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A Human Lymphokine Activates Macrophage C3 Receptors for Phagocytosis: Studies Using Monoclonal Anti‐Lymphokine Antibodies
Author(s) -
Griffin Frank M.,
Luben Richard A.,
Golde David W.
Publication year - 1984
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.36.2.95
Subject(s) - lymphokine , phagocytosis , macrophage , receptor , biology , monoclonal antibody , microbiology and biotechnology , cell surface receptor , macrophage activating factor , antibody , immunology , immune system , biochemistry , in vitro
We have identified a human T lymphocyte cell line, the Mo line, that constitu‐tively elaborates a lymphokine that activates macrophage receptors for the third complement component (C3) for phagocytosis. The molecule is physically, functionally, and immunologically very similar, if not identical, to a previously characterized murine lymphokine. Both molecules were inactivated by the same physical and chemical treatments, activated macrophage C3 receptors for phagocytosis, and freed macrophage C3 receptors to move within the cell's plasma membrane. In addition, both the human and the murine products were recognized by the same monoclonal antibodies. Treatment with monoclonal antibodies abolished both the ability of lympho‐kine‐containing supernatants to mobilize macrophage C3 receptors and the supernatants' ability to activate C3 receptor‐mediated phagocytosis. The dose‐response curves for both effects of the antibodies were identical, strongly suggesting that a single molecule was responsible for both effects and that the lymphokine activated macrophage C3 receptors for phagocytosis by freeing the anchored receptors and allowing them to diffuse within the cell's plasma membrane. These findings strengthen the hypothesis that, for a receptor to promote phagocytosis, it must be able to diffuse within the macrophage plasma membrane.