A Study of the Antibodies of the H'O‘I‐B Complex with Special Reference to Their Occurrence and Notation

Summary. Studies on seventy‐five sera containing antibodies of the H‘O’I‐B complex together with a survey of studies by other workers show that many of the antibodies formerly called anti‐‘O’ and some of those called anti‐H are in fact reacting with a joint product of the H and I genes. The serological specificities of these antibodies were shown by agglutination tests with cells of known H and I or B and I status, together with the use of neutralisation and absorption techniques. These tests revealed that many of the sera contain mixtures of antibody specificities. The occurrence of anti‐H‐HI antibodies is probably associated with pregnancy. An H notation based on that proposed by Wiener et al. is recommended for use in the classification of these antibodies.