Antibody-mediated depletion of select leukocyte subsets in blood and tissue of nonhuman primates

Understanding the immunological control of pathogens requires a detailed evaluation of the mechanistic contributions of individual cell types within the immune system. While knockout mouse models that lack certain cell types have been used to help define the role of those cells, the biological and physiological characteristics of mice do not necessarily recapitulate that of a human. To overcome some of these differences, studies often look towards nonhuman primates (NHPs) due to their close phylogenetic relationship to humans. To evaluate the immunological role of select cell types, the NHP model provides distinct advantages since NHP more closely mirror the disease manifestations and immunological characteristics of humans. However, many of the experimental manipulations routinely used in mice (e.g., gene knock-out) cannot be used with the NHP model. As an alternative, the in vivo infusion of monoclonal antibodies that target surface proteins on specific cells to either functionally inhibit or deplete cells can be a useful tool. Such depleting antibodies have been used in NHP studies to address immunological mechanisms of action. In these studies, the extent of depletion has generally been reported for blood, but not thoroughly assessed in tissues. Here, we evaluated four depleting regimens that primarily target T cells in NHP: anti-CD4, anti-CD8α, anti-CD8β, and immunotoxin-conjugated anti-CD3. We evaluated these treatments in healthy unvaccinated and IV BCG-vaccinated NHP to measure the extent that vaccine-elicited T cells - which may be activated, increased in number, or resident in specific tissues - are depleted compared to resting populations in unvaccinated NHPs. We report quantitative measurements of in vivo depletion at multiple tissue sites providing insight into the range of cell types depleted by a given mAb. While we found substantial depletion of target cell types in blood and tissue of many animals, residual cells remained, often residing within tissue. Notably, we find that animal-to-animal variation is substantial and consequently studies that use these reagents should be powered accordingly.

Systems immunology of transcriptional responses to viral infection identifies conserved antiviral pathways across macaques and humans

Viral pandemics and epidemics pose a significant global threat. While macaque models of viral disease are routinely used, it remains unclear how conserved antiviral responses are between macaques and humans. Therefore, we conducted a cross-species analysis of transcriptomic data from over 6,088 blood samples from macaques and humans infected with one of 31 viruses. Our findings demonstrate that irrespective of primate or viral species, there are conserved antiviral responses that are consistent across infection phase (acute, chronic, or latent) and viral genome type (DNA or RNA viruses). Leveraging longitudinal data from experimental challenges, we identify virus-specific response kinetics such as host responses to Coronaviridae and Orthomyxoviridae infections peaking 1-3 days earlier than responses to Filoviridae and Arenaviridae viral infections. Our results underscore macaque studies as a powerful tool for understanding viral pathogenesis and immune responses that translate to humans, with implications for viral therapeutic development and pandemic preparedness.

Antibody-mediated depletion of select T cell subsets in blood and tissue of nonhuman primates

Understanding the immunological control of pathogens requires a detailed evaluation of the mechanistic contributions of individual cell types within the immune system. While knockout mouse models that lack certain cell types have been used to help define the role of those cells, the biological and physiological characteristics of mice do not necessarily recapitulate that of a human. To overcome some of these differences, studies often look towards nonhuman primates (NHPs) due to their close phylogenetic relationship to humans. To evaluate the immunological role of select cell types, the NHP model provides distinct advantages since NHP more closely mirror the disease manifestations and immunological characteristics of humans. However, many of the experimental manipulations routinely used in mice (e.g., gene knock-out) cannot be used with the NHP model. As an alternative, the in vivo infusion of monoclonal antibodies that target surface proteins on specific cells to either functionally inhibit or deplete cells can be a useful tool. Such depleting antibodies have been used in NHP studies to address immunological mechanisms of action. In these studies, the extent of depletion has generally been reported for blood, but not thoroughly assessed in tissues. Here, we evaluated four depleting regimens that primarily target T cells in NHP: anti-CD4, anti-CD8α, anti-CD8β, and immunotoxin-conjugated anti-CD3. We evaluated these treatments in healthy unvaccinated and IV BCG-vaccinated NHP to measure the extent that vaccine-elicited T cells - which may be activated, increased in number, or resident in specific tissues - are depleted compared to resting populations in unvaccinated NHPs. We report quantitative measurements of in vivo depletion at multiple tissue sites providing insight into the range of cell types depleted by a given mAb. While we found substantial depletion of target cell types in blood and tissue of many animals, residual cells remained, often residing within tissue. Notably, we find that animal-to-animal variation is substantial and consequently studies that use these reagents should be powered accordingly.

Blood transcriptional correlates of BCG-induced protection against tuberculosis in rhesus macaques

Blood-based correlates of vaccine-induced protection against tuberculosis (TB) are urgently needed. Here, we analyze the blood transcriptome of rhesus macaques immunized with varying doses of intravenous (i.v.) BCG followed by Mycobacterium tuberculosis (Mtb) challenge. We use high-dose i.v. BCG recipients for "discovery" and validate our findings in low-dose recipients and in an independent cohort of macaques receiving BCG via different routes. We identify seven vaccine-induced gene modules, including an innate module (module 1) enriched for type 1 interferon and RIG-I-like receptor signaling pathways. Module 1 on day 2 post-vaccination highly correlates with lung antigen-responsive CD4 T cells at week 8 and with Mtb and granuloma burden following challenge. Parsimonious signatures within module 1 at day 2 post-vaccination predict protection following challenge with area under the receiver operating characteristic curve (AUROC) ≥0.91. Together, these results indicate that the early innate transcriptional response to i.v. BCG in peripheral blood may provide a robust correlate of protection against TB.

Airway T cells are a correlate of i.v. Bacille Calmette-Guerin-mediated protection against tuberculosis in rhesus macaques

Bacille Calmette-Guerin (BCG), the only approved Mycobacterium tuberculosis (Mtb) vaccine, provides limited durable protection when administered intradermally. However, recent work revealed that intravenous (i.v.) BCG administration yielded greater protection in macaques. Here, we perform a dose-ranging study of i.v. BCG vaccination in macaques to generate a range of immune responses and define correlates of protection. Seventeen of 34 macaques had no detectable infection after Mtb challenge. Multivariate analysis incorporating longitudinal cellular and humoral immune parameters uncovered an extensive and highly coordinated immune response from the bronchoalveolar lavage (BAL). A minimal signature predicting protection contained four BAL immune features, of which three remained significant after dose correction: frequency of CD4 T cells producing TNF with interferon γ (IFNγ), frequency of those producing TNF with IL-17, and the number of NK cells. Blood immune features were less predictive of protection. We conclude that CD4 T cell immunity and NK cells in the airway correlate with protection following i.v. BCG.

Using Donor-Derived Cell-Free DNA for Assessment of Myocardial Injury in Heart Transplant Recipients After SARS-CoV2 Infection

Purpose

A link between SARS-CoV2 infection and myocardial injury has been described. Our center utilizes non-invasive surveillance with gene expression profiling and donor-derived cell-free DNA (dd-cfDNA) in heart transplant (HTx) patients who are either stable or in whom invasive surveillance is contraindicated. We evaluated whether HTx recipients diagnosed with SARS-CoV2 infection demonstrated evidence of myocardial allograft injury using dd-cfDNA.

Methods

HTx recipients were included if they had dd-cfDNA testing (AlloSure; CareDx Inc., Brisbane, CA) within 60 days of their initial SARS-CoV2 diagnosis. Data on hospitalization, therapy, and clinical outcomes was captured. Dd-cfDNA results at the assay limit of detection (LOD, <0.12%) were set equal to the LOD.

Results

Between 3/2020 and 6/2021, we identified 12 HTx recipients with SARS-CoV2 and dd-cfDNA results within the specified time period; median age was 55 (IQR 28 - 64.5) with infection occurring 506.5 days (IQR 176 - 803.5) after transplant. Mean dd-cfDNA was 0.13 ± 0.03%, assessed 26 (IQR 20 - 35) days after infection. Prior results, available for 9 patients and obtained a median of 33 (IQR 27 - 59) days prior to infection, did not differ from post-infection values (0.13 ± 0.02%, p = 0.66). Following diagnosis, 8 (67%) patients were hospitalized; 5 had mycophenolate held, 2 received steroids, 2 received convalescent plasma, 4 received remdesivir, and 1 received monoclonal Ab therapy. At a median follow-up time of 304 (IQR 212.5 - 331) days after diagnosis, all twelve patients were alive with good allograft function (mean ejection fraction 59 ± 4.8%); interval clinically-relevant immunologic outcomes included one episode of rejection (pAMR1) and three (25%) findings of de novo donor-specific antibodies (dnDSA).

Conclusion

In this single-center pilot study assessing myocardial injury among HTx recipients within 2 months of SARS-CoV2 infection, the majority of patients had low dd-cfDNA results (<0.15%) and demonstrated good intermediate-term (6-12 months) graft function. While limited by sample size and protocol-based inclusion criteria, our findings suggest that sustained myocardial injury in HTx recipients after SARS-CoV2 infection may not be common. The impact of SARS-CoV2 infection on immunologic outcomes including rejection and dnDSA in this population merit further study.

Effect of COVID-19 Infection on HeartCare, Data from the SHORE Multicenter Registry

Purpose

Transplant patients represent a cohort in which COVID-19 (C19) may stimulate an unpredictable clinical course. The aim of this study was to evaluate the impact of C19 infection on AlloMap gene expression profiling (AM) and AlloSure donor derived cell free DNA (AS) results in patients post heart transplant.

Methods

The Surveillance Using HeartCare Outcomes Registry (SHORE) is a multicenter study for post heart transplant patients followed with AM/AS for 5 years. Patients enrolled were analyzed based on C19 . AM/AS were evaluated before, at the time and following infection. Both individual trends and the differences between the median AS and AS levels were studied. Nonparametric tests were used to assess categorical and longitudinal variables.

Results

21 patients developed C19 infection; 16 (76%) were males, median age 50 years. There was no significant difference in AM or AS in stable patients (no rejection, CAV, graft dysfunction, dnDSA) compared to the first AM/AS profile in the C19+ patients, Figure 1. Event rates in C19+ patients are described in Table 1. 12 C19+ patients had 28 biopsies, 2 of which were within 30 days of C19. 1 patient had ACR 2R and another AMR 1; all other biopsies were <ACR 2R/AMR1. Additionally, 5 patients developed dnDSA and 7 patients developed subsequent CMV viremia, a median of 67 and 158 days after C19 diagnosis, respectively. No CAV, graft dysfunction, or deaths were reported in this small group of C19+ patients.

Conclusion

The presence of C19 infection is not associated with a significant increase in AS or AM scores, suggesting AS and AM are not confounded by C19 and can be used safely as non-invasive surveillance in this population.

Prevention of tuberculosis in macaques after intravenous BCG immunization

Mycobacterium tuberculosis (Mtb) is the leading cause of death from infection worldwide¹. The only available vaccine, BCG (Bacillus Calmette-Guérin), is given intradermally and has variable efficacy against pulmonary tuberculosis, the major cause of mortality and disease transmission^1,2. Here we show that intravenous administration of BCG profoundly alters the protective outcome of Mtb challenge in non-human primates (Macaca mulatta). Compared with intradermal or aerosol delivery, intravenous immunization induced substantially more antigen-responsive CD4 and CD8 T cell responses in blood, spleen, bronchoalveolar lavage and lung lymph nodes. Moreover, intravenous immunization induced a high frequency of antigen-responsive T cells across all lung parenchymal tissues. Six months after BCG vaccination, macaques were challenged with virulent Mtb. Notably, nine out of ten macaques that received intravenous BCG vaccination were highly protected, with six macaques showing no detectable levels of infection, as determined by positron emission tomography-computed tomography imaging, mycobacterial growth, pathology and granuloma formation. The finding that intravenous BCG prevents or substantially limits Mtb infection in highly susceptible rhesus macaques has important implications for vaccine delivery and clinical development, and provides a model for defining immune correlates and mechanisms of vaccine-elicited protection against tuberculosis.

Protection against a mixed SHIV challenge by a broadly neutralizing antibody cocktail

HIV-1 sequence diversity presents a major challenge for the clinical development of broadly neutralizing antibodies (bNAbs) for both therapy and prevention. Sequence variation in critical bNAb epitopes has been observed in most HIV-1-infected individuals and can lead to viral escape after bNAb monotherapy in humans. We show that viral sequence diversity can limit both the therapeutic and prophylactic efficacy of bNAbs in rhesus monkeys. We first demonstrate that monotherapy with the V3 glycan-dependent antibody 10-1074, but not PGT121, results in rapid selection of preexisting viral variants containing N332/S334 escape mutations and loss of therapeutic efficacy in simian-HIV (SHIV)-SF162P3-infected rhesus monkeys. We then show that the V3 glycan-dependent antibody PGT121 alone and the V2 glycan-dependent antibody PGDM1400 alone both fail to protect against a mixed challenge with SHIV-SF162P3 and SHIV-325c. In contrast, the combination of both bNAbs provides 100% protection against this mixed SHIV challenge. These data reveal that single bNAbs efficiently select resistant viruses from a diverse challenge swarm to establish infection, demonstrating the importance of bNAb cocktails for HIV-1 prevention.

Complex, multi-scale small intestinal topography replicated in cellular growth substrates fabricated via chemical vapor deposition of Parylene C

Native small intestine possesses distinct multi-scale structures (e.g., crypts, villi) not included in traditional 2D intestinal culture models for drug delivery and regenerative medicine. The known impact of structure on cell function motivates exploration of the influence of intestinal topography on the phenotype of cultured epithelial cells, but the irregular, macro- to submicron-scale features of native intestine are challenging to precisely replicate in cellular growth substrates. Herein, we utilized chemical vapor deposition of Parylene C on decellularized porcine small intestine to create polymeric intestinal replicas containing biomimetic irregular, multi-scale structures. These replicas were used as molds for polydimethylsiloxane (PDMS) growth substrates with macro to submicron intestinal topographical features. Resultant PDMS replicas exhibit multiscale resolution including macro- to micro-scale folds, crypt and villus structures, and submicron-scale features of the underlying basement membrane. After 10 d of human epithelial colorectal cell culture on PDMS substrates, the inclusion of biomimetic topographical features enhanced alkaline phosphatase expression 2.3-fold compared to flat controls, suggesting biomimetic topography is important in induced epithelial differentiation. This work presents a facile, inexpensive method for precisely replicating complex hierarchal features of native tissue, towards a new model for regenerative medicine and drug delivery for intestinal disorders and diseases.

Management of foreign body aspiration or ingestion in dentistry

Foreign body aspiration or ingestion can be a potential complication during routine dental treatment. The handling of dental objects requires particular care, especially where the patient is supine or semi-recumbent. Dentist must be able to manage emergency situations in which patients accidentally swallow dental instruments or materials during treatment and procedures. This article reviews the complications, management and prevention of aspiration or ingestion of foreign bodies.

Assessment of the afferent vagal nerve in patients with gastroesophageal reflux

BACKGROUND

The objective of this study was to assess the integrity of the vagal nerve afferent pathways in patients with gastroesophageal reflux disease (GERD).

METHODS

Seven GERD patients (4 males and 3 females, mean age 39 +/- 8 years) were studied. Twelve healthy volunteers (11 males and 1 female, mean age 32 +/- 8 years) were used as the control group. Cortical evoked potentials were measured. Electrical stimulation of the esophageal mucosa was performed through a custom-built device. Latencies and N2/P2 amplitude were measured.

RESULTS

Reproducible cortical evoked potentials were obtained from all subjects. The stimulation threshold for GERD patients to electrical esophageal stimulation was 5.1 +/- 1.5 mA compared to 7.8 +/- 2.0 mA in healthy volunteers (p <0.05). There was no difference in peak latencies or N2/P2 amplitude between GERD patients and controls.

CONCLUSIONS

GERD patients have a normal vagal nerve function, but they exhibit a decreased threshold for esophageal perception. The mechanism responsible for increased esophageal sensitivity observed in GERD patients is still undetermined and warrants further study.

Recovery rates of regional sympathetic reinnervation and myocardial blood flow after acute myocardial infarction

BACKGROUND

The implication of an arrhythmogenic role for infarction-induced disruption of regional myocardial sympathetic nerve activity has led to a search for noninvasive methods to study regional sympathetic nerve activity in patients after infarction.

METHODS AND RESULTS

By using positron emission tomography, we measured the time course of myocardial hypoperfusion with [13N]-ammonia retention and sympathetic innervation with [18F]-6-fluorodopamine within the infarct zone in 10 patients at 2 weeks, 3 months, and 6 months after a first-onset Q-wave myocardial infarction. The time course for reestablishment of global cardiac autonomic function was also determined by measuring the power spectrum of heart rate variability with an autoregressive technique. The average infarct defect size as determined by the fractional uptake of [13N]-ammonia was 17.22% +/- 5.95% of the left ventricular myocardium. The fractional uptake of [18F]-fluorodopamine in the infarct zone was similar, at 15.83% +/- 4.45% (not significant). There was a significant increase (14% to 15%; P <.05) in myocardial blood flow and [18F]-fluorodopamine uptake to the infarct zone between 2 weeks and 3 months, with no further change between 3 months and 6 months. However, the average rate of loss (t1/ 2 hour) of [18F]- fluorodopamine continued to decrease between 2 weeks and 6 months. This paralleled a continuing fall in the low-frequency to high-frequency autospectral power ratio throughout the 6 months after infarction.

CONCLUSIONS

This study demonstrates a modest increase in myocardial blood flow and evidence for sympathetic reinnervation to the infarct zone between 2 weeks and 3 months after acute myocardial infarction. Despite a flow-dependent effect on the uptake of [18F]-fluorodopamine by 3 months, there is a suggestion that restoration of sympathetic activity within the infarct zone continues between 3 months and 6 months after acute myocardial infarction.

Modulation of neurocardiac function by oesophageal stimulation in humans

1. The heart and the oesophagus have similar sensory pathways, and sensations originating from the oesophagus are often difficult to differentiate from those of cardiac origin. We hypothesized that oesophageal sensory stimuli could alter neurocardiac function through autonomic reflexes elicited by these oesophageal stimuli. In the present study, we examined the neurocardiac response to oesophageal stimulation and the effects of electrical and mechanical oesophageal stimulation on the power spectrum of beat-to-beat heart rate variability in male volunteers. 2. In 14 healthy volunteers, beat-to-beat heart rate variability was compared at rest and during oesophageal stimulation, using either electrical (200 microns, 16 mA, 0.2 Hz) or mechanical (0.5 s, 14 ml, 0.2 Hz) stimuli. The power spectrum of beat-to-beat heart rate variability was obtained and its low- and high-frequency components were determined. 3. Distal oesophageal stimulation decreased heart rate slightly (both electrical and mechanical) (P < 0.005), and markedly altered heart rate variability (P < 0.001). Both electrical and mechanical oesophageal stimulation increased the absolute and normalized area of the high-frequency band within the power spectrum (P < 0.001), while simultaneously decreasing the low-frequency power (P < 0.005). 4. In humans, oesophageal stimulation, whether electrical or mechanical, appears to amplify respiratory-driven cardiac vagoafferent modulation while decreasing sympathetic modulation. The technique provides access to vagoafferent fibres and thus may yield useful information on the autonomic effects of visceral or oesophageal sensory stimulation.

A biotinylated undecylthiophene copolymer bioconjugate for surface immobilization: creating an alkaline phosphatase chemiluminescence-based biosensor

Methodology is described for the creation of a molecular assembly consisting of the enzyme alkaline phosphatase immobilized onto a glass surface using a biotinylated conjugated copolymer, poly(3-undecylthiophene-co-3-thiophenecarboxaldehyde) 6-biotinamidohexanohydrazone. The biotinylated polymer is attached to the inside walls of a silanized glass capillary via hydrophobic interactions, and a streptavidin-conjugated alkaline phosphatase is interfaced with the polymer through the classical biotin-streptavidin interaction. Utilizing a simple optical setup, we can detect the activity of as little as approximately 0.1 fmol of alkaline phosphatase with this molecular assembly. The assembly is mechanically robust and retains the majority of bound enzyme activity for up to 30 days. We have utilized this molecular assembly for the detection of organophosphorus-based pesticides. Both paraoxon and methyl parathion inhibit the enzyme-mediated generation of chemiluminescence signal. We are able to detect paraoxon and methyl parathion concentrations down to 500-700 ppb.

Exotica

This paper is an overview of the Exotica project, currently in progress at the IBM Almaden Research Center. The project aims at exploring several research areas from advanced transaction management concepts to client/server architectures and mobile computing within the context of business processes and workflow management. The ultimate goal is to incorporate these ideas into IBM's products and prototypes. The project involves IBM groups in Almaden (U.S.A.), Hursley (U.K.), Boeblingen (Germany), and Vienna (Austria). In this paper we briefly describe two IBM products, FlowMark, a workflow management system, and MQSeries, a messaging system, as the environments in which we are focusing our research. We also discuss some of our results in the areas of availability, replication, distribution, and advanced transaction models, as well as describe our future research directions. 10

Electrostimulation effects of the vagus nerve on balance in epilepsy

Preliminary results of selected postural measures in quiet standing indicate that stimulation of the vagus nerve appears not to be producing adverse effects. With this specific sample size, more testing is needed to determine long-term effects and future data analyses will examine correlations between electroencephalogram results, drug levels, and seizure frequency. In the present study three subjects have had old injuries to hips and ankles. Two subjects had normal values for postural control prior to stimulation, while other subjects were severely abnormal. In future, studies should include larger homogeneous sample sizes, as the current subjects show marked variability in age and premorbid health backgrounds. Future work should also control more vigorously for variables such as visual input (i.e., blindfolding subjects instead of simply closing the eyes). Evaluation of postural control mechanisms will be continued to assess stability changes in these patients as seizure frequency continues to subside.

A new one-step synthesis of hexahydrocannabinoid analogs

A one-step synthesis of hexahydrocannabinoid analogs (HHC) is described making use of the condensation of phenolic ketones and aldehydes with citronellal in the presence of pyridine.