Type 1 interferons (IFN-I) are potent innate antiviral effectors that constrain HIV-1 transmission. However, harnessing these cytokines for HIV-1 cure strategies has been hampered by an incomplete ...understanding of their antiviral activities at later stages of infection. Here, we characterized the IFN-I sensitivity of 500 clonally derived HIV-1 isolates from the plasma and CD4
T cells of 26 individuals sampled longitudinally after transmission or after antiretroviral therapy (ART) and analytical treatment interruption. We determined the concentration of IFNα2 and IFNβ that reduced viral replication in vitro by 50% (IC
) and found consistent changes in the sensitivity of HIV-1 to IFN-I inhibition both across individuals and over time. Resistance of HIV-1 isolates to IFN-I was uniformly high during acute infection, decreased in all individuals in the first year after infection, was reacquired concomitant with CD4
T cell loss, and remained elevated in individuals with accelerated disease. HIV-1 isolates obtained by viral outgrowth during suppressive ART were relatively IFN-I sensitive, resembling viruses circulating just before ART initiation. However, viruses that rebounded after treatment interruption displayed the highest degree of IFNα2 and IFNβ resistance observed at any time during the infection course. These findings indicate a dynamic interplay between host innate responses and the evolving HIV-1 quasispecies, with the relative contribution of IFN-I to HIV-1 control affected by both ART and analytical treatment interruption. Although elevated at transmission, host innate pressures are the highest during viral rebound, limiting the viruses that successfully become reactivated from latency to those that are IFN-I resistant.
The discovery of potent and broadly neutralizing antibodies (bNAbs) against human immunodeficiency virus (HIV) has made passive immunization a potential strategy for the prevention and treatment of ...HIV infection. We sought to determine whether passive administration of VRC01, a bNAb targeting the HIV CD4-binding site, can safely prevent or delay plasma viral rebound after the discontinuation of antiretroviral therapy (ART).
We conducted two open-label trials (AIDS Clinical Trials Group ACTG A5340 and National Institutes of Health NIH 15-I-0140) of the safety, side-effect profile, pharmacokinetic properties, and antiviral activity of VRC01 in persons with HIV infection who were undergoing interruption of ART.
A total of 24 participants were enrolled, and one serious alcohol-related adverse event occurred. Viral rebound occurred despite plasma VRC01 concentrations greater than 50 μg per milliliter. The median time to rebound was 4 weeks in the A5340 trial and 5.6 weeks in the NIH trial. Study participants were more likely than historical controls to have viral suppression at week 4 (38% vs. 13%, P=0.04 by a two-sided Fisher's exact test in the A5340 trial; and 80% vs. 13%, P<0.001 by a two-sided Fisher's exact test in the NIH trial) but the difference was not significant at week 8. Analyses of virus populations before ART as well as before and after ART interruption showed that VRC01 exerted pressure on rebounding virus, resulting in restriction of recrudescent viruses and selection for preexisting and emerging antibody neutralization-resistant virus.
VRC01 slightly delayed plasma viral rebound in the trial participants, as compared with historical controls, but it did not maintain viral suppression by week 8. In the small number of participants enrolled in these trials, no safety concerns were identified with passive immunization with a single bNAb (VRC01). (Funded by the National Institute of Allergy and Infectious Diseases and others; ACTG A5340 and NIH 15-I-0140 ClinicalTrials.gov numbers, NCT02463227 and NCT02471326 .).
The effect of a brief analytical treatment interruption (ATI) on the HIV-1 latent reservoir of individuals who initiate antiretroviral therapy (ART) during chronic infection is unknown.
We evaluated ...the impact of transient viremia on the latent reservoir in participants who underwent an ATI and at least 6 months of subsequent viral suppression in a clinical trial testing the effect of passive infusion of the broadly neutralizing Ab VRC01 during ATI.
Measures of total HIV-1 DNA, cell-associated RNA, and infectious units per million cells (IUPM) (measured by quantitative viral outgrowth assay QVOA) were not statistically different before or after ATI. Phylogenetic analyses of HIV-1 env sequences from QVOA and proviral DNA demonstrated little change in the composition of the virus populations comprising the pre- and post-ATI reservoir. Expanded clones were common in both QVOA and proviral DNA sequences. The frequency of clonal populations differed significantly between QVOA viruses, proviral DNA sequences, and the viruses that reactivated in vivo.
The results indicate that transient viremia from ATI does not substantially alter measures of the latent reservoir, that clonal expansion is prevalent within the latent reservoir, and that characterization of latent viruses that can reactivate in vivo remains challenging.
ClinicalTrials.gov NCT02463227FUNDING. Funding was provided by the NIH.
In murine schistosomiasis, immunopathology and cytokine production in response to parasite eggs are uneven and strain dependent. CBA/J (CBA) mice develop severe hepatic granulomatous inflammation ...associated with prominent Th17 cell responses driven by dendritic cell (DC)-derived IL-1β and IL-23. Such Th17 cells fail to develop in low-pathology C57BL/6 (BL/6) mice, and the reasons for these strain-specific differences in APC reactivity to eggs remain unclear. We show by gene profiling that CBA DCs display an 18-fold higher expression of the C-type lectin receptor CD209a, a murine homolog of human DC-specific ICAM-3-grabbing nonintegrin, compared with BL/6 DCs. Higher CD209a expression was observed in CBA splenic and granuloma APC subpopulations, but only DCs induced Th17 cell differentiation in response to schistosome eggs. Gene silencing in CBA DCs and overexpression in BL/6 DCs demonstrated that CD209a is essential for egg-elicited IL-1β and IL-23 production and subsequent Th17 cell development, which is associated with SRC, RAF-1, and ERK1/2 activation. These findings reveal a novel mechanism controlling the development of Th17 cell-mediated severe immunopathology in helminthic disease.
•DPPI−/− mice are protected from death following intranasal infection with Klebsiella pneumoniae.•The survival advantage is due to enhanced bacterial clearance by DPPI−/− mice.•DPPI−/− mice have ...significantly higher levels of surfactant protein D in their lungs.•BAL fluid from DPPI−/− mice aggregate bacteria more effectively than control BAL fluid.•The amino terminus of surfactant protein D is alternatively processed in DPPI−/− mice.
Prior work established that a deficiency in the cysteine protease dipeptidyl peptidase I (DPPI) improves survival following polymicrobial septic peritonitis. To test whether DPPI regulates survival from severe lung infections, DPPI−/− mice were studied in a Klebsiella pneumoniae lung infection model, finding that survival in DPPI−/− mice is significantly better than in DPPI+/+ mice 8d after infection. DPPI−/− mice have significantly fewer bacteria in the lung than infected DPPI+/+ mice, but no difference in lung histopathology, lung injury, or cytokine levels. To explore mechanisms of enhanced bacterial clearance in DPPI−/− mice, we examined the status of pulmonary collectins, finding that levels of surfactant protein D, but not of surfactant protein A, are higher in DPPI−/− than in DPPI+/+ BAL fluid, and that DPPI−/− BAL fluid aggregate bacteria more effectively than control BAL fluid. Sequencing of the amino terminus of surfactant protein D revealed two or eight additional amino acids in surfactant protein D isolated from DPPI−/− mice, suggesting processing by DPPI. These results establish that DPPI is a major determinant of survival following Klebsiella pneumoniae lung infection and suggest that the survival disadvantage in DPPI+/+ mice is in part due to processing of surfactant protein D by DPPI.
Prior work established that a deficiency in the cysteine protease dipeptidyl peptidase I (DPPI) improves survival following polymicrobial septic peritonitis. To test whether DPPI regulates survival ...from severe lung infections, DPPI
−/−
mice were studied in a
Klebsiella pneumonia
lung infection model
,
finding that survival in DPPI
−/−
mice is significantly better than in DPPI
+/+
mice 8 d after infection. DPPI
−/−
mice have significantly fewer bacteria in the lung than infected DPPI
+/+
mice, but no difference in lung histopathology, lung injury, or cytokine levels. To explore mechanisms of enhanced bacterial clearance in DPPI
−/−
mice, we examined the status of pulmonary collectins, finding that levels of surfactant protein D, but not of surfactant protein A, are higher in DPPI
−/−
than in DPPI
+/+
BAL fluid, and that DPPI
−/−
BAL fluid aggregate bacteria more effectively than control BAL fluid. Sequencing of the amino terminus of surfactant protein D revealed two or eight additional amino acids in surfactant protein D isolated from DPPI
−/−
mice, suggesting processing by DPPI. These results establish that DPPI is a major determinant of survival following
Klebsiella pneumoniae
lung infection and suggest that the survival disadvantage in DPPI
+/+
mice is in part due to processing of surfactant protein D by DPPI.
In HIV-infected patients, combination antiretroviral therapy (cART) during HIV-1 infection potently suppresses viral replication and slows progression to AIDS. Upon cessation of cART, however, ...systemic infection is rapidly re-established due to the long-lived pool of latently infected cells, or HIV reservoir, that is seeded early in infection and persists despite years of cART in patients. This long-lived reservoir is the target of novel curative strategies. In order to determine in vivo efficacy of these interventions, closely monitored analytical treatment interruption (ATI) is required. Previously conducted ATI trials have provided important baseline information regarding the kinetics and diversity of viruses emerging from latency. As future HIV curative clinical trials move towards prolonged periods of ATI, studies assessing the effect of ATI on host virus-immune dynamics will provide an important baseline that will further our understanding of trial outcomes. In this thesis, I conducted single genome sequencing (SGS) of HIV-1 env and neutralization assays using autologous antibodies to characterize the viral and immune dynamics of rebound in two clinical trials: a longitudinal ATI study in the absence of any intervention, and a brief ATI study involving administration of the broadly neutralizing antibody VRC01. Our data, consistent with previous studies, demonstrated that viral rebound occurs within four weeks of ATI and is established by multiple latently infected cells in the majority of HIV-infected participants. Analyses of plasma containing VRC01 and/or autologous antibodies show that latent reservoir viruses can experience an antibody-mediated neutralization sieve effect, thus preventing the persistence of antibody-sensitive viruses. Additionally, SGS of latent viruses before and after brief ATI show that the size and composition of the peripheral latent viral reservoir is not significantly altered during ATI, demonstrating that short-term ATI is safe. Taken together, these data highlight the complex virus-host dynamics during ATI, and further suggest that passively infused or host-derived neutralizing antibodies can exert selective pressure, altering the evolution of HIV in its host.
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