Identification of genes involved in the suppression of antibody production from human peripheral blood lymphocytes

Pretreatment with L-leucyl-L-leucine methyl ester (LLME) is a prerequisite for peripheral blood mononuclear cells (PBMCs) to produce antigen-specific antibodies when sensitized with an antigen. Little information, however, is available regarding the mechanisms involved in LLME-induced augmentation of antibody production from PBMCs that are antigen sensitized. In the present study, we attempted to identify the genes involved in the suppression of antibody production from PBMCs that was not treated with LLME, but sensitized with an antigen. Using subtractive screening, we obtained 63 independent genes, including 17 EST genes, that are specific for LLME-nontreated PBMC. Among these genes, the expression of heavy chain ferritin (H-ferritin), CC chemokine ligand 18 (CCL18), and matrix metalloproteinase 12 (MMP12) were augmented in LLME-nontreated PBMCs, suggesting that inflammatory factors might be involved in the suppression of antibody production in LLME-nontreated PBMCs.