Project description:This clinical trial studies the side effects of 18F-alphavbeta6-binding-peptide and how well it works in imaging patients with primary or cancer that has spread to the breast, colorectal, lung, or pancreatic. Radiotracers, such as 18F-alphavbeta6-binding-peptide, may improve the ability to locate cancer in the body.
Project description:IgE-binding monocytes are a rare peripheral immune cell type involved in the allergic response through binding of IgE on their surface. IgE-binding monocytes are present in both healthy and allergic individuals. We performed RNA sequencing to ask how the function of IgE-binding monocytes differs in the context of allergy. Using a large animal model of allergy, equine Culicoides hypersensitivity, we compared the transcriptome of IgE-binding monocytes in allergic and non-allergic horses at two seasonal timepoints: (i) when allergic animals were clinical healthy, in the winter “Remission Phase”, and (ii) during chronic disease, in the summer “Clinical Phase”. Most transcriptional differences between allergic and non-allergic horses occurred only during the “Remission Phase”, suggesting principal differences in monocyte function even in the absence of allergen exposure. F13A1, a subunit of fibrinoligase, was significantly upregulated at both timepoints in allergic horses. This suggested a role for increased fibrin deposition in the coagulation cascade to promote allergic inflammation. IgE-binding monocytes also downregulated CCR10 expression in allergic horses during the “Clinical Phase”, suggesting a defect in maintenance of skin homeostasis, which further promotes allergic inflammation. Together, this transcriptional analysis provides valuable clues into the mechanisms used by IgE-binding monocytes in allergic individuals.
Project description:The high-affinity Fc receptor for IgE, mainly present on mast cells and basophils, plays a crucial role in the development of allergic diseases. Monomeric IgE binding to receptor regulates mast cell survival, differentiation, and maturation. However, the underlying molecular mechanism remains unclear. Here we demonstrate that, prior to IgE binding, IgE receptor mostly exists as a homo-dimer on human mast cell membrane. The structure of human IgE receptor confirms the dimeric organization. Cholesterol-like molecules embedded within the transmembrane domain may stabilize the dimeric assembly. Upon IgE binding, the dimeric IgE receptor dissociates into two protomers, each binding to an IgE molecule. Importantly, this process elicits transcriptional activation of Egr1/3 and Ccl2 in rat basophils, which can be attenuated by inhibiting the IgE receptor dimer-to-monomer transition. Collectively, our study unveils the mechanism of antigen-independent, IgE-mediated receptor activation.
Project description:IgE antibody is known as a common mediator of allergic responses, generally produced in type 2 immune responses to allergens. It is known that IgE binding to FcεRI without allergen binding promotes survival or proliferation of mast cells, basophils and other cells. Thus, spontaneously produced IgE, namely natural IgE, can increase an individual’s susceptibility to allergic diseases. Mice with a genetic defect in MyD88, a major signaling molecule downstream of Toll-like receptors, have a high level of serum natural IgE, the mechanism for which remains unknown. Here, we demonstrated that the maintenance of high serum IgE levels depends on memory B cells (MBCs). IgE from plasma cells and the sera from most of Myd88–/– mice, but none of Myd88+/– mice, recognized Streptococcus azizii (S. azizii), a commensal bacterium over-represented in the lung of Myd88–/– mice. IgG1+ MBCs from spleen also recognized S. azizii. The serum IgE levels declined by administration of antibiotics and were boosted by challenge with S. azizii in Myd88–/– mice. Moreover, bulk IgH repertoire analysis revealed that CDR3 sequences were highly shared between IgE+ PCs and IgG1+ or IgG2+ MBCs, indicating the contribution of S. azizii-specific IgG1+ MBCs to the natural IgE production.
Project description:Here we describe the dynamics underlying the generation of IgE-antibody secreting cells (ASC) in human nasal polyps (NP), mucosal tissues rich in ASC without germinal centers (GC). Using VH next generation sequencing, we identified an extrafollicular (EF) mucosal IgD+ naïve-like intermediate B cell population with high connectivity to the mucosal IgE ASC. Mucosal IgD+ B cells, express germline epsilon transcripts and predominantly co-express IgM. However, a small but significant fraction co-express IgG or IgA instead which also show connectivity to ASC IgE. Phenotypically, NP IgD+ B cells display an activated profile and molecular evidence of BCR engagement. Transcriptionally, mucosal IgD+ B cells reveal an intermediate profile between naïve B cells and ASC. Single cell IgE ASC analysis demonstrates lower mutational frequencies relative to IgG, IgA, and IgD ASC consistent with IgE ASC derivation from mucosal IgD+ B cell with low mutational load. In conclusion, we describe a novel mechanism of GC-independent, extrafollicular IgE ASC formation at the nasal mucosa whereby activated IgD+ naïve B cells locally undergo direct and indirect (through IgG and IgA), IgE class-switch.
Project description:The aim of the study was to determine the epitope targeted by 31E10/E7 mouse monoclonal antibody (mAb) and the cross-reactivity to linear peptide epitopes of 10 different Neisserial Heparin Binding Antigen (NHBA) variants. mAb 31E10/E7 was diluted at 1:200 and incubated on a custom PepStar Peptide Microarray platform printed with 560 different peptides in three independent experiments.
Project description:Allergy is one of the most prevalent chronic diseases, affecting hundreds of millions of people worldwide. In allergy, environmental allergens induce B cells to undergo class switch recombination and produce Immunoglobulin E (IgE) antibodies. IgE is a key molecule that mediates allergic responses by coating mast cell or basophil surfaces and inducing degranulation upon binding a specific allergen. IgE can also be spontaneously produced in the absence of exogenous allergens, yet the origin, regulation, and functions of such “natural” IgE still remains largely unknown. Here, we discovered that glucocorticoids, which are steroid stress hormones, enhance IgE isotype class switching in B cells both in vivo and ex vivo without antigenic challenge. Such IgE class switching is promoted by B cell-intrinsic glucocorticoid receptor signaling that reinforces CD40 signaling and synergizes with the IL-4/STAT6 pathway. In addition, we found that rare B cells in the mesenteric lymph nodes are responsible for the production of glucocorticoid-inducible IgE. Furthermore, we showed that locally produced glucocorticoids in the gut may induce natural IgE during perturbations of gut homeostasis such as dysbiosis. Notably, mice preemptively treated with glucocorticoids were protected from subsequent IgE-mediated pathogenic anaphylaxis in vivo. Together, our results suggest that glucocorticoids, classically considered to be broadly immunosuppressive, have a selective immunostimulatory role in B cells.