Innate immunity stimulation via CpG oligodeoxynucleotides ameliorates Alzheimer's disease pathology in aged squirrel monkeys.

Alzheimer's disease is the most common cause of dementia and the only illness among the top 10 causes of death for which there is no disease-modifying therapy. The failure rate of clinical trials is very high, in part due to the premature translation of successful results in transgenic mouse models to patients. Extensive evidence suggests that dysregulation of innate immunity and microglia/macrophages plays a key role in Alzheimer's disease pathogenesis. Activated resident microglia and peripheral macrophages can display protective or detrimental phenotypes depending on the stimulus and environment. Toll-like receptors (TLRs) are a family of innate immune regulators known to play an important role in governing the phenotypic status of microglia. We have shown in multiple transgenic Alzheimer's disease mouse models that harnessing innate immunity via TLR9 agonist CpG oligodeoxynucleotides (ODNs) modulates age-related defects associated with immune cells and safely reduces amyloid plaques, oligomeric amyloid-ß, tau pathology, and cerebral amyloid angiopathy (CAA) while promoting cognitive benefits. In the current study we have used a non-human primate model of sporadic Alzheimer's disease pathology that develops extensive CAA-elderly squirrel monkeys. The major complications in current immunotherapeutic trials for Alzheimer's disease are amyloid-related imaging abnormalities, which are linked to the presence and extent of CAA; hence, the prominence of CAA in elderly squirrel monkeys makes them a valuable model for studying the safety of the CpG ODN-based concept of immunomodulation. We demonstrate that long-term use of Class B CpG ODN 2006 induces a favourable degree of innate immunity stimulation without producing excessive or sustained inflammation, resulting in efficient amelioration of both CAA and tau Alzheimer's disease-related pathologies in association with behavioural improvements and in the absence of microhaemorrhages in aged elderly squirrel monkeys. CpG ODN 2006 has been well established in numerous human trials for a variety of diseases. The present evidence together with our earlier, extensive preclinical research, validates the beneficial therapeutic outcomes and safety of this innovative immunomodulatory approach, increasing the likelihood of CpG ODN therapeutic efficacy in future clinical trials.

Divergent HIV-1-Directed Immune Responses Generated by Systemic and Mucosal Immunization with Replicating Single-Cycle Adenoviruses in Rhesus Macaques.

Most human immunodeficiency virus type 1 (HIV-1) infections begin at mucosal surfaces. Providing a barrier of protection at these may assist in combating the earliest events in infection. Systemic immunization by intramuscular (i.m.) injection can drive mucosal immune responses, but there are data suggesting that mucosal immunization can better educate these mucosal immune responses. To test this, rhesus macaques were immunized with replicating single-cycle adenovirus (SC-Ad) vaccines expressing clade B HIV-1 gp160 by the intranasal (i.n.) and i.m. routes to compare mucosal and systemic routes of vaccination. SC-Ad vaccines generated significant circulating antibody titers against Env after a single i.m. immunization. Switching the route of second immunization with the same SC-Ad serotype allowed a significant boost in these antibody levels. When these animals were boosted with envelope protein, envelope-binding antibodies were amplified 100-fold, but qualitatively different immune responses were generated. Animals immunized by only the i.m. route had high peripheral T follicular helper (pTfh) cell counts in blood but low Tfh cell counts in lymph nodes. Conversely, animals immunized by the i.n. route had high Tfh cell counts in lymph nodes but low pTfh cell counts in the blood. Animals immunized by only the i.m. route had lower antibody-dependent cellular cytotoxicity (ADCC) antibody activity, whereas animals immunized by the mucosal i.n. route had higher ADCC antibody activity. When these Env-immunized animals were challenged rectally with simian-human immunodeficiency virus (SHIV) strain SF162P3 (SHIVSF162P3), they all became infected. However, mucosally SC-Ad-immunized animals had lower viral loads in their gastrointestinal tracts. These data suggest that there may be benefits in educating the immune system at mucosal sites during HIV vaccination.IMPORTANCE HIV-1 infections usually start at a mucosal surface after sexual contact. Creating a barrier of protection at these mucosal sites may be a good strategy for to protect against HIV-1 infections. While HIV-1 enters at mucosa, most vaccines are not delivered here. Most are instead injected into the muscle, a site well distant and functionally different than mucosal tissues. This study tested if delivering HIV vaccines at mucosa or in the muscle makes a difference in the quality, quantity, and location of immune responses against the virus. These data suggest that there are indeed advantages to educating the immune system at mucosal sites with an HIV-1 vaccine.

Regulation of cyclin T1 during HIV replication and latency establishment in human memory CD4 T cells.

BACKGROUND: The regulatory cyclin, Cyclin T1 (CycT1), is a host factor essential for HIV-1 replication in CD4 T cells and macrophages. The importance of CycT1 and the Positive Transcription Elongation Factor b (P-TEFb) complex for HIV replication is well-established, but regulation of CycT1 expression and protein levels during HIV replication and latency establishment in CD4 T cells is less characterized. METHODS: To better define the regulation of CycT1 levels during HIV replication in CD4 T cells, multiparameter flow cytometry was utilized to study the interaction between HIV replication (intracellular p24) and CycT1 of human peripheral blood memory CD4 T cells infected with HIV in vitro. CycT1 was further examined in CD4 T cells of human lymph nodes. RESULTS: In activated (CD3+CD28 costimulation) uninfected blood memory CD4 T cells, CycT1 was most significantly upregulated in maximally activated (CD69+CD25+ and HLA.DR+CD38+) cells. In memory CD4 T cells infected with HIV in vitro, two distinct infected populations of p24+CycT1+ and p24+CycT1- cells were observed during 7 days infection, suggestive of different phases of productive HIV replication and subsequent latency establishment. Intriguingly, p24+CycT1- cells were the predominant infected population in activated CD4 T cells, raising the possibility that productively infected cells may transition into latency subsequent to CycT1 downregulation. Additionally, when comparing infected p24+ cells to bystander uninfected p24- cells (after bulk HIV infections), HIV replication significantly increased T cell activation (CD69, CD25, HLA.DR, CD38, and Ki67) without concomitantly increasing CycT1 protein levels, possibly due to hijacking of P-TEFb by the viral Tat protein. Lastly, CycT1 was constitutively expressed at higher levels in lymph node CD4 T cells compared to blood T cells, potentially enhancing latency generation in lymphoid tissues. CONCLUSIONS: CycT1 is most highly upregulated in maximally activated memory CD4 T cells as expected, but may become less associated with T cell activation during HIV replication. The progression into latency may further be predicated by substantial generation of p24+CycT1- cells during HIV replication.

A Replicating Single-Cycle Adenovirus Vaccine Against Ebola Virus.

Recent West African Ebola virus (EBOV) epidemics have led to testing different anti-EBOV vaccines, including a replication-defective adenovirus (RD-Ad) vector (ChAd3-EBOV) and an infectious, replication-competent recombinant vesicular stomatitis virus expressing the EBOV glycoprotein (rVSV-EBOV; also known as rVSV-ZEBOV). While RD-Ads elicit protection, when scaled up to human trials, the level of protection may be much lower than that of vaccines containing viruses that can replicate. Although a replication-competent Ad (RC-Ad) vaccine might generate a level of protection approximating that of rVSV, this infectious vector would also risk causing adenovirus disease. We recently described a "single-cycle" adenovirus (SC-Ad) vector that amplifies antigen genes like RC-Ad, but that avoids the risk of adenovirus infection. Here we have tested an SC-Ad6 vector expressing the glycoprotein (GP) from a 2014 EBOV strain in mice, hamsters, and rhesus macaques. We show that SC-Ad6-EBOV GP induces a high level of serum antibodies in all species and mediates significant protection against pseudo-challenge with rVSV-EBOV expressing luciferase in mice and hamsters. These data suggest that SC-Ad6-EBOV GP may be useful during future EBOV outbreaks.

Efficacy of sustained delivery of GC-1 from a Nanofluidic system in a spontaneously obese non-human primate: a case study.

With nearly 40% of U.S. adults obese, and childhood and adolescent rates rising, obesity and associated comorbidities are serious public health concerns with massive societal costs. Often, lifestyle interventions do not offer sufficient weight loss to improve health, requiring surgery and medications as adjunct management strategies. Here, we present a 4-month case study in which the sustained, low-dose, and constant administration of the thyroid receptor ß selective agonist GC-1 (sobetirome) from a novel nanochannel membrane implant was assessed in an obese, pre-diabetic rhesus macaque. Dramatic loss of white adipose tissue in the abdomen from 36 to 18% was observed via magnetic resonance imaging in conjunction with normalized serum insulin and glycemia, with no signs of cardiotoxicity shown. The non-human primate study highlights sustained low-dose delivery of GC-1 from our minimally invasive subcutaneous implant as a valuable approach to induce weight loss and manage obesity and comorbidities, including type 2 diabetes.

Infectious SIV resides in adipose tissue and induces metabolic defects in chronically infected rhesus macaques.

BACKGROUND: HIV reservoirs pose major challenges to viral eradication. The main cellular reservoirs include CD4 T cells and macrophages, whereas anatomic reservoirs are thought to be primarily lymphoid tissues. Adipose tissue represents a potentially important non-lymphoid location for HIV replication and persistence because the stromal-vascular-fraction (AT-SVF) contains activated innate and adaptive immune cells that increase in number during infections, obesity, and chronic inflammation. RESULTS: Adipose tissue from two groups of SHIV-SF162p3-infected (~4 weeks acute infection) or SIVmac251-infected (~38 weeks chronic infection) rhesus macaques (N = 8 for each group) were studied for immune cell content, viral infectiousness, and metabolic health. The AT-SVF cells from SHIV-infected monkeys contained abundant memory CD4 and CD8 T cells, with fewer NKT cells and macrophages, and no B cells. Proviral DNA (Gag and Env) was readily detectable by nested PCR in AT-SVF cells from multiple adipose depots (subcutaneous and visceral) of acutely infected monkeys, but mostly from visceral fat. More importantly, viral outgrowth assays using input CD4 T cells derived from AT-SVF cells or peripheral blood of chronically infected monkeys resulted in robust replication of infectious virus from both AT-SVF and peripheral blood CD4 T cells. Chronically infected monkeys also experienced adipocyte dysfunction (suppression of major adipogenic genes) and systemic dyslipidemia (decreased serum total cholesterol and free fatty acids, and increased triglycerides), similar to metabolic abnormalities of HIV patients. CONCLUSIONS: Adipose tissues of SIV-infected rhesus macaques become major compartments for infected immune cells, which in turn induce defects in adipose tissue metabolism.

Identification of Specific Cell Surface Markers on Immune Cells of Squirrel Monkeys (Saimiri sciureus).

Nonhuman primates are an important experimental model for the development of targeted biological therapeutics because of their immunological closeness to humans. However, there are very few antibody reagents relevant for delineating the different immune cell subsets based on nonhuman primate antigens directly or with cross-reactivity to those in humans. Here, we report specific expression of HLA-DR, PD-1, and CD123 on different circulating immune cell subsets in the peripheral blood that included T cells (CD3+), T cells subsets (CD4+ and CD8+), B cells (CD20+), natural killer (NK) cells (CD3-CD16+), and natural killer T cells (CD3+CD16+) along with different monocyte subsets in squirrel monkey (Saimiri sciureus). We established cross-reactivity of commercial mouse antihuman monoclonal antibodies (mAbs), with these various immune cell surface markers. These findings should aid further future comprehensive understanding of the immune parameters and identification of new biomarkers to significantly improve SQM as a model for biomedical studies.

Reactivity of HLADR antibody manifests expression of surface MHC II molecules on peripheral blood T lymphocytes in new world monkeys.

BACKGROUND: Major histocompatibility complex (MHC) class II molecules expressed on B cells, monocytes and dendritic cells present processed peptides to CD4+ T cells as one of the mechanisms to combat infection and inflammation. AIM: To study MHC II expression in a variety of nonhuman primate species, including New World (NWM) squirrel monkeys (Saimiri boliviensis boliviensis), owl monkeys (Aotus nancymae), common marmosets (Callithrix spp.), and Old World (OWM) rhesus (Macaca mulatta), baboons (Papio anubis). METHODS: Two clones of cross-reactive mouse anti-human HLADR monoclonal antibodies (mAb) binding were analyzed by flow cytometry to evaluate MHC II expression on NHP immune cells, including T lymphocytes in whole blood (WB) and peripheral blood mononuclear cells (PBMC). RESULTS: MHC class II antibody reactivity is seen with CD20+ B cells, CD14+ monocytes and CD3+ T lymphocytes. Specific reactivity with both clones was demonstrated in T lymphocytes: this reactivity was not inhibited by purified CD16 antibody but was completely inhibited when pre-blocked with purified unconjugated MHC II antibody. Freshly prepared PBMC also showed reactivity with T lymphocytes without any stimulation. Interestingly, peripheral blood from rhesus macaques and olive baboons (OWM) showed no such T lymphocyte associated MHCII antibody reactivity. DISCUSSION & CONCLUSION: Our results from antibody (MHC II) reactivity clearly show the potential existence of constitutively expressed (with no stimulation) MHC II molecules on T lymphocytes in new world monkeys. These results suggest that additional study is warranted to evaluate the functional and evolutionary significance of these finding and to better understand MHC II expression on T lymphocytes in new world monkeys.

Antiviral potency of long-acting islatravir subdermal implant in SHIV-infected macaques.

Treatment nonadherence is a pressing issue in people living with HIV (PLWH), as they require lifelong therapy to maintain viral suppression. Poor adherence leads to antiretroviral (ARV) resistance, transmission to others, AIDS progression, and increased morbidity and mortality. Long-acting (LA) ARV therapy is a promising strategy to combat the clinical drawback of user-dependent dosing. Islatravir (ISL) is a promising candidate for HIV treatment given its long half-life and high potency. Here we show constant ISL release from a subdermal LA nanofluidic implant achieves viral load reduction in SHIV-infected macaques. Specifically, a mean delivery dosage of 0.21 ± 0.07 mg/kg/day yielded a mean viral load reduction of -2.30 ± 0.53 log10 copies/mL at week 2, compared to baseline. The antiviral potency of the ISL delivered from the nanofluidic implant was higher than oral ISL dosed either daily or weekly. At week 3, viral resistance to ISL emerged in 2 out of 8 macaques, attributable to M184V mutation, supporting the need of combining ISL with other ARV for HIV treatment. The ISL implant produced moderate reactivity in the surrounding tissue, indicating tolerability. Overall, we present the ISL subdermal implant as a promising approach for LA ARV treatment in PLWH.

Changes in local tissue microenvironment in response to subcutaneous long-acting delivery of tenofovir alafenamide in rats and non-human primates.

Several implantable long-acting (LA) delivery systems have been developed for sustained subcutaneous administration of tenofovir alafenamide (TAF), a potent and effective nucleotide reverse transcriptase inhibitor used for HIV pre-exposure prophylaxis (PrEP). LA platforms aim to address the lack of adherence to oral regimens, which has impaired PrEP efficacy. Despite extensive investigations in this field, tissue response to sustained subcutaneous TAF delivery remains to be elucidated as contrasting preclinical results have been reported in the literature. To this end, here we studied the local foreign body response (FBR) to sustained subdermal delivery of three forms of TAF, namely TAF free base (TAFfb), TAF fumarate salt (TAFfs), and TAFfb with urocanic acid (TAF-UA). Sustained constant drug release was achieved via titanium-silicon carbide nanofluidic implants previously shown to be bioinert. The analysis was conducted in both Sprague-Dawley (SD) rats and rhesus macaques over 1.5 and 3 months, respectively. While visual observation did not reveal abnormal adverse tissue reaction at the implantation site, histopathology and Imaging Mass Cytometry (IMC) analyses exposed a local chronic inflammatory response to TAF. In rats, UA mitigated foreign body response to TAF in a concentration-dependent manner. This was not observed in macaques where TAFfb was better tolerated than TAFfs and TAF-UA. Notably, the level of FBR was tightly correlated with local TAF tissue concentration. Further, regardless of the degree of FBR, the fibrotic capsule (FC) surrounding the implants did not interfere with drug diffusion and systemic delivery, as evidenced by TAF PK results and fluorescence recovery after photobleaching (FRAP).

Long-acting refillable nanofluidic implant confers protection against SHIV infection in nonhuman primates.

The impact of pre-exposure prophylaxis (PrEP) on slowing the global HIV epidemic hinges on effective drugs and delivery platforms. Oral drug regimens are the pillar of HIV PrEP, but variable adherence has spurred development of long-acting delivery systems with the aim of increasing PrEP access, uptake, and persistence. We have developed a long-acting subcutaneous nanofluidic implant that can be refilled transcutaneously for sustained release of the HIV drug islatravir, a nucleoside reverse transcriptase translocation inhibitor that is used for HIV PrEP. In rhesus macaques, the islatravir-eluting implants achieved constant concentrations of islatravir in plasma (median 3.14 nM) and islatravir triphosphate in peripheral blood mononuclear cells (median 0.16 picomole per 106 cells) for more than 20 months. These drug concentrations were above the established PrEP protection threshold. In two unblinded, placebo-controlled studies, islatravir-eluting implants conferred 100% protection against infection with SHIVSF162P3 after repeated low-dose rectal or vaginal challenge in male or female rhesus macaques, respectively, compared to placebo control groups. The islatravir-eluting implants were well tolerated with mild local tissue inflammation and no signs of systemic toxicity over the 20-month study period. This refillable islatravir-eluting implant has potential as a long-acting drug delivery system for HIV PrEP.

TSLP production by epithelial cells exposed to immunodeficiency virus triggers DC-mediated mucosal infection of CD4+ T cells.

Mucosal dendritic cells have been implicated in the capture, storage, and transmission of HIV to CD4(+) T cells as well as in the promotion of HIV replication in activated CD4(+) T cells during the cognate T-cell and DC interaction. We report that HIV induces human genital mucosal epithelial cells to produce thymic stromal lymphopoietin (TSLP) via activation of the NFkappaB signaling pathway. The TSLP secreted by HIV exposed epithelial cells activated DC, which promoted proliferation and HIV-1 replication of co-cultured autologous CD4(+) T cells. In rhesus macaques, we observed dramatic increases in TSLP expression concurrent with an increase in viral replication in the vaginal tissues within the first 2 weeks after vaginal SIV exposure. These data suggest that HIV-mediated TSLP production by mucosal epithelial cells is a critical trigger for DC-mediated amplification of HIV-infection in activated CD4(+) T cells. The cross talk between mucosal epithelial cells and DC, mediated by HIV-induced TSLP, may be an important mechanism for the high rate of HIV infection in women through the vaginal mucosa.

Physiological and Welfare Consequences of Transport, Relocation, and Acclimatization of Chimpanzees (Pan troglodytes).

Manipulations of the environments of captive nonhuman primates often have welfare consequences to the animals, including behavioral effects, and for certain manipulations, physiological effects as well. The processes of transporting, relocating, and acclimatizing nonhuman primates across facilities represent manipulations that are likely to have welfare, behavioral, and physiological consequences to the relocated animals. Seventy-two chimpanzees were relocated from the Primate Foundation of Arizona (PFA) in Arizona to the Keeling Center (KCCMR) in Texas. Animals were transported for approximately 21 h in single cages in a USDA-approved, climate-controlled trailer. Chimpanzees were weighed, anesthetized, and blood samples were collected 1) immediately prior to departure from PFA, 2) immediately upon arrival at the KCCMR, and 3) at additional time point(s) between 3 and 12 weeks after arrival at the KCCMR. Chimpanzees were quarantined in familiar pairs or social groups for 60-90 days at the KCCMR. Blood samples were analyzed for hematological and clinical chemistry parameters and compared across time points. In addition, samples from a subset of animals were assayed for cell-mediated immune parameters. Comparisons of the data obtained just prior to transport, to the data obtained immediately upon arrival, revealed numerous statistically significant differences in hematological, clinical chemistry, and immunological parameters. Some of these were indicative of stress, and thus, changes in welfare state, although many remained within the published normal ranges for chimpanzees. Additional analyses showed that many of the clinical chemistry values collected 3 to 12 weeks after arrival at the KCCMR had returned to pre-transport values. In contrast, of the cell-mediated immune parameters that were affected by transport and relocation, few had returned to pre-transport levels 8 weeks after transport, and three of the four hematology variables analyzed had not returned to pre-transport levels 12 weeks after transport. Comparisons of body weights before and immediately after transport revealed that animals lost an average of 2.5 kg during the 21-h transport, a statistically significant reduction that some animals never regained. These results demonstrate that transport and relocation affect a variety of physiological parameters with potential welfare implications and that some of these effects last as long as 3 months. These findings have important implications for the welfare and use of recently transported nonhuman primates, especially chimpanzees, in biomedical research. In order to allow animals to adapt to their new surroundings and to prevent unwanted confounds from influencing experiments, sufficient time must be provided after transport for chimpanzees to acclimatize.

Extending drug release from implants via transcutaneous refilling with solid therapeutics.

Long-acting (LA) implantable drug delivery systems (IDDS) offer an effective approach for the management or prevention of chronic conditions by sustained parenteral therapeutic administration. LA IDDS can and improve adherence to treatment regimens by minimizing dosing frequency. However, their clinical deployment is challenged by factors such as poor drug loading capacity, which limit their lifespan and require repeated surgical replacement for continued therapy. To address these challenges, and by leveraging previous work on nanofluidic systems, a reservoir-based IDDS that enables transcutaneous refilling of solid drug formulations through minimally invasive needle injection is presented. With thousand-fold higher drug loading efficiency, the implant affords minimal volume and aspect ratio suitable for discrete subcutaneous deployment. Key parameters for clinical acceptability, namely implant safety, access port robustness, and refilling method were systematically evaluated. The implant and refilling procedure are studied in rats and nonhuman primates with therapeutics used clinically for type 2 diabetes and human immunodeficiency virus (HIV) pre-exposure prophylaxis (PrEP). The ability to extend drug release and maintain equivalent pharmacokinetics (PK) profiles pre- and post-drug refilling is demonstrated. This technology presents a clinically viable LA approach to prolong drug release for lifelong prevention or management of chronic conditions.

Implantable niche with local immunosuppression for islet allotransplantation achieves type 1 diabetes reversal in rats.

Pancreatic islet transplantation efficacy for type 1 diabetes (T1D) management is limited by hypoxia-related graft attrition and need for systemic immunosuppression. To overcome these challenges, we developed the Neovascularized Implantable Cell Homing and Encapsulation (NICHE) device, which integrates direct vascularization for facile mass transfer and localized immunosuppressant delivery for islet rejection prophylaxis. Here, we investigated NICHE efficacy for allogeneic islet transplantation and long-term diabetes reversal in an immunocompetent, male rat model. We demonstrated that allogeneic islets transplanted within pre-vascularized NICHE were engrafted, revascularized, and functional, reverting diabetes in rats for over 150 days. Notably, we confirmed that localized immunosuppression prevented islet rejection without inducing toxicity or systemic immunosuppression. Moreover, for translatability efforts, we showed NICHE biocompatibility and feasibility of deployment as well as short-term allogeneic islet engraftment in an MHC-mismatched nonhuman primate model. In sum, the NICHE holds promise as a viable approach for safe and effective islet transplantation and long-term T1D management.

Effects of relocation on immunological and physiological measures in female squirrel monkeys (Saimiri boliviensis boliviensis).

In the present study, we have quantified the effects of transport, relocation and acclimate/adapt to their new surroundings on female squirrel monkey. These responses are measured in blood samples obtained from squirrel monkeys, at different time points relative to their relocation from their old home to their new home. A group of squirrel monkeys we transported, by truck, for approximately 10 hours. Peripheral blood mononuclear cells (PBMCs) were assayed in order to evaluate the phenotype of lymphocyte subsets by flow, mitogen-specific immune responses of PBMCs in vitro, and levels of cytokines at various time points including immediately before transport, immediately upon arrival, and after approximately 150 days of acclimation. We observed significant changes in T cells and subsets, NK and B cells (CD4+, CD8+, CD4+/CD8+, CD16+, and CD20+). Mitogen specific (e.g. PHA, PWM and LPS) proliferation responses, IFN-γ by ELISPOT assay, and cytokines (IL-2, IL-4 and VEGF) significant changes were observed. Changes seen in the serum chemistry measurements mostly complement those seen in the hematology data. The specific goal was to empirically assess the effects of relocation stress in squirrel monkeys in terms of changes in the numbers and functions of various leukocyte subsets in the blood and the amount of time required for acclimating to their new environment. Such data will help to determine when newly arrived animals become available for use in research studies.

Short-Term Relocation Stress-Induced Hematological and Immunological Changes in Saimiri boliviensis boliviensis.

Nonhuman primates are frequently transported to a new location or temporarily relocated within their colony. Both transportation and relocation expose animals to new environments, causing them to undergo a stress response (before adapting). In our NHP colony, the mentioned situations are not infrequent for many reasons, including maintenance. The objective of this study was to determine whether abrupt changes consisting of relocation, housing, separation, and grouping could influence hematological and immunological parameters and thereby functional activity. The current study used squirrel monkeys as a model to investigate the stress-inducing effects of relocation within a facility, while animals acclimated to new situations (physical, housing). A detailed blood analysis revealed significant changes in lymphocytes, triglycerides, total protein, creatinine, and ALT. Flow cytometric analysis of peripheral blood showed reduction in CD3+, CD4+, and CD8+ T cells and monocytes, while B cells and natural killer (NK) cells changed with relocation. Simultaneously, changes in functional activity of immune cells altered proliferative responses and as shown by ELISpot (IFN γ). Though the parameters studied are not affected as severely as those in animals transported by road or air, stress responses induced by intrafacility relocation are significant and worth consideration. Our findings indicate that squirrel monkeys mimic the features seen in humans exposed to social stressors and may serve an important model for understanding the mechanisms of stress-induced immune dysfunction in humans.

Preventive efficacy of a tenofovir alafenamide fumarate nanofluidic implant in SHIV-challenged nonhuman primates.

Pre-exposure prophylaxis (PrEP) using antiretroviral oral drugs is effective at preventing HIV transmission when individuals adhere to the dosing regimen. Tenofovir alafenamide (TAF) is a potent antiretroviral drug, with numerous long-acting (LA) delivery systems under development to improve PrEP adherence. However, none has undergone preventive efficacy assessment. Here we show that LA TAF using a novel subcutaneous nanofluidic implant (nTAF) confers partial protection from HIV transmission. We demonstrate that sustained subcutaneous delivery through nTAF in rhesus macaques maintained tenofovir diphosphate concentration at a median of 390.00 fmol/106 peripheral blood mononuclear cells, 9 times above clinically protective levels. In a non-blinded, placebo-controlled rhesus macaque study with repeated low-dose rectal SHIVSF162P3 challenge, the nTAF cohort had a 62.50% reduction (95% CI: 1.72% to 85.69%; p=0.068) in risk of infection per exposure compared to the control. Our finding mirrors that of tenofovir disoproxil fumarate (TDF) monotherapy, where 60.00% protective efficacy was observed in macaques, and clinically, 67.00% reduction in risk with 86.00% preventive efficacy in individuals with detectable drug in the plasma. Overall, our nanofluidic technology shows potential as a subcutaneous delivery platform for long-term PrEP and provides insights for clinical implementation of LA TAF for HIV prevention.

Prime-boost vaccination using chemokine-fused gp120 DNA and HIV envelope peptides activates both immediate and long-term memory cellular responses in rhesus macaques.

HIV vaccine candidates with improved immunogenicity and induction of mucosal T-cell immunity are needed. A prime-boost strategy using a novel HIV glycoprotein 120 DNA vaccine was employed to immunize rhesus macaques. The DNA vaccine encoded a chimeric gp120 protein in fusion with monocyte chemoattractant protein-3, which was hypothesized to improve the ability of antigen-presenting cells to capture viral antigen through chemokine receptor-mediated endocytosis. DNA vaccination induced virus-reactive T cells in peripheral blood, detectable by T cell proliferation, INFgamma ELISPOT and sustained IL-6 production, without humoral responses. With a peptide-cocktail vaccine containing a set of conserved polypeptides of HIV-1 envelope protein, given by nasogastric administration, primed T-cell immunity was significantly boosted. Surprisingly, long-term and peptide-specific mucosal memory T-cell immunity was detected in both vaccinated macaques after one year. Therefore, data from this investigation offer proof-of-principle for potential effectiveness of the prime-boost strategy with a chemokine-fused gp120 DNA and warrant further testing in the nonhuman primate models for developing as a potential HIV vaccine candidate in humans.

Corrigendum to "Prime-Boost Vaccination Using Chemokine-Fused gp120 DNA and HIV Envelope Peptides Activates Both Immediate and Long-Term Memory Cellular Responses in Rhesus Macaques".

[This corrects the article DOI: 10.1155/2010/860160.].