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Comparative reactivity of human IgE to cynomolgus monkey and human effector cells and effects on IgE effector cell potency.

ABSTRACT: Due to genetic similarities with humans, primates of the macaque genus such as the cynomolgus monkey are often chosen as models for toxicology studies of antibody therapies. IgE therapeutics in development depend upon engagement with the Fc?RI and Fc?RII receptors on immune effector cells for their function. Only limited knowledge of the primate IgE immune system is available to inform the choice of models for mechanistic and safety evaluations.The recognition of human IgE by peripheral blood lymphocytes from cynomolgus monkey and man was compared. We used effector cells from each species in ex vivo affinity, dose-response, antibody-receptor dissociation and potency assays.We report cross-reactivity of human IgE Fc with cynomolgus monkey cells, and comparable binding kinetics to peripheral blood lymphocytes from both species. In competition and dissociation assays, however, human IgE dissociated faster from cynomolgus monkey compared with human effector cells. Differences in association and dissociation kinetics were reflected in effector cell potency assays of IgE-mediated target cell killing, with higher concentrations of human IgE needed to elicit effector response in the cynomolgus monkey system. Additionally, human IgE binding on immune effector cells yielded significantly different cytokine release profiles in each species.These data suggest that human IgE binds with different characteristics to human and cynomolgus monkey IgE effector cells. This is likely to affect the potency of IgE effector functions in these two species, and so has relevance for the selection of biologically-relevant model systems when designing pre-clinical toxicology and functional studies.

SUBMITTER: Saul L

PROVIDER: S-EPMC3984339 | biostudies-literature | 2014 Mar-Apr

REPOSITORIES: biostudies-literature

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Comparative reactivity of human IgE to cynomolgus monkey and human effector cells and effects on IgE effector cell potency.

Saul Louise L Josephs Debra H DH Cutler Keith K Bradwell Andrew A Karagiannis Panagiotis P Selkirk Chris C Gould Hannah J HJ Jones Paul P Spicer James F JF Karagiannis Sophia N SN

mAbs 20140114 2

<h4>Background</h4>Due to genetic similarities with humans, primates of the macaque genus such as the cynomolgus monkey are often chosen as models for toxicology studies of antibody therapies. IgE therapeutics in development depend upon engagement with the FcεRI and FcεRII receptors on immune effector cells for their function. Only limited knowledge of the primate IgE immune system is available to inform the choice of models for mechanistic and safety evaluations.<h4>Methods</h4>The recognition ...[more]

PMID: 24492303

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Project description:BACKGROUND: Non-human primates (NHP) are now being considered as models for investigating human metabolic diseases including diabetes. Analyses of cholesterol and triglycerides in plasma derived from NHPs can easily be achieved using methods employed in humans. Information pertaining to other lipid species in monkey plasma, however, is lacking and requires comprehensive experimental analysis. METHODOLOGIES/PRINCIPAL FINDINGS: We examined the plasma lipidome from 16 cynomolgus monkey, Macaca fascicularis, using liquid chromatography coupled with mass spectrometry (LC/MS). We established novel analytical approaches, which are based on a simple gradient elution, to quantify polar lipids in plasma including (i) glycerophospholipids (phosphatidylcholine, PC; phosphatidylethanolamine, PE; phosphatidylinositol, PI; phosphatidylglycerol, PG; phosphatidylserine, PS; phosphatidic acid, PA); (ii) sphingolipids (sphingomyelin, SM; ceramide, Cer; Glucocyl-ceramide, GluCer; ganglioside mannoside 3, GM3). Lipidomic analysis had revealed that the plasma of human and cynomolgus monkey were of similar compositions, with PC, SM, PE, LPC and PI constituting the major polar lipid species present. Human plasma contained significantly higher levels of plasmalogen PE species (p<0.005) and plasmalogen PC species (p<0.0005), while cynomolgus monkey had higher levels of polyunsaturated fatty acyls (PUFA) in PC, PE, PS and PI. Notably, cynomolgus monkey had significantly lower levels of glycosphingolipids, including GluCer (p<0.0005) and GM(3) (p<0.0005), but higher level of Cer (p<0.0005) in plasma than human. We next investigated the biochemical alterations in blood lipids of 8 naturally occurring diabetic cynomolgus monkeys when compared with 8 healthy controls. CONCLUSIONS: For the first time, we demonstrated that the plasma of human and cynomolgus monkey were of similar compositions, but contained different mol distribution of individual molecular species. Diabetic monkeys exhibited decreased levels of sphingolipids, which are microdomain-associated lipids and are thought to be associated with insulin sensitivity. Significant increases in PG species, which are precursors for cardiolipin biosynthesis in mitochondria, were found in fasted diabetic monkeys (n?=?8).

Project description:Objective: To examine the effects of the phytoestrogen metabolite, equol, on gene expression in the monkey iliac artery. Design: Eight ovariectomized cynomolgus monkeys were on a high fat diet for 6.5 years. The left iliac artery was biopsied prior to randomization to equol (0.0237 g/100 g chow, n=4) or vehicle (n=4) for 8 months. The right iliac artery was obtained at necropsy. Gene expression in the iliac arteries in response to equol was determined by DNA microarray and confirmed by real time RT-PCR. Results: Atherosclerotic lesions in the iliac arteries ranged in size from 0.113-1.003 mm2 in equol-treated animals and from 0-0.873 mm2 in control animals. 59 genes were down-regulated and 279 were up-regulated in response to equol. Comparison of these data to previous work identified 10 genes regulated in opposite directions by equol compared to presence of atherosclerosis plaque. 55 genes were differentially expressed in the same direction in response to both equol and estradiol. Conclusions: Similar responses of genes to both equol and estradiol may reflect the extent to which equol serves as a natural selective estrogen receptor modulator in the arteries. Opposite responses of 10 genes to equol versus the presence of atherosclerosis implicates those genes in the potential protective effects of equol in the vasculature. Experiment Design: Goal of the experiment: To examine differential gene expression in the iliac arteries of ovariectomized cynomolgous monkeys on a high fat diet in response to treatment with equol. Brief description of the experiment: Objective: To examine the effects of the phytoestrogen metabolite, equol, on gene expression in the monkey iliac artery. Design: Four ovariectomized cynomolgous monkeys were on a high fat diet for 6.5 years. The left iliac artery was biopsied prior to randomization to equol (0.0237 g/100 g chow, n=4 or vehicle (n=4) for 8 months. The right iliac artery was obtained at necropsy. Gene expression in response to equol was determined by CodeLink Whole Human Genome DNA microarrays and confirmed by real time RT-PCR. Results: Atherosclerotic lesions in the iliac arteries ranged in size from 0.113-1.003 mm2 (mean 0.512 ± 0.19 mm2) in pretreatment arteries and 0.025-1.217 mm2 (mean 0.748 ± 0.22 mm2) post-equol treatment. 59 genes were down-regulated and 279 were up-regulated in response to equol. Comparison of these data to previous work identified 10 genes regulated in opposite directions by equol compared to presence of atherosclerosis plaque. 55 genes were differentially expressed in the same direction in response to both equol and estradiol. Conclusions: Similar responses of genes to both equol and estradiol may reflect the extent to which equol serves as a natural selective estrogen receptor modulator in the arteries. Opposite responses of 10 genes to equol versus the presence of atherosclerosis implicates those genes in the potential protective effects of equol in the vasculature. Keywords: nonhuman primate, equol treatment, soy isoflavones Experimental factors: equol treatment Experimental design: Female cynomolgous monkeys (n=4) had been ovariectomized for 4 years and on a high fat diet for 6.5 years. The left iliac artery was removed at surgical biopsy. Animals were treated with equol for 8 months, then necropsied. The right iliac artery was obtained at necropsy. The presence and size of atherosclerotic plaque was quantified in the iliac arteries. Arterial tissue from the iliac arteries was used for DNA microarray analysis of gene expression. Quality control steps: The cRNA that was synthesized from each iliac artery was used for hybridization to a single CodeLink (Applied Microarrays, Tempe, AZ) whole human microarray. Only one sample was hybridized with each slide and only one dye (Alexa 647) was used so no dye swaps were necessary. Bacterial control spikes were used as per manufacturer's instructions. Samples used, extract preparation and labeling: The origin of each biological sample: The samples were iliac arterial tissue from cynomolgous monkeys. Manipulations of biological samples and protocols used: Cynomolgous monkeys were placed on a high fat diet 6.5 years before the experiment and ovariectomized 4 years prior to the experiment to induce a surgical menopause. The left iliac artery was surgically removed from each animal in the study before treatment with equol, the the right iliac artery was removed after the treatment period at necropsy. The presence and size of atherosclerotic plaque was quantified in the iliac arteries Experimental factor: hormone treatment Technical protocols: The iliac arteries were homogenized in TRI reagent, bromochloropropane and sodium acetate were added, and the samples were centrifuged to separate the phases. The RNA-containing layer was removed and the RNA purified on an RNeasy extraction column (Qiagen). The sample was treated with an on-column DNase treatment (RNase-free DNase, Qiagen). The purity and quantity of RNA were evaluated by an Agilent Bioanalyzer using the RNA 6000 Nanoassay LabChip. Labeled cRNA was prepared using the MessageAmp II-Biotin enhanced kit (Ambion). 0.275 microgram of total iliac artery RNA was mixed with bacterial control RNA spikes and primed with T7 oligo(dT) primer for 10 min at 70C. (The bacterial control spikes included araB, entF, fixB, gnd, hisB, and leuB.) The first strand of cDNA was synthesized with first strand buffer, dNTP mix, RNase inhibitor, and reverse transcriptase for 2 h at 42C. The second strand cDNA synthesis reaction was prepared using second strand buffer, dNTP mix, DNA polymerase mix, and RNase H; the reaction was carried out for 2h at 16C. The double-stranded cDNA was purified on QIAquick columns (Qiagen) and the eluent was dried down in a SpeedVac concentrator. The double-stranded cDNA was resuspended in a mixture containing T7 reaction buffer, T7 ATP, T7 GTP, T7 UTP, T7 CTP, biotin-11-UTP, and T7 enzyme mix for the synthesis of cRNA. The cRNA synthesis reaction was terminated after 14h at 37C by purifying the cRNA on RNeasy columns (Qiagen). The concentration of cRNA was determined by spectrophotometry. Hybridization procedures and parameters: 10 micrograms of cRNA was mixed with fragmentation buffer and heated to 94C for 20 min. The fragmented cRNA was mixed with CodeLink hybridization buffer, loaded on the microarray slides, and hybridized for 18 hours at 37C. The slides were washed in 0.75x TNT (Tris-HCl, NaCl, Tween-20) at 46C for 1h then incubated with streptavidin-Alexa 647 fluorescent dye for 30 min at room temperature. The Alexa fluor was prepared in TNB blocking buffer (0.1M Tris-HCl, 0.15M NaCL, 0.5% NEN Blocking Reagent-PerkinElmer) The slides were then washed 4 times for 5 min each in 1x TNT and twice in 0.05% Tween 20 for 5 sec each. The slides were dried by centrifugation and scanned in an Axon GenePix 4000B scanner.

Dataset Information

Comparative reactivity of human IgE to cynomolgus monkey and human effector cells and effects on IgE effector cell potency.

Publications

Comparative reactivity of human IgE to cynomolgus monkey and human effector cells and effects on IgE effector cell potency.

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