Haemagglutinin activity in Acrididae (grasshopper) haemolymph

The haemolymph of Acrididae causes haemagglutination of human and animal erythrocytes. Thirteen of seventeen species tested had detectable activity and gave agglutination titres in the range 2–64, Melanoplus bivittatus, and M. sanguinipes showed greatest activity. Haemagglutinin activity is continuously present in male and female insects from 4th instar and throughout adulthood. Females contain slightly more activity than do males. M. sanguinipes haemolymph agglutinates rabbit, calf, human (all ABO types) guinea pig, mouse, chicken, cat, pig and sheep erythrocytes. Rabbit red cells are agglutinated most strongly and sheep and chicken cells least. M. sanguinipes haemolymph also agglutinates the protozoan Nosema locustae, a natural grasshopper pathogen. Preabsorption of haemolymph with different erythrocyte types selectively removes haemagglutinin activity suggesting the presence of multiple or heteroagglutinins. M. sanguinipes haemagglutinin is inhibited by glycoproteins, simple carbohydrates and carbohydrate derivatives. The inhibitory pattern is complex and among the sugars tested only mannose and derivatives of mannose are exclusively non-inhibitory. Haemolymph haemagglutinin activity is destroyed by heat and EDTA. It is totally precipitated by dialysis against water and may be partially recovered in phosphate or Tris buffer. Activity is stable in frozen haemolymph.