Toxoplasma gondii is well-known to subvert normal immune responses, however, mechanisms are incompletely understood. In particular, its capacity to alter receptor-activated Ca(2+)-mediated signaling processes has not been well-characterized. In initial experiments, we found evidence that T. gondii infection inhibits Ca(2+) responses to fMetLeuPhe in murine macrophages. To further characterize t...

Mast cells originate from pluripotent hematopoietic stem cells. Two mast cell specific antibodies, mAbsAA4 and BGD6, have previously been used to identify and study committed mast cell precursors (MCcps) in the bone marrow of adult mice and rats. However, the embryonic origin of MCcps is still not known. In the present study, we identified MCcps in rat embryos using these previously characteriz...

BACKGROUND/AIMS MicroRNAs (miRNAs) are critical regulators of immune responses and immunologic disorders. However, little is known about miRNA expression and function during mast cell differentiation, proliferation and activation. This study aimed to determine the miRNA expression profiles in mast cells stimulated by immunoglobulin E (IgE) and antigen and to analyze the potential functions of s...

Immunoglobulin E (IgE) is the antibody that plays a central role in the mechanisms of allergic diseases such as asthma. Interactions with its receptors, FcεRI on mast cells and CD23 on B cells, are mediated by the Fc region, a dimer of the Cε2, Cε3 and Cε4 domains. A sub-fragment lacking the Cε2 domains, Fcε3-4, also binds to both receptors, although receptor binding almost exclusively involves...

Mast cells are major players in allergic responses. IgE-dependent activation through FcεR leads to degranulation and cytokine production, both of which require Gab2. To clarify how the signals diverge at Gab2, we established Gab2 knock-in mice that express Gab2 mutated at either the PI3K or SH2 domain-containing protein tyrosine phosphatase-2 (SHP2) binding sites. Examination of these mutants s...

Dendritic cells (DCs) are sentinels of the immune system for antigen recognition and uptake, as well as presentation to naïve T cells for stimulation or priming. Internalization and endocytic degradation of allergens by DCs are important steps required for T cell priming. In the current study we investigated binding and internalization of purified recombinant non-glycosylated grass pollen aller...

165 words Text: 4999 words Running title: Role of RabGEF1 Vps9 domain in cell activation Category: Immunobiology Corresponding Author: Stephen J. Galli Department of Pathology, Stanford University School of Medicine, Stanford, CA 943055324, USA [email protected] Phone: (650) 723-7975 Fax: (650) 725-6902 Blood First Edition Paper, prepublished online March 6, 2007; DOI 10.1182/blood-2007-01-06...