Suppression of PAMPs, Pathogen-Associated Microbial Patterns, Induced Cytokine Synthesis of PBMC, Human Blood Mononuclear Cells, by Immunoglobulin Preparation

The applications of immunoglobulin preparation for intravenous injection (IVIg) for various intractable diseases are increasing. The two major clinical indications for IVIg are the replacement therapy and the anti-inflammation therapy for a variety of acute and chronic autoimmune diseases. One of the proposed mechanisms of IVIg activity is the modulation of cytokine expression and function; therefore, we analyzed the effect of IVIg on pathogen-associated molecular pattern (PAMP)-induced cytokine production by peripheral blood mononuclear cells (PBMCs). The production of tumor necrosis factor-α (TNF-α) as a result of stimulation with lipopolysaccharide (LPS), polyinosinic-polycytidylic acid sodium salt (Poly I:C), or Pam3CysSerLys4 (Pam3) was significantly inhibited by sulfonated-IVIg (S-IVIg), or by F(ab')2. Assessed by one-color microarray analysis, the expressions of 229 genes were inhibited to 1/200 or less by F(ab')2. On the other hand, the expressions of 159 genes were increased by more than 100-fold by F(ab')2. According to these results, it was suggested that IVIg inhibits inflammatory PAMPs-induced cytokine production by PBMCs, due to the modulation of varieties of gene expression.