Transfection of L929 cells with complement subcomponent C1q B-chain antisense cDNA inhibits tumor necrosis factor-alpha binding to mediate cytotoxicity and nitric oxide generation.
The role of complement subcomponent C1q in the modulation of TNF-alpha binding to L929 cells to mediate cytotoxicity and nitric oxide (NO) generation was investigated. Transfection of L929 with murine C1q B-chain antisense plasmid cDNA rendered them markedly less susceptible to TNF-mediated cytotoxicity coincident with a decreased capacity for TNF-alpha binding and expression of cell surface C1q protein. The inhibitory effects of L929 transfection with C1q B-chain antisense were transiently expressed at 24 hr post-transfection with full recovery of cellular functions by 72 hr. Transfected L929 cells were fully reconstituted in their TNF-alpha binding and in their cytotoxic response following exposure to soluble C1q which was bound to their cell surface. Transfection with C1q B-chain antisense also significantly inhibited NO generation by L929 cells in response to stimulation by TNF-alpha, IFN-alpha/beta, and LPS. Taken together, these results indicate that endogenously synthesized C1q is prerequisite for binding of TNF-alpha to L929 cells to mediate cytotoxicity and NO generation.
Jiang
H
H
Oklahoma Medical Research Foundation, Oklahoma City 73104-5046, USA.
Stewart
C A
CA
Tan
S Y
SY
Fast
D J
DJ
Rummage
J A
JA
Leu
R W
RW
D000818:Animals; D015922:Complement C1q / Q000502:physiology*; D003602:Cytotoxicity, Immunologic; D016373:DNA, Antisense; D018076:DNA, Complementary / Q000235:genetics; D007739:L Cells; D008264:Macrophages / Q000502:physiology; D051379:Mice; D009569:Nitric Oxide / Q000096:biosynthesis*; D015398:Signal Transduction; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
D016373:DNA, Antisense; D018076:DNA, Complementary; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D015922:Complement C1q