DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.48120#0115
Abstracts
97
cy of sera with significant FP5 reactivity was less (12/99, IgG; 11/53, IgM) than
FP2. On the other hand, FP2 and FP6 reactivities showed a positive correlation
(r = 0.86, P>0.01, IgG; r = 0.89, P>0.01, IgM), indicating that the predominant
epitopes for autoimmune sera were present in FP6, but not in FP5. In addition,
because FP5 contains a region of reported homology with retroviral p30gag an-
tigen, our results imply that cross-reactivities with the viral antigen might not be
the primary mechanism of anti-p68K autoantibody production.
These results suggest that the main epitopes for serum IgG and IgM autoan-
tibodies to p68K are located in the region of amino acids 312-372, whereas
monoclonal antibodies are directed to the region of amino acids 373-437. Fur-
thermore, autoantibodies to epitopes in the region of amino acids 373-437 ap-
pear to switch infrequently from IgM to IgG.
Contributions of Molecular and Cell Biology to Understanding of the
B-Cell Response in Systemic Autoimmunity
E.M. Tan
W. M. Keck Autoimmune Disease, Research Institute of Scripps Clinic, La Jolla,
CA 92037, USA
Systemic autoimmunity in diseases such as systemic lupus erythematosus,
Sjogrens syndrome, scleroderma and dermato/polymyositis all have a very
characteristic B-cell response which has two features: specificity and polyclonali-
ty. Specificity is demonstrated by the presence of antibodies such as anti-Sm and
anti-native DNA which are almost exclusively seen in patients with lupus and an-
tibodies to Scl-70 and centromere proteins which are almost exclusively seen in
scleroderma. Polyclonality is manifested by the presence of antibodies reactive
with at least ten different antigens in the case of lupus and against several epitopes
on individual antigens. Similarly, autoantibodies in scleroderma are directed to
at least seven different antigens, with several epitopes demonstrated on at least
one of these, the centromere B protein.
What is immunologically defined as the Sm antigen has been shown to consist
of several proteins B, B', D and E (28, 29, 16 and 13 kD) which are components
of Ul, U2, U4, U5 and U6 small nuclear ribonucleoprotein (snRNP) particles.
These particles contain a family of “uridine-rich” nuclear RNAs. Similarly, the
SS-B/La antigen has also been shown to be a subcellular particle composed of
a 48 kD phosphoprotein frequently complexed with nascent RNA pol III
97
cy of sera with significant FP5 reactivity was less (12/99, IgG; 11/53, IgM) than
FP2. On the other hand, FP2 and FP6 reactivities showed a positive correlation
(r = 0.86, P>0.01, IgG; r = 0.89, P>0.01, IgM), indicating that the predominant
epitopes for autoimmune sera were present in FP6, but not in FP5. In addition,
because FP5 contains a region of reported homology with retroviral p30gag an-
tigen, our results imply that cross-reactivities with the viral antigen might not be
the primary mechanism of anti-p68K autoantibody production.
These results suggest that the main epitopes for serum IgG and IgM autoan-
tibodies to p68K are located in the region of amino acids 312-372, whereas
monoclonal antibodies are directed to the region of amino acids 373-437. Fur-
thermore, autoantibodies to epitopes in the region of amino acids 373-437 ap-
pear to switch infrequently from IgM to IgG.
Contributions of Molecular and Cell Biology to Understanding of the
B-Cell Response in Systemic Autoimmunity
E.M. Tan
W. M. Keck Autoimmune Disease, Research Institute of Scripps Clinic, La Jolla,
CA 92037, USA
Systemic autoimmunity in diseases such as systemic lupus erythematosus,
Sjogrens syndrome, scleroderma and dermato/polymyositis all have a very
characteristic B-cell response which has two features: specificity and polyclonali-
ty. Specificity is demonstrated by the presence of antibodies such as anti-Sm and
anti-native DNA which are almost exclusively seen in patients with lupus and an-
tibodies to Scl-70 and centromere proteins which are almost exclusively seen in
scleroderma. Polyclonality is manifested by the presence of antibodies reactive
with at least ten different antigens in the case of lupus and against several epitopes
on individual antigens. Similarly, autoantibodies in scleroderma are directed to
at least seven different antigens, with several epitopes demonstrated on at least
one of these, the centromere B protein.
What is immunologically defined as the Sm antigen has been shown to consist
of several proteins B, B', D and E (28, 29, 16 and 13 kD) which are components
of Ul, U2, U4, U5 and U6 small nuclear ribonucleoprotein (snRNP) particles.
These particles contain a family of “uridine-rich” nuclear RNAs. Similarly, the
SS-B/La antigen has also been shown to be a subcellular particle composed of
a 48 kD phosphoprotein frequently complexed with nascent RNA pol III