[Anti-RaRBC antibodies in human serum. I. The presence of complete anti-RaRBC antibodies in the serum of healthy persons and their isotype specificity].

Agglutinins against rabbit erythrocytes (RaRBC) were detected in 60 investigated normal human ser in titres ranging 1:20 - 1:1280. Titres of saline anti-RaRBC were not dependent to temperature nor to the blood groups of donor sera. Saline agglutinins were identified as antibodies of IgM class based on the result of gelfiltration and absorptions on anion exchanger and SpA-Sepharose immunoadsorbent as well as on mercaptoethanol and sulfitolysis sensitivity. IgG anti-RaRBC antibodies incapable to agglutinate RaRBC in saline were detected using indirect Coombs test in the second protein peak of gelfiltration. Some characteristics of anti-RaRBC saline agglutinins were compared with human natural isohemagglutinins.