CROI 2020 Abstract eBook

Abstract eBook

Poster Abstracts

263 POLY/AUTOREACTIVITY AND BROAD NEUTRALIZATION ARE DETERMINED BY DIFFERENT MUTATIONS Xiaojun Li 1 , Dongmei Liao 1 , Zhengyang Li 2 , Shobhit Srivastava 1 , Jixi Li 2 , Laurent Verkoczy 3 , Feng Gao 1 1 Duke University, Durham, NC, USA, 2 Fudan University, Shanghai, China, 3 San Diego Biomedical Research Institute, San Diego, CA, USA Background: Nearly half of broadly neutralizing antibodies (bnAbs) are polyreactive and/or autoreactive (poly/autoreactive). Some of them, like CH103, gain poly/autoreactivity during bnAb maturation. However, whether poly/ autoreactivity and broad neutralization are governed by the same mutations during bnAb maturation is not well understood. Methods: Mutations in Ab pairs differing in poly/autoreactivity within the CH103 lineage were individually introduced back into the Ab from each pair with less (or no) poly/autoreactivity. Recombinant Abs were expressed and purified from transfected Expi293 cells. Neutralization activity against HIV-1 was determined using the TZM-bl assay. Poly/autoreactivity was analyzed by their ability to bind HEp-2 cells, host proteins and UBE3A. Positions and properties of mutations were analyzed using Swiss-Model. Results: Poly/autoreactivity became detectable for intermediate antibody 1 (IA1) and mature bnAbs during evolution of the CH103 lineage. There were 2, 17 and 11 amino acid (aa) differences between IA2/IA1, IA3/IA1, and CH103/ CH106 Abs, respectively. Each of these aa differences was introduced into the Abs without (IA2 or IA3) or weak (CH103) poly/autoreactivity, and they had little effects on neutralization. The IA2 variable heavy (VH) N60S mutant Ab and the CH103 VH E56H mutant Ab reacted to HEp-2 and many host proteins and dsDNA, while the IA2 VH E64K mutant Ab was only reactive to histone. The protein array analysis using ~9000 human proteins showed that the IA2 N60S mutant Ab is poly/autoreactive, while the E64K mutation did not render IA2 poly/ autoreactive. The UBE3A binding analysis of all mutants showed that only the VH E64K mutation in IA2 and IA3 as well as the VH E56H and VL E45D mutations in CH103 rendered their parental Abs reactive to UBE3A. Structure modeling showed all those mutations were in VH CDR2 or upstream of VL CDR2 but the aa substitutions were not thought to affect binding to HIV-1 Env. However, aa charge changes in the VH and VL CDR2 regions may play an important role in increased poly/autoreactivity. Conclusion: Development of poly/autoreactivity during maturation of the bnAb CH103 lineage is determined by several somatic mutations not required for developing broad neutralization. The charge changes in the CDR2 regions of VH and VL mini-genes may play an especially important role in specifying poly/ autoreactivity in this bnAb lineage. 264 POLYFUNCTIONAL ANTIBODY RESPONSE TO SHORT-SCHEDULE EBOLA VACCINE IN HIV+/– SUBJECTS Dominic Paquin-Proulx 1 , Michael A. Eller 1 , Aljawharah Alrubayyi 1 , Jack N. Hutter 2 , Leigh Anne Eller 3 , Lucy Ward 4 , Janice Rusnak 4 , Callie Bounds 4 , Georgi Shukarev 5 , Viki Bockstal 5 , Kerstin Luhn 5 , Macaya Douoguih 5 , Cynthia Robinson 6 , Julie Ake 2 1 Henry M Jackson Foundation, Silver Spring, MD, USA, 2 Walter Reed Army Institute of Research, Silver Spring, MD, USA, 3 Henry M Jackson Foundation, Bethesda, MD, USA, 4 Joint Program Executive Office for Chemical, Biological, Radiological and Nuclear Defense, Frederick, MD, USA, 5 Janssen Prevention and Vaccines, Leiden, Netherlands, 6 Walter Reed Army Institute of Research, Bethesda, MD, USA Background: Ebola outbreaks occur in areas with a higher prevalence of HIV infection that may impact vaccine efficacy as ART-treated HIV+ subjects have been shown to generate lower responses to other vaccines. Non-neutralizing functions of antibodies may contribute to protection from Ebola virus infection, but it is unclear if HIV modulates these responses after vaccination. Antibody functionality was explored in HIV+ and HIV-subjects following an accelerated Ebola vaccination schedule that is not intended for licensure. Methods: Polyfunctional antibody effector functions were examined following IM administration of 1x108 Inf U MVA-BN-Filo (dose 1) followed by 5x1010 vp Ad26.ZEBOV IM 14 days later in ART-treated HIV + and HIV- adults in the US. Plasma samples from days 1, 36, and 380 were used to evaluate antibody dependent cellular phagocytosis (ADCP), complement deposition (ADCD), and induction of NK cell cytokine production by flow cytometry. Results: 40 HIV- and 20 HIV+ subjects received the heterologous vaccine schedule and 15 individuals received placebo (10 HIV- and 5 HIV+). The vaccine was well tolerated and binding antibodies were detected to the Ebola glycoprotein in all vaccinees after completion of the 2 dose regimen. Significant

increases from baseline in effector antibody responses were observed at day 36 (peak) in HIV+ and HIV- subjects. Placebo subjects had no response. At day 36, there was no significant difference between HIV+ and HIV- subjects in effector antibody functions but responses in HIV+ subjects tended to be lower. Responses declined in both populations by day 380, see figure 1. The majority of subjects in both populations (HIV-infected 50%, HIV- uninfected 59%) show polyfunctional capability, defined as 2 or more effectors, at day 380. Lower antibody polyfunctionality in HIV-infected subjects was not associated with the CD4 to CD8 ratio. Given the small sample size, definitive conclusions about any observed differences can not be made. Conclusion: Polyfunctional antibody effector functions were significantly increased from baseline in response to an accelerated Ebola vaccination schedule in HIV+ and HIV-subjects. Although responses declined in both populations, at least 2 antibody effector functions persisted in the majority of subjects until day 380.

Poster Abstracts

265 PULMONARY TUBERCULOSIS DISEASE ENHANCES HIV-1 ANTIBODY RESPONSES Bukola Adeoye 1 , Alex J. Olson 2 , Lydia Nakiyingi 3 , Yukari C. Manabe 4 , Karen R. Jacobson 2 , Jerrold Ellner 5 , Manish Sagar 1 1 Boston University, Boston, MA, USA, 2 Boston Medical Center, Boston, MA, USA, 3 Makerere University College of Health Sciences, Kampala, Uganda, 4 Johns Hopkins University School of Medicine, Baltimore, MD, USA, 5 Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, USA Background: Mycobacterium tuberculosis (TB) is an integral component of complete Freund’s adjuvant which is known to augment antibody production. We hypothesized that active TB disease enhances the development of HIV-1 broadly neutralizing antibodies (bnAbs) in people living with HIV-1. Methods: We compared anti-HIV-1 antibody response among treatment-naive plasma samples from 15 HIV-1 patients with active pulmonary TB (HIV-1/TB) and 16 HIV-1 only infected individuals. Ability to inhibit 12 different tier 1 and 2 HIV-1 variants of diverse subtypes in the TZM-bl neutralization assay was used to estimate a neutralization breadth and potency (BP) score. Total IgG and cytokine levels were estimated using multiplex Luminex based assays. Neutralization heatmaps were used to identify potential targeted HIV-1 envelope epitopes. Comparisons were done using the Wilcoxon rank-sum and Fischer’s exact tests. Results: HIV-1/TB and HIV-1 only infected individuals had similar baseline plasma virus levels (p= 0.33) and CD4 counts (p= 0.40). HIV-1/TB individuals had a significantly higher BP score (0.59 ± 0.05, range 0.34-0.98) than the HIV-1 only group (0.43 ± 0.02, range 0.25-0.59, p= 0.006). Four of the HIV-1/TB but

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CROI 2020