Autoantibodies directed against ribosomal P proteins: use of a multiple antigen peptide as the coating agent in ELISA

Diagnostic Tests for Antiribosomal P Protein Antibodies: A Comparative Evaluation of Immunoblotting and ELISA Assays

“…This discrepancy may be explained by the better sensitivity of techniques based on multiple antigen peptides compared with that based on single linear peptides, at least in ELISA. As demonstrated in the setting-up of MAP-based ELISA [32], the ability to bind anti-P antibodies by the branched peptide coated onto the plate was higher than the one shown by the single linear peptide. This property, that resulted much more evident with weakly positive samples, may be due to a couple of reasons.…”

“…A cut-off value of 10% was calculated as the mean+3 SD of results obtained on 100 normal human sera. The specificity of the antibody binding was demonstrated by a liquid phase inhibition assay, as previously reported [32]. Moreover, each serum was also tested in duplicate on uncoated wells and the OD developed (always very low) was subtracted from the OD of the respective serum on the antigen coated wells before calculating the results.…”

“…The ELISA assay was developed according to Caponi L. et al [32] using a branched multiple antigen peptide (MAP) carrying four copies of the carboxy-terminal 13-mer peptide common to the three P proteins, attached on a poly-lysine core. The MAP was synthesized by a solid-phase method [33] and purified by gel-filtration on a PD-10 column.…”

Autoantibodies Directed Against the Ribosomal P Proteins are not only Directed Against a Common Epitope of the P0, P1 and P2 Proteins

“…Previous studies have shown that the epitopes recognized by the RPP aAb are located mainly within the C-terminal sequence common to the three ribosomal P proteins [9,14]. These findings suggest that the RPP aAb could be detected with an enzyme-linked immunosorbent assay (ELISA) using only a C-terminal peptide of ribosomal P proteins [15] or a recombinant P0 fusion protein [16].…”

Autoantibodies in Neuropsychiatric Lupus

“…[41] A multiple antigen peptide comprising four copies of the C-terminal 13 amino acid residues of the P2 protein has also been used in an ELISA for these antibodies. [42] Ribosomal proteins have been purified from human, pig and rat for use in these assays with the human source giving the best detection sensitivity. [37,38] An association between anti-ribosomal P antibodies and SLE psychosis was first reported by Bonfa et al [39] They found 18 out of 20 (90%) of patients with SLE psychosis had serum autoantibodies to ribosomal P protein.…”