Transfection and overexpression of the human 60-kDa Ro/SS-A autoantigen in HEp-2 cells

Abstract

A full-length cDNA encoding human 60-kDa Ro/SS-A protein was transfected into and overexpressed in the human cell line HEp-2, with the aim of developing an improved reagent for indirect immunofluorescence (IF) detection of anti-Ro autoantibodies. Stable transfectants were analyzed by IF using a panel of 20 precipitin-positive anti-Ro human sera. Transfectants showed bright finely speckled nuclear and nucleolar staining. No surface membrane expression was detected despite marked overexpression of 60-kDa Ro. All human anti-Ro sera reacted with the transfectants with titers ranging from 1:320 to 1:40,960. The same sera tested on untransfected cells showed titers from negative (3 sera) to 1:160...