Natural killer T (NKT) cells are distinct glycolipid reactive innate lymphocytes that are implicated in the resistance to pathogens and tumors. Earlier attempts to mobilize NKT cells, specifically, in vivo in humans met with limited success. Here, we evaluated intravenous injection of monocyte-derived mature DCs that were loaded with a synthetic NKT cell ligand, α-galactosyl-ceramide (α-GalCer; KRN-7000) in five patients who had advanced cancer. Injection of α-GalCer–pulsed, but not unpulsed, dendritic cells (DCs) led to >100-fold expansion of several subsets of NKT cells in all patients; these could be detected for up to 6 mo after vaccination. NKT activation was associated with an increase in serum levels of interleukin-12 p40 and IFN-γ inducible protein-10. In addition, there was an increase in memory CD8+ T cells specific for cytomegalovirus in vivo in response to α-GalCer–loaded DCs, but not unpulsed DCs. These data demonstrate the feasibility of sustained expansion of NKT cells in vivo in humans, including patients who have advanced cancer, and suggest that NKT activation might help to boost adaptive T cell immunity in vivo.

Background Young men who have sex with men (YMSM) are a key population for implementation of PrEP interventions. This open-label study examined adherence to PrEP and assessed sexual behavior among a diverse sample of YMSM in 12 U.S. cities. Methods Eligible participants were 18–22 year old HIV-uninfected MSM who reported HIV transmission risk behavior in the past 6 months. Participants were provided daily TDF/FTC (Truvada®). Study visits occurred at baseline, monthly through week 12, then quarterly through week 48. Dried blood spots (DBS) were serially collected for the quantification of tenofovir diphosphate (TFV-DP). Results Between March-September 2013, 2186 individuals were approached and 400 were found to be preliminarily eligible. Of those 400, 277 were scheduled for an in-person screening visit and 200 were enrolled (mean age=20.2; 54.5% Black, 26.5% Latino). Diagnoses of sexually transmitted infections (STIs), including urethral and rectal chlamydial/gonococcal infection and syphilis, at baseline was 22% and remained high across visits. At week 4, 56% of participants had TFV-DP levels consistent with ≥4 pills/week. By week 48, 34% of participants had TFV-DP levels consistent with ≥4 pills/week, with a noticeable drop-off occurring at Week 24. Four HIV seroconversions occurred on study (3.29/100 person-years). Condomless sex was reported by >80% of participants and condomless anal sex with last partner was associated with higher TFV-DP levels. Conclusions Acceptability of PrEP was high and most participants achieved protective drug levels during monthly visits. As visit frequency decreased, so did adherence. YMSM in the US may need PrEP access in youth-friendly settings with tailored adherence support and potentially augmented visit schedules.

IMPORTANCE Adolescents represent a key population for implementing preexposure prophylaxis (PrEP) interventions worldwide, yet tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) for PrEP is only licensed for adults.OBJECTIVE To examine the safety of and adherence to PrEP along with changes in sexual risk behavior among adolescent men who have sex with men (MSM).DESIGN, SETTING, AND PARTICIPANTS Adolescent Medicine Trials Network for HIV/AIDS Interventions 113 (Project PrEPare) was a PrEP demonstration project that evaluated the safety, tolerability, and acceptability of TDF/FTC and patterns of use, rates of adherence, and patterns of sexual risk behavior among healthy young MSM aged 15 to 17 years. Participants were recruited from adolescent medicine clinics and their community partners in 6 US cities, had negative test results for human immunodeficiency virus (HIV) but were at high risk for acquiring an infection, and were willing to participate in a behavioral intervention and accept TDF/FTC as PrEP.EXPOSURES All participants completed an individualized evidence-based behavioral intervention and were provided with daily TDF/FTC as PrEP for 48 weeks. MAIN OUTCOMES AND MEASURESThe main objectives were to: (1) provide additional safety data regarding TDF/FTC use among young MSM who had negative test results for HIV;(2) examine the acceptability, patterns of use, rates of adherence, and measured levels of tenofovir diphosphate in dried blood spots; and (3) examine patterns of risk behavior when young MSM were provided with a behavioral intervention in conjunction with open-label TDF/FTC. RESULTS Among 2864 individuals screened (from August 2013 to September 2014), 260 were eligible and 78 were enrolled (mean [SD] age, 16.5 [0.73] years), of whom 2 (3%) were Asian/Pacific Islander, 23 (29%) were black/African American, 11 (14%) were white, 16 (21%) were white Hispanic, and 26 (33%) were other/mixed race/ethnicity. Over 48 weeks of PrEP use, 23 sexually transmitted infections were diagnosed in 12 participants. The HIV seroconversion rate was 6.4 (95% CI: 1.3-18.7) per 100 person-years. Tenofovir diphosphate levels consistent with a high degree of anti-HIV protection (>700 fmol/punch) were found in 42 (54%), 37 (47%), 38 (49%), 22 (28%), 13 (17%), and 17 (22%) participants at weeks 4, 8, 12, 24, 36, and 48, respectively. CONCLUSIONS AND RELEVANCE Adolescent Medicine Trials Network for HIV/AIDS Interventions 113 enrolled a diverse sample of adolescent MSM at risk for HIV who consented to study participation. Approximately half achieved protective drug levels during the monthly visits, but adherence decreased with quarterly visits. Youth may need additional contact with clinical staff members to maintain high adherence.

IntroductionNatural killer T (NKT) cells are T lymphocytes bearing NK markers that recognize glycolipid ligands in the context of CD1d molecules. 1 NKT cells play an important role in immune regulation and protection against tumors and pathogens. 1,2 These cells mediate antitumor effects by several mechanisms, including direct effects on tumor cells, strong cytokine production, antiangiogenesis, and activation of other cells, particularly NK cells and dendritic cells. 2 Thalidomide and its analog lenalidomide have shown clinical activity in myeloma and myelodysplastic syndrome (MDS). 3,4 However, the mechanism of their observed antitumor effects remains unclear. 5 Haslett et al 6 demonstrated that thalidomide can costimulate human T cells, which led to the development of lenalidomide (LEN) as an immune-modulatory derivative. 5,7,8 Initial studies of thalidomide in myeloma described an effect on NK cells. 9 However, subsequent studies have suggested that the observed effects on NK cells were indirect. 10 We hypothesized that innate CD1d-restricted NKT cells may be a proximal cellular target of LEN. Here we show that LEN greatly enhances liganddependent activation, proliferation, and cytokine production by human NKT cells, as well as enhance NKT cells in vivo. Study design Cells and materialsPeripheral blood mononuclear cells (PBMCs) from healthy donors were isolated from buffy coats purchased from New York Blood Center, or from patients with multiple myeloma, following informed consent approved by the Rockefeller University (New York, NY), Memorial Sloan-Kettering Cancer Center (New York, NY), and St Vincent's Cancer Center (New York, NY) institutional review boards. Lenalidomide (LEN; Celgene, Warren, NJ) was dissolved in dimethyl sulfoxide (DMSO; Sigma, St Louis, MO) at 1 mM. NKT ligand ␣-galactosyl-ceramide (␣-GalCer) was kindly provided by Kirin Breweries, Tokyo, Japan. Dendritic cell-mediated NKT expansionCD14 ϩ monocytes were isolated from PBMCs using immunomagnetic bead selection with CD14 microbeads and cultured in the presence of granulocyte macrophage-colony-stimulating factor (GM-CSF) and interleukin 4 (IL-4) to generate dendritic cells (DCs), as described. 11,12 After day 5 to 6 of culture, DCs were matured by adding an inflammatory cytokine cocktail as described. 12 To stimulate NKT cells, DCs were pulsed with ␣-GalCer (100 ng/mL) and cultured with CD14 Ϫ cells at a DC-to-responder ratio of 1:10 to 1:20 with or without LEN (Celgene) at 1 M, or as otherwise indicated. 12,13 For some experiments, DEX (0.5 nM) was also added as indicated at the beginning of expansion. NKT expansion was moninored by flow cytometry based on the expression of invariant T-cell receptor (V␣24/V␤11) and/or binding to CD1d-dimer loaded with ␣-GalCer, as described. 12 Intracellular cytokine staining (ICS)The ability of NKT cells to secrete cytokines following stimulation with NKT ligand (␣-GalCer) was tested using both intracellular cytokine staining and TaqMan assays, as described. 12,14 Freshly isolated PBMCs were stimulated ...