Influence of anti-MHC class II antibody and MHC class II binding peptide treatments on interleukin-6 gene expression by B lymphocytes

Interleukin-6 (IL-6) has been known to be one of the most critical factors involved in B cell differentiation. It has been previously reported that anti-MHC class II antibodies inhibit the B cell differentiation and proliferation. In order to understand the mechanisms involved in anti-MHC class II antibody mediated inhibition of B cell differentiation and proliferation, influence of the anti-MHC class II antibodies and MHC class II binding peptides on IL-6 gene expression has been investigated by measuring the level of IL-6 gene transcripts through quantitative PCR. Anti-MHC class II antibody treatments dramatically inhibit IL-6 gene expression as haplotype- and dose-dependent manners. In addition, haplotype-restricted epitope peptides are able to inhibit IL-6 gene expression in the similar manners, although they should be applied as a dimer form to conjugate the MHC class II molecules. These results suggest that anti-MHC class II antibody mediated inhibition of B cell differentiation and proliferation could be exerted through the inhibition of IL-6 gene expression.