bluuebunny/crossref_metadata_2025 huggingface dataset:
B-104 Presence of HIV-1 RNA in extracellular vesicles from HIV-1 cART-treated cells
Authors: Kashanchi Fatah , Demarino Catherine , Pleet Michelle , Barclay Robert , Royal Walter , Noren Hooten Nicole
Published: April 2019

HIV-1 is a complex retrovirus that produces chronic infection affecting approximately 40 million people worldwide and 1.1 million new infections each year.

We have previously shown that during infection, EVs contain a non-coding HIV-1 RNA, which has been shown to elicit responses in recipient cells (1–3).

First, we investigated the effect of exosomes derived from uninfected cells on latent HIV-1–infected cells and found that there is an abundant level of short noncoding RNA in infected cells, arguing that a true “transcriptional latency” may not exist in vivo since cells are constantly in contact with exosomes from uninfected cells.

A possible mechanism for this finding revealed that the exosomes cause an increase in RNA Polymerase II loading onto the DNA within the infected cells; this was possibly driven by the presence of specific kinases in the exosomes, some of which were unique to T-cell-derived and myeloid-derived exosomes. Subsequently transcribed viral transcripts, which include TAR and a novel RNA termed “TAR-gag”, can then be packaged into exosomes and potentially be exported to neighboring uninfected cells. TAR-gag is a long, noncoding RNA that is 615 bases long, contains the TAR element, and terminates within the p17 region of HIV-1 gag (1). In the presence of transcription inhibitors F07#13 (a Tat peptide mimetic) and CR8#13 (an ATP-binding analog of Cdk9), TAR-gag is capable of binding to SWI/SNF components in the nucleus, including the mSin3A/HDAC-1 complex, and serves as a scaffolding RNA. Additionally, TAR-gag can recruit suppressive factors and RNA-binding proteins to the HIV-1 promoter, resulting in transcriptional gene silencing (TGS) (2).

In our most recent data, we found altered levels of genomic RNA within EVs while other RNAs, such as TAR RNA, remained unaffected by the addition of cART treatment in both cell lines, primary macrophages, and patient biofluids. Furthermore, we determined possible mechanisms involved in the selective packaging of HIV-1 RNA products into EVs specifically, an increase in EV-associated RNA-binding protein hnRNPA2/B1, and a “reader” for methylated RNA.
B-105 Extracellular vesicles as advance forces in cancer
Authors: Breakefield Xandra
Published: April 2019

Extracellular vesicles (EVs) provide a unique mode of communication between cells during development, normal physiology and disease. They can transfer non-secreted molecules, including cytoplasmic and nuclear proteins, as well as RNA and DNA. This capacity has the potential to expand informational transfer to a previously unimagined level of control. Here we focus on the action of EVs released by glioblastoma cells on normal cells in the brain which receive a continuous barrage of these infiltrators. EV cargo released by cancer cells is delivered by endocytosis or fusion with the plasma membrane. We have documented functional transfer of miRNA from glioblastoma cells to microglia, macrophages and astrocytes in their vicinity. In addition, we have found dramatic changes in the transcriptome of these target cells in vivo which serve to change their phenotypes such that they support tumor growth and invasion, act to suppress the immune response to tumor antigens and “accept” the tumor as self. Although the mechanistic aspects of this functional delivery are still being explored, increasing evidence implicates EVs as an important mode of informational transfer between tumor and normal surrounding cells, with the tumor EVs taking control of their environment.
C-102 Early stage non small cell lung cancer
Authors: Brahmer Julie
Published: April 2019

No abstract.
C-104 Development of cancer immunotherapy by targeting neoantigens
Authors: Wang Rongfu
Published: April 2019

Despite significant progresses in cancer immunotherapy, only a fraction of cancer patients respond to immune checkpoint blockade therapy, which relies on tumor-specific T cells, mutation loads and PD-L1 expression. Mutational loads are correlated with immune checkpoint blockade response, suggesting that tumor neoantigens are ideal targets for cancer immunotherapy. Here, we build a systematic approach to identify tumor neoantigens by deploying non-synonymous mutation library screening generated by next generation sequencing as well as the autologous cDNA library screening. The tumor infiltrated T cells and their T cell clones were used for the screening and characterization of neoantigens. We show that the number of neoantigens is limited, but with the existence of dominant neoantigens in MHC class I and II restricted antigens. Furthermore, the processing and presentation of neoantigens are controlled by multiple mechanisms, which may render the resistance to cancer immunotherapy. Furthermore, we will show novel vaccine strategies to generate potent immune responses against cancer. Our studies provide comprehensive understanding of how to identify neoantigens for personalized immunotherapy and what kind of neoantigens are the best as potential targets for T cell based cancer immunotherapy.
C-106 Tumor targeting antibodies to improve tumor immunity: The role of microbiota
Authors: Fu Yang-Xin
Published: April 2019

Tumor cells express a panel of surface molecules to promote their growth and evade immune responses, such as oncogenic receptors, PD-L1, andCD47. Tumor targeting antibodies have been designed to kill tumor cells. Several mechanisms have been proposed, including stress-induced apoptosis, antibody-dependent cytotoxicity, complement dependent cytotoxicity, and increased phagocytosis. We have now observed that anti-Her2/neu-mediated tumor regression depends on MyD88, interferon, CD4+ or CD8+ T cells. Anti-CD20 mediated tumor eradication depends on IFN and CD8. CD47 is highly expressed stem-like cancer cells that are more resistant to conventional treatment. Using xenograft and in vitro models, anti-CD47antibody (Ab) that blocks SIRP signaling by CD47 is thought to enhance “eat me” signaling to kill tumor cells by macrophage-mediated phagocytosis. Our study is revealing that local anti-CD47 antibody regresses tumor cells depending on cGAS/STING but not MyD88, IFN, and CD8+ T cells. Therefore, our studies have now revealed a distinct mechanism for antibody-mediated tumor regression that include different innate sensing and adaptive pathways and open new avenues for combinational therapies with other conventional drugs andimmunotherapy.

We have further observed that the anti-tumor efficacy of anti-CD47 antibody blockade relies on the gut microbiota. Gut microbiota are generally hypothesized to influence anti-tumor responses by initiating gut immunity. However, we observed the primary site of enhancing anti-tumor immunity is inside tumor by microbiota. Furthermore, intratumoral administration of a microbiota isolated from tumor tissues restore anti-tumor immunity in non-responder of anti-CD47 treatment. Together, our study has identified gut microbiota colonized in the tumor sites facilitates CD47-based immunotherapy by STING signaling and has applicability to improve anti-CD47 immunotherapy.
D-101 Expression of evolutionarily novel genes in tumors—The possible role of tumors in evolution
Authors: Kozlov Andrei
Published: April 2019

Earlier I formulated the hypothesis of the possible evolutionary role of tumors. This hypothesis suggests that heritable tumors at earlier stages of progression supply evolving multicellular organisms with extra cell masses for the expression of newly evolving genes. After expression of novel genes in tumor cells, tumors differentiate in new directions and may give rise to new cell types, tissues and organs (A.P. Kozlov, “Evolution by Tumor Neofunctionalization”, Elsevier/Academic Press, 2014).

In my lab we described several genes with dual specificity—evolutionary novel genes expressed specifically or predominantly in tumors (OTP, ESRG, PVT1, ELFN1-AS1, HHLA1, DCD, SPRR1A, CLLU1, PBOV1 and others).

We also described the evolutionary novelty of the whole classes of genes expressed predominantly in tumors, that is, CT-X genes and genes of noncoding tumor specifically expressed RNAs.

We studied the phylogenetic distribution of the orthologs of genes expressed in tumors and found that different functional gene classes have different evolutionary novelty. Some of them are enriched by evolutionarily novel genes. We showed the evolution of oncogenes, tumor suppressor genes and differentiation genes occurred in a parallel way, which supports the participation of tumors in the origin of new cell types. Some human genes which determine progressive traits originated in fishes and were first expressed in fish tumors.

The existing data obtained in our lab and by other authors suggest that genes originated by gene duplication; from endogenous retroviruses; by exon shuffling; and de novo are expressed in tumors, sometimes with high tumor specificity.

The conclusion will be made that the expression of evolutionarily novel genes in tumors may be a novel biological phenomenon with important evolutionary role.
D-104 Harnessing the potential of HDAC inhibitors for immunotherapy combinations
Authors: Gameiro Sofia , Hicks Kristin C. , Hodge James W. , Schlom Jeffrey
Published: April 2019

The clinical promise of cancer immunotherapy relies on the immune system recognizing and eliminating tumor cells identified as non-self. However, the tumor microenvironment (TME) can evade a tumor targeted immune response by increasing immunosuppressive elements that hamper maturation, recruitment, and function of immune effector cells through numerous pathways, including upregulation of immune checkpoints such as PD-L1. Hence, there is an unmet clinical need to develop effective therapeutic strategies that can reprogram the TME to restore tumor immune recognition and reverse immune evasion. Studies in our laboratory recently demonstrated that Entinostat, a class I histone deacetylase (HDAC) inhibitor, reverses carcinoma immune escape to human T cell- and NK-mediated lysis and augments the effector function of human NK cells. In preclinical studies, the IL-15/IL-15Rasuperagonist ALT803 has been shown to exhibit tumor control in multiple murine models of cancer through the expansion of NK and CD8+T cells with high effector function. We hypothesized that the antitumor activity promoted by ALT803 in combination with PD-L1 checkpoint blockade or a therapeutic adenoviral vaccine targeting CEA (Ad-CEA) could be augmented by the epigenetic reprograming of the TME induced by Entinostat. The immune mechanisms associated with antitumor efficacy of these multivalent therapies were examined in the TME as well as in the periphery. Results of these studies provide a rationale for combining Entinostat with multivalent immunotherapy combinations, including cytokines, antibodies targeting PD-L1, and therapeutic cancer vaccines.
D-105 Cellular memory and rare cell variability in cancer
Authors: Shaffer Sydney
Published: April 2019

Targeted therapies for cancer are a promising class of drugs that inhibit the specific molecular alterations that underlie the uncontrolled proliferation seen in cancer. The primary shortcoming of targeted therapy is disease relapse, which is driven by a subpopulation of cells that are resistant to these drugs. This phenomenon is generally thought to be genetic in origin; however, our recent work on melanoma shows that non-genetic cellular plasticity may provide a mechanism of resistance to these therapies. Furthermore, we showed that through the addition of the drug itself, cells transition from this transient plasticity into a new, stably resistant cell state via cellular reprogramming, suggesting that the time an individual cell exists in a state is important for producing the divergent resistance phenotype. However, there are currently no methods available to quantify the timescale of these fluctuations for the whole transcriptome. Thus, broadly generalizing this concept of timescales for cellular plasticity, we developed a novel method for genome-wide quantification of the timescales of gene expression memory based on a modern version of the ingenious Luria-Delbrück fluctuation analysis. In melanoma, this method revealed the gene expression state of rare cells resistant to targeted therapy. In a completely new model, triple negative breast cancer, this method revealed a novel rare subpopulation of cells exhibiting resistance to chemotherapy. More generally, this method has the potential to reveal other new phenotypes associated with rare cell biology including metastasis and the early stages of stem cell differentiation. Taken together, our findings in melanoma and novel methods for studying cellular plasticity outline a framework for using single-cell technologies for applications in basic biology and clinical medicine.
E-101 UPR in coordinated regulation of microbiome and anti-tumor immunity
Authors: Ronai Ze'ev
Published: April 2019

RNF5 is a ubiquitin ligase implicated in the control of ER stress and ER associated degradation, part of the greater Unfolded Protein Response. RNF5 mutant mice were found to limit tumor growth, of both melanoma and colon cancer models, owing to enhanced anti-tumor immunity. Enhanced TLR signaling resulted in enhanced infiltration of CD4/8+ T cells as well as Dendritic cells to the tumors grown in RNF5 mutant mice. Cross of RNF5 mutant with MYD88 KO or use of neutralizing antibodies against CD4/8+ T cells effectively attenuated anti-tumor immunity and tumor inhibition phenotypes. Coincided with the enhanced anti-tumor immunity was reduced UPR signaling in intestinal epithelial cells of RNF5 mutant mice. Indeed, cultured intestinal epithelial MODE-K cells that were subjected to inhibition of RNF5 expression exhibited reduced UPR signaling, and were able to activate, in co-culture studies, DC and T cells. Surprisingly, co-housing of RNF5 mutant and WT mice resulted in loss of anti-tumor immunity and the loss of tumor growth inhibition, suggesting that microbiota of RNF5 mutant mice may play a key role in activating anti-tumor immunity. Analysis of gut microbiota composition in RNF5 KO mice led to the identification of specific bacterial strains that were able to induce anti-tumor immunity and limit melanoma growth, when administered to germ free mice. The role of altered UPR in the coordinated regulation of microbiome and anti-tumor immunity will be discussed.
E-103 Inflammation-driven networks in the regulation of breast cancer progression
Authors: Ben-Baruch Adit , Liubomirski Yulia , Lerrer Shalom , Meshel Tsipi , Rubinstein Linor , Morein Dina
Published: April 2019

Accumulating evidence substantiates potent pro-malignancy roles for stromal cells, such as bone marrow-derived mesenchymal stem cells and cancer-associated fibroblasts, in breast cancer. In parallel, the breast tumor microenvironment (TME) is enriched with pro-inflammatory cytokines that play causative roles in promoting disease course. Focusing on the aggressive triple negative subtype of breast cancer (TNBC), we have analyzed by patient dataset studies, in vitro co-culture experiments and in vivo model systems the interactions between TNBC cells, stromal cells and pro-inflammatory cytokines, and their pro-metastatic potential. This integrative approach demonstrated that the stimulation of TNBC:stroma co-cultures by pro-inflammatory cytokines has led to elevated pro-metastatic phenotypes at multiple levels: (1) The expression levels of chemokines that are pro-angiogenic and can lead to high levels of myeloid inflammatory cells at the TME was much increased. (2) The cytokine-stimulated TNBC:stroma co-cultures were enriched with angiogenic factors that promoted endothelial cell sprouting (3) The tumor cells gained high migratory and invasive capabilities. Moreover, studies in animal model systems indicated that TNBC cells that formed contacts with stromal cells in the context of pro-inflammatory stimulation became more aggressive, as indicated by increased incidence of mice having lungmicro-metastases. Molecular studies with siRNA and CRISPR in TNBC cells and/or in stromal cells identified the cellular source for elevated chemokines in cytokine-stimulated TNBC:stroma co-cultures. We have identified the molecules that participate in mediating TNBC:stroma cell-to-cell contacts in the context of pro-inflammatory signals, and the transcription factors regulating these processes. Overall, our findings identified novel players controlling pro-metastatic events TNBC, regulating the triage formed by tumor-stroma-inflammation interactions. These findings pose pro-inflammatory factors as candidate targets whose inhibition may break detrimental networks that promote TNBC progression.
F-103 Catching chances: The movement to be on the ground and research ready before an outbreak
Authors: Brett-Major David
Published: April 2019

What does it mean to be ready to conduct clinical virologic research in an emergency? After the thousands of cases of Ebola virus disease in West Africa duringccthe 2014–2016 epidemic, the world remains without a licensed vaccine or therapeutic broadly available and demonstrated to alleviate suffering. This deficiency has been felt acutely in the 2, short, following years with 2 Ebola virus outbreaks in the Democratic Republic of Congo (DRC), and a Marburg virus outbreak in Uganda. Much of the fault lies in a lack of clinical research preparedness complicating just-in-time research efforts in the field. In this brief presentation, critical aspects of readiness will be discussed.
G-101 PEPFAR-challenges and opportunities
Authors: Dybul Mark
Published: April 2019

The Lancet called the US President's Emergency Plan for AIDS Relief “the most effective international health initiative in history.” Launched in President George W. Bush's 2003 State of the Union address, the session will look back on the past 15 years and look forward to the challenges and opportunities ahead.
G-102 Getting to the last mile in HIV epidemic control
Authors: Mulwanda Jabbin
Published: April 2019

There is greater global focus on increasing efforts towards the HIV epidemic control. To achieve this, nations should limit the annual number of new HIV infections to less than the number of deaths among people living with HIV.

Dr. Mulwanda discusses the status of the Sub-Saharan Africa epidemic and uses the Zambian approach on being granular and employing targeted, data-driven and cost-efficient approach, in order to reach the last mile. He discusses how taking this scientific evidence to scale requires reorienting HIV program leadership and augmenting health workforce so as to accelerate progress towards HIV Epidemic Control.
G-103 Research in the age of PEPFAR: Evidence generation and utilization
Authors: Guay Laura
Published: April 2019

No abstract.
G-104
Authors: Geibel Scott
Published: April 2019

No abstract.
I-103 HIV-1 cell-to-cell infection during acute infection and resistance to neutralizing antibodies
Authors: Chen Benjamin , Law Kenneth , Li Hongru
Published: April 2019

Interactions between infected T cells and uninfected T cells called virological synapses (VS) enhance HIV-1 infection. When studied in vitro, this mode of transmission results in the frequent co-transmission of multiple copies of HIV-1 across the VS, which can reduce sensitivity to antiretroviral drugs. Our studies of HIV-1 infection in humanized mice, have measured the frequency of co-transmission and the spatiotemporal organization of infected cells as indicators of cell-to-cell transmission in vivo. We inoculated mice with cells co-infected with 2 viral genotypes distinguished by 2 different fluorescent proteins, and observed high levels of co-transmission to target cells. The mixed genotype of the input cells was preserved in the first round of infection in vivo, suggesting that cell-to-cell transmission occurs in vivo. Micro-anatomical clustering of viral genotypes within lymphoid tissue indicates that viral spread is driven by local processes and not a diffuse viral cloud. Intravital splenic imaging reveals that anchored HIV-infected cells can induce arrest of interacting, uninfected CD4(+) T cells to form Env-dependent cell-cell conjugates. Viral neutralization studies indicate that antibodies are less potent in their inhibitory capacity against cell-to-cell infection, when compared with the same virus presented in a cell-free form. Antibodies are both less potent and also can display significant decreases in the maximum inhibitory potential. We present models whereby HIV-1 spread between immune cells can be anatomically localized into infectious clusters and is represents an important mechanism of evasion from antibody responses.
I-104 Distinct chromosomal positions of intact HIV-1 proviruses
Authors: Lichterfeld Mathias
Published: April 2019

A small reservoir of chromosomally-integrated, genome-intact but transcriptionally-silent HIV-1 proviruses persists lifelong despite suppressive antiretroviral therapy, and makes HIV-1 infection an incurable disease. Yet, very little is known about the positions of such intact proviruses in the human genome, or the mechanisms that contribute to maintaining their transcriptional latency. Here, we used a novel experimental approach involving multiple displacement amplification of individual HIV-1 proviral species, followed by near full-length HIV-1 next-generation sequencing and corresponding chromosomal integration site analysis to selectively map the chromosomal positions of intact HIV-1 proviruses in 3 HIV-1-infected individuals undergoing long-term antiretroviral therapy. We observed that in comparison to defective proviral sequences, intact HIV-1 proviruses were enriched for non-genic chromosomal positions and more frequently displayed an opposite orientation relative to host genes. In addition, intact HIV-1 proviruses were preferentially integrated either in relative proximity or in increased distance to active transcriptional start sites and to accessible chromatin regions. These studies strongly suggest selection of intact proviruses with features of deeper viral latency during prolonged antiretroviral therapy, and may be important for developing targeted strategies to purge the genome-intact viral reservoir.
I-105 Nonhuman primate models in the study of early events in AIDS virus infection
Authors: Lifson Jeff
Published: April 2019

Nonhuman primate (NHP) models have proven invaluable for the detailed study of many aspects of AIDS virus pathogenesis difficult or impossible to study with comparable rigor in HIV infected humans. Key aspects of HIV infection in humans can be authentically recapitulated in NHP models. Experimental advantages of NHP models include the ability to exactly control the identity, dose, route, and timing of the viral inoculum employed, control over the timing of initiation and discontinuation of various experimental interventions and the ability to conduct in vivo proof of concept studies of promising but unproven and potentially dangerous treatments. As AIDS virus infection is a tissue based disease, perhaps the most important advantage of NHP models is the ability to obtain extensive longitudinal tissue samples, including from scheduled euthanasia and necropsy with extensive tissue collection and analysis.

Early events in the course of AIDS virus infection are critically important, but difficult to study in HIV infected humans, due to factors that often include delayed diagnosis, and uncertainty about the exact timing of exposure, along with lack of availability of informative tissue specimens. NHP models therefore have an important role to play in the study of early events in AIDS virus infection. Using examples from our recent studies, results will be presented in a series of vignettes demonstrating the utility of NHP models for the study of early events in infection, including: (1) the use of a sequence tagged viral inoculum for tracking independent chains of infection events in vivo involved in mucosal viral transmission and systemic dissemination of infection; (2) the impact of early implementation of combination antiretroviral drug treatment (cART) on limiting the extent of establishment of a durable, recrudescence competent viral reservoir; (3) the contribution of arrest of viral replication at distal sites, after initial dissemination from a mucosal portal of entry, to protection from infection mediated by broadly neutralizing monoclonal antibodies; and iv. the early establishment of expanded clones of CD4+ T cells harboring clonally integrated proviruses that may contribute to the recrudescence competent viral reservoir that persists during cART.
J-104 Towards a functional cure for HBV: An industry perspective
Authors: Gaggar Anuj
Published: April 2019

Globally, Hepatitis B Virus (HBV) remains a public health concern. Despite the availability of safe and effective suppressive therapies and an effective prophylactic vaccine, there remains a need for the development of medication regimens that can lead to durable HBsAg loss with a finite-duration therapy, a functional cure. The dentification of novel therapies to achieve a functional cure for HBV requires a thorough understanding of the viral life cycle within the hepatocyte as well as the complex interactions of the virus with the immune system. The development of appropriate model systems that faithfully recapitulate the virology and immunology of chronic HBV infection (CHB) facilitate screening efforts and can help evaluate efficacy of emerging therapeutic targets. Current approaches for a functional HBV cure include targeting viral RNA or protein products and augmenting the innate and adaptive immune response to HBV. It is expected that a combination of approaches will be required to achieve high rates of a functional cure. Further efforts to understand better patient heterogeneity will aid the development of these novel agents.
J-105 Novel antiviral targets for HBV elimination
Authors: Hawkins Claudia
Published: April 2019

Chronic hepatitis B virus (CHB) infection continues to be a major global public health issue despite the availability of effective HBV vaccines. Approximately 257 million people worldwide are infected with CHB and complications from HBV are now a leading cause of morbidity and mortality. The number of deaths from CHB now exceed >1 million per year.

In 2016, the WHO Global health sector strategy on viral hepatitis, announced new goals to achieve a 90% reduction in new cases of HBV and hepatitis C (HCV) and a 65% reduction in mortality due to HBV and HCV by 2030. To achieve the ambitious HBV targets, significant progress is needed in several key intervention areas along the continuum of HBV care including (1) improved access to HBV vaccination and drugs for the prevention of mother to child transmission; (2) more rapid and affordable diagnostics for improved screening and detection of HBV; and (3) innovative therapeutics that can result in HBV cure.

Current recommended therapies for CHB include either pegylated interferon-alpha which stimulates innate immune responses against HBV or oral nucleoside reverse transcriptase inhibitor (NUC) therapies which block the maturation of HBV genome into its infectious form and thus release of infectious virus containing HBV DNA. While both therapies effectively suppress HBV DNA, they rarely result in complete loss of HBsAg, which is needed to achieve functional cure, a serological state associated with a higher remission rate after treatment cessation, and lower rates of cirrhosis and hepatocellular carcinoma. Sterilizing cure is unlikely to be achievable at the current time because of the persistence of the active transcriptional template of HBV covalently closed circular DNA (cccDNA).

Recently there have been promising advances in the treatment of HBV that could potentially achieve widespread functional cure and bring us closer to achieving the ambitious WHO goals of HBV elimination. These include the development of novel therapeutics that target various stages of the HBV lifecycle (eg, HBV entry, viral replication, HBV cccDNA production, and viral protein expression) and immunotherapeutic agents, as well as innovative treatment approaches with existing HBV therapies that seek to maximize the possibility of functional cure. This goal of this talk us to provide a comprehensive overview of these new developments in HBV therapeutics, covering the following key areas: (1) current goals of treatment, and definitions of HBV “cure”; (3) the HBV life cycle, antiviral targets and investigational agents currently being developed that target virus including inhibition of viral entry, HBV surface antigen production and elimination or silencing of cccDNA; and (4) the use of novel surrogate markers (ie, quantitative HBsAg) to assess treatment response in clinical trials.
J-106 Immune correlates of HBV cure
Authors: Poonia Bhawna
Published: April 2019

Hepatitis B infection in adults results in resolution and development of protective immunity, while in neonates, it results in HBV persistence without development of protective immunity. Current treatment for chronic hepatitis B includes long term suppression with nucleotide analogs, which does not lead to viral clearance. Though viral elimination strategies are actively being researched, sterilizing cure is unlikely to be feasible in near future and HBV cure efforts are moving towards the more achievable functional cure. A clear understanding of immune correlates of HBV phenotypes in different patient populations is vital in pushing a functional cure strategy for chronic HBV infection. HBV specific B and T cells exhibit persistent exhaustion or anergy in most patients with treated chronic infection. Developing strategies for reversal of exhaustion such as use of checkpoint block or breaking tolerance by reducing serum HBs antigen levels in NUC treated patients will be critical for restoring HBV specific immunity to levels that achieve functional cure. Apart from adaptive immunity, strategies to boost innate immunity such as use of TLR agonists will further aid in development of HBV specific immunity in these patients. A combination strategy using antiviral and immunomodulation will thus be needed to achieve HBV functional cure.
J-109 Sequential administration of LASER ART and CRISPR-Cas9 can facilitate HIV-1 elimination in humanized mice
Authors: Gendelman Howard E. , Khalili Kamel
Published: April 2019

Eradication of the human immunodeficiency virus type one (HIV-1) requires either the clearance of infected cells or the removal of integrated proviral DNA from its cellular tissue reservoirs. Success is affirmed by the absence of viral rebound following prolonged cessation of antiretroviral therapy (ART). Here, we demonstrate that inhibition of HIV-1 infection in humanized mice with long-acting slow-effective release ART (LASER ART) followed by the treatment with CRISPR-Cas9 gene editing molecules aimed for the removal of the proviral DNA from host genome eliminates viral infection. In greater than third of HIV-1 infected dual treated mice virus could not be detected in blood, spleen, lung, kidney, liver, gut-associated lymphoid tissue and brain by ultrasensitive nested and digital droplet PCR and RNAscope tests. Excision of HIV-1 sub-genomic DNA fragments, spanning the LTRs and the Gag gene, was demonstrated with no evidence for off-target effects. No viral rebound was observed followed ART cessation and CD4+ T cell restoration. Progeny virus was not recovered after adoptive transfer of human immunocytes from dual treated virus-free animals to uninfected humanized mice. Direct co-cultivation of bone marrow and spleen human cells from virus eradicated animals with uninfected mitogen stimulated lymphocytes also failed in any attempt to recover progeny virus. In contrast, replication competent HIV-1 was readily detected in infected animals treated with LASER ART or CRISPR-Cas9 alone. These data provide the first proof-of-concept that viral sterilization is possible.
PC-3 A reappraisal of CTLA-4 checkpoint blockade hypothesis in cancer immunotherapy
Authors: Du Xuexiang , Tang Fei , Liu Mingyue , Zheng Pan , Liu Yang
Published: April 2019

The classic checkpoint blockade hypothesis states that cancer immunity is restrained by 2 distinct checkpoints: the first is the CTLA-4:B7 interaction that limits priming of naive T cells in lymphoid organs, while the second is the PD-1/B7-H1(PD-L1) interaction that results in exhaustion of effector T cells within the tumor microenvironment. Ipilimumab, a clinically-used so-called immune checkpoint inhibitor (ICI) has been FDA approved for the treatment of metastatic melanoma and might get clinical approval for additional oncological indications, most likely in combination with other drugs, for example anti-PD-1/PD-L1. It is assumed that anti-CTLA-4 antibodies cause tumor rejection by blocking negative signaling from the B7-CTLA-4 interactions.

Surprisingly, at concentrations considerably higher than plasma levels achieved by Ipilimumab blocks neither B7 transendocytosis by CTLA-4 nor CTLA-4 binding to immobilized or cell-associated B7. In Ctla4

h/m
mice expressing both human and mouse CTLA4 genes, anti-CTLA-4 antibodies that bind to human but not mouse CTLA-4 efficiently induce Treg-depletion and Fc receptor-dependent tumor rejection. The blocking antibody L3D10 is comparable to the non-blocking Ipilimumab in causing tumor rejection. Remarkably, L3D10 progenies (HL12/HL32) that lost blocking activity during humanization remain fully competent in Treg depletion and tumor rejection.

We also set out to test 3 commercially available anti-mouse Ctla-4 mAbs(4F10/9H10/9D9) that had been shown to induce tumor rejection for their ability to block the B7-Ctla-4 interaction under physiologically relevant conditions, these data also argue against a role for blocking the B7-Ctla-4 interaction in the induction of antitumor immunity by anti-mouse Ctla-4 mAbs. Since these mAbs showed comparable immunotherapeutic effect and comparable depletion of Treg cells in the tumor microenvironment. Thus, both anti-human CTLA-4 mAbs and anti-mouse CTLA-4 mAbs cause tumor rejection by mechanisms that are independent of checkpoint blockade but dependent on host Fc receptor. These data have important implications for the development of the next generation of immunotherapeutic anti-CTLA-4 mAbs and call for a reappraisal of the checkpoint blockade hypothesis.
PC-5 En masse discovery of human anti-cancer antibodies
Authors: Zhang Peng , Chou Hung-Yen , Zheng Pan , Liu Yang
Published: April 2019

Generation of specific antibodies for cancer therapy is a major endeavor. As a radical departure from conventional approach, we hereby describe rapid and potentially en masse identification of cancer-specific antibodies directly from human cancer tissues. A computational framework was developed and successfully tested for antibody discovery by mining TCGA RNA-seq data from 1945 cases of solid tumor samples. Surprisingly, synthetic antibodies based on high-abundance CDR3 sequences from lung adenocarcinoma (LUAD) patients bound all lung cancer samples tested and cross-reactive to other cancer types but rarely to normal tissues. Targeted DNA sequencing of the B cell receptor from 5 lung tumortissues also allowed us to identify variable region sequences with somaticmutations. Antibodies based on predominant variable region sequences showed specific binding to autologous lung cancer samples. Our platform dramatically reduces barrier in developing human anti-cancer antibodies and paved the way for cancer treatment using patient-derived tumor-reactive monoclonal antibodies.
PC-7 Uncoupling therapeutic from immunotherapy-related adverse effects for safer and effective anti-CTLA-4 antibodies in CTLA4 humanized mice
Authors: Liu Mingyue , Du Xuexiang , Su Juanjuan , Zhang Peng , Liu Yang , Zheng Pan
Published: April 2019

Anti-CTLA-4 monoclonal antibodies (mAbs) confer cancer immunotherapeutic effect (CITE) but cause severe immunotherapy-related adverse events (irAE). Targeting CTLA-4 has shown remarkable long-term benefit and thus remains a valuable tool for cancer immunotherapy if the irAE can be brought under control. An animal model that recapitulates clinical irAE and CITE would be valuable for developing safer CTLA-4-targeting reagents. Here we report such a model using mice with the humanized Ctla4 gene. In this model, clinical drug Ipilimumab induced severe irAE especially when combined with anti-PD-1 antibody; while another mAb L3D10 induced comparable CITE with very mild irAE under the same condition. The irAE corresponded to systemic T cell activation and reduced Treg/Teff ratios among autoreactive T cells. Using mice that were either homozygous or heterozygous for the human allele, we found that irAE required biallelic engagement, while CITE only required monoallelic engagement. As the immunological distinction for monoallelic vs biallelic engagement, we found that biallelic engagement of Ctla4 gene was necessary for preventing conversion of autoreactive T cells into Treg. Humanization of L3D10 that led to loss of blocking activity further increased safety without affecting the therapeutic effect. Taken together, our data demonstrate that complete CTLA-4 occupation, systemic T cell activation and preferential expansion of self-reactive T cells are dispensable for tumor rejection but correlate with irAE, while blocking B7-CTLA-4 interaction impacts neither safety nor efficacy of anti-CTLA-4 antibodies. These data provide important insights for clinical development of safer and potentially more effective CTLA-4 targeting immunotherapy.
PD-1 Genetic risk factors for high-risk human papillomavirus (HPV) infections and persistence among African women
Authors: Adebamowo Sally , Adeyemo Adebowale , Adebamowo Clement
Published: April 2019

Background:

Genetic factors may influence the susceptibility to high-risk human papillomavirus (hrHPV) infection and persistence. We conducted a genome-wide association study (GWAS) to identify variants associated with hrHPV infection and persistence among women of African ancestry.

Methods:

Participants were 522 Nigerian women evaluated at baseline and 6 months follow-up visits for HPV. HPV was characterized using SPF25/LiPA10. hrHPV infection was positive if at least one carcinogenic HPV genotype was detected in a sample provided at the baseline visit and persistent if at least one carcinogenic HPV genotype was detected in each of the samples provided at the baseline and follow-up visits. Genotyping was done using the Illumina Multi-Ethnic Genotyping Array (MEGA) and imputation was done using the African Genome Resources Haplotype Reference Panel. Association analysis was done under additive genetic models adjusted for age, HIV status and the first 3 principal components of the genotypes.

Results:

The mean (±SD) age of the study participants was 38 (±8) years, 46% were HIV negative, 24% were hrHPV positive and 10% had persistent hrHPV infections. The GWAS yielded 71 and 107 variants associated with hrHPV infection and persistence, respectively, with suggestive genome-wide significance [P value <1.0 × 10−5]. The top variants (rs149473200, rs147344426, rs151071053 and rs572823632) associated with hrHPV infections are in or near KLF12 [all P = 1.5 × 10−6]. KLF12 is an important regulator of gene expression during carcinogenesis, and it is highly expressed by human immune cells. In several studies, it was associated with HPV and cervical cancer. The top variants associated with persistent hrHPV infections were 3 variants upstream of AL450244 (rs143668247, rs12740341, rs2502139), a cluster of 5 intronic variants in JPH2 (rs116834259, rs74358070, rs11452236, rs79032354, rs6130527) and 2 intronic variants in GPR39 (rs16832308, rs62167448) [all P < 7.0 × 10−7]. These variants are in enhancer histone marks in several tissues and alter the motifs Ets, GATA, NR4A, RXRA, which have been associated with several cancers of the female reproductive system and leiomyosarcomas.

Conclusions:

This exploratory GWAS yielded risk loci that provide clues to the pathogenesis of hrHPV infection and persistence in women of African ancestry. Given the limited sample, larger discovery and replication studies are under way to further characterize the reported associations.
PE-1 Vaginal microbiota composition and persistent high-risk HPV infection in HIV negative and HIV positive women
Authors: Dareng Eileen , Adebamowo Sally , Ma Bing , Ravel Jacques , Pharoah Paul , Adebamowo Clement
Published: April 2019

Background:

Reports from previous studies suggest that the vaginal microbiota may play a role in cervical HPV pathogenesis. In this study, we examined associations between the vaginal microbiome and persistent high-risk human papillomarvirus (hrHPV) infection among HIV-negative and HIV-positive women.

Methods:

We used 16S rRNA gene amplicon sequencing to characterize the vaginal microbiota in 2 serial mid-vaginal samples taken approximately 6 months apart in 211 Nigerian women and the SPF10LIPA25 system for HPV detection. We used generalized estimating equation (GEE) logistic regression models with robust variance estimation and the cluster option for repeated measures, to evaluate the association between the vaginal microbiota composition and persistent hrHPV infection (defined as being positive for hrHPV at 2 visits 6 months apart); Linear discriminant analysis effect size (LEfSe) to identify phylotype biomarkers of persistent hrHPV; Markov chain transition probabilities to evaluate transition patterns and hierarchical clustering algorithms for community state (CST) assignments.

Results:

Some 142 women were HIV-positive and 69 were HIV-negative. Of the 211 participants, 71 were persistently positive for hrHPV. Mean age (SD) of participants was 38 (8) years. Most participants (84%, 175/211) were premenopausal. High diversity, low Lactobacillus spp. bacterial community state types, CST IV (A and B) were the most prevalent community state types (CST) in HIV-negative (57% at baseline and 40% at the follow-up visit) and HIV-positive (73% at baseline and 65% at the follow-up visit) women. There was effect modification by HIV status (P = 0.02). Among HIV-negative women, those who had a high relative abundance of Lactobacillus spp. were less likely to have persistent hrHPV (OR: 0.35, 95% CI: 0.14 to 0.89, P = 0.03) compared to women with low relative abundance of Lactobacillus spp. LEfSe analysis identified Sneathia spp as being differentially more abundant in HIV-negative women with persistent hrHPV. Markov chain transition probabilities showed that most CST transitions were to the highly diverse, low Lactobacillus spp., CST IV. In HIV-positive women, there was no significant association between the relative abundance of Lactobacillus spp and persistent hrHPV.

Conclusions:

Our results provide evidence to suggest that persistent hrHPV is associated with a lack of Lactobacillus spp in the vaginal microbiota of HIV-negative women.
PG-1 Compromised growth among HIV exposed compared to unexposed children in Nigeria
Authors: Jumare Jibreel , Datong Pam , Osawe Sophia , Okolo Felicia , Inyang Bukola , Abimiku Alash'le
Published: April 2019

Introduction:

HIV exposed but uninfected (HEU) children may be at an increased risk of impaired growth and development when compared to their unexposed and uninfected (HUU) counterparts. We compared growth pattern between HEU and HUU children in Nigeria.

Methods:

HIV infected and uninfected pregnant women were enrolled at the Plateau State Specialist Hospital (PSSH) Jos Nigeria. Babies born to these mothers were recruited at birth and the mother-infant pairs followed up until 18 months. Weight, length, and head circumference of the babies were measured at each study visit. Age and gender standardized z scores were generated for each anthropometric measure using the World Health Organization Child Growth Standards. Children with length for age (LAZ), weight for age (WAZ) and weight for length (WLZ) z scores <−2 were classified as stunted, underweight, and wasted respectively.

Results:

A total of 415 children (307 HEU and 108 HUU) were included in this analysis. At birth, 117 (28.4%), 9 (2.2%) and 32 (7.8%) babies were stunted, underweight and wasted respectively. In a multivariable longitudinal analysis, the odds of stunting was higher among HEU as compared to HUU children (OR: 2.4 [95% CI: 1.4 to 4.1]; P = 0.001). Similarly, odds of being underweight was higher among the HEU children (OR: 1.6 [95% CI: 1.1 to 2.2]; P = 0.009). While the odds of wasting appeared higher for the HEU children (OR: 1.5 [95% CI: 0.9 to 2.4]; P = 0.128), the difference did not reach statistical significance.

Conclusions:

We found strong evidence of greater impairment of linear and ponderal growth among HEU as compared to HUU children during the first 18 months of life in Nigeria. Further studies are needed to explore the causal basis for these differences.
PG-5 Assessment of knowledge, attitude and practice towards post exposure prophylaxis for HIV among health care workers in Federal Capital Territory, Abuja, Nigeria
Authors: Iowdi Clementina , Olayemi Olayemi , Dung John , Edokwe Chidozie , Okuma James , Peters Samuel , Dakum Patrick , Ekong Ernest
Published: April 2019

Background:

HIV/AIDS infection in the health care facility is a major health problem in resource limited settings. Health Care Workers (HCW) are caring for a large number of HIV infected patients. This makes them exposed to HIV infection, warranting the use of Post Exposure Prophylaxis (PEP) for HIV very critical. Here we assess Knowledge, Attitude and Practice of HCW towards PEP for HIV.

Methods:

This study was cross-sectional and was conducted among health care workers in 20 health care facilities providing primary health care, secondary, tertiary and private care in June 2018 under the US President Emergency Plan For AIDS Relief (PEPFAR). Data was collected using self-administered questionnaire. Results were summarized in percentages, median and Interquartile range (IQR).

Results:

A total of 195 HCWs completed the survey, 74 (37.9%), 34 (17.4%), 46 (23.6%) and 41 (21.1%) from Primary health care, private, secondary and tertiary health care facilities respectively. Majority of the HCWs were females, 128 (66.7%), 134 (70.2%) were aged 18–39 years and 66 (34.4%) were nurses. The median number of patients seen daily was 28 (IQR 20–50) and the median number of years in practice was 8 (IQR 4–12).

One hundred and seventy-seven (92.7%) HCWs had heard of PEP for HIV and 107 (58.5%) had excellent/good knowledge about PEP for HIV. Majority of HCW 168 (92.8%) had good attitude and would recommend PEP for HIV to others; 150 (81.5%) of HCW consider themselves to be at risk and 88 (46.1%), had occupational exposure. Among those exposed, 75 (85.2%) screened for HIV.

One hundred and sixty-three (86.7%) of the HCW are aware of hospital policy after occupational exposure and 107 (57.6%) would recommend commencing PEP for HIV within 1–72 hours after exposure; 131 (72.4%) are satisfied with current HIV infection protocol at their facility while 177 (92.7%) feel that more training is required for staff on HIV prevention.

Conclusions:

Majority of HCW had excellent/good knowledge, favorable attitude and practice towards PEP for HIV. There is need for policy makers in health sector to put policies, guidelines and pogram that will rapidly scale up PEP for HIV services in health care settings. This is much more important given the increased need for staff at these facilities to multitask and can self-expose. Keywords: Health care workers, Post exposure prophylaxis, HIV.