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HLA antigen expression and malignant mesothelioma
T I Christmas1, L S Manning, M R Davis
1Department of Medicine, University of Western Australia, Queen Elizabeth II Medical Centre, Nedlands.
Abstract:
The expression of HLA antigens by a tumor may determine its progression and metastatic potential by influencing the immune response to that tumor. The upregulation of HLA antigen expression on some cell types by interferons (IFNs) may contribute to their antitumor activity. Malignant mesothelioma (MM) is a tumor that has a poor prognosis and is unaffected by conventional therapy, although immunotherapy has not been adequately assessed. In this study, we have examined the constitutive and IFN-inducible expression of class I and class II HLA antigens on MM cell lines using indirect immunofluorescence and Northern blotting. All MM cell lines constitutively expressed class I, but not class II, surface antigen, and all three class I loci (HLA-A, HLA-B, and HLA-C) were expressed. The MM cell lines were heterogeneous in their response to the IFNs. Treatment with IFN-alpha marginally increased class I surface expression, but not class II. Class I mRNA was, however, clearly increased in all cell lines after IFN-alpha treatment, suggesting that class I surface antigen was already maximally expressed. IFN-gamma increased class I mRNA expression in all but one cell line and induced DR expression on three of the cell lines. DQ-beta, but not DQ-alpha, mRNA was inducible in the same three cell lines, but DQ surface antigen was never demonstrable.(ABSTRACT TRUNCATED AT 250 WORDS)
Insights
Malignant mesothelioma cells express HLA class I antigens constitutively. Interferon-gamma (IFN-γ) can induce HLA class II expression, suggesting potential for immunotherapy in treating this cancer.
Area of Science:
- Immunology
- Oncology
- Molecular Biology
Background:
- Tumor expression of Human Leukocyte Antigen (HLA) impacts immune response, tumor progression, and metastasis.
- Interferons (IFNs) can upregulate HLA antigen expression, potentially contributing to anti-tumor activity.
- Malignant mesothelioma (MM) is an aggressive cancer with a poor prognosis, and its response to immunotherapy remains under-assessed.
Purpose of the Study:
- To investigate the constitutive and interferon-inducible expression of class I and class II HLA antigens on malignant mesothelioma (MM) cell lines.
- To assess the potential of IFNs to modulate HLA antigen expression in MM cells for therapeutic strategies.
Main Methods:
- Indirect immunofluorescence was used to analyze surface antigen expression.
- Northern blotting was employed to examine mRNA levels of HLA antigens.
- MM cell lines were treated with Interferon-alpha (IFN-α) and Interferon-gamma (IFN-γ).
Main Results:
- All examined MM cell lines constitutively expressed class I HLA antigens (HLA-A, HLA-B, HLA-C) but not class II.
- IFN-α treatment led to a marginal increase in class I surface expression but a significant increase in class I mRNA, suggesting maximal surface expression.
- IFN-γ increased class I mRNA in most cell lines and induced class II (DR) expression in three cell lines, with inducible DQ-beta mRNA but not surface antigen.
Conclusions:
- MM cells inherently express class I HLA antigens.
- Interferon-gamma shows potential in modulating HLA class II expression in MM, indicating a possible avenue for immunotherapy.
- Heterogeneous responses to IFNs highlight the complexity of HLA regulation in malignant mesothelioma.