K-562 cells lack MHC class II expression due to an alternatively spliced CIITA transcript with a truncated coding region

Leuk Res. 2003 Nov;27(11):1027-38. doi: 10.1016/s0145-2126(03)00072-9.


The focus of this study was to determine the functional capacity of class II transactivator (CIITA), a regulatory factor of major histocompatibility complex (MHC) class II genes, in K-562 cells. We show that CIITA mRNA is present in K-562 cells and the interferon-gamma (IFN-gamma)-inducible CIITA promoter-IV exhibits low levels of basal activity, which is greatly enhanced upon treatment with IFN-gamma. Further study revealed that the CIITA cDNA contains an insertion of genomic sequence, which introduces a stop codon. The truncated coding region of the CIITA transcript in K-562 cells provides a possible explanation for the absence of MHC class II molecules.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alternative Splicing
  • Amino Acid Sequence
  • Codon, Terminator*
  • DNA Transposable Elements
  • Genes, MHC Class II*
  • Histocompatibility Antigens Class II / metabolism
  • Humans
  • Interferon-gamma / pharmacology
  • K562 Cells / metabolism*
  • Molecular Sequence Data
  • Nuclear Proteins*
  • Promoter Regions, Genetic
  • RNA, Messenger / metabolism
  • Trans-Activators / genetics*


  • Codon, Terminator
  • DNA Transposable Elements
  • Histocompatibility Antigens Class II
  • MHC class II transactivator protein
  • Nuclear Proteins
  • RNA, Messenger
  • Trans-Activators
  • Interferon-gamma