Analysis of an HL-A antiserum by iso-electric focusing

An anti-HL-A 3 antiserum with cross-reacting activity for HL-A 1 and HL-A 11 was subjected to isoelectric focusing over a pH 5-8 gradient. The cytotoxic activity of the serum focused into three distinct peaks, one at the basic end of the gradient, one between pH 6 and pH 7 and one at the acidic end. The first and second peaks reacted with HL-A 3 positive cells and HL-A 3 negative cells positive for cross-reacting antigens. The third peak reacted only with HL-A 3 positive cells.