Anti-SS-B (La) antibody

The target antigen against SS-B (La) is a helper protein of RNA polymerase III (48 & times; 103). The molecular biological properties of La protein have been elucidated. The transcription unit of RNA polymerase also includes small hY-RNAs, which are components of ribonucleic acid protein particles, which are also recognized by anti-SS-A (Ro). Therefore, at least from the present point of view, Ro protein and La protein are the same components in the cell, or part of the ribonuclein protein particles. This may be why even if Ro and La do not have the same sequence that may cross-react, they can usually be detected in the patient's serum at the same time.