Vesicular transport of Charcot-Leyden crystal protein in tumor-promoting phorbol diester-stimulated human basophils.
Secretion from human basophils (HB) that are stimulated with a phorbol ester takes place with slower kinetics than typically regulated secretion, which is stimulated by the IgE-mediated mechanism associated with classical granule exocytosis. Phorbol ester stimulation of HB induces emptying of granule contents (with retention of granule containers) and increases the number of cytoplasmic vesicles, an anatomic process similar to one termed piecemeal degranulation (PMD), which is a secretory process originally described in HB that migrate from the blood in vivo into contact allergy skin lesions. Charcot-Leyden crystal (CLC) protein is a basophil granule-associated protein that is readily imaged by using a postembedding immunogold procedure. This method was used to localize this granule protein in phorbol ester-stimulated, isolated human peripheral blood basophil cytoplasmic vesicles in samples collected within a time frame for which histamine was secreted. The results of this study showed that the proportion of cytoplasmic vesicles that were gold-labeled in stimulated HB, which indicated the presence of CLC protein, increased significantly over unstimulated cells at 2, 5, and 10 minutes after stimulation. Additionally, CLC protein-labeled vesicles in the cells that were stimulated for 10 minutes significantly exceeded the number in stimulated cells at 0, 30, and 45 minutes after exposure to phorbol ester. Thus, transport vesicles carrying a granule-associated protein (CLC protein) were increased in phorbol ester-stimulated HB in the time frame for histamine secretion and the anatomic development of PMD. These findings support vesicular transport as a major mechanism for effecting PMD, which is morphologically the most frequent activation anatomy displayed by HB in human disease in vivo.
Dvorak
A M
AM
Department of Pathology, Beth Israel Hospital, Boston, Massachusetts 02215, USA.
Ackerman
S J
SJ
Letourneau
L
L
Morgan
E S
ES
Lichtenstein
L M
LM
MacGlashan
D W
DW
D001491:Basophils / Q000378:metabolism* / Q000648:ultrastructure; D001692:Biological Transport; D015550:Cell Degranulation; D003460:Crystallization; D003594:Cytoplasmic Granules / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism*; D006636:Histamine Release; D006801:Humans; D007150:Immunohistochemistry; D008245:Lysophospholipase; D016253:Microscopy, Immunoelectron; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
D006023:Glycoproteins; D008245:Lysophospholipase; C011711:lysolecithin acylhydrolase; D013755:Tetradecanoylphorbol Acetate