In-depth immunophenotyping reveals significant alteration of lymphocytes in buffalo with brucellosis.

Water buffalo (Bubalus bubalis) has a prominent position in the livestock industry worldwide but still suffers from limited knowledge on the mechanisms regulating the immune against infections, including brucellosis (BRC), one of the most significant neglected zoonotic diseases of livestock. Seventy-three buffalo were recruited for the study. Thirty-five were naturally infected with Brucella spp. The aims of the study were to (i) verify the cross-reactivity of 16 monoclonal antibodies (mAbs) developed against human, bovine, and ovine antigens; (ii) evaluate lymphocyte subset alterations in BRC positive buffalo; (iii) evaluate the use of the canonical discriminant analysis (CDA), with flow cytometric data, to discriminate BRC positive from negative animals. A new set of eight mAbs (anti CD3e, CD16, CD18, CD45R0, CD79a; CD172a) were shown to cross-react with water buffalo orthologous molecules. BRC positive animals presented a significant (p < 0.0001) decrease in the percentage of PBMC (29.5 vs. 40.3), total, T and B lymphocytes (23.0 vs. 35.5, 19.2 vs. 28.9, 2.6 vs. 5.7, respectively). In contrast, they showed an increase in percentage of granulocytes (65.2 vs. 55.1; p < 0.0001) and B lymphocytes CD21neg (22.9 vs. 16.1; p = 0.0067), a higher T/B lymphocyte ratio (10.3 vs. 6.4; p = 0.0011) and CD3+ /CD21+ (14.7 vs. 8.3; p = 0.0005) ratio. The CDA, applied to 33 different flow cytometric traits, allowed the discrimination of all BRC positive from negative buffalo. Although this is a preliminary study, our results show that flow cytometry can be used in a wide range of applications in livestock diseases, including in support of uncertain BRC diagnoses.

Isolation of canine adipose-derived mesenchymal stem cells from falciform tissue obtained via laparoscopic morcellation: A pilot study.

OBJECTIVE: To evaluate the feasibility of stem cell isolation from falciform fat harvested via laparoscopic morcellation. STUDY DESIGN: Pilot study. ANIMALS: Eleven client-owned dogs. METHODS: Falciform was harvested traditionally via laparotomy and laparoscopically via tissue morcellation. Harvested tissue was processed with a commercially available adipose tissue dissociation kit to obtain a stromal vascular fraction (SVF). Cells were subsequently labeled for CD90, CD45, and CD44 cell surface antigens by using magnetic-activated cell sorting (MACS) and fluorescence-activated cell sorting flow cytometry. CD90+ cells were quantitated, and their viability was assessed with a hemocytometer and a trypan blue exclusion test of cell viability. RESULTS: No perioperative complications occurred in dogs undergoing laparoscopic morcellation. Laparoscopically and traditionally harvested samples yielded an average of 0.39 (±0.1) × 106 and 0.33 (±0.1) × 106 CD90+ cells, respectively, per 10 million SVF cells. CD90+ cell viability after MACS was 89% (±11%) for morcellated and 86% (±7%) for traditionally harvested samples. Neither CD90+ cell quantity nor viability was different between samples obtained via traditional laparotomy vs laparoscopic morcellation (P = .38 and P = .63, respectively). Populations of CD90+ cells isolated with each harvest technique had similar CD44 and CD45 expression profiles. CONCLUSION: Viable populations of CD90+ cells with similar CD44/CD45 expression profiles were isolated from laparoscopically morcellated and traditionally harvested falciform tissue. No appreciable morbidity was associated with laparoscopic falciform morcellation. CLINICAL SIGNIFICANCE: Laparoscopic morcellation is a safe and effective minimally invasive approach to falciform tissue harvest for adipose-derived mesenchymal stem cell isolation.

Mapping of CD4+ T-cell epitopes in bovine leukemia virus from five cattle with differential susceptibilities to bovine leukemia virus disease progression.

BACKGROUND: Bovine leukemia virus (BLV), which is closely related to human T-cell leukemia virus, is the etiological agent of enzootic bovine leukosis, a disease characterized by a highly prolonged course involving persistent lymphocytosis and B-cell lymphoma. The bovine major histocompatibility complex class II region plays a key role in the subclinical progression of BLV infection. In this study, we aimed to evaluate the roles of CD4+ T-cell epitopes in disease progression in cattle. METHODS: We examined five Japanese Black cattle, including three disease-susceptible animals, one disease-resistant animal, and one normal animal, classified according to genotyping of bovine leukocyte antigen (BoLA)-DRB3 and BoLA-DQA1 alleles using polymerase chain reaction sequence-based typing methods. All cattle were inoculated with BLV-infected blood collected from BLV experimentally infected cattle and then subjected to CD4+ T-cell epitope mapping by cell proliferation assays. RESULTS: Five Japanese Black cattle were successfully infected with BLV, and CD4+ T-cell epitope mapping was then conducted. Disease-resistant and normal cattle showed low and moderate proviral loads and harbored six or five types of CD4+ T-cell epitopes, respectively. In contrast, the one of three disease-susceptible cattle with the highest proviral load did not harbor CD4+ T-cell epitopes, and two of three other cattle with high proviral loads each had only one epitope. Thus, the CD4+ T-cell epitope repertoire was less frequent in disease-susceptible cattle than in other cattle. CONCLUSION: Although only a few cattle were included in this study, our results showed that CD4+ T-cell epitopes may be associated with BoLA-DRB3-DQA1 haplotypes, which conferred differential susceptibilities to BLV proviral loads. These CD4+ T-cell epitopes could be useful for the design of anti-BLV vaccines targeting disease-susceptible Japanese Black cattle. Further studies of CD4+ T-cell epitopes in other breeds and using larger numbers of cattle with differential susceptibilities are required to confirm these findings.

A Mycobacterium avium subsp. paratuberculosis relA deletion mutant and a 35 kDa major membrane protein elicit development of cytotoxic T lymphocytes with ability to kill intracellular bacteria.

Efforts to develop live attenuated vaccines against Mycobacterium avium subspecies paratuberculosis (Map), using indirect methods to screen Map deletion mutants for potential efficacy, have not been successful. A reduction in the capacity to survive in macrophages has not predicted the ability of mutants to survive in vivo. Previous studies for screening of three deletion mutants in cattle and goats revealed one mutant, with a deletion in relA (ΔMap/relA), could not establish a persistent infection. Further studies, using antigen presenting cells (APC), blood dendritic cells and monocyte derived DC, pulsed with ΔMap/relA or a 35 kDa Map membrane protein (MMP) revealed a component of the response to ΔMap/relA was directed towards MMP. As reported herein, we developed a bacterium viability assay and cell culture assays for analysis and evaluation of cytotoxic T cells generated against ΔMap/relA or MMP. Analysis of the effector activity of responding cells revealed the reason ΔMap/relA could not establish a persistent infection was that vaccination elicited development of cytotoxic CD8 T cells (CTL) with the capacity to kill intracellular bacteria. We demonstrated the same CTL response could be elicited with two rounds of antigenic stimulation of APC pulsed with ΔMap/relA or MMP ex vivo. Cytotoxicity was mediated through the perforin granzyme B pathway. Finally, cognate recognition of peptides presented in context of MHC I and II molecules to CD4 and CD8 T cells is required for development of CTL.

Classical scrapie prions are associated with peripheral blood monocytes and T-lymphocytes from naturally infected sheep.

BACKGROUND: Classical scrapie is a transmissible spongiform encephalopathy (TSE) that affects sheep and goats. Our previous bioassay studies in lambs revealed that scrapie prions could be detected in association with peripheral blood monocular cells (PBMC), B lymphocytes and platelet-rich plasma fractions. In the present study, bioassay in lambs was again used to determine if scrapie prions are associated with the other two subsets of PBMC, monocytes and T lymphocytes. RESULTS: PBMC, monocytes and T lymphocytes were isolated from two preclinically affected VRQ/VRQ sheep naturally infected with classical ovine scrapie and intravenously transfused into VRQ/VRQ lambs post-weaning. As determined using standard immunohistochemistry for scrapie, abnormal isoforms of prion protein were detected in lymphoid tissues of lambs inoculated with PBMC (4/4 recipient lambs), monocytes (2/5) and T lymphocytes (1/4). Prion protein misfolding activity was detected by serial protein misfolding cyclic amplification (sPMCA) in PBMC from monocyte and T lymphocyte recipient sheep in agreement with antemortem rectal biopsy results, but such prion protein misfolding activity was not detected from other recipients. CONCLUSIONS: These findings show that scrapie prions are associated with monocytes and T lymphocytes circulating in the peripheral blood of sheep naturally infected with classical scrapie. Combined with our previous findings, we can now conclude that all three major subsets of PBMC can harbor prions during preclinical disease and thus, present logical targets for development of a sensitive assay to detect scrapie prions. In this regard, we have also demonstrated that sPMCA can be used to detect scrapie prions associated with PBMC.

Biochemical characterization of prostate-specific membrane antigen from canine prostate carcinoma cells.

BACKGROUND: Prostate-specific membrane antigen (PSMA) remains an important target for diagnostic and therapeutic application for human prostate cancer. Model cell lines have been recently developed to study canine prostate cancer but their PSMA expression and enzymatic activity have not been elucidated. The present study was focused on determining PSMA expression in these model canine cell lines and the use of fluorescent small-molecule enzyme inhibitors to detect canine PSMA expression by flow cytometry. METHODS: Western blot and RT-PCR were used to determine the transcriptional and translational expression of PSMA on the canine cell lines Leo and Ace-1. An endpoint HPLC-based assay was used to monitor the enzymatic activity of canine PSMA and the potency of enzyme inhibitors. Flow cytometry was used to detect the PSMA expressed on Leo and Ace-1 cells using a fluorescently tagged PSMA enzyme inhibitor. RESULTS: Canine PSMA expression on the Leo cell line was confirmed by Western blot and RT-PCR, the enzyme activity, and flow cytometry. Kinetic parameters Km and Vmax of PSMA enzymatic activity for the synthetic substrate (PABGγG) were determined to be 393 nM and 220 pmol min(-1) mg protein(-1) , respectively. The inhibitor core 1 and fluorescent inhibitor 2 were found to be potent reversible inhibitors (IC50 = 13.2 and 1.6 nM, respectively) of PSMA expressed on the Leo cell line. Fluorescent labeling of Leo cells demonstrated that the fluorescent PSMA inhibitor 2 can be used for the detection of PSMA-positive canine prostate tumor cells. Expression of PSMA on Ace-1 was low and not detectable by flow cytometry. CONCLUSIONS: The results described herein have demonstrated that PSMA is expressed on canine prostate tumor cells and exhibits similar enzymatic characteristics as human PSMA. The findings show that the small molecule enzyme inhibitors currently being studied for use in diagnosis and therapy of human prostate cancer can also be extended to include canine prostate cancer. Importantly, the findings demonstrate that the potential of the inhibitors for use in diagnosis and therapy can be evaluated in an immunocompetent animal model that naturally develops prostate cancer before use in humans.

An update on the development of a bottlenose dolphin, Tursiops truncatus, immune reagent toolkit.

There are extensive immunological reagents available for laboratory rodents and humans. However, for veterinary species there is a need for expansion of immunological toolkits, with this especially evident for marine mammals, such as cetaceans. In addition to their use in a research setting, immune assays could be employed to monitor the health status of cetaceans and serve as an adjunct to available diagnostic tests. Such development of specific and sensitive immune assays will enhance the proper care and stewardship of wild and managed cetacean populations. Our goal is to provide immune reagents and immune assays for the research community, clinicians, and others involved in care of bottlenose dolphins. This review will provide an update on our development of a bottlenose dolphin immunological toolkit. The future availability and continued development of these reagents is critical for improving wild and managed bottlenose dolphin population health through enhanced assessment of their responses to alterations in the marine environment, including pathogens, and improve our ability to monitor their status following vaccination.

Progress in the development and use of monoclonal antibodies to study the evolution and function of the immune systems in the extant lineages of ungulates.

Details on the origin and function of the immune system are beginning to emerge from genomic studies tracing the origin of B and T cells and the major histocompatibility complex. This is being accomplished through identification of DNA sequences of ancestral genes present in the genomes of lineages of vertebrates that have evolved from a common primordial ancestor. Information on the evolution of the composition and function of the immune system is being obtained through development of monoclonal antibodies (mAbs) specific for the MHC class I and II molecules and differentially expressed on leukocytes differentiation molecules (LDM). The mAbs have provided the tools needed to compare the similarities and differences in the phenotype and function of immune systems that have evolved during speciation. The majority of information currently available on evolution of the composition and function of the immune system is derived from study of the immune systems in humans and mice. As described in the present review, further information is beginning to emerge from comparative studies of the immune systems in the extant lineages of species present in the two orders of ungulates, Perissodactyla and Artiodactyla. Methods have been developed to facilitate comparative research across species on pathogens affecting animal and human health.

SDF-1-CXCR4 differentially regulates autoimmune diabetogenic T cell adhesion through ROBO1-SLIT2 interactions in mice.

AIMS/HYPOTHESIS: We had previously reported that stromal cell-derived factor 1 (SDF-1) mediates chemorepulsion of diabetogenic T cell adhesion to islet microvascular endothelium through unknown mechanisms in NOD mice. Here we report that SDF-1-mediated chemorepulsion occurs through slit homologue (SLIT)2-roundabout, axon guidance receptor, homologue 1 (Drosophila) (ROBO1) interactions. METHODS: C-X-C receptor (CXCR)4 and ROBO1 protein expression was measured in mouse and human T cells. Parallel plate flow chamber adhesion and detachment studies were performed to examine the molecular importance of ROBO1 and SLIT2 for SDF-1-mediated T cell chemorepulsion. Diabetogenic splenocyte transfer was performed in NOD/LtSz Rag1(-/-) mice to examine the effect of the SDF-1 mimetic CTCE-0214 on adoptive transfer of diabetes. RESULTS: CXCR4 and ROBO1 protein expression was elevated in diabetic NOD/ShiLtJ T cells over time and coincided with the onset of hyperglycaemia. CXCR4 and ROBO1 expression was also increased in human type 1 diabetic T cells, with ROBO1 expression maximal at less than 1 year post diagnosis. Cell detachment studies revealed that immunoneutralisation of ROBO1 prevented SDF-1-mediated chemorepulsion of NOD T cell firm adhesion to TNFα-stimulated islet endothelial cells. SDF-1 increased NOD T cell adhesion to recombinant adhesion molecules, a phenomenon that was reversed by recombinant SLIT2. Finally, we found that an SDF-1 peptide mimetic prevented NOD T cell adhesion in vitro and significantly delayed adoptive transfer of autoimmune diabetes in vivo. CONCLUSIONS/INTERPRETATION: These data reveal a novel molecular pathway, which regulates diabetogenic T cell recruitment and may be useful in modulating autoimmune diabetes.

Estimation of bovine leukemia virus (BLV) proviral load harbored by lymphocyte subpopulations in BLV-infected cattle at the subclinical stage of enzootic bovine leucosis using BLV-CoCoMo-qPCR.

BACKGROUND: Bovine leukemia virus (BLV) is associated with enzootic bovine leukosis (EBL), which is the most common neoplastic disease of cattle. BLV infection may remain clinically silent at the aleukemic (AL) stage, cause persistent lymphocytosis (PL), or, more rarely, B cell lymphoma. BLV has been identified in B cells, CD2+ T cells, CD3+ T cells, CD4+ T cells, CD8+ T cells, γ/δ T cells, monocytes, and granulocytes in infected cattle that do not have tumors, although the most consistently infected cell is the CD5+ B cell. The mechanism by which BLV causes uncontrolled CD5+ B cell proliferation is unknown. Recently, we developed a new quantitative real-time polymerase chain reaction (PCR) method, BLV-CoCoMo-qPCR, which enabled us to demonstrate that the proviral load correlates not only with BLV infection, as assessed by syncytium formation, but also with BLV disease progression. The present study reports the distribution of BLV provirus in peripheral blood mononuclear cell subpopulations isolated from BLV-infected cows at the subclinical stage of EBL as examined by cell sorting and BLV-CoCoMo-qPCR. RESULTS: Phenotypic characterization of five BLV-infected but clinically normal cattle with a proviral load of > 100 copies per 1 × 105 cells identified a high percentage of CD5+ IgM+ cells (but not CD5- IgM+ B cells, CD4+ T cells, or CD8+T cells). These lymphocyte subpopulations were purified from three out of five cattle by cell sorting or using magnetic beads, and the BLV proviral load was estimated using BLV-CoCoMo-qPCR. The CD5+ IgM+ B cell population in all animals harbored a higher BLV proviral load than the other cell populations. The copy number of proviruses infecting CD5- IgM+ B cells, CD4+ cells, and CD8+ T cells (per 1 ml of blood) was 1/34 to 1/4, 1/22 to 1/3, and 1/31 to 1/3, respectively, compared with that in CD5+ IgM+ B cells. Moreover, the BLV provirus remained integrated into the genomic DNA of CD5+ IgM+ B cells, CD5- IgM+ B cells, CD4+ T cells, and CD8+ T cells, even in BLV-infected cattle with a proviral load of <100 copies per 105 cells. CONCLUSIONS: The results of the recent study showed that, although CD5+ IgM+ B cells were the main cell type targeted in BLV-infected but clinically normal cattle, CD5- IgM+ B cells, CD4+ cells, and CD8+ T cells were infected to a greater extent than previously thought.

Development of a centrifugal bioreactor for rapid expansion of CD8 cytotoxic T cells for use in cancer immunotherapy.

One of the current difficulties limiting the use of adoptive cell therapy (ACT) for cancer treatment is the lack of methods for rapidly expanding T cells. As described in the present report, we developed a centrifugal bioreactor (CBR) that may resolve this manufacturing bottleneck. The CBR operates in perfusion by balancing centrifugal forces with a continuous feed of fresh medium, preventing cells from leaving the expansion culture chamber while maintaining nutrients for growth. A bovine CD8 cytotoxic T lymphocyte (CTL) cell line specific for an autologous target cell infected with a protozoan parasite, Theileria parva, was used to determine the efficacy of the CBR for ACT purposes. Batch culture experiments were conducted to predict how CTLs respond to environmental changes associated with consumption of nutrients and production of toxic metabolites, such as ammonium and lactate. Data from these studies were used to develop a kinetic growth model, allowing us to predict CTL growth in the CBR and determine the optimal operating parameters. The model predicts the maximum cell density the CBR can sustain is 5.5 × 107 cells/mL in a single 11-mL conical chamber with oxygen being the limiting factor. Experimental results expanding CTLs in the CBR are in 95% agreement with the kinetic model. The prototype CBR described in this report can be used to develop a CBR for use in cancer immunotherapy.

Flow cytometric detection of IFN-γ production and Caspase-3 activation in CD4+ T lymphocytes to discriminate between healthy and Mycobacterium bovis naturally infected water buffaloes.

Tuberculosis has a negative economic impact on buffalo farming, and it poses a potential threat to human health. Interferon-gamma (IFN-γ) plays a central role in protection against mycobacterial diseases, illustrating the importance of T-cell mediated immune responses in tuberculosis infection. Recently, the expression of Caspase-3, a critical executor of apoptosis, in M. tuberculosis-specific IFN-γ+CD4+ T cells was used as a new marker to distinguish active from latent tuberculosis infection in humans. The aims of this work were to develop a whole blood flow cytometric assay to detect the production of IFN-γ and the activation of Caspase-3 by CD4+ T lymphocytes from water buffalo and to evaluate whether these parameters can discriminate between healthy and M. bovis naturally infected buffaloes. A total of 35 Italian Mediterranean buffaloes were grouped in two groups: uninfected and M. bovis infected (based on the results of antemortem diagnostic tests: single intradermal tuberculin (SIT) and ELISA IFN-γ tests). Whole blood was incubated for 6 h with tubercular antigens: PPD-B, PPD-A, ESAT-6/CFP-10 and a new mix of precocious secreted antigens (PA). Our results showed a significant increase in the percentage of IFN-γ+CD4+ T cells in infected compared to the uninfected animals after each stimulus. Improved sensitivity of the assay was obtained by including the stimulation with the new mix of PA. Interestingly, we observed a concomitant decrease in percentage of Caspase-3+CD4+ T cells in M. bovis infected animals compared to the control healthy ones, regardless of the stimulus used. Overall, these results showed that M. bovis infection activates CD4+ T lymphocytes to produce IFN-γ and at the same time causes a concomitant decrease of Caspase-3 activation in CD4+ T cells. This study for the first time in water buffalo describes the development of a whole blood flow cytometric assay for the detection of IFN-γ producing CD4+ T cells and proposes the expression of active Caspase-3 as an additional bovine TB biomarker. Although further studies are needed to better understand the mechanisms of Caspase-3-mediated cell death during tuberculosis, our data can help to better understand the cellular immune response to M. bovis infection in buffalo species.

Infection with Mycobacterium avium subsp. paratuberculosis results in rapid interleukin-1ß release and macrophage transepithelial migration.

Pathogen processing by the intestinal epithelium involves a dynamic innate immune response initiated by pathogen-epithelial cell cross talk. Interactions between epithelium and Mycobacterium avium subsp. paratuberculosis have not been intensively studied, and it is currently unknown how the bacterium-epithelial cell cross talk contributes to the course of infection. We hypothesized that M. avium subsp. paratuberculosis harnesses host responses to recruit macrophages to the site of infection to ensure its survival and dissemination. We investigated macrophage recruitment in response to M. avium subsp. paratuberculosis using a MAC-T bovine macrophage coculture system. We show that M. avium subsp. paratuberculosis infection led to phagosome acidification within bovine epithelial (MAC-T) cells as early as 10 min, which resulted in upregulation of interleukin-1ß (IL-1ß) at transcript and protein levels. Within 10 min of infection, macrophages were recruited to the apical side of MAC-T cells. Inhibition of phagosome acidification or IL-1ß abrogated this response, while MCP-1/CCL-2 blocking had no effect. IL-1ß processing was dependent upon Ca(2+) uptake from the extracellular medium and intracellular Ca(2+) oscillations, as determined by EGTA and BAPTA-AM [1,2-bis(2-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid tetrakis (acetoxymethyl ester)] treatments. Thus, M. avium subsp. paratuberculosis is an opportunist that takes advantage of extracellular Ca(2+)-dependent phagosome acidification and IL-1ß processing in order to efficiently transverse the epithelium and enter its niche--the macrophage.

Chemoaffinity capture of pre-targeted prostate cancer cells with magnetic beads.

BACKGROUND: Prostate circulating tumor cells (PCTCs) in circulation are shed from either a primary tumor or metastases, which are directly responsible for most prostate cancer deaths. Quantifying exfoliated PCTCs may serve as an indicator for the clinical management of prostate cancer, isolating and removing of PCTCs could potentially reduce prostate cancer metastasis, and culturing and characterizing captured PCTCs could facilitate the development of personalized treatment options. Prostate-specific membrane antigen (PSMA) is an established biomarker for prostate cancer being strongly expressed on prostate tumor cells associated with high-grade primary, androgen independent, and metastatic tumors. METHODS: Suspensions of PSMA+ (LNCaP) cells were pre-targeted with the irreversible PSMA inhibitor biotin-PEG(12)-CTT-54 to serve as a bait to capture PSMA+ cells using streptavidin-coated magnetic beads. Decreasing numbers of LNCaP cells were spiked into blood to determine the cell captured efficiency, recovery and viability. RESULTS: High selectivity, recovery, and viability were achieved for the capture of PSMA+ cells in both model experiments with mixtures of LNCaP cells and WBCs as well as blood samples spiked with LNCaP cells. As low as 10 cells were captured from 1 ml of blood with nearly 90% viability. More importantly, captured cells could be subsequently propagated in vitro. CONCLUSIONS: This methodology for the detection, isolation, and culture of PCTCs from peripheral blood can serve as an effective tool for the detection of metastatic prostate cancer, treatment monitoring, and the development of personalized therapy based on the responsiveness of PCTCs to chemotherapeutic strategies.

Cell-surface expression of PrPC and the presence of scrapie prions in the blood of goats.

Although host-encoded prion protein (PrP(C)) expression in ovine PBMCs and prion infectivity in scrapie-infected sheep blood have been demonstrated, such studies have not been reported in goats. Therefore, this study characterized cell-surface expression of PrP(C) on PBMC subsets derived from normal goats and sheep, by flow cytometry, and determined prion infectivity in blood from a scrapie-infected goat using a transfusion bioassay in goat kids. Cell-surface PrP(C) expression was detected on all subsets of goat PBMCs. The highest PrP(C) cell-surface expression was found in CD2(+) T lymphocytes in goats. Transmission of infection was detected in all three recipients who received whole blood from a goat with classical scrapie. It was concluded that caprine PBMCs express PrP(C) similarly to sheep but with relative differences among PBMCs subsets, and that blood-borne infectious prions can be detected in scrapie-infected goats. Thus, similar to sheep, goat blood may be a suitable diagnostic target for the detection of scrapie infection.

Ex vivo Platforms to Study the Primary and Recall Immune Responses to Intracellular Mycobacterial Pathogens and Peptide-Based Vaccines.

Progress in the study of the immune response to pathogens and candidate vaccines has been impeded by limitations in the methods to study the functional activity of T-cell subsets proliferating in response to antigens processed and presented by antigen presenting cells (APC). As described in this review, during our studies of the bovine immune response to a candidate peptide-based vaccine and candidate rel deletion mutants in Mycobacterium avium paratuberculosis (Map) and Mycbacterium bovis (BCG), we developed methods to study the primary and recall CD4 and CD8 T-cell responses using an ex vivo platform. An assay was developed to study intracellular killing of bacteria mediated by CD8 T cells using quantitative PCR to distinguish live bacteria from dead bacteria in a mixed population of live and dead bacteria. Through use of these assays, we were able to demonstrate vaccination with live rel Map and BCG deletion mutants and a Map peptide-based vaccine elicit development of CD8 cytotoxic T cells with the ability to kill intracellular bacteria using the perforin-granzyme B pathway. We also demonstrated tri-directional signaling between CD4 and CD8 T cells and antigen-primed APC is essential for eliciting CD8 cytotoxic T cells. Herein, we describe development of the assays and review progress made through their use in the study of the immune response to mycobacterial pathogens and candidate vaccines. The methods obviate some of the major difficulties encountered in characterizing the cell-mediated immune response to pathogens and development of attenuated and peptide-based vaccines.

Comparative analysis of the specificity of monoclonal antibodies developed against the bottlenose dolphin, Tursiops truncatus, TNF-α, IL1-ß, IL-6, IL-8, IL-10 with monoclonal antibodies made against ovine IFN-γ bovine IL-17A and IL-1ß revealed they recognize epitopes conserved on dolphin and bovine orthologues.

Opportunities to include Cetancodontamorpha in the study of the evolution of the immune system in the clades of Artiodactylamorpha, Ruminantiamorpha, Suinamorpha, and Camelidamorpha have increased with the use of the bottlenose dolphin, Tursiops truncatus, as a sentinel species to study the effects of environmental pollutants on the health of marine mammals. Efforts are currently underway to increase the number reagents needed for detailed studies. Thus far, screening of monoclonal antibodies (mAbs) made to leukocyte differentiation molecules (LDM) and the major histocompatibility (MHC) class I and class II molecules in Ruminantiamorpha have yielded some mAbs that recognize conserved epitopes expressed on orthologues in the bottlenose dolphin. More direct approaches are in progress to identify additional mAbs to bottlenose LDM and cytokines. As reported here, both direct and indirect approaches were used to identify mAbs specific for cytokines useful in monitoring the effects of environmental pollutants on the immune system. Immunization of mice with expressed bottlenose dolphin cytokines yielded mAbs specific for IFN-γ, TNF-α, IL-6, IL-8, IL-10, and IL-17A. Screening of previously developed mAbs used in livestock immunology research revealed mAbs developed against ovine IFN-γ and bovine IL-17 and IL-1ß recognize conserved epitopes in bottlenose dolphin orthologues. The mAbs identified in the present study expand the reagents available to study the function of the immune system in bottlenose dolphins and cattle.

Au@PtPd enhanced immunoassay with 3D printed smartphone device for quantification of diaminochlorotriazine (DACT), the major atrazine biomarker.

Increased use of pesticides in agriculture requires new advanced techniques to monitor both environmental levels and human exposure of pesticides to avoid potential adverse health outcomes in sensitive populations. Atrazine is widely used to control broadleaf weeds, and here we developed a new sensor capable of detecting diaminochlorotriazine (DACT), the major metabolite and biomarker of atrazine exposure. We established an Au@PtPd nanoparticles labeled lateral flow immunoassay (LFIA) for immunochromatographic based rapid detection of urinary DACT. The detection was based on competitive immunoassay between the analyte and the BSA-conjugated antigen. As evaluated, the coupled mesoporous core-shell Au@PtPd nanoparticles, with superior peroxidase-like activity, as the signal indicator offers a rapid direct chromatographic readout inversely correlated with the concentration of analytes, providing a detection limit of 0.7 ng/mL for DACT. Moreover, the detection limits were boosted to as low as 11 pg/mL with the detectable range from 10 pg/ml to 10 ng/mL, through a one-step catalytic chromogenic reaction. A rapid readout device was developed by 3D printing to provide a stable real-time quantification of the color intensity capable of assessing both chromatographic and absorbance results. This Au@PtPd nanoparticle-based immunosensing platform, as well as the 3D printed readout device, provide a promising tool for on-site and ultrasensitive detection of pesticide biomarkers.

Flow cytometric detection of prostate tumor cells using chemoaffinity labels.

BACKGROUND: The enzyme-biomarker prostate-specific membrane antigen (PSMA) is an emerging target for imaging and therapeutic applications for prostate cancer. However, the use of PSMA for detecting circulating prostate tumor cells remains under-explored. The present study focuses on the specific labeling of PSMA+ prostate cancer cells with a fluorescent PSMA inhibitor and the quantitation of PSMA+ cells in blood by flow cytometry (FC) using a gating strategy to separate labeled PSMA+ cells from peripheral blood mononuclear cells. METHODS: Suspensions of PSMA+ (LNCaP) and PSMA- (DU145) cells were incubated with the fluorescent PSMA inhibitor FAMX-CTT-54. Incubation parameters (time, temperature, and label concentration) were varied to optimize cell labeling. A gating protocol based on double fluorescent labeling of CD45 and PSMA was developed for the quantitiation of LNCaP cells in the presence of white blood cells from bovine blood. Nonfluorescent beads were added to the labeled cell mixture and served as internal standard for precise cellular quantification of LNCaP cells by flow cytometry. RESULTS: The fluorescent PSMA inhibitor FAMX-CTT-54 was specific for PSMA+ cells. The minimum time and concentration of FAMX-CTT-54 for effective labeling of PSMA+ cell suspensions at 37°C was 7.5 min and 35 nM, respectively; no labeling was observed on PSMA- cells. Co-incubation or pre-incubation of PSMA+ cells with the unlabeled PSMA inhibitor CTT-54 resulted in a concentration-dependent reduction in fluorescent labeling with FAMX-CTT-54 thereby confirming that the labeling was specific for PSMA. In blood samples in which LNCaP cells were added, an average of five cells were detected in a 115 µl sample of the most dilute sample examined (29 cells/ml); three cells were expected theoretically. The greater loss of labeling of PSMA+ cells with FAMX-CTT-54 when pre-incubated with CTT-54 is consistent with the irreversible mode of binding of CTT-54 to PSMA and subsequent internalization of the PSMA-inhibitor complex. CONCLUSIONS: The results suggest that fluorescent PSMA inhibitors can be utilized to effectively detect and quantify PSMA+ cells by FC. These results support the use of such compounds in the application of FC to detect, quantify, and characterize circulating prostate tumor cells.

Tuberculosis immunity: opportunities from studies with cattle.

Mycobacterium tuberculosis and M. bovis share >99% genetic identity and induce similar host responses and disease profiles upon infection. There is a rich history of codiscovery in the development of control measures applicable to both human and bovine tuberculosis (TB) including skin-testing procedures, M. bovis BCG vaccination, and interferon-γ release assays. The calf TB infection model offers several opportunities to further our understanding of TB immunopathogenesis. Recent observations include correlation of central memory immune responses with TB vaccine efficacy, association of SIRPα(+) cells in ESAT-6:CFP10-elicited multinucleate giant cell formation, early γδ T cell responses to TB, antimycobacterial activity of memory CD4(+) T cells via granulysin production, association of specific antibody with antigen burden, and suppression of innate immune gene expression in infected animals. Partnerships teaming researchers with veterinary and medical perspectives will continue to provide mutual benefit to TB research in man and animals.