Summary
The ultrastructure of lysosomes from megakaryocytes (MK) and platelets of cattle with
the Chediak-Higashi syndrome (CHS) was characterized using acid phosphatase histochemistry
with beta-glycerophosphate as substrate and cerium as a capturing agent. Acid phosphatase
was localized in the trans aspect of the Golgi complex and/or granules in MK at all
stages of maturation. Morphometric analysis of the diameter of each lysosome was performed
on MK from CHS cattle and compared to MK from normal cattle. Lysosomes in CHS MK were
neither enlarged nor different with respect to classification as secondary lysosomes,
which composed 35% of the lysosomes in CHS MK. Lysosomes were demonstrated in 22%
of the CHS platelet sections and appeared similar to those from normal cattle, 56%
of them being classified as secondary lysosomes. Why lysosomes are not enlarged in
bovine CHS MK and platelets, whereas they are enlarged in most other cell types, remains
unknown.