The Demonstration of Anti‐HI/HI‐H Activity in Seed Anti‐H Reagents

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 O H + ii cells whereas the Cytisus and Laburnum extracts contained anti‐HI‐H agglutinins that cross‐reacted with O H + ii cells. Lactose (7.1 g/100 ml) 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 40°C.