CHARACTERIZATION OF FUNCTIONS OF NEUTROPHILS FROM BONE-MARROW OF CATTLE WITH LEUKOCYTE ADHESION DEFICIENCY

Marked differences in bone marrow cellularity were observed between ca ttle affected with leukocyte adhesion deficiency (LAD) and control cat tle. The number of nucleated cells in bone marrow was 2.9 to 8.8 times higher in cattle affected with LAD, compared with controls. The myelo id-to-erythroid ratio of bone marrow from 3 cattle affected with LAD r anged from 2.4 to 12. Deficient CD18 expression on neutrophils isolate d from bone marrow of cattle with LAD was clearly detected by flow cyt ometric analysis. Neutrophils from bone marrow of cattle affected with LAD appeared round and not flat, after adherence to plastic wells und er agarose, whereas neutrophils from bone marrow of clinically normal cattle were firmly spread on the surface of plastic wells. In the chem otaxis under-agarose assay, many pseudopodia were detected on bone mar row neutrophils from clinically normal cattle, but were not detected o n bone marrow neutrophils from cattle with LAD. Activities of chemotac tic movements and phagocytosis of neutrophils isolated from bone marro w of cattle affected with LAD were documented to be severely impaired.