Figure 1.

Antibodies from SLE and normal sera from CMV-antibody-positive and -negative individuals target primarily the U1-70k protein in the spliceosome as determined by immunoblot analysis. Lane 1, second antibody control; lanes 2 and 3, SLE sera; lanes 4–11, sera from normal individuals. Sm proteins A, B'/B, and C are designated on the left. Molecular-weight markers are designated on the right. All sera were diluted 1/2000. ^*As determined by ELISA.