Development of a Novel IgG Anaphylaxis Mouse Model with Uniquely Characteristic Skin Manifestations Induced Through the FcγRIII-Histamine Pathway.

Background: Studies of passive anaphylaxis, in which mouse immunoglobulin G (IgG) and its antigens are administered to mice, believe that platelet-activating factor (PAF) is more important than histamine and that basophils or macrophages are primarily involved. However, the full extent of IgG-dependent anaphylaxis is still unclear; that is, little agreement has been reached about the mechanism.

Methods: First, we established the novel model of IgG anaphylaxis induced by the intravenous administration of two types of IgG and a fluorescent dye-labeled antigen, as IgG immune complex in HR-1 hairless mice.

Immunoglobulin a suppresses B cell receptor-mediated activation of mouse B cells with differential inhibition of signaling molecules.

Context: We previously reported that monoclonal mouse immunoglobulin (Ig) A, OA-4, attenuates sensitization in mice by suppressing B cell activation.

Objective: Here, it is demonstrated for the first time that mouse IgA inhibits mouse B cell activation under natural conditions (i.e.