Interleukin-10 contributes to reservoir establishment and persistence in SIV-infected macaques treated with antiretroviral therapy.

Interleukin-10 (IL-10) is an immunosuppressive cytokine that signals through STAT3 to regulate T follicular helper (Tfh) cell differentiation and germinal center formation. In SIV-infected macaques, levels of IL-10 in plasma and lymph nodes (LNs) were induced by infection and not normalized with antiretroviral therapy (ART). During chronic infection, plasma IL-10 and transcriptomic signatures of IL-10 signaling were correlated with the cell-associated SIV-DNA content within LN CD4+ memory subsets, including Tfh cells, and predicted the frequency of CD4+ Tfh cells and their cell-associated SIV-DNA content during ART, respectively. In ART-treated rhesus macaques, cells harboring SIV-DNA by DNAscope were preferentially found in the LN B cell follicle in proximity to IL-10. Finally, we demonstrated that the in vivo neutralization of soluble IL-10 in ART-treated, SIV-infected macaques reduced B cell follicle maintenance and, by extension, LN memory CD4+ T cells, including Tfh cells and those expressing PD-1 and CTLA-4. Thus, these data support a role for IL-10 in maintaining a pool of target cells in lymphoid tissue that serve as a niche for viral persistence. Targeting IL-10 signaling to impair CD4+ T cell survival and improve antiviral immune responses may represent a novel approach to limit viral persistence in ART-suppressed people living with HIV.

Rapid Absorption of Dry-Powder Intranasal Oxytocin.

PURPOSE: To probe the suitability of a dry-powder oxytocin formulation containing a carrier (µco™; SNBL, Ltd.) for intranasal (IN) administration to treat post-partum hemorrhage in the developing world. Specifically, to investigate (1) whether IN administration can achieve rapid systemic absorption in cynomolgus monkeys, and (2) whether the formulation exhibits sufficient physical and chemical stability. This study was conducted to support Merck for Mothers, Merck's 10-year global initiative to end preventable maternal deaths. METHODS: A partial-crossover pharmacokinetic (PK) study in cynomolgus monkeys (n = 6) was utilized to compare in vivo absorption of dry-powder IN oxytocin at three dose levels against an IM injection of an aqueous oxytocin formulation. Particle size distribution, delivered dose and chemical assay were monitored over a 12 month stability study. RESULTS: IN administration of oxytocin resulted in short (5 min) Tmax and good dose linearity in AUC and Cmax over the dose range tested (10-80 IU per animal). The relative bioavailability (BA) of IN oxytocin to IM injection was approximately 12%. The 80 IU formulation exhibited good physical stability and consistent dosing. After 12 months at 30°C/65%RH, pouched samples retained 86.0% of their original assay value. CONCLUSIONS: The PK and stability data suggests that IN administration of oxytocin formulated in the µco™ carrier may represent a viable option for rapid systemic absorption in humans and a product compatible with resource-scarce regions.

Plasma Levels of Risk-Variant APOL1 Do Not Associate with Renal Disease in a Population-Based Cohort.

Two common missense variants in APOL1 (G1 and G2) have been definitively linked to CKD in black Americans. However, not all individuals with the renal-risk genotype develop CKD, and little is known about how APOL1 variants drive disease. Given the association of APOL1 with HDL particles, which are cleared by the kidney, differences in the level or quality of mutant APOL1­HDL particles could be causal for disease and might serve as a useful risk stratification marker. We measured plasma levels of G0 (low risk), G1, and G2 APOL1 in 3450 individuals in the Dallas Heart Study using a liquid chromatography-MS method that enabled quantitation of the different variants. Additionally, we characterized native APOL1­HDL from donors with no or two APOL1 risk alleles by size-exclusion chromatography and analysis of immunopurified APOL1­HDL particles. Finally, we identified genetic loci associated with plasma APOL1 levels and tested for APOL1-dependent association with renal function. Although we replicated the previous association between APOL1 variant status and renal function in nondiabetic individuals, levels of circulating APOL1 did not associate with microalbuminuria or GFR. Furthermore, the size or known components of APOL1­HDL did not consistently differ in subjects with the renal-risk genotype. Genetic association studies implicated variants in loci harboring haptoglobin-related protein (HPR), APOL1, and ubiquitin D (UBD) in the regulation of plasma APOL1 levels, but these variants did not associate with renal function. Collectively, these data demonstrate that the risk of renal disease associated with APOL1 is probably not related to circulating levels of the mutant protein.

Enhancement of the anti-tumor efficacy of a GM-CSF-secreting tumor cell immunotherapy in preclinical models by cytosine arabinoside.

OBJECTIVE: Acute myeloid leukemia (AML) is a highly malignant neoplasm responsible for nearly 10,000 cancer-related deaths annually in the United States. Treatment options for elderly patients with AML remain limited. Standard regimens using cytarabine (cytosine arabinoside [AraC]), a nucleotide analogue, result in significant toxicity with poor overall response. Combination of a cytotoxic chemotherapy and tumor-specific immunotherapy has the potential to improve overall efficacy by inducing an anti-tumor immune response against minimal residual disease. The studies reported here were performed to evaluate the therapeutic benefit of combining a granulocyte macrophage colony-stimulating factor (GM-CSF)-secreting tumor cell immunotherapy with AraC treatment. MATERIALS AND METHODS: C57Bl/6 mice were challenged with C1498-luc cells intravenously and evaluated by in vivo imaging throughout the study to monitor the systemic progression of the tumor. Individual animals were euthanized when in vivo total photon counts exceeded 5 x 10(8) and/or when they were in poor clinical condition. Cytotoxicity assay was performed to evaluate effector function and flow cytometry was used for phenotyping of splenocytes from experimental animals. RESULTS: Administration of GM-CSF-secreting tumor cell immunotherapy during AraC -induced cytopenia enhanced the anti-tumor efficacy of the immunotherapy, resulting in prolonged survival. AraC treatment did not negatively impact antigen-specific T-cell activation elicited by the immunotherapy and surviving animals treated with the combination demonstrated strong tumor-specific memory responses. CONCLUSION: GM-CSF-secreting tumor cell immunotherapy in combination with AraC prolongs survival of tumor-bearing mice, with a median survival time of 61 days observed in mice treated with AraC alone and 90% of mice treated with the combination therapy still alive by day 150.