IDENTIFICATION OF A FAMILY OF HUMAN CENTROMERE PROTEINS USING AUTOIMMUNE SERA FROM PATIENTS WITH SCLERODERMA

Preimmune serum samples were examined from a patient who progressively developed the symptoms of scleroderma CREST [calcinosis, Raynauds phenomenon, esophageal dysmotility, sclerodactyly, telangiectasia] over a period of several years. During this period, anti-centromere antibodies (recognized by indirect immunofluorescence) appeared in the serum. Concomitant with the appearance of the anti-centromere antibodies, antibody species recognizing 3 chromosomal antigens in immunoblots of SDS [sodium dodecyl sulfate] polyacrylamide gels appeared in the patient''s serum. These antigens migrate with electrophoretic mobilities corresponding to MW = 17, 80 and 140 kilodaltons (kd). Affinity-eluted antibody fractions recognizing the antigens were prepared from sera of 3 other patients. Indirect immunofluorescence labeling of mitotic cells using these antibody fractions demonstrates that the antigens are centromere components. They are designated CENP (CENtromere Protein)- A (17kd), CENP-B (80kd), and CENP-C (140kd). The 3 CENP antigens share antigenic determinants. Immunoblotting experiments show that these patients make antibody species recognizing at least 3 distinct epitopes on CENP-B and 2 on CENP-C. Sera from different patients contain different mixtures of the antibody species.