Partial purification and characterization of a novel human factor that augments the expression of class I MHC antigens on tumour cells.
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Date
1996-03
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Abstract
A cytokine which augments the expression of major histocompatibility complex
(MHC) I antigens on K562 and gastric carcinoma tumour (HR) cells, has been isolated from the
culture supernatant of Concanavalin-A (Con-A) activated human peripheral blood mononuclear
cells. The factor, termed MHC augmenting factor (MHC-AF) has been partially purified by
Sephadex G-100 column chromatography, preparative isoelectric focusing and HPLC with
ion-exchange as well as sizing columns. MHC-AF activity is associated with a 35 kDa molecule
which has pI of 6·0. Interferon (IFN)-α, ß, tumour necrosis factor (TNF), Interleukin (IL)-2,
IL-4, IL-5 and IL-7 had no significant effect in MHC-AF bioassay, but IFN-γ had significant
MHC-AF activity. Antibodies to IFN-α, IFN-ß and TNF-α did not block the activity of
MHC-AF, but anti-IFN-y antibodies could partially neutralize the activity. However, unlike
IFN-γ, MHC-AF activity was resistant to pH 2·0 treatment. Purified MHC-AF preparations
did not have any activity in WISH cell/encephalo myocarditis virus (EMC) IFN bioassays. In
addition, anti-IFN-y affinity column did not retain MHC-AF activity. These results indicate that
a MHC-AF distinct from IFN-γ, is produced by activated human mononuclear cells.
Description
Keywords
Cytokine, MHC-AF, class I MHC, interferon, NK-RIF
Citation
Saxena R K, Saxena Q B, Whiteside T L, Goldfarb R H, Herberman R B. Partial purification and characterization of a novel human factor that augments the expression of class I MHC antigens on tumour cells. Journal of Biosciences. 1996 Mar; 21(1): 13-25.