided a proof of concept that HIV-1 elimination could be achieved. Our goal is to extend and improve those results by creating: (1) multiple viral exons (gp41, tat, and rev) gRNAs; (2) viral tissue reservoir targeted lipid nanoparticles (LNPs); and (3) decorating LNPs with CXC chemokine receptor-4 (CXCR4) for targeting cellular reservoir. The biodistribution of LNPs was evaluated in humanized mice. We posit that effective gRNA delivery and, subsequently, viral DNA elimination can be achieved with our approach. Methods: A library of gRNAs was designed to disrupt five HIV-1 exons (tat1-2/rev1-2/gp41). These were derived from a consensus sequence of the transcriptional regulator tat from 4004 HIV-1 strains. CXCR4-targeting cyclic peptide (CycPep) was conjugated with PEG-lipid to make DSPE-PEG-CycPep and LNP was formulated by microfluidic mixing. The specificity of the CXCR4 receptor was shown by blocking the CXCR4 receptor to demonstrate lymphoid targeting. CRISPR gRNA delivery and excision were tested in lymphocytic (JLat

8.4, Jurkat E6) and monocytic (U1) cell lines and confirmed in primary human lymphoblasts. Results: A compositionally unique CXCR4 targeted LNP (T-LNP) was formulated with CRISPR gRNA-Cas9, D-Lin-MC3-DMA, DOPE, DOPS, DSPE-PEG-CycPep, DMG-PEG and β-sitosterol. T-LNP showed a significant shift in tropism in hu-mice from the liver to the spleen - one of the major HIV reservoirs. Further analysis revealed a substantially high mRNA expression in primary CD4+ T cells compared to nontargeted LNP. T-LNP demonstrated nearly 60% excision of viral DNA in lymphocytic cell lines; however, it was only 15% in myeloid cells. Moreover, in the presence of the CXCR4 blocker, T-LNP demonstrated decreased DNA excision, confirming CXCR4-specificity as compared to the control- LNP which lacked CXCR4 targeting. Conclusion: This work introduces a novel, non-viral delivery system to target HIV reservoirs. Our preliminary work shows that CXCR4-targeted LNP reached HIV reservoirs and enabled excision of integrated latent HIV-1 DNA, potentially leading to its elimination. The figure, table, or graphic for this abstract has been removed. The Humanized DRAGA Mouse as a Model for HIV Latency and Cure Jiae Kim 1 , Nicholas Castrejon-Oropeza 2 , Manuel Lopez 3 , Barbara A. Force 4 , Shahab Soltani 4 , Phuong Nguyen 4 , Kristina Peachman 2 , Ahmad F. Karim 5 , Teodor Brumeanu 6 , Sofia Casares 5 , Francois J. Villinger 7 , Chisu Song 8 , Richard T. D'Aquila 8 , Mangala Rao 2 1 Henry M Jackson Foundation, Bethesda, MD, USA, 2 Walter Reed Army Institute of Research, Silver Spring, MD, USA, 3 Henry M Jackson Foundation, Rockville, MD, USA, 4 Henry M Jackson Foundation, Silver Spring, MD, USA, 5 Naval Medical Research Center, Silver Spring, MD, USA, 6 Uniformed Services University of the Health Sciences, Bethesda, MD, USA, 7 University of Louisiana at Lafayette, Lafayette, LA, USA, 8 Northwestern University, Chicago, IL, USA Background: HIV infection is now a chronic disease due to the availability of antiretroviral therapy (ART) which suppresses plasma viral loads to below the limit of detection and prevents AIDS. However, the virus establishes latency and persists, a clear barrier to curing HIV. Interruption of ART causes viral rebound and thus requires a lifetime of medication for these individuals. We have previously demonstrated that the humanized DRAGA (hDRAGA) mouse (HLA-A2.HLA-DR4.RAG1 KO.IL-2RγcKO.NOD) generated by engrafting CD34+ hematopoietic stem cells from human cord blood is a suitable model to study HIV infection. Subsequently, we evaluated if this mouse could also serve as a model for HIV cure and latency studies. We examined the effects of NU611 in HIV infected hDRAGA mice on viral rebound following ART interruption (ATI). NU611 is a compound that boosts the expression of APOBEC3G, a human antiviral protein that decreases virion infectivity in cells. Methods: Humanized DRAGA mice (n=11) were intravaginally infected with HIV. Three weeks post-infection the standard 3-drug regimen: TDF, FTC, DTG in chow was administered for 6-10 weeks and then removed for observation of viral rebound. One week prior to ATI, 6 mice were administered NU611 intraperitoneally weekly and plasma viral loads were monitored by qRT-PCR. The tissues were also evaluated for viral RNA and DNA. Cellular profiles examining any changes in the human immune cells in the blood were performed using flow cytometry. Statistics were performed using Mann-Whitney analyses. Results: The plasma viral load decreased within a week of ART administration to below the limit of detection (700 copies/mL) within 5 weeks and remained suppressed while on ART for up to 10 weeks with no viral blips. Following ATI, the viral rebound in all 5 control mice was either higher than or similar to levels before ART administration. In mice treated with NU611, although viral rebound was observed in the plasma 2 weeks post ATI, plasma viral set points were 1 log lower in 5/6 treated mice compared to 5/5 untreated control mice. Conclusion: These results demonstrate the persistence of a viral reservoir in this model and the suitability of an APOBEC3G booster to contribute to the control of viral replication. The hDRAGA mice recapitulate some key aspects of HIV remission and rebound following ATI. This knowledge is important as it establishes the hDRAGA mouse as a model for HIV latency and can be utilized to investigate potential therapeutics for HIV cure. Retinoids Enhance NK Natural and Antibody-Dependent Cell Cytotoxicity of HIV-Infected CD4 T-Cells Elyse K McMahon , J. Natalie Howard, Rebecca M. Lynch, Alberto Bosque George Washington University, Washington, DC, USA Background: Novel approaches to sensitize latently infected cells to apoptosis may provide additional methods to eliminate latent reservoirs. Prior research identified several retinoids as potential drugs that increase the sensitivity of

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CROI 2024 144