MVA-based vaccines are protective against lethal eastern equine encephalitis virus aerosol challenge in cynomolgus macaques.

MVA-based monovalent eastern equine encephalitis virus (MVA-BN-EEEV) and multivalent western, eastern, and Venezuelan equine encephalitis virus (MVA-BN-WEV) vaccines were evaluated in the cynomolgus macaque aerosol model of EEEV infection. Macaques vaccinated with two doses of 5 × 108 infectious units of the MVA-BN-EEEV or MVA-BN-WEV vaccine by the intramuscular route rapidly developed robust levels of neutralizing antibodies to EEEV that persisted at high levels until challenge at day 84 via small particle aerosol delivery with a target inhaled dose of 107 PFU of EEEV FL93-939. Robust protection was observed, with 7/8 animals receiving MVA-BN-EEEV and 100% (8/8) animals receiving MVA-BN-WEV surviving while only 2/8 mock vaccinated controls survived lethal challenge. Complete protection from viremia was afforded by both vaccines, with near complete protection from vRNA loads in tissues and any pathologic evidence of central nervous system damage. Overall, the results indicate both vaccines are effective in eliciting an immune response that is consistent with protection from aerosolized EEEV-induced disease.

Lymphoid tissues contribute to plasma viral clonotypes early after antiretroviral therapy interruption in SIV-infected rhesus macaques.

The rebound-competent viral reservoir, composed of a virus that is able to persist during antiretroviral therapy (ART) and mediate reactivation of systemic viral replication and rebound viremia after ART interruption (ATI), remains the biggest obstacle to treating HIV infection. A better understanding of the cellular and tissue origins and the dynamics of viral populations that initiate rebound upon ATI could help develop therapeutic strategies for reducing the rebound-competent viral reservoir. In this study, barcoded simian immunodeficiency virus (SIV), SIVmac239M, was used to infect rhesus macaques to enable monitoring of viral barcode clonotypes contributing to virus detectable in plasma after ATI. Blood and tissues from secondary lymphoid organs (spleen, mesenteric lymph nodes, and inguinal lymph nodes) and from the colon, ileum, lung, liver, and brain were analyzed using viral barcode sequencing, intact proviral DNA assay, single-cell RNA sequencing, and combined CODEX and RNAscope in situ hybridization. Four of seven animals had viral barcodes detectable by deep sequencing of plasma at necropsy, although plasma viral RNA remained below 22 copies per milliliter. Among the tissues studied, mesenteric lymph nodes, inguinal lymph nodes, and spleen contained viral barcodes detected in plasma. CD4+ T cells were the main cell type harboring viral RNA after ATI. Furthermore, T cell zones in lymphoid tissues showed higher viral RNA abundance than B cell zones for most animals. These findings are consistent with lymphoid tissues contributing to the virus present in plasma early after ATI.

A combined adjuvant approach primes robust germinal center responses and humoral immunity in non-human primates.

Adjuvants and antigen delivery kinetics can profoundly influence B cell responses and should be critically considered in rational vaccine design, particularly for difficult neutralizing antibody targets such as human immunodeficiency virus (HIV). Antigen kinetics can change depending on the delivery method. To promote extended immunogen bioavailability and to present antigen in a multivalent form, native-HIV Env trimers are modified with short phosphoserine peptide linkers that promote tight binding to aluminum hydroxide (pSer:alum). Here we explore the use of a combined adjuvant approach that incorporates pSer:alum-mediated antigen delivery with potent adjuvants (SMNP, 3M-052) in an extensive head-to-head comparison study with conventional alum to assess germinal center (GC) and humoral immune responses. Priming with pSer:alum plus SMNP induces additive effects that enhance the magnitude and persistence of GCs, which correlate with better GC-TFH cell help. Autologous HIV-neutralizing antibody titers are improved in SMNP-immunized animals after two immunizations. Over 9 months after priming immunization of pSer:alum with either SMNP or 3M-052, robust Env-specific bone marrow plasma cells (BM BPC) are observed. Furthermore, pSer-modification of Env trimer reduce targeting towards immunodominant non-neutralizing epitopes. The study shows that a combined adjuvant approach can augment humoral immunity by modulating immunodominance and shows promise for clinical translation.

The Impact of SIV-Induced Immunodeficiency on Clinical Manifestation, Immune Response, and Viral Dynamics in SARS-CoV-2 Coinfection.

Persistent and uncontrolled SARS-CoV-2 replication in immunocompromised individuals has been observed and may be a contributing source of novel viral variants that continue to drive the pandemic. Importantly, the effects of immunodeficiency associated with chronic HIV infection on COVID-19 disease and viral persistence have not been directly addressed in a controlled setting. Here we conducted a pilot study wherein two pigtail macaques (PTM) chronically infected with SIVmac239 were exposed to SARS-CoV-2 and monitored for six weeks for clinical disease, viral replication, and viral evolution, and compared to our previously published cohort of SIV-naïve PTM infected with SARS-CoV-2. At the time of SARS-CoV-2 infection, one PTM had minimal to no detectable CD4+ T cells in gut, blood, or bronchoalveolar lavage (BAL), while the other PTM harbored a small population of CD4+ T cells in all compartments. Clinical signs were not observed in either PTM; however, the more immunocompromised PTM exhibited a progressive increase in pulmonary infiltrating monocytes throughout SARS-CoV-2 infection. Single-cell RNA sequencing (scRNAseq) of the infiltrating monocytes revealed a less activated/inert phenotype. Neither SIV-infected PTM mounted detectable anti-SARS-CoV-2 T cell responses in blood or BAL, nor anti-SARS-CoV-2 neutralizing antibodies. Interestingly, despite the diminished cellular and humoral immune responses, SARS-CoV-2 viral kinetics and evolution were indistinguishable from SIV-naïve PTM in all sampled mucosal sites (nasal, oral, and rectal), with clearance of virus by 3-4 weeks post infection. SIV-induced immunodeficiency significantly impacted immune responses to SARS-CoV-2 but did not alter disease progression, viral kinetics or evolution in the PTM model. SIV-induced immunodeficiency alone may not be sufficient to drive the emergence of novel viral variants.

Comparison of fine-needle aspiration techniques.

BACKGROUND: Fine-needle aspiration (FNA) has been reported since 1912 beginning with the use of trocars and other specialized instruments that were impractical. Since then, FNA has proven to be a successful alternative technique to excisional biopsy for some assays despite a few limitations. METHODS: In this study, we compared four different techniques for FNA in rhesus macaques by evaluating total live cells recovered and cell viability using a standard 6 mL syringe and 1.5-inch 22-gauge needle. RESULTS: Technique B which was the only technique in which the needle was removed from the syringe after collection of the sample to allow forced air through the needle to expel the contents into media followed by flushing of the syringe and needle resulted in the highest total cell count and second highest cell viability in recovered cells. CONCLUSION: Based on our results, Technique B appears to be the superior method.

Lymphoid tissues contribute to viral clonotypes present in plasma at early post-ATI in SIV-infected rhesus macaques.

The rebound-competent viral reservoir (RCVR), comprised of virus that is able to persist during antiretroviral therapy (ART) and mediate reactivation of systemic viral replication and rebound viremia after antiretroviral therapy interruption (ATI), remains the biggest obstacle to the eradication of HIV infection. A better understanding of the cellular and tissue origins and the dynamics of viral populations that initiate rebound upon ATI could help develop targeted therapeutic strategies for reducing the RCVR. In this study, barcoded SIVmac239M was used to infect rhesus macaques to enable monitoring of viral barcode clonotypes contributing to virus detectable in plasma after ATI. Blood, lymphoid tissues (LTs, spleen, mesenteric and inguinal lymph nodes), and non-lymphoid tissues (NLTs, colon, ileum, lung, liver, and brain) were analyzed using viral barcode sequencing, intact proviral DNA assay, single-cell RNA sequencing, and combined CODEX/RNAscope/ in situ hybridization. Four of seven animals had viral barcodes detectable by deep sequencing of plasma at necropsy although plasma viral RNA remained < 22 copies/mL. Among the tissues studied, mesenteric and inguinal lymph nodes, and spleen contained viral barcodes detected in plasma, and trended to have higher cell-associated viral loads, higher intact provirus levels, and greater diversity of viral barcodes. CD4+ T cells were the main cell type harboring viral RNA (vRNA) after ATI. Further, T cell zones in LTs showed higher vRNA levels than B cell zones for most animals. These findings are consistent with LTs contributing to virus present in plasma early after ATI. One Sentence Summary: The reemerging of SIV clonotypes at early post-ATI are likely from the secondary lymphoid tissues.

A randomized controlled trial of varenicline and brief behavioral counseling delivered by lay counselors for adolescent vaping cessation: Study protocol.

Background: Approximately one-fifth of high-school seniors and college students currently vape nicotine. Adolescents express a desire to quit vaping, and case reports have shown promise for e-cigarette tapering with dual behavioral and pharmacologic therapies. However, there are no published clinical trials to date that test these intervention approaches for adolescent nicotine vaping cessation. In this three-arm randomized, placebo-controlled, parallel-group study, we aim to assess the efficacy of varenicline in combination with brief behavioral counseling and texting support on vaping cessation in adolescents dependent on vaped nicotine. Methods: The study will enroll 300 individuals between the ages of 16-25 with daily or near-daily nicotine vaping who reside in the Greater Boston area. Participants will be randomly assigned in a 1:1:1 ratio in blocks of six to one of the three arms: (1) a 12-week course of varenicline titrated to 1 mg bid, brief behavioral counseling delivered by a lay counselor, and an introduction to This is Quitting (TIQ) texting support created by the Truth Initiative; (2) a 12-week course of placebo, brief behavioral counseling, and TIQ; and (3) 12 weeks of enhanced usual care, consisting of advice to quit and an introduction to TIQ. The primary outcome will be biochemically verified continuous vaping abstinence at the end of the treatment (week 12). Secondary outcomes include continuous abstinence at follow-up (week 24), 7-day point prevalence abstinence at weeks 12 and 24, safety and tolerability of varenicline in an adolescent vaping population, as well as change in mood and nicotine withdrawal symptoms across the intervention period. Exploratory outcomes include change in comorbid substance use behaviors and nicotine dependence. Analysis will be intent-to-treat, with multiple imputation sensitivity analyses for participants with missing or incomplete outcome data. Discussion: This is the first study to evaluate varenicline in combination with a novel, brief, lay counselor delivered vaping cessation program for adolescents who vape nicotine. Results will inform clinicians on the effectiveness and acceptability of this promising, but not yet tested intervention.Clinical trial registration: ClinicalTrials.gov, identifier NCT05367492.

Duration of antiretroviral therapy impacts the degree of residual SIV infection in the gut in long-term non-progressing Chinese rhesus macaques.

The gut is a major reservoir in HIV-infected individuals on antiretroviral therapy (ART) and in long-term non-progressors (LTNPs). Whether ART reduces gut infection and reservoirs in LTNPs is unknown. Herein, SIV-infected LTNP Rhesus macaques were treated with short- or long-term ART, and SIV envelope gp120 sequences obtained from single genome amplification were analyzed before and after ART in peripheral blood and the intestine. Although ART does not eliminate SIV in these LTNPs, a longer ART period dramatically reduces SIV infection in the gut. This study highlights the importance of long-term ART in LTNPs to minimize gut infection and prolong remission.

Long-primed germinal centres with enduring affinity maturation and clonal migration.

Germinal centres are the engines of antibody evolution. Here, using human immunodeficiency virus (HIV) Env protein immunogen priming in rhesus monkeys followed by a long period without further immunization, we demonstrate germinal centre B (BGC) cells that last for at least 6 months. A 186-fold increase in BGC cells was present by week 10 compared with conventional immunization. Single-cell transcriptional profiling showed that both light- and dark-zone germinal centre states were sustained. Antibody somatic hypermutation of BGC cells continued to accumulate throughout the 29-week priming period, with evidence of selective pressure. Env-binding BGC cells were still 49-fold above baseline at 29 weeks, which suggests that they could remain active for even longer periods of time. High titres of HIV-neutralizing antibodies were generated after a single booster immunization. Fully glycosylated HIV trimer protein is a complex antigen, posing considerable immunodominance challenges for B cells1,2. Memory B cells generated under these long priming conditions had higher levels of antibody somatic hypermutation, and both memory B cells and antibodies were more likely to recognize non-immunodominant epitopes. Numerous BGC cell lineage phylogenies spanning more than the 6-month germinal centre period were identified, demonstrating continuous germinal centre activity and selection for at least 191 days with no further antigen exposure. A long-prime, slow-delivery (12 days) immunization approach holds promise for difficult vaccine targets and suggests that patience can have great value for tuning of germinal centres to maximize antibody responses.

Durable protection against the SARS-CoV-2 Omicron variant is induced by an adjuvanted subunit vaccine.

Despite the remarkable efficacy of COVID-19 vaccines, waning immunity and the emergence of SARS-CoV-2 variants such as Omicron represents a global health challenge. Here, we present data from a study in nonhuman primates demonstrating durable protection against the Omicron BA.1 variant induced by a subunit SARS-CoV-2 vaccine comprising the receptor binding domain of the ancestral strain (RBD-Wu) on the I53-50 nanoparticle adjuvanted with AS03, which was recently authorized for use in individuals 18 years or older. Vaccination induced neutralizing antibody (nAb) titers that were maintained at high concentrations for at least 1 year after two doses, with a pseudovirus nAb geometric mean titer (GMT) of 1978 and a live virus nAb GMT of 1331 against the ancestral strain but not against the Omicron BA.1 variant. However, a booster dose at 6 to 12 months with RBD-Wu or RBD-ß (RBD from the Beta variant) displayed on I53-50 elicited high neutralizing titers against the ancestral and Omicron variants. In addition, we observed persistent neutralization titers against a panel of sarbecoviruses, including SARS-CoV. Furthermore, there were substantial and persistent memory T and B cell responses reactive to Beta and Omicron variants. Vaccination resulted in protection against Omicron infection in the lung and suppression of viral burden in the nares at 6 weeks after the final booster immunization. Even at 6 months after vaccination, we observed protection in the lung and rapid control of virus in the nares. These results highlight the durable and cross-protective immunity elicited by the AS03-adjuvanted RBD-I53-50 nanoparticle vaccine.

Neuroinflammatory Profiling in SIV-Infected Chinese-Origin Rhesus Macaques on Antiretroviral Therapy.

The central nervous system (CNS) HIV reservoir is an obstacle to achieving an HIV cure. The basal ganglia harbor a higher frequency of SIV than other brain regions in the SIV-infected rhesus macaques of Chinese-origin (chRMs) even on suppressive combination antiretroviral therapy (ART). Since residual HIV/SIV reservoir is associated with inflammation, we characterized the neuroinflammation by gene expression and systemic levels of inflammatory molecules in healthy controls and SIV-infected chRMs with or without ART. CCL2, IL-6, and IFN-γ were significantly reduced in the cerebrospinal fluid (CSF) of animals receiving ART. Moreover, there was a correlation between levels of CCL2 in plasma and CSF, suggesting the potential use of plasma CCL2 as a neuroinflammation biomarker. With higher SIV frequency, the basal ganglia of untreated SIV-infected chRMs showed an upregulation of secreted phosphoprotein 1 (SPP1), which could be an indicator of ongoing neuroinflammation. While ART greatly reduced neuroinflammation in general, proinflammatory genes, such as IL-9, were still significantly upregulated. These results expand our understanding of neuroinflammation and signaling in SIV-infected chRMs on ART, an excellent model to study HIV/SIV persistence in the CNS.

Chronic binge alcohol and ovariectomy-mediated impaired insulin responsiveness in SIV-infected female rhesus macaques.

Aging people living with HIV (PLWH), especially postmenopausal women may be at higher risk of comorbidities associated with HIV, antiretroviral therapy (ART), hypogonadism, and at-risk alcohol use. Our studies in simian immunodeficiency virus (SIV)-infected male macaques demonstrated that chronic binge alcohol (CBA) reduced acute insulin response to glucose (AIRG), and at-risk alcohol use decreased HOMA-ß in PLWH. The objective of this study was to examine the impact of ovariectomy (OVX) on glucose-insulin dynamics and integrity of pancreatic endocrine function in CBA/SIV-infected female macaques. Female macaques were administered CBA (12-15 g/kg/wk) or isovolumetric water (VEH) intragastrically. Three months after initiation of CBA/VEH administration, all macaques were infected with SIVmac251, and initiated on antiretroviral therapy (ART) 2.5 mo postinfection. After 1 mo of ART, macaques were randomized to OVX or sham surgeries (n = 7 or 8/group), and euthanized 8 mo post-OVX (study endpoint). Frequently sampled intravenous glucose tolerance tests (FSIVGTT) were performed at selected time points. Pancreatic gene expression and islet morphology were determined at study endpoint. There was a main effect of CBA to decrease AIRG at Pre-SIV and study endpoint. There were no statistically significant OVX effects on AIRG (P = 0.06). CBA and OVX decreased the expression of pancreatic markers of insulin docking and release. OVX increased endoplasmic stress markers. CBA but not OVX impaired glucose-insulin expression dynamics in SIV-infected female macaques. Both CBA and OVX altered integrity of pancreatic endocrine function. These findings suggest increased vulnerability of PLWH to overt metabolic dysfunction that may be exacerbated by alcohol use and ovarian hormone loss.

Adjuvanting a subunit COVID-19 vaccine to induce protective immunity.

The development of a portfolio of COVID-19 vaccines to vaccinate the global population remains an urgent public health imperative1. Here we demonstrate the capacity of a subunit vaccine, comprising the SARS-CoV-2 spike protein receptor-binding domain displayed on an I53-50 protein nanoparticle scaffold (hereafter designated RBD-NP), to stimulate robust and durable neutralizing-antibody responses and protection against SARS-CoV-2 in rhesus macaques. We evaluated five adjuvants including Essai O/W 1849101, a squalene-in-water emulsion; AS03, an α-tocopherol-containing oil-in-water emulsion; AS37, a Toll-like receptor 7 (TLR7) agonist adsorbed to alum; CpG1018-alum, a TLR9 agonist formulated in alum; and alum. RBD-NP immunization with AS03, CpG1018-alum, AS37 or alum induced substantial neutralizing-antibody and CD4 T cell responses, and conferred protection against SARS-CoV-2 infection in the pharynges, nares and bronchoalveolar lavage. The neutralizing-antibody response to live virus was maintained up to 180 days after vaccination with RBD-NP in AS03 (RBD-NP-AS03), and correlated with protection from infection. RBD-NP immunization cross-neutralized the B.1.1.7 SARS-CoV-2 variant efficiently but showed a reduced response against the B.1.351 variant. RBD-NP-AS03 produced a 4.5-fold reduction in neutralization of B.1.351 whereas the group immunized with RBD-NP-AS37 produced a 16-fold reduction in neutralization of B.1.351, suggesting differences in the breadth of the neutralizing-antibody response induced by these adjuvants. Furthermore, RBD-NP-AS03 was as immunogenic as a prefusion-stabilized spike immunogen (HexaPro) with AS03 adjuvant. These data highlight the efficacy of the adjuvanted RBD-NP vaccine in promoting protective immunity against SARS-CoV-2 and have led to phase I/II clinical trials of this vaccine (NCT04742738 and NCT04750343).

Adjuvanting a subunit SARS-CoV-2 nanoparticle vaccine to induce protective immunity in non-human primates.

The development of a portfolio of SARS-CoV-2 vaccines to vaccinate the global population remains an urgent public health imperative. Here, we demonstrate the capacity of a subunit vaccine under clinical development, comprising the SARS-CoV-2 Spike protein receptor-binding domain displayed on a two-component protein nanoparticle (RBD-NP), to stimulate robust and durable neutralizing antibody (nAb) responses and protection against SARS-CoV-2 in non-human primates. We evaluated five different adjuvants combined with RBD-NP including Essai O/W 1849101, a squalene-in-water emulsion; AS03, an alpha-tocopherol-containing squalene-based oil-in-water emulsion used in pandemic influenza vaccines; AS37, a TLR-7 agonist adsorbed to Alum; CpG 1018-Alum (CpG-Alum), a TLR-9 agonist formulated in Alum; or Alum, the most widely used adjuvant. All five adjuvants induced substantial nAb and CD4 T cell responses after two consecutive immunizations. Durable nAb responses were evaluated for RBD-NP/AS03 immunization and the live-virus nAb response was durably maintained up to 154 days post-vaccination. AS03, CpG-Alum, AS37 and Alum groups conferred significant protection against SARS-CoV-2 infection in the pharynges, nares and in the bronchoalveolar lavage. The nAb titers were highly correlated with protection against infection. Furthermore, RBD-NP when used in conjunction with AS03 was as potent as the prefusion stabilized Spike immunogen, HexaPro. Taken together, these data highlight the efficacy of the RBD-NP formulated with clinically relevant adjuvants in promoting robust immunity against SARS-CoV-2 in non-human primates.

Alterations of the gut bacterial microbiota in rhesus macaques with SIV infection and on short- or long-term antiretroviral therapy.

Gut dysbiosis and microbial translocation are associated with chronic systemic immune activation and inflammation in HIV-1 infection. However, the extent of restoration of gut microbiota in HIV-1 patients with short or long-term antiretroviral therapy (ART) is unclear. To understand the impact of ART on the gut microbiota, we used the rhesus macaque model of SIV infection to characterize and compare the gut microbial community upon SIV infection and during ART. We observed altered taxonomic compositions of gut microbiota communities upon SIV infection and at different time points of ART. SIV-infected animals showed decreased diversity of gut microbiome composition, while the ART group appeared to recover towards the diversity level of the healthy control. Animals undergoing ART for various lengths of time were observed to have differential gut bacterial abundance across different time points. In addition, increased blood lipopolysaccharide (LPS) levels during SIV infection were reduced to near normal upon ART, indicating that microbial translocation and immune activation can be improved during therapy. In conclusion, while short ART may be related to transient increase of certain pathogenic bacterial microbiome, ART may promote microbiome diversity compromised by SIV infection, improve the gut microbiota towards the healthy compositions and alleviate immune activation.

Co-immunization of DNA and Protein in the Same Anatomical Sites Induces Superior Protective Immune Responses against SHIV Challenge.

We compare immunogenicity and protective efficacy of an HIV vaccine comprised of env and gag DNA and Env (Envelope) proteins by co-administration of the vaccine components in the same muscles or by separate administration of DNA + protein in contralateral sites in female rhesus macaques. The 6-valent vaccine includes gp145 Env DNAs, representing six sequentially isolated Envs from the HIV-infected individual CH505, and matching GLA-SE-adjuvanted gp120 Env proteins. Interestingly, only macaques in the co-administration vaccine group are protected against SHIV CH505 acquisition after repeated low-dose intravaginal challenge and show 67% risk reduction per exposure. Macaques in the co-administration group develop higher Env-specific humoral and cellular immune responses. Non-neutralizing Env antibodies, ADCC, and antibodies binding to FcγRIIIa are associated with decreased transmission risk. These data suggest that simultaneous recognition, processing, and presentation of DNA + Env protein in the same draining lymph nodes play a critical role in the development of protective immunity.

Differential contribution of chronic binge alcohol and antiretroviral therapy to metabolic dysregulation in SIV-infected male macaques.

The incidence of alcohol use disorder (AUD) is higher among people living with HIV (PLWH). The advent and continued development of antiretroviral therapy (ART) has significantly reduced mortality, shifting the course of HIV infection to a chronic illness. However, this is associated with an increased incidence of comorbid conditions, including type 2 diabetes mellitus, insulin resistance, and cardiovascular complications. Using a nonhuman primate model of simian immunodeficiency virus (SIV) infection, previous studies have demonstrated that chronic binge alcohol (CBA) administration decreases whole body insulin responsiveness, irrespective of ART administration. The objective of the current study was to determine the effects of CBA and ART on insulin-sensitive peripheral tissues before the development of overt clinical symptoms of SIV disease. Our results show that CBA reduced omental adipocyte cell size, increased collagen expression, and decreased the in vitro differentiation potential of adipose-derived stem cells. In contrast, it did not alter skeletal muscle or omental or hepatic expression of insulin signaling proteins. However, ART significantly decreased skeletal muscle expression of phosphatase and tensin homolog, total mechanistic target of rapamycin, and ribosomal protein S6. In addition, ART increased hepatic phosphorylation of AMP-activated protein kinase α and increased gene expression of key enzymes required for gluconeogenesis and fatty acid synthesis. These findings suggest that CBA and ART differentially promote adverse metabolic effects in an organ-specific manner that may underlie insulin resistance associated with alcohol, SIV, and ART. Whether this is translated in PLWH with AUD remains to be determined.

Beneficial Effects of Human Anti-Interleukin-15 Antibody in Gluten-Sensitive Rhesus Macaques with Celiac Disease.

Overexpression of interleukin-15 (IL-15) is linked with immunopathology of several autoimmune disorders including celiac disease. Here, we utilized an anti-human IL-15 antibody 04H04 (anti-IL-15) to reverse immunopathogenesis of celiac disease. Anti-IL-15 was administered to six gluten-sensitive rhesus macaques with celiac disease characteristics including gluten-sensitive enteropathy (GSE), and the following celiac-related metrics were evaluated: morphology (villous height/crypt depth ratio) of small intestine, counts of intestinal intraepithelial lymphocytes, IFN-γ-producing CD8+ and CD4+ T cells, plasma levels of anti-gliadin and anti-intestinal tissue transglutaminase IgG antibodies, as well as peripheral effector memory (CD3+CD28-CD95+) T cells. Anti-IL-15 treatment reversed the clinically relevant disease endpoints, intraepithelial lymphocyte counts, and villous height/crypt depth ratios within jejunal biopsies to normal levels (P < 0.001). Additionally, intestinal CD8+ and CD4+ T cell IFN-γ production was reduced (P < 0.05). Extra-intestinally, anti-IL-15 treatment reduced peripheral NK cell counts (P < 0.001), but otherwise, non-NK peripheral lymphocytes including effector memory T cells and serum blood chemistry were unaffected. Overall, providing the beneficial disease-modulatory and immunomodulatory effects observed, anti-IL-15 treatment might be considered as a novel therapy to normalize intestinal lymphocyte function in celiac disease patients with GSE.

Hydrocephalus after Intrathecal Administration of Dextran to Rhesus Macaques (Macaca mulatta).

Dextrans have been used extensively as medical therapies and labeling agents in biomedical research to investigate the blood-brain barrier and CSF flow and absorption. Adverse effects from dextrans include anaphylactic reaction and dilation of the cerebral ventricles due to administration into the subarachnoid space. This retrospective study describes 51 rhesus macaques (Macaca mulatta) that received dextran intrathecally. The purpose of intrathecal administration was to enable detection of long-lived, dextran-labeled macrophages and to study monocyte-macrophage turnover in the CNS of SIV- or SHIV- infected and uninfected animals by using immunofluorescence. Of the 51 dextran-treated macaques, 8 that received dextran diluted in saline developed hydrocephalus; 6 of these 8 animals exhibited neurologic signs. In contrast, none of the macaques that received intrathecal dextran diluted in PBS developed hydrocephalus. These data suggest the use of saline diluent and the duration of dextran exposure as potential factors contributing to hydrocephalus after intrathecal dextran in rhesus macaques.