title: Production of TGF-beta1 as a Mechanism for Defective Antigen-presenting Cell Function of Macrophages Generated in vitro with M-CSF.
abstract: BACKGROUND
  Macrophages generated in vitro using macrophage-colony stimulating factor (M-CSF) and interleukin (IL)-6 from bone marrow cells (BM-Mp) are defective in antigen presenting cell (APC) function as shown by their ability to induce the proliferation of anti-CD3 mAb-primed syngeneic T cells. However, they do express major histocompatibility (MHC) class I and II molecules, accessory molecules and intracellular adhesion molecules. Here we demonstrate that the defective APC function of macrophages is mainly due to production of TGF-beta1 by BM-Mp.
  
  
  METHODS
  Microarray analysis showed that TGF-beta1 was highly expressed in BM-Mp, compared to a macrophage cell line, B6D, which exerted efficient APC function. Production of TGF-beta1 by BM-Mp was confirmed by neutralization experiments of TGF-beta1 as well as by real time-polymerase chain reaction (PCR).
  
  
  RESULTS
  Addition of anti-TGF-beta1 monoclonal antibody to cultures of BM-Mp and anti-CD3 mAb-primed syngeneic T cells efficiently induced the proliferation of syngeneic T cells. Conversely, the APC function of B6D cells was almost completely suppressed by addition of TGF-beta1. Quantitative real time-PCR analysis also confirmed the enhanced expression of TGF-beta1 in BM-Mp.
  
  
  CONCLUSIONS
  The defective APC function of macrophages generated in vitro with M-CSF and IL-6 was mainly due to the production of TGF-beta1 by macrophages.
authors.affiliation: School of Science Education (Biology), Chungbuk National University, Cheongju, Korea.
authors.forename: Jae Kwon
authors.initials: JK
authors.lastname: Lee
authors.forename: Young-Ran
authors.initials: YR
authors.lastname: Lee
authors.forename: Young-Hee
authors.initials: YH
authors.lastname: Lee
authors.forename: Kyungjae
authors.initials: K
authors.lastname: Kim
authors.forename: Chong-Kil
authors.initials: CK
authors.lastname: Lee