Serologic and IgG subclass characterization of Cartwright (Yt) and Gerbich (Ge) antibodies

Examples of anti-Yta and anti-Ge were tested for reactivity with red cells treated with proteolytic enzymes and with antisera of known IgG specificity. Eight of 14 examples of anti-Yta did not react as well with cells treated with either papain or ficin; treatment with trypsin did not reduce reactivity. Four examples of the anti-Yta were IgG4; the others tested did not react with IgG subclass antisera. Of 13 examples of anti-Ge, seven failed to react with red cells treated with trypsin, ficin, or papain. Nine examples were IgG1, one was IgG1 plus IgG3, and three did not react with IgG subclass antisera.