title: Anti-CD45 antibody enhances lipoxygenase pathway of human naïve mononuclear cells and cyclooxygenase pathway of neutrophils.
abstract: OBJECTIVE
  Anti-CD45 antibody exhibits multiple biological effects on human mononuclear cells (MNC) and polymorphonuclear neutrophils (PMN). We intended to determine whether anti-CD45 antibody could affect arachidonic acid metabolism and thereby, the interactions between human naïve MNC and PMN.
  
  
  METHODS
  Human naïve MNC and PMN were incubated with monoclonal anti-human CD45 IgG F(ab')(2) antibody or non-specific IgG F(ab')(2) for 30 min. The mRNA expression of cyclooxygenase type 1 (COX-1), type 2 (COX-2), 5-lipoxygenase (5-LOX) and leukotriene A(4) hydrolase (LTA(4) hydrolase) in both cells was detected by RT-PCR and quantified by densitometric determination. The presence of COX-1 and COX-2 molecules in the cells was detected by Western blot. The concentration of PGE(2) and LTB(4) in cultured supernatants was measured by EIA kits.
  
  
  RESULTS
  Anti-CD45 IgG F(ab')(2) up-regulated LTA(4) hydrolase mRNA expression and LTB(4) production, but down-regulated COX-1 and COX-2 mRNA expression and PGE2 production, of naïve MNC compared to non-specific IgG F(ab')(2). In contrast, a reverse modulation by the specific antibody on PMN was observed including up-regulation of cyclooxygenase pathway and down-regulation of lipoxygenase pathway.
  
  
  CONCLUSIONS
  A novel activity of anti-CD45 with reverse modulation on cyclooxygenase/lipoxygenase pathways was found such that the expression of COX-1 and COX-2 in PMN, and 5-LOX and LTA(4) hydrolase in MNC were enhanced.
authors: Department of Internal Medicine, National Taiwan University Hospital, 7 Chung-Shan South Road, Taipei, Taiwan.
authors: C-H
authors: CH
authors: Wu
authors: S-C
authors: SC
authors: Hsieh
authors: H-S
authors: HS
authors: Yu
authors: K-J
authors: KJ
authors: Lee
authors: M-C
authors: MC
authors: Lu
authors: C-Y
authors: CY
authors: Tsai
authors: C-L
authors: CL
authors: Yu