Faculty Bibliography

HIV-1 envelope (Env) is a trimer of gp120-gp41 heterodimers, synthesized from a precursor gp160 that contains an ER-targeting signal peptide (SP) at its amino-terminus. Each trimer is swathed by ~90 N-linked glycans, comprising complex-type and oligomannose-type glycans, which play an important role in determining virus sensitivity to neutralizing antibodies. We previously examined the effects of single point SP mutations on Env properties and functions. Here, we aimed to understand the impact of the SP diversity on glycosylation of virus-derived Env and virus neutralization by swapping SPs. Analyses of site-specific glycans revealed that SP swapping altered Env glycan content and occupancy on multiple N-linked glycosites, including conserved N156 and N160 glycans in the V1V2 region at the Env trimer apex and N88 at the trimer base. Virus neutralization was also affected, especially by antibodies against V1V2, V3, and gp41. Likewise, SP swaps affected the recognition of soluble and cell-associated Env by antibodies targeting distinct V1V2 configurations, V3 crown, and gp41 epitopes. These data highlight the contribution of SP sequence diversity in shaping the Env glycan content and its impact on the configuration and accessibility of V1V2 and other Env epitopes.

Following a 1983 chromic acid (hexavalent chromium [CrVI]) spill from a Garfield, NJ electroplating plant, CrVI-contaminated water was found in a local firehouse basement in 1993. An ATSDR public health advisory was issued for the plant site in 2010, and from 2008-2015, fourteen residential properties have required remediation to address CrVI-contaminated dust in the basements. As part of the Community Outreach and Engagement Core of the NYU NIEHS Center, seventytwo Garfield residents aged 18-65 years, participated in a community survey with the goal of identifying concerns related to environmental and community health. Thirty-two percent responded that they 'didn't know' if they were exposed to chemicals or pollutants where they live. This finding suggests a limited awareness of environmental chemical exposures, chromium contamination and/or potential exposure to CrVI. Furthermore, toenail clippings were collected from forty-seven Garfield residents and analyzed for total chromium levels to assess potential long-term exposure. On average, residents living on/inside the contaminated plume area had higher total chromium levels in their toenail clippings than residents living outside the plume area. However, chromium levels for all participants were within the range of historical normal. This study highlights the value of partnerships between environmentally-impacted community's and academic scientists working together to identify potential contaminant exposures and address public health concerns through research and environmental health education.

Genetic and immunologic analyses of epidemiologically-linked HIV transmission enable insights into the impact of immune responses on clinical outcomes. Human vaccine trials and animal studies of HIV-1 infection have suggested immune correlates of protection; however, their role in natural infection in terms of protection from disease progression is mostly unknown. Four HIV-1⁺ Cameroonian individuals, three of them epidemiologically-linked in a polygamous heterosexual relationship and one incidence-matched case, were studied over 15 years for heterologous and cross-neutralizing antibody responses, antibody binding, IgA/IgG levels, antibody-dependent cellular cytotoxicity (ADCC) against cells expressing wild-type or CD4-bound Env, viral evolution, Env epitopes, and host factors including HLA-I alleles. Despite viral infection with related strains, the members of the transmission cluster experienced contrasting clinical outcomes including cases of rapid progression and long-term non-progression in the absence of strongly protective HLA-I or CCR5Δ32 alleles. Slower progression and higher CD4/CD8 ratios were associated with enhanced IgG antibody binding to native Env and stronger V1V2 antibody binding responses in the presence of viruses with residue K169 in V2. ADCC against cells expressing Env in the CD4-bound conformation in combination with low Env-specific IgA/IgG ratios correlated with better clinical outcome. This data set highlights for the first time that V1V2-directed antibody responses and ADCC against cells expressing open, CD4-exposed Env, in the presence of low plasma IgA/IgG ratios, can correlate with clinical outcome in natural infection. These parameters are comparable to the major correlates of protection, identified post-hoc in the RV144 vaccine trial; thus, they may also modulate the rate of clinical progression once infected. The findings illustrate the potential of immune correlate analysis in natural infection to guide vaccine development.

Atlantic sturgeon and shortnose sturgeon co-occur in many estuaries along the Atlantic Coast of North America. Both species are protected under the U.S. Endangered Species Act and internationally on the IUCN Red list and by CITES. Early life-stages of both sturgeons may be exposed to persistent aromatic hydrocarbon contaminants such as PCBs and PCDD/Fs which are at high levels in the sediments of impacted spawning rivers. Our objective was to compare the PCBs and TCDD sensitivities of both species with those of other fishes and to determine if environmental concentrations of these contaminants approach those that induce toxicity to their young life-stages under controlled laboratory conditions. Because our previous studies suggested that young life-stages of North American sturgeons are among the more sensitive of fishes to coplanar PCB and TCDD-induced toxicities, we were interested in identifying the molecular bases of this vulnerability. It is known that activation of the aryl hydrocarbon receptor 2 (AHR2) in fishes mediates most toxicities to these contaminants and transcriptional activation of xenobiotic metabolizing enzymes such as cytochrome P4501A (CYP1A). Previous studies demonstrated that structural and functional variations in AHRs are the bases for differing sensitivities of several vertebrate taxa to aromatic hydrocarbons. Therefore, in this study we characterized AHR2 and its expression in both sturgeons as an initial step in understanding the mechanistic bases of their sensitivities to these contaminants. We also used CYP1A expression as an endpoint to develop Toxicity Equivalency Factors (TEFs) for these sturgeons. We found that critical amino acid residues in the ligand binding domain of AHR2 in both sturgeons were identical to those of the aromatic hydrocarbon-sensitive white sturgeon, and differed from the less sensitive lake sturgeon. AHR2 expression was induced by TCDD (up to 6-fold) and by three of four tested coplanar PCB congeners (3-5-fold) in Atlantic sturgeon, but less so in shortnose sturgeon. We found that expression of AHR2 and CYP1A mRNA significantly covaried after exposure to TCDD and PCB77, PCB81, PCB126, but not PCB169 in both sturgeons. We also determined TEFs for the four coplanar PCBs in shortnose sturgeon based on comparison of CYP1A mRNA expression across all doses. Surprisingly, the TEFs for all four coplanar PCBs in shortnose sturgeon were much higher (6.4-162 times) than previously adopted for fishes by the WHO.

Immunization with HIV AIDSVAX gp120 vaccines in the phase III VAX003 and VAX004 trials did not confer protection. To understand the shortcomings in antibody (Ab) responses induced by these vaccines, we evaluated the kinetics of Ab responses to the V1V2 and V3 regions of gp120 and the induction of Ab-mediated antiviral functions during the course of 7 vaccinations over a 30.5-month period. Plasma samples from VAX003 and VAX004 vaccinees and placebo recipients were measured for ELISA-binding Abs and for virus neutralization, Ab-dependent cellular phagocytosis (ADCP), and Ab-dependent cellular cytotoxicity (ADCC). Ab responses to V1V2 and V3 peaked after 3 to 4 immunizations and declined after 5 to 7 immunizations. The deteriorating responses were most evident against epitopes in the underside of the V1V2 β-barrel and in the V3 crown. Correspondingly, vaccinees demonstrated higher neutralization against SF162 pseudovirus sensitive to anti-V1V2 and anti-V3 Abs after 3 or 4 immunizations than after 7 immunizations. Higher levels of ADCP and ADCC were also observed at early or mid-time points as compared with the final time point. Hence, VAX003 and VAX004 vaccinees generated V1V2- and V3-binding Abs and functional Abs after 3 to 4 immunizations, but subsequent boosts did not maintain these responses.

Background: HIV-1 infection of four individuals and subsequent superinfection of one of these individuals with related strains enables valuable insight into the impact of natural immune responses and host factors on clinical outcome from comparably "primed" individuals.
Method(s): Four HIV-1+ individuals, epidemiologically linked by their infecting viruses, were studied longitudinally for neutralization, antibody binding, IgA/IgG quantitation and antibody-dependent cellular cytotoxicity (ADCC). Immune responses and viral signatures were analyzed for correlates of protection and clinical parameters.
Result(s): Despite viral infection with related strains, the course of HIV-1+ infection varied greatly between each individual. For example, whereas the two slow progressors exhibited the highest neutralization, ADCC towards CD4-induced Env epitopes, SOSIP and/or V1V2 antibody binding, the two progressors had the highest envelope specific IgA/IgG ratios in plasma. One of the progressors additionally experienced superinfection with a virus that was traced back genetically to one of the slow progressors (linked superinfection). Of interest, superinfection induced immune responses comparable to the linked HIV-1+ individual including Envspecific IgA/IgG ratios, neutralization and antibody binding patterns. In the combined longitudinal data set, ADCC against cells expressing untriggered Env did not correlate with clinical parameters; however both heterologous neutralization and antibody binding against two different V1V2 scaffolded antigens were significantly associated with higher CD4/CD8 ratios.
Conclusion(s): Superinfection with a genetically linked HIV-1 strain induced comparable immune responses as observed in the related singly infected individual. Our longitudinal data set of four epidemiologically linked cases underline the importance of polyfunctional immune responses, including neutralization and V1V2 antibody binding, for beneficial clinical outcomes and possibly even protection of superinfection

The global intensification of ART can lead to increased rates of HIV drug resistance (HIVDR) mutations in treated, and also in ART naive patients. ART naive HIV-1 infected patients from Cameroon were subjected to a multimethod HIVDR analysis using Amplification Refractory Mutation System (ARMS)-PCR, Sanger sequencing, and longitudinal Next-Generation Sequencing (NGS), to determine their mutation profiles for K103N, Y181C, K65R, M184V, and T215F/Y. We processed 66 ART-naive HIV-1+ patients with highly diverse subtypes, underlining the predominance of CRF02_AG and the increasing rate of F2 and other recombinant forms in Cameroon. We compared three resistance testing methods for 5 major mutation sites. Using Sanger sequencing, the overall prevalence of HIVDR mutations was 7.6% (5/66) and included all studied mutations except K65R. Comparing ARMS-PCR with Sanger sequencing as a reference, we obtained a sensitivity of 100% (5/5) and a specificity of 95% (58/61), caused by three false positive calls with ARMS-PCR. For 32/66 samples we obtained NGS data and we observed two additional mismatches made up by minority variants (7%, 18%) that might not be clinically relevant. Longitudinal NGS analyses revealed changes in HIVDR mutations in all five positive subjects that could not be attributed to treatment. In one of these cases, superinfection led to the temporary masking of a resistant virus.HIVDR mutations can be sensitively detected by ARMS-PCR and Sequencing methods with comparable performance. Longitudinal changes in HIVDR mutations have to be considered even in the absence of treatment.

The V3 loop in the HIV envelope gp120 is one of the immunogenic sites targeted by Abs. The V3 crown in particular has conserved structural elements recognized by cross-reactive neutralizing Abs, indicating its potential contribution in protection against HIV. Crystallographic analyses of anti-V3 crown mAbs in complex with the V3 peptides have revealed that these mAbs recognize the conserved sites on the V3 crown via two distinct strategies: a cradle-binding mode (V3C) and a ladle-binding (V3L) mode. However, almost all of the anti-V3 crown mAbs studied in the past were isolated from chronically HIV-infected individuals. The extents to which the two types of anti-V3 crown Abs are generated by vaccination are unknown. This study analyzed the prevalence of V3C-type and V3L-type Ab responses in HIV-infected individuals and in HIV envelope-immunized humans and animals using peptide mimotopes that distinguish the two Ab types. The results show that both V3L-type and V3C-type Abs were generated by the vast majority of chronically HIV-infected humans, although the V3L-type were more prevalent. In contrast, only one of the two V3 Ab types was elicited in vaccinated humans or animal models, irrespective of HIV-1 envelope clades, envelope constructs (oligomeric or monomeric), and protocols (DNA plus protein or protein alone) used for vaccinations. The V3C-type Abs were produced by vaccinated humans, macaques, and rabbits, whereas the V3L-type Abs were made by mice. The V3C-type and V3L-type Abs generated by the vaccinations were able to mediate virus neutralization. These data indicate the restricted repertoires and the species-specific differences in the functional V3-specific Ab responses induced by the HIV envelope vaccines. The study implies the need for improving immunogen designs and vaccination strategies to broaden the diversity of Abs in order to target the different conserved epitopes in the V3 loop and, by extension, in the entire HIV envelope.

The V3 loop in the HIV envelope gp120 is one of the immunogenic sites targeted by virus-neutralizing Abs. The V3 crown in particular has conserved structural elements recognized by cross-reactive Abs, implicating its potential contribution in protection against HIV. Crystallographic analyses of anti-V3 crown mAbs in complex with the V3 peptides have revealed that these mAbs recognize the conserved sites on the V3 crown via two distinct strategies: A cradle-binding mode (V3C) and a ladle-binding (V3L) mode. However, almost all of the anti-V3 crown mAbs studied in the past were isolated from chronically HIV-infected individuals. The extents to which the two types of anti-V3 crown Abs are generated by HIV envelope vaccines are unknown. This study analyzed the prevalence and levels of V3C-Type and V3L-Type Ab responses in HIVinfected individuals and in HIV envelope-immunized humans and animals using peptide mimotopes that distinguish the two V3 Ab types. The results show that both V3L-Type and V3C-Type Abs were generated by the vast majority of chronically HIV-infected humans, although the V3L-Type were more prevalent. In contrast, only one type of V3 Abs was elicited in humans or animal models after receiving the HIV envelope vaccines. Irrespective of the HIV envelopes and immunization regimens used, the V3C-Type Abs were produced by vaccinated humans, macaques, and rabbits, whereas the V3L-Type Abs were made by mice. The V3C-Type and V3L-Type Abs generated by the HIV envelope vaccines were able to mediate virus neutralization. These data indicate the restricted repertoires and the species-specific differences in the functional V3 Ab responses induced by the HIV envelope vaccines. The study implicates the need for improving immunogen designs and vaccination strategies to broaden the diversity of Abs and target the different conserved epitopes in the V3 loop and in the HIV envelope as a whole

INTRODUCTION: Hookahs (water pipes) are rapidly increasing in popularity worldwide. Evidence suggests that although perceived as safer than cigarette smoke, hookah smoke may be as, or even more, dangerous as cigarette smoke. METHODS: Air samples from 33 homes-11 where only hookah-smoking occurred, 12 with only cigarettes and 10 with no smoking-were collected to analyse concentrations of particulate matter (PM2.5), black carbon, elemental and organic carbon and carbon monoxide (CO). Air quality was assessed in rooms where smoking occurred and in an adjacent room. RESULTS: Hookah and cigarette smoking impaired home air quality. The rooms in which hookahs were smoked showed the highest concentrations for all pollutants. CO was significantly greater in the rooms where hookahs were smoked than in the cigarette-smoking rooms and the non-smoking households (p<0.05). In addition, CO levels in the rooms adjacent to where hookah was smoked were 2.5-fold to 4-fold greater than those in the smoking and non-smoking rooms of the cigarette homes (p<0.05). PM2.5 levels were also elevated in hookah homes compared to cigarette and non-smoking homes, although not significantly different. CONCLUSIONS: This study, the first of its kind, demonstrates potentially hazardous levels of home air pollution in rooms where hookahs are being smoked as well as in adjacent rooms. These levels were greater than those in cigarette smoking homes, raising concerns about potential negative health effects on all individuals living in homes where hookahs are smoked.