NK cell functions are tightly regulated by the balance between the inhibitory and stimulatory surface receptors. We investigated the surface expression of galectin-9 (Gal-9) and its function in NK cells from HIV-infected individuals on antiretroviral therapy, long-term nonprogressors, and progressors compared with healthy controls. We also measured the expression of TIGIT and TIM-3 on different NK cell subpopulations and compared their functionality to Gal-9⁺ NK cells. Our data demonstrated significant upregulation of Gal-9 on NK cells in HIV-infected groups versus healthy controls. Gal-9 expression was associated with impaired expression of cytotoxic effector molecules granzyme B, perforin, and granulysin. In contrast, Gal-9 expression significantly enhanced IFN-γ expression in NK cells of HIV-1–infected individuals. We also found an expansion of TIGIT⁺ NK cells in HIV-infected individuals; however, dichotomous to Gal-9⁺ NK cells, TIGIT⁺ NK cells expressed significantly higher amounts of cytotoxic molecules but lower IFN-γ. Moreover, lower expression of cytotoxic effector molecules in Gal-9⁺ NK cells was associated with higher CD107a expression, which suggests indiscriminate degranulation. Importantly, a positive correlation between the plasma viral load and Gal-9⁺ NK cells was observed in progressors. Finally, we found that a cytokine mixture (IL-12, IL-15, and IL-18) can improve effector functions of Gal-9⁺ NK cells in HIV-infected individuals, although, such an effect was observed for Gal-9⁻ NK cells, as well. Overall, our data highlight the important role of Gal-9 in dysfunctional NK cells and, more importantly, a dichotomy for the role of Gal-9 versus TIGIT and suggest a potential new avenue for the development of therapeutic approaches.

Background and method: We examined specimens from 111 HIV-infected participants virally suppressed on ART for a minimum of 5 years who had donated serial peripheral blood mononuclear cell (PBMC) specimens to the University of Washington/Fred Hutch Center for AIDS Research (CFAR) Specimen Repository. We determined the HIV proviral copy number per million PBMCs, corrected for CD4⁺ cell count, in 477 specimens collected after a minimum of 5 years of follow-up and up to 15.5 years of clinical viral suppression. Generalized estimating equation regression was used to examine the association between the reservoir size and time, age at study entry, antiretroviral regimen, and risk factors for HIV acquisition. Results and conclusion: We found that the inter-participant baseline HIV DNA level varied widely between 0.01 and 4.8 pol-copies per microgram genomic DNA and per CD4⁺ cell number/micoliter; the HIV DNA level declined with time (half-life was estimated at 12 years, 95% confidence interval of 6.2–240 years); the HIV DNA level was lower for those who achieved viral suppression at a younger age; and the HIV DNA level was not affected by the specific antiretroviral regimen used to achieve and maintain suppression.

Background: We are developing cytotoxic immunoconjugates (CICs) to eliminate HIV-infected cells. We investigated the efficacy and kinetics of killing by different forms of CICs targeted by the same monoclonal antibody (mAb), an immunotoxin (IT), antibody-drug conjugate (ADC), and radioimmunoconjugate (RIC). Methods: We compared in vitro effects of CICs made by conjugating anti-gp41 mAb 7B2 to deglycosylated ricin A chain (7B2-dgA), the anthracycline derivative PNU-159682 (7B2-PNU), or the α-emitting isotope actinium-225 (7B2-²²⁵Ac). Kinetic analyses of cell growth were performed measuring electrical impedance every 15 min over a 7-day period using cells stably expressing the HIV envelope and Env-negative parent cells. Results: 7B2-dgA and 7B2-²²⁵Ac were more potent and acted more rapidly to kill cells than 7B2-PNU. Both the 7B2-PNU and 7B2-²²⁵Ac induced bystander-cell killing, whereas the IT did not and consequently allowed the outgrowth of Env-negative cells. Low dose or brief exposure to 7B2-PNU resulted in an increased rate of cell growth. Conclusions: An IT, ADC, and RIC showed substantial differences in the degree of specific toxicity, kinetics, and mechanisms of killing. The results of this side-by-side comparison have implications for the development of CICs to treat HIV, as well as other conditions.

We conducted an in vitro investigation of the selective cytotoxicity of alpha-emitting radioimmunoconjugates (α-RICs) directed against cells expressing HIV envelope (Env) proteins. It is well known that monoclonal antibody (mAb)-targeted α-emitting radionuclides can effectively kill antigen-expressing cells; however, the expected low-level expression of HIV antigens on latently infected cells poses an obstacle to all anti-HIV immune-based treatments, including α-RICs. This investigation tested the cytotoxicity of the HIV envelope antigen-binding mAbs, PGT126 (binding gp120) and 7B2 (binding gp41), conjugated with labeling chelators that bind the α-emitters astatine-211 (²¹¹At), actinium-225 (²²⁵Ac) or thorium-227 (²²⁷Th). High specific activity (SA) preparations of the α-RICs were made to increase the proportion of mAb conjugates carrying the α-emitting isotope. RIC cytolytic activity was evaluated against a cell line stably expressing the HIV envelope. ²¹¹At-labeled mAb conjugates did not demonstrate specific cell killing, while the longer lived radiometal α-RICs, ²²⁷Th and ²²⁵Ac, efficiently and specifically killed HIV envelope expressing cells. Potential explanations for these differential effects include the longer half-lives of ²²⁵Ac and ²²⁷Th compared to ²¹¹At and differences in the decay properties of radiometals compared to radiohalogens. These encouraging in vitro results suggest that in vivo evaluations of α-RIC in depleting the HIV harboring cells are warranted.

Adherence to antiretroviral medications is a key determinant of clinical outcomes. Many adherence intervention trials investigated the effects of time-intensive or costly interventions that are not feasible in most clinical care settings. We set out to evaluate a collaborative care approach as a feasible intervention applicable to patients in clinical care including those with mental illness and/or substance use issues. We developed a randomized controlled trial (RCT) investigating an integrated, clinic-based care management approach to improve clinical outcomes that could be integrated into the clinical care setting. This is based on the routine integration and systematic follow-up of a clinical assessment of patient-reported outcomes targeting adherence, depression, and substance use, and adapts previously developed and tested care management approaches. The primary health coach or care management role is provided by clinic case managers allowing the intervention to be generalized to other human immunodeficiency virus (HIV) clinics that have case managers. We used a stepped-care approach to target interventions to those at greatest need who are most likely to benefit rather than to everyone to maintain feasibility in a busy clinical care setting. The National Institutes of Health funded this study and had no role in study design, data collection, or decisions regarding whether or not to submit manuscripts for publication. This trial is currently underway, enrollment was completed in 2015, and follow-up time still accruing. First results are expected to be ready for publication in early 2017. This paper describes the protocol for an ongoing clinical trial including the design and the rationale for key methodological decisions. There is a need to identify best practices for implementing evidence-based collaborative care models that are effective and feasible in clinical care. Adherence efficacy trials have not led to sufficient improvements, and there remains little guidance regarding how adherence interventions should be implemented into clinical care. By focusing on improving adherence within care settings using existing staff, routine assessment of key domains, such as depression, adherence, and substance use, and feasible interventions, we propose to evaluate this innovative way to improve clinical outcomes. Clinicaltrials.gov NCT01505660; http://clinicaltrials.gov/ct2/show/NCT01505660 (Archived by WebCite at http://www.webcitation/ 6ktOq6Xj7).

Nor98-like atypical scrapie is a sporadic disease that affects the central nervous system of sheep and goats that, in contrast to classical scrapie, is not generally regarded as naturally transmissible. However, infectivity has been demonstrated via bioassay not only of brain tissue but also of certain peripheral nerves, lymphoid tissues, and muscle. This study examines placental tissue, a well characterized route of natural transmission for classical scrapie. Further, this study was conducted in sheep homozygous for the classical scrapie resistant ARR genotype and is the first to characterize the transmission of Nor98-like scrapie between homozygous-ARR sheep. Nor98-like scrapie isolated from a United States ARR/ARR sheep was transmitted to four ARR/ARR ewes via intracerebral inoculation of brain homogenate. These ewes were followed and observed to 8 years of age, remained non-clinical but exhibited progression of infection that was consistent with Nor98-like scrapie, including characteristic patterns of PrP^Sc accumulation in the brain and a lack of accumulation in peripheral lymphoid tissues as detected by conventional methods. Immunoblots of placental tissues from the infected ewes revealed accumulation of a distinct conformation of PrP^res, particularly as the animals aged; however, the placenta showed no infectivity when analyzed via ovinized mouse bioassay. Taken together, these results support a low risk for natural transmission of Nor98-like scrapie in ARR/ARR sheep.