Expression of fusion regulatory proteins (FRPs) on human peripheral blood monocytes. Induction of homotypic cell aggregation and formation of multinucleated giant cells by anti-FRP-1 monoclonal antibodies.
Fusion regulatory proteins (FRPs) are newly defined cell surface molecules that enhance and/or induce virus-mediated cell fusion. Anti-FRP-1 Abs reacted with all of the established cells derived from humans and monkeys, whereas FRPs were found to be selectively expressed on a fraction of monocytes in human PBMCs. Granulocytes expressed no FRP-1 molecules, but approximately 18% of granulocytes expressed FRP-2 molecules. Alveolar macrophages also expressed FRP-1 molecules. FRP-1 expression was enhanced by culture of monocytes, but CD14 expression was not influenced by cultivation. Anti-FRP-1 Abs induced homotypic cell aggregation and multinucleated giant cell formation of monocytes. Anti-beta 2 integrin Ab blocked anti-FRP-1 Ab-induced cell aggregation, and anti-beta 1 integrin Ab and fibronectin inhibited anti-FRP-1 Ab-induced polykaryocyte formation. There was no competitive binding to monocytes between anti-FRP-1 Ab and anti-beta 1 or anti-beta 2 integrin Ab or fibronectin. Furthermore, there was no enhancement of beta 1 and beta 2 integrin expression by anti-FRP-1 Ab on monocytes. These findings suggest that anti-FRP-1 Ab activated integrin systems, and that the functions of anti-FRP-1 Ab were demonstrated through the activated integrin systems. Furthermore, it is inferred that integrin systems are involved in polykaryocyte formation of monocytes.
Tabata
N
N
Department of Microbiology, Mie University, School of Medicine, Tsu-Shi, Japan.
Ito
M
M
Shimokata
K
K
Suga
S
S
Ohgimoto
S
S
Tsurudome
M
M
Kawano
M
M
Matsumura
H
H
Komada
H
H
Nishio
M
M
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000276:immunology; D000954:Antigens, Surface / Q000378:metabolism*; D002449:Cell Aggregation; D002459:Cell Fusion / Q000187:drug effects; D005353:Fibronectins / Q000494:pharmacology; D006801:Humans; D016023:Integrins / Q000378:metabolism; D016676:Macrophages, Alveolar / Q000378:metabolism; D008969:Molecular Sequence Data; D009000:Monocytes / Q000378:metabolism*; D009842:Oligopeptides / Q000737:chemistry / Q000494:pharmacology
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D005353:Fibronectins; D016023:Integrins; D009842:Oligopeptides