Characterization of HLA class I altered phenotypes in a panel of human melanoma cell lines.
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.
Méndez
Rosa
R
Departamento de Análisis Clínicos, Hospital Universitario Virgen de las Nieves, Universidad de Granada, Avd. Fuerzas Armadas 2, 18014, Granada, Spain.
Rodríguez
Teresa
T
Del Campo
Ana
A
Monge
Eva
E
Maleno
Isabel
I
Aptsiauri
Natalia
N
Jiménez
Pilar
P
Pedrinaci
Susana
S
Pawelec
Graham
G
Ruiz-Cabello
Francisco
F
Garrido
Federico
F
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
D015395:Histocompatibility Antigens Class I