Use of indium-111 in antibody-dependent complement-mediated cytotoxicity assay for detection of B locus alloantigens on chicken lymphocytes.

An antibody-dependent complement-mediated cytotoxicity assay has been devised to detect B locus alloantigens on the surface of peripheral blood lymphocytes. The assay utilizes unheated chicken antiserum and guinea pig complement, which cooperate to yield specific lysis of 111In-labeled target cells. Specific cell lysis appears to be mediated by the classical complement pathway and can be inhibited by heat inactivation of the guinea pig complement. Heat inactivation of the chicken antiserum results in partial inhibition of cell lysis which can be restored by the addition of a small amount of unheated normal chicken serum. The use of a 111In-oxine chelate was found to be a quick and efficient way to label chicken cells. It has a high labeling efficiency, localizes primarily in the cytoplasm, and is released specifically from dead cells in a form that cannot be reutilized. The highly sensitive detection of B locus alloantigens with this assay strongly suggest that it will be of equal value in the detection of other alloantigens, tumor-specific (transplantation) antigens, and differentiation antigens on the surface of chicken cells.