Among the analyzed APM components, TAP1 was expressed at a low frequency in the two [[beta].sub.m]-negative cell lines, and while LMP2 was abundantly expressed in all of three cell lines, LMP7 expression was detectable only at a very low percentage of sHCC63 cells (Figure 3(c)).
Effect of IFN-[gamma] on the [[beta].sub.m], LMP2, LMP7, TAP1, and TAP2 Transcripts in the Three sHCC Cell Lines.
The mechanism underlying this abnormality includes [[beta].sub.2]m loss, which is caused by a >49 kb deletion at the (2M locus, and marked downregulation of HLA class I heavy chain, TAP1 and LMP7 expression.
In the present study, we found that both sHCC29 and sHCC63 cells had marked HLA-A, HLA-B, and HLA-C allospecificity, TAP1 and LMP7 downregulation.
(b) Cytoplasmic expression of additional HLA-A, HLA-B, -C allospecificities and APM components TAP1, TAP2, LMP2, and LMP7 were determined cytofluormetrically.
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