UNSPECIFIED (1992) THE LOSS OF CLASS-II MHC ANTIGEN EXPRESSION BY RAS-TRANSFORMED MURINE FIBROBLASTS PASSAGED AS TUMORS CORRELATES WITH INCREASED TUMORIGENICITY BUT IS NOT MEDIATED BY T-CELLS. CANCER IMMUNOLOGY IMMUNOTHERAPY, 35 (1). pp. 46-52. ISSN 0340-7004

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Abstract

In several murine tumour systems, expression of class II major histocompatibility complex (MHC) antigens by tumour cells, either constitutive or inducible, correlates with reduced tumorigenicity as compared with equivalent class-II-negative cells, and CD4 phenotype T cells together with interferon-gamma (which induces the expression of class II) may be involved in the control of the proliferation of class-II-expressing tumours. This implies a potential T-cell-mediated selection pressure against class II expression. To test this possibility, we have repeatedly passaged as tumours in euthymic, syngeneic mice ras-transformed murine fibroblast lines, which are class-II-inducible, to determine whether class-II-non-inducible variants are selected. We examined the expression of both class I and class II antigen in tumour cells re-established in vitro. It was found that the inducibility of class II, but not class I, expression rapidly diminished, correlating with augmented tumorigenicity. However, this loss of class II inducibility occurred in athymic as well as euthymic mice. Therefore, despite the fact that the tumorigenicity of these lines is augmented in euthymic mice depleted of CD4 T cells or interferon-gamma, we found no evidence of T-cell-mediated selection against class II expression. The loss of class II expression observed must be due to mechanisms other than immune selection. The possibility that this might result from other soluble factors modulating the response to interferon-gamma in vivo is discussed.

Item Type:	Journal Article
Subjects:	R Medicine > RC Internal medicine > RC0254 Neoplasms. Tumors. Oncology (including Cancer) Q Science > QR Microbiology > QR180 Immunology
Journal or Publication Title:	CANCER IMMUNOLOGY IMMUNOTHERAPY
Publisher:	SPRINGER VERLAG
ISSN:	0340-7004
Date:	May 1992
Volume:	35
Number:	1
Number of Pages:	7
Page Range:	pp. 46-52
Publication Status:	Published
URI:	http://wrap.warwick.ac.uk/id/eprint/22093

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