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Dual pertussis toxin‐sensitive pathway of zymosan‐induced activation in guinea pig macrophages
Author(s) -
Hazeki Kaoru,
Tamoto Koichi,
Ui Michio,
Mori Yoki
Publication year - 1994
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(94)80578-4
Subject(s) - zymosan , opsonin , pertussis toxin , phagocytosis , chemistry , antibody opsonization , guinea pig , properdin , ingestion , microbiology and biotechnology , biochemistry , receptor , complement system , g protein , antibody , biology , immunology , endocrinology , in vitro
Complement receptor type 3 (CR3)‐mediated cellular responses in guinea pig macrophages were investigated by using zymosan and serum‐opsonized zymosan (SOZ) as the multivalent ligand for CR3. The ingestion of zymosan and SOZ was accompanied by O 2 − generation and arachidonate release. These responses were suppressed by prior exposure of macrophages to pertussis toxin (PT). Opsonization of zymosan gave rise to more than 6‐fold activation of the ingestion, whereas the magnitude of either arachinonate release or O 2 − generation was unchanged. The Fab' fragment of anti‐Z‐1, a monoclonal antibody specific for the α chain of guinea pig CR3, inhibited the ingestion of zymosan by 60% without affecting zymosan‐induced arachidonate release and O 2 − generation. These data suggested that there might be at least two functionally distinct binding sites for zymosan. O 2 − generation and arachidonate release might be regulated through one site and phagocytosis another. Both sites should be coupled to PT‐sensitive GTP binding protein.