Granule formation in guinea pig and rat heterophil promyelocytes

468

Cell Biology

international

Reports,

Vol. 5, No. 5, May

1981

GRANULE FORMATION IN GUINEA PIG AND RAT HETEROPHIL PROMYELOCYTES P. BREDEROO and J.

van

der

MEULEN

Laboratory for Electron Microscopy University of Leiden, The Netherlands

In general, periodic-structurecontaining granules in heterophi1 (in man neutrophil) granulocytes are considered to be azurophi1 granules, because both are peroxidase-positive. However,our morphological studies on guinea pig and rat bone marrow have shown that nucleated granules are formed before the azurophil granules appear. In these species, promyelocytes were found to show two developmental stages, each represented by a characteristic granule population. In early progranules mye locytes , nucleated

Detail Fig.1. Detail Fig.2. ated but also Bar: 0.1 urn

are formed (Fig-l), whereas in late promyelocytes azurophil granules appear (Fig.21.The mature nucleated granules are oval to spindle-shaped and their matrix contains a nucleoid of crystalline nature. Azurophil granules are usually round with a homogeneous, dense matrix. Because specific granules are added to the granule population in the myelocyte stage, it may be concluded that in the guinea pig and rat three types of granule are formed successively in heterophil granulocytes.

of an early promyelocyte (rat) with nucleatedgranules. of a late promyelocyte (rat) showing not only nucleimmature and mature azurophil granules (arrowheads).

References Res. 194, 183-205, 1978 P. Brederco, W.Th. Daems, Cell Tiss. P. Brederoo, J. van der Meulen, In: ElectronMicroscopy 1980. Proc. Microscopy. Vo1.2, pp. 64-65 Seventh Europ. Congr. on Electron Received:

18th February

0309-1651/81/050468-01/$02.00/0

1981

Accepted:

24th March 1981

0 1981 Academic

Press Inc. (London)

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