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Scientific Publications

Human IgG Fc-engineering for enhanced plasma half-life, mucosal distribution and killing of cancer cells and bacteria

Stian Foss, Siri A. Sakya, Leire Aguinagalde, Marta Lustig, Jutamas Shaughnessy, Ana Rita Cruz, Lisette Scheepmaker, Line Mathiesen, Fulgencio Ruso-Julve, Aina Karen Anthi, Torleif Tollefsrud Gjølberg, Simone Mester, Malin Bern, Mitchell Evers, Diane B. Bratlie, Terje E. Michaelsen, Tilman Schlothauer, Devin Sok, Jayanta Bhattacharya, Jeanette Leusen, Thomas Valerius, Sanjay Ram, Suzan H. M. Rooijakkers, Inger Sandlie, and Jan Terje Andersen

Nat Commun. 15(1): 2007.

Abstract

Monoclonal IgG antibodies constitute the fastest growing class of therapeutics. Thus, there is an intense interest to design more potent antibody formats, where long plasma half-life is a commercially competitive differentiator affecting dosing, frequency of administration and thereby potentially patient compliance. Here, we report on an Fc-engineered variant with three amino acid substitutions Q311R/M428E/N434W (REW), that enhances plasma half-life and mucosal distribution, as well as allows for needle-free delivery across respiratory epithelial barriers in human FcRn transgenic mice. In addition, the Fc-engineered variant improves on-target complement-mediated killing of cancer cells as well as both gram-positive and gram-negative bacteria. Hence, this versatile Fc technology should be broadly applicable in antibody design aiming for long-acting prophylactic or therapeutic interventions.

Scientific Publications

Human immunoglobulin gene allelic variation impacts germline-targeting vaccine priming

Allan C. deCamp, Martin M. Corcoran, William J. Fulp, Jordan R. Willis, Christopher A. Cottrell, Daniel L. V. Bader, Oleksandr Kalyuzhniy, David J. Leggat, Kristen W. Cohen, Ollivier Hyrien, Sergey Menis, Greg Finak, Lamar Ballweber-Fleming, Abhinaya Srikanth, Jason R. Plyler, Farhad Rahaman, Angela Lombardo, Vincent Philiponis, Rachael E. Whaley, Aaron Seese, Joshua Brand, Alexis M. Ruppel, Wesley Hoyland, Celia R. Mahoney, Alberto Cagigi, Alison Taylor, David M. Brown, David R. Ambrozak, Troy Sincomb, Tina-Marie Mullen, Janine Maenza, Orpheus Kolokythas, Nadia Khati, Jeffrey Bethony, Mario Roederer, David Diemert, Richard A. Koup, Dagna S. Laufer, Juliana M. McElrath, Adrian B. McDermott, Gunilla B. Karlsson Hedestam & William R. Schief

npj Vaccines 9(1): 58.

Abstract

Vaccine priming immunogens that activate germline precursors for broadly neutralizing antibodies (bnAbs) have promise for development of precision vaccines against major human pathogens. In a clinical trial of the eOD-GT8 60mer germline-targeting immunogen, higher frequencies of vaccine-induced VRC01-class bnAb-precursor B cells were observed in the high dose compared to the low dose group. Through immunoglobulin heavy chain variable (IGHV) genotyping, statistical modeling, quantification of IGHV1-2 allele usage and B cell frequencies in the naive repertoire for each trial participant, and antibody affinity analyses, we found that the difference between dose groups in VRC01-class response frequency was best explained by IGHV1-2 genotype rather than dose and was most likely due to differences in IGHV1-2 B cell frequencies for different genotypes. The results demonstrate the need to define population-level immunoglobulin allelic variations when designing germline-targeting immunogens and evaluating them in clinical trials.

Scientific Publications

Synthetic development of a broadly neutralizing antibody against snake venom long-chain α-neurotoxins

Irene S. Khalek, R. R. Senji Laxme, Yen Thi Kim Nguyen, Suyog Khochare, Rohit N. Patel, Jordan Woehl, Jessica M. Smith, Karen Saye-Francisco, Yoojin Kim, Laetitia Misson Mindrebo, Quoc Tran, Mateusz Kędzior, Evy Boré, Oliver Limbo, Megan Verma, Robyn L. Stanfield, Stefanie K. Menzies, Stuart Ainsworth, Robert A. Harrison, Dennis R. Burton, Devin Sok, Nicholas R. Casewell, and Joseph G. Jardine

Sci Transl Med. 16(735): eadk1867.

Abstract

Snakebite envenoming is a major global public health concern for which improved therapies are urgently needed. The antigenic diversity present in snake venom toxins from various species presents a considerable challenge to the development of a universal antivenom. Here, we used a synthetic human antibody library to find and develop an antibody that neutralizes long-chain three-finger α-neurotoxins produced by numerous medically relevant snakes. Our antibody bound diverse toxin variants with high affinity, blocked toxin binding to the nicotinic acetylcholine receptor in vitro, and protected mice from lethal venom challenge. Structural analysis of the antibody-toxin complex revealed a binding mode that mimics the receptor-toxin interaction. The overall workflow presented is generalizable for the development of antibodies that target conserved epitopes among antigenically diverse targets, and it offers a promising framework for the creation of a monoclonal antibody–based universal antivenom to treat snakebite envenoming.

Scientific Publications

Vulnerability to Sexually Transmitted Infections (STI) / Human Immunodeficiency Virus (HIV) among adolescent girls and young women in India: A rapid review

Sohini Paul, Anupam Sharma, Radhika Dayal, Mahika Mehta, Sudeshna Maitra, Kuhika Seth, Monal Nagrath, Sowmya Ramesh, Niranjan Saggurti

PLoS One. 19(2): e0298038

Abstract

Limited evidence is available on the vulnerability of Adolescent Girls and Young Women (AGYW) to sexual risk behaviour and STI/HIV. Though there are almost no statistics available on vulnerability, related literature suggests that AGYW have low awareness about sexual risk behaviour/ transmission and the prevalence of STI/HIV, making them vulnerable. We conducted a rapid review of peer-reviewed studies addressing transmission network, prevalence, incidence awareness, common determinants of sexual risk behaviour/STI/HIV, health-seeking behaviour and existing interventions addressing the situation among AGYW (age 15–24) to inform the evidence gap in this crucial area of research. We registered the study in PROSPERO (CRD42023403713). We developed detailed inclusion/exclusion criteria, searched JSTOR, PubMed, Google Scholar, Science Direct and Population Council Knowledge Commons databases and followed the guidance from Cochrane Rapid Review to develop the rapid review. We also searched the bibliography of the included studies. We included the English language peer-reviewed quantitative, qualitative, mixed method studies published from Jan 1 2000 to Mar 31 2023. Six reviewers extracted data, and the seventh reviewer independently assessed the quality. Ninety-six studies met the inclusion criteria. We used descriptive statistics and narrative synthesis methods for data analysis. We also conducted a Risk of Bias Assessment (RoB) to check the quality of the included studies. Inadequate literature was found on the transmission network. Prevalence and awareness of STI/HIV are low among AGYW. However, Female Sex Workers, sex-trafficked women or drug users in this age group suffer more. Age, education, income, relationship dynamics with spouses/partners, multiple partners, and substance use are crucial in determining STI/HIV. Traditional sources of health seeking are more popular than formal sources because of social stigma. Mass media campaigns, community mobilization programs, and life skills training programs increase awareness about HIV, condom use and self-efficacy. The inclusion of only English language studies and not conducting meta-analysis because of high heterogeneity are some of the limitations of the study.

Scientific Publications

Understanding the Acceptability of Broadly Neutralizing Antibodies for HIV Prevention Among At-Risk Populations and Feasibility Considerations for Product Introduction in India: Protocol for a Qualitative Study

Joyeeta Mukherjee; Shruta Rawat; Saif ul Hadi; Pritha Aggarwal; Venkatesan Chakrapani; Pratyasha Rath; Pallavi Manchi; Srikrishnan Aylur; Shelly Malhotra; Margaret Keane; Alok Gangaramany

JMIR Research Protocols. 13: e47700.

Abstract

Background:
Acceptability and preference research play a crucial role in the design, evaluation, and implementation of any new prevention product in any geographical setting. They also play a critical role in the development of clinical guidelines and policies. A wide range of acceptability studies have been conducted in diverse general and key populations for various new HIV prevention products worldwide. As clinical development strategies are being developed for clinical studies of broadly neutralizing antibodies (bNAbs) as potential HIV prevention products, appropriately tailoring them to address the type of HIV epidemic at hand would be critical for efficient uptake within in-country public health systems and decrease adoption and adherence challenges. Accomplishing this will require comprehensive acceptability and feasibility studies to inform multisectoral efforts that increase access to these products and national policies supportive of access to health care for those in most need. Thus, it is both opportune and important to undertake focused efforts toward informing product development strategies.

Objective:
This study aims to understand preferences for product attributes and key behavioral factors influencing adoption and uptake of bNAb prevention products among end-users including female sex workers, men who have sex with men, transgender women, people who inject drugs, and adolescent girls and young women in India and understand the key health system and programmatic perspectives toward the introduction of bNAb prevention products from health service providers and policy makers in India.

Methods:
A multisite study will be conducted in Delhi, Mumbai, and Chennai to capture the differences in perspectives among diverse end-users and key informants across the country. The study will use a multimethods design using focus group discussions, in-depth interviews, simulated behavioral experiments, and key informant interviews. A total of 30 focus group discussions, 45 in-depth interviews, 15 simulated behavioral experiments sessions, and 15 key informant interviews will be conducted across 3 sites.

Results:
The data collected and analyzed will enable insights on which specific product attributes matter the most to the populations and why some attributes are less preferred; contextual drivers of preferences and choices at individual, interpersonal, social, and structural levels; and relative positioning of bNAb products among other potential HIV prevention products. Insights from the health service providers and policy makers will provide a critical understanding of the need perception of the potential product in the existing product landscape and what additional efforts and resources are required for potential introduction, delivery, and uptake of the bNAb products in the Indian context.

Conclusions:
Insights generated from the abovementioned objectives will represent perspectives of populations of interest across geographies in India, will provide an overview of the acceptability of bNAb products and the feasibility of their introduction in this region, and will inform product development strategies.

Scientific Publications

Engagement of vulnerable communities in HIV prevention research in India: a qualitative investigation

Venkatesan Chakrapani, Vijayalakshmi Loganathan, Paromita Saha, Devi Leena Bose, Nabeela Khan, Tiara Aurora, Jyoti Narayan, Joyeeta Mukherjee, Saif ul Hadi & Chitrangna Dewan

Research Involvement and Engagement 10(1): 12 (2024)

Abstract

Background
Meaningful community engagement (CE) in HIV prevention research is crucial for successful and ethically robust study implementation. We conducted a qualitative study to understand the current CE practices in HIV prevention research and to identify expressed and implicit reasons behind translational gaps highlighted by communities and researchers.

Methods
For this exploratory qualitative study, we recruited a purposive sample of participants from Indian government-recognised key populations such as men who have sex with men, transgender women, people who inject drugs and female sex workers; general population adults and adolescents/youth; and researchers. We conducted 13 virtual focus groups (n = 86) between July and October 2021. Data were explored from a critical realist perspective and framing analysis (i.e., examining how the participants framed the narratives).

Results
Participants reported that study communities, especially those from key populations, were primarily involved in data collection, but not necessarily with optimal training. Involvement of communities before the start of the study (e.g., obtaining feedback on the study’s purpose/design) or once the study is completed (e.g., sharing of findings) were highlighted as priorities for meaningful engagement. Participants suggested meaningful CE in all stages of the study: (1) before the study—to get inputs in finalising the study design, drafting comprehensible informed consent forms and culturally-appropriate data collection tools, and deciding on appropriate monetary compensation; (2) during the study—adequate training of community field research staff; and (3) after the study—sharing the draft findings to get community inputs, and involving communities in advocacy activities towards converting evidence into action, policy or programs. Timely and transparent communications with communities were explicitly stated as critical for gaining and maintaining trust. Mutual respect, reciprocity (e.g., appropriate monetary compensation) and robust community feedback mechanisms were considered critical for meaningful CE.

Conclusions
The findings highlighted the translational gaps and priority areas for capacity building to strengthen CE in HIV prevention research. It is not only important to engage communities at various stages of research but to understand that trust, dignity, respect, and reciprocity are fundamentally preferred ways of meaningful community engagement.

Scientific Publications

Finding women in fishing communities around Lake Victoria: “Feasibility and acceptability of using phones and tracking devices”

Gertrude Nanyonjo, Zachary Kwena, Sarah Nakamanya, Elialilia Okello, Bertha Oketch, Ubaldo M. Bahemuka, Ali Ssetaala, Brenda Okech, Matt A. Price, Saidi Kapiga, Pat Fast, Elizabeth Bukusi, Janet Seeley, the LVCHR study team

PLoS One. 19(1): e0290634

Abstract

Introduction
Women in fishing communities have both high HIV prevalence and incidence, hence they are a priority population for HIV prevention and treatment interventions. However, their mobility is likely to compromise the effectiveness of interventions. We assessed the acceptability, feasibility and of using phones and global positioning system (GPS) devices for tracking mobility, to inform future health research innovations.

Methods
A mult-site formative qualitative study was conducted in six purposively selected Fishing Communities on the shores of Lake Victoria in Kenya, Tanzania, and Uganda. Participants were selected based on duration of stay in the community and frequency of movement. Sixty-four (64) women participated in the study (16 per fishing community). Twenty-four (24) participants were given a study phone; 24 were asked to use their own phones and 16 were provided with a portable GPS device to understand what is most preferred. Women were interviewed about their experiences and recommendations on carrying GPS devices or phones. Twenty four (24) Focus Group Discussions with 8–12 participants were conducted with community members to generate data on community perceptions regarding GPS devices and phones acceptability among women. Data were analyzed thematically and compared across sites/countries.

Results
Women reported being willing to use tracking devices (both phones and GPS) because they are easy to carry. Their own phone was preferred compared to a study phone and GPS device because they were not required to carry an additional device, worry about losing it or be questioned about the extra device by their sexual partner. Women who carried GPS devices suggested more sensitization in communities to avoid domestic conflicts and public concern. Women suggested changing the GPS colour from white to a darker colour and, design to look like a commonly used object such as a telephone Subscriber Identity Module (SIM) card, a rosary/necklace or a ring for easy and safe storage.

Conclusion
Women in the study communities were willing to have their movements tracked, embraced the use of phones and GPS devices for mobility tracking. Devices need to be redesigned to be more discrete, but they could be valuable tools to understanding movement patterns and inform design of interventions for these mobile populations.

Scientific Publications

Exposure to common infections may shape basal immunity and potentially HIV-1 acquisition amongst a high-risk population in Coastal Kenya

Lynn Fwambah, Cheryl Andisi, Claire Streatfield, Rachel Bromell, Jonathan Hare, Joakim Esbjörnsson, Thumbi Ndung’u, Eduard J. Sanders, Amin S. Hassan, and Eunice Nduati

Front Immunol. 14: 1283559

Abstract

Introduction
The impact of exposure to endemic infections on basal immunity and susceptibility to HIV-1 acquisition remains uncertain. We hypothesized that exposure to infections such as cytomegalovirus (CMV), malaria and sexually transmitted infections (STIs) in high-risk individuals may modulate immunity and subsequently increase susceptibility to HIV-1 acquisition.

Methods
A case-control study nested in an HIV-1 negative high-risk cohort from Coastal Kenya was used. Cases were defined as volunteers who tested HIV-1 positive during follow-up and had a plasma sample collected 3 ± 2 months prior to the estimated date of HIV-1 infection. Controls were individuals who remained HIV-1 negative during the follow-up and were matched 2:1 to cases by sex, age, risk group and follow-up time. STI screening was performed using microscopic and serologic tests. HIV-1 pre-infection plasma samples were used to determined exposure to CMV and malaria using enzyme-linked immunosorbent assays and to quantify forty-one cytokines and soluble factors using multiplexing assays. Multiplexing data were analyzed using principal component analysis. Associations between cytokines and soluble factors with subsequent HIV-1 acquisition were determined using conditional logistic regression models.

Results and discussion
Overall, samples from 47 cases and 94 controls were analyzed. While exposure to malaria (p=0.675) and CMV (p=0.470) were not associated with HIV-1 acquisition, exposure to STIs was (48% [95% CI, 33.3 – 63] vs. 26% [95% CI, 17.3 – 35.9]. Ten analytes were significantly altered in cases compared to controls and were clustered into four principal components: PC1 (VEGF, MIP-1β, VEGF-C and IL-4), PC2 (MCP-1, IL-2 and IL-12p70), PC3 (VEGF-D) and PC4 (Eotaxin-3). PC1, which is suggestive of a Th2-modulatory pathway, was significantly associated with HIV-1 acquisition after controlling for STIs (adjusted odds ratio, (95% CI), p-value: 1.51 [1.14 – 2.00], p=0.004). Elevation of Th2-associated pathways may dampen responses involved in viral immunity, leading to enhanced susceptibility to HIV-1 acquisition. Immunomodulatory interventions aimed at inhibiting activation of Th2-associated pathways may be an additional strategy to STI control for HIV-1 prevention and may reduce dampening of immune responses to vaccination.

Scientific Publications

Turning the Gaze from Survive to Thrive for Children in India: Learnings from Two Case Studies

Jessy Joseph, Ruchita Jalal, Mangla Sood, Harish Chellani, R M Pandey, Rajat Goyal, Siddarth Ramji, Rajib Dasgupta

Indian J Pediatr. 90(Suppl 1): 71-76

Abstract

Despite significant efforts and progress made in newborn care programs in India, implementation gaps persist across the continuum of care. The present case studies of two districts in Himachal Pradesh revealed that pathways of care were often fragmented with inconsistent linkages between facility and community due to poor documentation, lack of tiered referral, health system weaknesses, low utilization of primary level institutions, and inadequate post-natal home visits by Accredited Social Health Activists (ASHAs). Involvement of healthcare providers (HCPs) and frontline health workers (FHWs) was low and uneven in generating awareness across the districts with limited participation in supporting care in the community. Ensuring functionality of health centers and first-level care facilities; strengthening referral systems; adequate/trained human resources; strengthening routine health management systems, discharge processes and community-based care with adequate integration with facilities are necessary in closing access gaps.

Scientific Publications

Temporal trends and transmission dynamics of pre-treatment HIV-1 drug resistance within and between risk groups in Kenya, 1986–2020 

George M Nduva, Frederick Otieno, Joshua Kimani, Yiakon Sein, Dawit A Arimide, Lyle R Mckinnon, Francois Cholette, Morris K Lawrence, Maxwell Majiwa, Moses Masika, Gaudensia Mutua, Omu Anzala, Susan M Graham, Larry Gelmon, Matt A Price, Adrian D Smith, Robert C Bailey, Patrik Medstrand, Eduard J Sanders, Joakim Esbjörnsson, Amin S Hassan

J Antimicrob Chemother.

Abstract

Background
Evidence on the distribution of pre-treatment HIV-1 drug resistance (HIVDR) among risk groups is limited in Africa. We assessed the prevalence, trends and transmission dynamics of pre-treatment HIVDR within and between MSM, people who inject drugs (PWID), female sex workers (FSWs), heterosexuals (HETs) and perinatally infected children in Kenya.

Methods
HIV-1 partial pol sequences from antiretroviral-naive individuals collected from multiple sources between 1986 and 2020 were used. Pre-treatment reverse transcriptase inhibitor (RTI), PI and integrase inhibitor (INSTI) mutations were assessed using the Stanford HIVDR database. Phylogenetic methods were used to determine and date transmission clusters.

Results
Of 3567 sequences analysed, 550 (15.4%, 95% CI: 14.2–16.6) had at least one pre-treatment HIVDR mutation, which was most prevalent amongst children (41.3%), followed by PWID (31.0%), MSM (19.9%), FSWs (15.1%) and HETs (13.9%). Overall, pre-treatment HIVDR increased consistently, from 6.9% (before 2005) to 24.2% (2016–20). Among HETs, pre-treatment HIVDR increased from 6.6% (before 2005) to 20.2% (2011–15), but dropped to 6.5% (2016–20). Additionally, 32 clusters with shared pre-treatment HIVDR mutations were identified. The majority of clusters had R0 ≥ 1.0, indicating ongoing transmissions. The largest was a K103N cluster involving 16 MSM sequences sampled between 2010 and 2017, with an estimated time to the most recent common ancestor (tMRCA) of 2005 [95% higher posterior density (HPD), 2000–08], indicating propagation over 12 years.

Conclusions
Compared to HETs, children and key populations had higher levels of pre-treatment HIVDR. Introduction of INSTIs after 2017 may have abrogated the increase in pre-treatment RTI mutations, albeit in the HET population only. Taken together, our findings underscore the need for targeted efforts towards equitable access to ART for children and key populations in Kenya.

Scientific Publications

Accelerating HIV vaccine development through meaningful engagement of local scientists and communities

Chinyenze, K., E. Nduati, and V. Muturi-Kioi

Current Opinion in HIV and AIDS. 18(6):p 284-289, November 2023

Abstract

Purpose of review
There is a need to conduct multiple experimental medicine trials in regions with significant burden of disease to ensure the global relevance of vaccines under development including the African context.

Recent findings
African scientists can support accelerated HIV vaccine development by leading EMVTs in the region in a complementary fashion to global efforts and augment evidence generated to optimize and advance relevant vaccines towards licensure. The ADVANCE program enables EMVTs, where local scientists lead trial implementation and immunogenicity endpoint analysis of promising vaccine approaches. Concerted efforts towards scientific collaboration, enhancing specific clinical and lab capacity, and improving ethical and regulatory systems to review EMVTs in Africa will be catalytic. Appropriate engagement of local communities and stakeholders will be equally important, and the field needs to refine existing research literacy approaches to effectively partner with communities around current complex scientific approaches. Review of inclusion of relevant populations in early research is also needed.

Summary
African scientists and communities can help accelerate HIV vaccine development through stronger global collaboration. Now is the time for bold investments to enable the conduct of innovative EMVTs in Africa where the eventual vaccines will have the greatest impact.

Scientific Publications

Cost-effectiveness of broadly neutralizing antibodies for infant HIV prophylaxis in settings with high HIV burdens: a simulation modeling study

Alba, C., S. Malhotra, S. Horsfall, M. E. Barnhart, A. Bekker, K. Chapman

medRxiv. 2023 Nov 7:2023.11.06.23298184.

Abstract

Introduction: Approximately 130 000 infants acquire HIV annually despite global maternal antiretroviral therapy scale-up. We evaluated the potential clinical impact and cost-effectiveness of offering long-acting, anti-HIV broadly neutralizing antibody (bNAb) prophylaxis to infants in three distinct settings.

Methods: We simulated infants in Côte d'Ivoire, South Africa, and Zimbabwe using the Cost-Effectiveness of Preventing AIDS Complications-Pediatric (CEPAC-P) model. We modeled strategies offering a three-bNAb combination in addition to WHO-recommended standard-of-care oral prophylaxis to infants: a) with known, WHO-defined high-risk HIV exposure at birth (HR-HIVE); b) with known HIV exposure at birth (HIVE); or c) with or without known HIV exposure (ALL). Modeled infants received 1-dose, 2-doses, or Extended (every 3 months through 18 months) bNAb dosing. Base case model inputs included 70% bNAb efficacy (sensitivity analysis range: 10-100%), 3-month efficacy duration/dosing interval (1-6 months), and $20/dose cost ($5-$100/dose). Outcomes included pediatric HIV infections, life expectancy, lifetime HIV-related costs, and incremental cost-effectiveness ratios (ICERs, in US$/year-of-life-saved [YLS], assuming a ≤50% GDP per capita cost-effectiveness threshold).

Results: The base case model projects that bNAb strategies targeting HIVE and ALL infants would prevent 7-26% and 10-42% additional pediatric HIV infections, respectively, compared to standard-of-care alone, ranging by dosing approach. HIVE-Extended would be cost-effective (cost-saving compared to standard-of-care) in Côte d'Ivoire and Zimbabwe; ALL-Extended would be cost-effective in South Africa (ICER: $882/YLS). BNAb strategies targeting HR-HIVE infants would result in greater lifetime costs and smaller life expectancy gains than HIVE-Extended. Throughout most bNAb efficacies and costs evaluated in sensitivity analyses, targeting HIVE infants would be cost-effective in Côte d'Ivoire and Zimbabwe, and targeting ALL infants would be cost-effective in South Africa.

Discussion: Adding long-acting bNAbs to current standard-of-care prophylaxis would be cost-effective, assuming plausible efficacies and costs. The cost-effective target population would vary by setting, largely driven by maternal antenatal HIV prevalence and postpartum incidence.

Scientific Publications

Mosaic HIV-1 vaccination induces anti-viral CD8(+) T cell functionality in the phase 1/2a clinical trial APPROACH

Janine van Duijn, Daniel Stieh, Natalia Fernandez, Deborah King, Jill Gilmour, Jeroen Tolboom, Katleen Callewaert, Wouter Willems, Maria G. Pau, Stephen C. De Rosa, M. Juliana McElrath, Dan H. Barouch, Peter Hayes

J Virol: e0112623

Abstract

The ability of vaccine-induced T cells to inhibit viral replication may contribute to protect against human immunodeficiency virus (HIV) acquisition. Here, we tested ex vivo viral inhibitory activity of T cell responses induced by a multivalent HIV vaccine based on the replication-incompetent recombinant adenovirus serotype 26 vector with a mosaic immunogen strategy (Ad26.Mos.HIV), designed for broad immune coverage of diverse HIV-1 strains. Using clinical trial samples with a diverse range of T cell responses measured by IFN-γ ELISpot, anti-viral function of vaccine-induced CD8+ T cells was assessed by inhibition of HIV-1 replication in autologous CD4+ T cells to a panel of HIV-1 isolates. Ex vivo expanded CD8+ T cells were able to inhibit replication of HIV in autologous CD4+ T cells, with 94% of vaccinees inhibiting at least one out of eight HIV isolates, and a median of 5 isolates inhibited at peak immunogenicity. Correlations between viral inhibition and ICS as well as ELISpot responses were explored, demonstrating positive correlations. Broad ELISpot responsiveness to different regions of the Env, Gag, and Pol proteins was associated with breadth of viral inhibitory responses. Moreover, polyfunctionality of CD8+ T cells correlated well with viral inhibition. These findings indicate that functional immunological breadth as well as antigenic breadth is important to induce antiviral activity. This study advances the understanding of vaccine-induced T cell functionality and demonstrates for the first time that Ad26.Mos.HIV vaccination in combination with adjuvanted gp140 can induce broad viral inhibitory activity toward a panel of diverse HIV-1 clades.