Antibodies associated with the Kell blood group system.

The Kell blood group presently includes 23 antigens [1], a null (K 0 ) phenotype, a number of phenotypes characterized by weak Kell antigen activity, and an independent antigen, designated Kx, which appears to play a role in Kell antigen expression. Kell blood-group antigens are markers on the surface-exposed domain of a 93,000 daltons (93 kD) membrane glycoprotein [2]. Intrachain disulfide linkages [3], and probably the proper intra-membrane milieu, are important for the antigenic integrity of Kell 93 kD protein. Separated 93 kD Kell protein does not react by Western blot analysis with the Kell antibody used for its initial immuno-precipitation [1]. Incubation of intact red cells with solutions containing papain/DTT mixture [4] or 2-aminoethylisothiouronium bromide (AET) inactivates all antigens of the Kell complex except for Kx [5]. Five monoclonal antibodies have been examined for serological specificity within the Kell system and for their ability to recognize epitopes on a 93 kD red cell membrane protein by Western blot analysis.