title: Down regulation of Qa gene expression on drug-modified tumor cells.
abstract: BACKGROUND
  Mouse leukemia, L1210, strongly enhances its immunogenicity following in vivo treatment with 5-(3-3'-dimethyl-1-triazeno) imidazole-4-carboxamide (DTIC). Previous experiments have shown that transformed cells elicit a cell-mediated response accountable for rejection and resistance to a subsequent injection of parental tumor into a syngeneic host. L1210 expresses classical H-2 class I molecules, and since it has been shown that DTIC treatment does not modify the expression of these molecules, this is a suitable model to study nonclassical class I antigens, such as Qa2 glycoproteins, and their potential role in tumorigenicity.
  
  
  METHODS
  Cloned cells from L1210 were treated with DTIC and then H-2D, and Qa antigen expression was studied on four clones, before and after xenogenization with DTIC.
  
  
  CONCLUSIONS
  a strong decrease of Qa2 molecule expression was demonstrated by radioimmunoassay and immunofluorescent staining and was confirmed by FACS and 2D-gel analysis. The presence or the absence of Qa antigens on tumor cells could thus be involved in tolerance or rejection of tumor cells in syngeneic animals.
authors.affiliation: Department of Pharmacology, School of Medicine, University of Milan, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Leroy
authors.forename: D
authors.initials: D
authors.lastname: Lattuada
authors.forename: C
authors.initials: C
authors.lastname: Casnici
authors.forename: P
authors.initials: P
authors.lastname: Franco
authors.forename: O E
authors.initials: OE
authors.lastname: Marelli
mesh_terms: D000818:Animals; D003606:Dacarbazine / Q000494:pharmacology*; D015536:Down-Regulation; D005260:Female; D005455:Fluorescent Antibody Technique; D015973:Gene Expression Regulation, Leukemic / Q000187:drug effects*; D005805:Genes, MHC Class I / Q000187:drug effects*; D007939:Leukemia L1210 / Q000235:genetics / Q000276:immunology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008811:Mice, Inbred DBA; D014407:Tumor Cells, Cultured
chemical_list: D003606:Dacarbazine