['Prostaglandins (PGs) play pathogenic and protective roles in inflammatory diseases. The novel concept of PGs as immune modulators is being documented by several investigators. By establishing an in vitro experimental model containing human follicular dendritic cell-like cells, HK cells, we reported that HK cells produce prostaglandin E(2) (PGE(2)) and prostaglandin I(2) (PGI(2)) and that these PGs regulate biological functions of T and B cells.', 'To investigate the respective contribution of cyclooxygenase-1 (COX-1) and COX-2 to PGE(2) and PGI(2) production in HK cells, we performed siRNA technology to knock down COX enzymes and examined the effect on PG production.', 'Both PGE(2) and PGI(2) productions were almost completely inhibited by the depletion of COX-2. In contrast, COX-1 knockdown did not significantly affect PG production induced by lipopolysaccharide (LPS).'] Is production of prostaglandin e ( 2 ) and i ( 2 ) coupled with cyclooxygenase-2 in human follicular dendritic cells?