Selected Grantee Publications
American Alligators Are Capable of West Nile Virus Amplification, Mosquito Infection and Transmission
Byas et al., Virology. 2022.
https://www.doi.org/10.1016/j.virol.2022.01.009
West Nile virus (WNV) overwintering is poorly understood and likely multifactorial. Interest in alligators as a potential amplifying host arose when it was shown that they develop viremias theoretically sufficient to infect mosquitoes. Researchers examined potential ways in which alligators may contribute to the natural ecology of WNV. They experimentally demonstrated that alligators are capable of WNV amplification with subsequent mosquito infection and transmission capability, that WNV-infected mosquitoes readily infect alligators, and that water can serve as a source of infection for alligators but does not easily serve as an intermediate means for transmission between birds and alligators. These findings indicate potential mechanisms for maintenance of WNV outside of the primary bird–mosquito transmission cycle. Supported by ORIP (T32OD010437) and NIAID.
Presence of Natural Killer B Cells in Simian Immunodeficiency Virus–Infected Colon That Have Properties and Functions Similar to Those of Natural Killer Cells and B Cells but Are a Distinct Cell Population
Cogswell et al., mSphere. 2022.
https://www.doi.org/10.1128/jvi.00235-22
HIV infection of the gut is associated with increased mucosal inflammation, and the role of natural killer B (NKB) cells in this process requires further investigation. In this study, the researchers used rhesus and cynomolgus macaque models to characterize the function and characteristics of NKB cells in response to simian immunodeficiency virus (SIV) infection. They reported that NKB cells can kill target cells, proliferate, and express several inflammatory cytokines. The properties of NKB cells could provide insight into the inflammation observed in the gut during SIV infection, and the individual contributions of each cytokine and receptor–ligand interaction could be explored in a future study. Supported by ORIP (P51OD011106), NIAID, and NIGMS.
Using the Autofluorescence Finder on the Sony ID7000TM Spectral Cell Analyzer to Identify and Unmix Multiple Highly Autofluorescent Murine Lung Populations
Wanner et al., Frontiers in Bioengineering and Biotechnology. 2022.
https://www.doi.org/10.3389/fbioe.2022.827987
The investigators explored a new imaging approach to detect faint fluorescent signals that are masked in the background of cell types that emit high‑intensity autofluorescence (AF) signals in a flow cytometry panel. Using a novel AF finder tool on the Sony ID7000™ spectral cell analyzer, the investigators studied multiple AF subsets in complex and heterogeneous murine lung single-cell suspensions. Major immune and lung tissue resident cells in a murine model of asthma were easily identified in a multicolor panel using AF subtraction. The findings demonstrate the practicality of the AF finder tool, particularly when analyzing samples with multiple AF populations of varying intensities, to reduce fluorescence background and increase signal resolution in spectral flow cytometry. Supported by ORIP (S10OD025207) and NHLBI.
A Novel Wireless ECG System for Prolonged Monitoring of Multiple Zebrafish for Heart Disease and Drug Screening Studies
Le et al., Biosensors and Bioelectronics. 2022.
https://pubmed.ncbi.nlm.nih.gov/34801796/
Zebrafish and their mutant lines have been extensively used in cardiovascular studies. In the current study, the novel system Zebra II is presented for prolonged electrocardiogram (ECG) acquisition and analysis for multiple zebrafish within controllable working environments. The Zebra II is composed of a perfusion system, apparatuses, sensors, and an in-house electronic system. First, the Zebra II is validated in comparison with a benchmark system, namely iWORX, through various experiments. The validation displayed comparable results in terms of data quality and ECG changes in response to drug treatment. The effects of anesthetic drugs and temperature variation on zebrafish ECG were subsequently investigated in experiments that need real-time data assessment. The Zebra II's capability of continuous anesthetic administration enabled prolonged ECG acquisition up to 1 h compared to that of 5 min in existing systems. The novel cloud-based automated analysis with data obtained from four fish further provided a useful solution for combinatorial experiments and helped save significant time and effort. The system showed robust ECG acquisition and analytics for various applications, including arrhythmia in sodium-induced sinus arrest, temperature-induced heart rate variation, and drug-induced arrhythmia in Tg(SCN5A-D1275N) mutant and wildtype fish. The multiple channel acquisition also enabled the implementation of randomized controlled trials on zebrafish models. The developed ECG system holds promise and solves current drawbacks in order to greatly accelerate drug screening applications and other cardiovascular studies using zebrafish. Supported by ORIP (R44OD024874) and NHLBI.
Phagocytosis by an HIV Antibody Is Associated with Reduced Viremia Irrespective of Enhanced Complement Lysis
Spencer et al., Nature Communications. 2022.
https://doi.org/10.1038/s41467-022-28250-7
Researchers used the bNAb 10E8v4 targeting the HIV Env protein to examine the role of antibody-mediated effector and complement (C′) activity when 10E8v4 was administered prophylactically to rhesus monkeys challenged with simian-human immunodeficiency virus (SHIV). With sub-protective dosing, the researchers found a 78–88% reduction in post-acute viremia that was associated with 10E8v4–mediated phagocytosis. These results suggest that effector functions inherent to unmodified 10E8v4 contribute to therapeutic efficacy against SHIV, while C′ functions do not contribute to efficacy in this context. This research informs the design of bNAb modifications for improving the protective efficacy of this therapeutic approach against HIV. Supported by ORIP (P51OD011092, U42OD023038) and NIAID.
Complex Decay Dynamics of HIV Virions, Intact and Defective Proviruses, and 2LTR Circles Following Initiation of Antiretroviral Therapy
White et al., PNAS. 2022.
https://doi.org/10.1073/pnas.2120326119
In people living with HIV-1 (PLWH) who start antiretroviral therapy (ART), virus in blood decreases rapidly to below detection, but remaining infected cells may become part of the latent reservoir. Researchers investigated viral decay dynamics and identified decay processes with pronounced differences between intact and defective proviruses. Infected cells that survive second-phase decay may down-regulate HIV-1 gene expression and enter the stable latent reservoir. This research provides insight into meaningful latent reservoir markers and mechanisms for elimination of cells with intact viral genomes. Supported by ORIP (R01OD011095) and NIAID.
Vaccine-Induced, High-Magnitude HIV Env-Specific Antibodies with Fc-Mediated Effector Functions Are Insufficient to Protect Infant Rhesus Macaques against Oral SHIV Infection
Curtis et al., mSphere. 2022.
https://www.doi.org/10.1128/msphere.00839-21
A tailored, effective HIV vaccine is needed to prevent mother-to-child viral transmission. In nonhuman primate models, infection with simian–human immunodeficiency virus (SHIV) can be prevented by administering broadly neutralizing HIV envelope (Env)–specific antibodies. Investigators tested the efficacy of an intramuscular vaccine regimen against SHIV infection in male and female infant rhesus macaques. The vaccine induced Env-specific antibodies in plasma, with antibody-dependent cellular cytotoxicity and phagocytic function. These antibodies, however, were insufficient for protection against infection. Future studies could focus on improving the breadth of antibody response and improving cell-mediated immunity. Supported by ORIP (P51OD011107), NCI, NIAID, and NIDCR.
CAR/CXCR5–T Cell Immunotherapy Is Safe and Potentially Efficacious in Promoting Sustained Remission of SIV Infection
Pampusch et al., PLOS Pathogens. 2022.
https://www.doi.org/10.1371/journal.ppat.1009831
HIV and simian immunodeficiency virus (SIV) replication are concentrated within the B cell follicles of secondary lymphoid tissues. In this study, the researchers developed immunotherapeutic chimeric antigen receptor (CAR) T cells that home to follicles and clear SIV-infected cells in a rhesus macaque model. The CAR T cells localized to the follicle, replicated, and interacted directly with infected cells. Most of the treated animals maintained lower viral loads in the blood and follicles, compared to control animals. These findings demonstrate the safety and potential efficacy of this immunotherapy approach for long-term remission of HIV without requiring the lifelong use of antiretroviral therapy. Supported by ORIP (P51OD011106), NIAID, and NHLBI.
Characterization of Near Full-Length Transmitted/Founder HIV-1 Subtype D and A/D Recombinant Genomes in a Heterosexual Ugandan Population (2006–2011)
Balinda et al., Viruses. 2022.
https://www.doi.org/10.3390/v14020334
About 80 percent of heterosexual HIV-1 transmission events are thought to be attributable to a single transmitted/founder (T/F) virus. Studies of HIV T/F viruses could yield valuable insights on transmission and help inform the design of vaccines and therapeutics. To date, most T/F studies have focused on subtype B and C viruses; few studies have focused on subtype D. In this study, the researchers characterized near full-length T/F viral genomes to identify subtype D and A/D recombinants from heterosexual mucosal transmissions in humans. They reported high viral diversity and high pathogenicity, underscoring the importance of matching vaccine designs to the predominant subtypes within populations. Further studies of the full genome sequence could provide additional information for subtyping. Supported by ORIP (P51OD011132) and NIAID.
Expression, Activity, and Regulation of Phosphorylating Enzymes in Tissues and Cells Relevant to HIV-1 Sexual Transmission
Hu et al., AIDS Research and Human Retroviruses. 2022.
https://www.doi.org/10.1089/AID.2020.0250
Phosphorylating enzymes (PEs) are critical for activating nucleoside/nucleotide reverse transcriptase inhibitors (e.g., tenofovir [TFV]), but limited information is available about the expression of PEs in the female genital tract and colon tissue. Investigators compared the mRNA expression of seven PEs involved in metabolism of TFV in cervicovaginal and colon tissues. This work involved human, pigtailed macaque, and rabbit tissues; human cervicovaginal epithelial cell lines; T cell lines; and primary CD4+ T cells. Taken together, this study suggests that TFV activation differs among immune cells and local tissues under varying conditions. Additionally, the variability of PE expression levels found across species provides critical information to assist with the interpretation of data obtained using these animal models. Supported by ORIP (P51OD010425) and NIAID.