Immunoblot analysis of anti-LSP antibodies

Proteins from human LSP were separated according to their molecular weight by sodium dodecyl-sulphate polyacrylamide gel electrophoresis. The proteins were then transferred to nitrocellulose sheets and incubated with sera from 10 normal subjects and from 6 patients with autoimmune chronic active hepatitis (CAH) and 6 with primary biliary cirrhosis (PBC). All normal sera reacted with several common bands in LSP. Four CAH sera presented various bands in addition to those recognized by normal sera, whose molecular weight ranged from 22 to 70 KD. PBC sera recognized 3 major bands with molecular weight 60, 70 and 75 KD: the last was poorly recognized also by normal sera. These results confirm that anti LSP represent a population of antibodies with specificities for different components of LSP preparation. PBC immunoblot pattern is quite uniform and different from that of CAH which presents different reactivity patterns in each patient.