Presence of antibodies to different subunits of replication protein A in autoimmune sera.

AUTOR(ES)

Garcia-Lozano, R

RESUMO

A human cDNA expression library was used to investigate the nature of molecules recognized by serum from a patient with Sjögren syndrome that exhibits a mixed immunofluorescence pattern and reacts with multiple components on an immunoblot. The data demonstrated that this serum contains IgG antibodies specific for the 70- and 32-kDa subunits of replication protein A (RPA; RPA-70 and RPA-32, respectively), a highly conserved multisubunit DNA binding protein. Affinity purification of serum autoantibodies demonstrated a complete lack of cross-reactivity between RPA-70 and RPA-32, suggesting a direct participation of the native protein complex in the autoimmune response in this patient. Purified anti-RPA-70 and anti-RPA-32 antibodies labeled nuclear and cytoplasmic components in an immunofluorescence assay, suggesting that RPA is present in both cellular compartments. Additional sera from 55 patients with different autoimmune conditions were screened against purified RPA-70 and RPA-32 recombinant proteins. One of these 55 sera was positive and reacted with only RPA-32. Twenty sera from healthy control individuals did not react with RPA. These results show that RPA is a target for autoantibodies in human autoimmune diseases, although its precise frequency, occurrence in other autoimmune diseases, and pathological significance remain to be fully elucidated.

Documentos Relacionados

• Patterns of antibodies to staphylococcal DNases in dog sera.
• Prevalence of antibodies to human papillomavirus type 8 in human sera.
• Characterisation of nucleolar proteins as autoantigens using human autoimmune sera.
• Purification of TR-b, a Reiter treponeme protein antigen precipitating with antibodies in human syphilitic sera.
• Amount, avidity, and specificity of antibodies to Pseudomonas aeruginosa in normal human sera.