title: Characterization of HLA class I altered phenotypes in a panel of human melanoma cell lines.
abstract: BACKGROUND
  Altered HLA class I cell surface expression is one of the major mechanisms by which tumor cells escape from T lymphocytes. Immunohistochemistry-defined phenotypes of lost HLA class I expression have been described in human solid tumors, nut less information is available on melanoma cell lines.
  
  
  OBJECTIVE
  To describe the frequency and distribution of different types of HLA class I antigen alterations in 91 melanoma cell lines from the European Searchable Tumour Cell and Databank (ESTDAB).
  
  
  METHODS
  The HLA class I expression was assessed by flow cytometry and HLA genotyping.
  
  
  RESULTS
  We found various types of HLA class I cell surface alterations in about 67% of the melanoma cell lines. These alterations range from total to selective HLA class I loss due to loss of heterozygosity (LOH), haplotype loss, beta2-microglobulin gene mutation, and/or total or selective down-regulation of HLA class I molecules. The most frequently observed phenotype is down-regulation of HLA-B locus that was reversible after treatment with IFN -gamma.
  
  
  CONCLUSIONS
  In general, HLA class I alterations in the majority of the cells analyzed were of regulatory nature and could be restored by IFN-gamma. Analysis of the frequency of distinct HLA class I altered phenotypes in these melanoma cell lines revealed specific differences compared to other types of tumors.
authors.affiliation: Departamento de Análisis Clínicos, Hospital Universitario Virgen de las Nieves, Universidad de Granada, Avd. Fuerzas Armadas 2, 18014, Granada, Spain.
authors.forename: Rosa
authors.initials: R
authors.lastname: Méndez
authors.forename: Teresa
authors.initials: T
authors.lastname: Rodríguez
authors.forename: Ana
authors.initials: A
authors.lastname: Del Campo
authors.forename: Eva
authors.initials: E
authors.lastname: Monge
authors.forename: Isabel
authors.initials: I
authors.lastname: Maleno
authors.forename: Natalia
authors.initials: N
authors.lastname: Aptsiauri
authors.forename: Pilar
authors.initials: P
authors.lastname: Jiménez
authors.forename: Susana
authors.initials: S
authors.lastname: Pedrinaci
authors.forename: Graham
authors.initials: G
authors.lastname: Pawelec
authors.forename: Francisco
authors.initials: F
authors.lastname: Ruiz-Cabello
authors.forename: Federico
authors.initials: F
authors.lastname: Garrido
mesh_terms: D045744:Cell Line, Tumor; D005434:Flow Cytometry; D015870:Gene Expression; D015395:Histocompatibility Antigens Class I / Q000235:genetics*; D006801:Humans; D008545:Melanoma / Q000235:genetics*; D018895:Microsatellite Repeats; D010641:Phenotype; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D015395:Histocompatibility Antigens Class I