TNF-alpha release by monocytic THP-1 cells through cross-linking of the extended V-region of the oral streptococcal protein I/II.
We tested the hypothesis of a conserved activation mode of monocytic THP-1 cells by proteins I/II expressed by several species of oral streptococci through the specific role of the extended V-region. We studied the binding and modulating activities of six proteins I/II purified from strains representing four different species of oral streptococci, and of expression products of polymerase chain reaction-amplified sequences encoding corresponding extended V-regions. We found that the different proteins I/II bound to THP-1 cells in a sugar-dependent mode involving the extended V-region. Furthermore, all the proteins I/II stimulated THP-1 cells to produce tumor necrosis factor alpha, indicating that these properties are not strain- or species-specific. Despite the weak stimulation of THP-1 cells by the extended V-region alone, we obtained evidence that cross-linking of this region can be one of the mechanisms involved in monocytic cell activation by proteins I/II.
Chatenay-Rivauday
C
C
Institut National de la Santé et de la Recherche Médicale U392, Faculté de Pharmacie, Université Louis Pasteur, Illkirch, France.
Yamodo
I
I
Sciotti
M A
MA
Troffer-Charlier
N
N
Klein
J P
JP
Ogier
J A
JA
D000595:Amino Acid Sequence; D000942:Antigens, Bacterial / Q000737:chemistry / Q000502:physiology; D001426:Bacterial Proteins / Q000737:chemistry / Q000502:physiology*; D002460:Cell Line; D003432:Cross-Linking Reagents; D006801:Humans; D008562:Membrane Glycoproteins; D008969:Molecular Sequence Data; D009000:Monocytes / Q000382:microbiology* / Q000502:physiology*; D013290:Streptococcal Infections / Q000503:physiopathology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D003432:Cross-Linking Reagents; D008562:Membrane Glycoproteins; C055764:S-layer proteins; D014409:Tumor Necrosis Factor-alpha