Changes in neutrophil surface protein composition accompany phagocytosis
KM Skubitz and TK Kinkead
Phagocytosis is a critical host defense mechanism of neutrophils. In this
study, membrane protein changes occurring during phagocytosis were studied
in human neutrophils using surface radiolabeling before or after
phagocytosis of various target particles. Cells were labeled at the cell
surface using lactoperoxidase-catalyzed iodination or
neuraminidase-galactose oxidase-NaB3H4, galactose oxidase-NaB3H4, or
periodate-NaB3H4 techniques. Such studies are complicated by the fact that
these techniques identify many surface proteins on the phagocyte, and
labeling after phagocytosis occurs often results in radiolabeling proteins
of the target particle, thus making changes in cell-surface proteins more
difficult to detect. Immunoprecipitation with monoclonal antibody AHN-1,
which reacts with a carbohydrate present on several human neutrophil
surface proteins and inhibits phagocytosis, eliminated interference caused
by radiolabeled proteins of the target particle and simplified analysis by
restricting the study to a limited number of proteins. AHN-1
immunoprecipitated less radiolabeled protein from neutrophils labeled after
phagocytosis of particles opsonized with IgG or complement than from cells
labeled before phagocytosis. Isolation of phagocytic vesicles containing
opsonized emulsified paraffin oil demonstrated that three proteins of mol
wt 105,000, 140,000, and 170,000 recognized by AHN-1 were internalized in
the phagocytic vesicle during phagocytosis.
Volume 70,
Issue 1,
pp. 60-68,
07/01/1987
Copyright © 1987 by The American Society of Hematology
