No abstract

A(2) cord bloods do not react with Dolichos bif. anti-A and their H status is equivalent to that of group O cord bloods, indicating that the A components of these bloods are formed independently of H. Bloods reacting with Dolichos bif. extract require H for the development of their A(1) components and this is reflected in the lower H status of these bloods. As the alternative pathway is necessary for the development of the first formed parts of A both the alternative and the orthodox pathways are necessary for the development of bloods with A(1) components.

No abstract

Extracts from seeds of Lotus tetragon., Cytisus sessil, and Laburnum alp. give lower titration scores with O H + ii cells than with O H + I + cells although both have a similar H status in studies with Ulex europ. reagent. Absorption and elution studies indicate that the Lotus extract contained anti-HI agglutinins with little activity for OH+ii cells whereas the Cytisus and Laburnum extracts contained anti-HI-H agglutinins that cross-reacted with O H+ ii cells. Lactose (7.1g/100ml) strongly inhibited the anti-HI-H reactions with little effect on the Ulex anti-H reagent. The anti-HI/HI-H reagents gave maximum activity at lower temperatures whereas the Ulex anti-H extract was just as active at 37°C as at 4°C.

Studies on seventy-five sera containing antibodies of the H‘0’I-B complex together with a survey of studies by other workers show that many of the antibodies formerly called anti-‘0’ 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.