A Contribution to the Definition of Monospecific Antileukocyte Sera

Abstract

The majority of antileukocyte sera used for leukocyte antigen typing are polyvalent. Since leukocyte antigens are complexes of antigenic factors*, a polyvalent serum (Iványi and Dausset, 1966). The number of antibodies present in a serum can be reduced by means of absorptions with leukocytes of suitably chosen individuals, which react positively with the serum. The serum absorbed with leukocytes of a positively reacting individual chosen at random is retested with the leukocytes of the donor. If the absorbed serum does not react with the leukocytes of the donor, the antibody population has not been refined, since the leukocytes used for absorption possessed antigens (a.f.) for all which antibodies present in the serum. If, after absorption, the serum reacts positively with the leukocytes of the donor, it has been refined, since the leukocytes used for absorption did not possess all antigens (a.f.) against all antibodies present in the serum. A serum whose polyvalency cannot be proven by as many as thirty absorptions is called an operationally monospecific or a defined serum (Walford and Troup, 1967; Walford et al, 1967). The number of absorptions needed in order to divide the serum gives a rough idea of the association of antigens (a.f.) against which the antibodies in the serum react.