Sensitization of Mice with Human IgA

Abstract

IT is well known that an increased vascular permeability produced by various agents can be visualized by the leakage of intravenously administered dye through the affected vessels. The vascularity and high histamine and serotonin content of mouse ears¹ suggested that these organs might be useful in the visualization of in vivo antigen–antibody reactions. While investigating the ability of intravenously administered pollen extracts to induce blueing of the ears of mice², Kind et al. also found that mice sensitized with bovine serum albumin (BSA) developed blueing of the ears when later challenged intravenously with BSA and Evans blue dye. When blueing of the ears was produced in normal mice by the intravenous injection of BSA, rabbit anti-BSA and dye, no latent period was found to be necessary for the ‘fixation’ of antigen or antibody³. Indeed, in mice, maximal incidence of anaphylaxis with rabbit antibody can be obtained by injecting antibody and antigen intravenously in rapid succession⁴. The apparent absence of a requirement for tissue fixation in mice suggested that blueing of the ears in anaphylactic mice might be useful for detecting such proteins as normal human IgA or myeloma IgA, which will not sensitize guinea-pig skin for reverse passive cutaneous anaphylaxis probably because of the lack of fixation sites on such molecules⁵.