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英文摘要
Systemic lupus erythematosus (SLE) is a prototypic systemic
autoimmune disease characterized by the production of
autoantibodies against nuclear components . Dexoxyribonuclease I
(DNase I), an endonuclease capable of hydrolyzing of DNA, is
normally present in human serum and urine. In our study,
antibodies binding to bovine DNase I were investigated by ELISA
in SLE patients and anti-nuclear antibody (ANA) negative
normal sera. About 62.4% of SLE patients (63/101) were positive
for anti-DNase antibodies while only 8% of normal controls
(8/98) were positive. A positive correlation was found between
the concentrations of anti-DNase and anti-DNA antibodies in
SLE patients. Affinity-purified anti-DNase IgG from pooled SLE
patients serum and BALB/c mice immunized with bovine DNase
bound to DNase as well as DNA coated ELISA plates. A synthetic
peptide which cross-response to the catalytic site of DNase was
able to completely inhibit anti-DNase IgG bound to DNase but
not DNA coated plate. Indirect immunofluorescence of anti-DNase
IgG displayed speckled and nucleolar patterns of Hep-2 cells
but no reaction to the kinetoplast DNA in Crithidia luciliae.
In addition to bovine DNase, anti-DNase IgG also bound to DNase
in streptococcal supernatants and human urine and inhibited
their enzymatic activities . It was also noticed that BALB/c
and NZB/NZW mice immunized with bovine DNase I produced more
anti-DNase and anti-DNA antibodies than na鴳e mice. Besides,
immunized BALB/c mice showed fibroblast cells in renal tubule
walls under histological examination showed.Based on the
data above, we conclude that it is possible that the
inhibition of DNase I activity by the anti-DNase antibodies
may cause a defect in DNA degradation and stimulate or
enhance anti-DNA antibodies production.
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