Cancer Immune Therapy Edited by G. Stuhler and P. Walden ...

76 5 Major Histocompatibility Complex Modulation and Loss
A
B
Fig. 5.15 Selective (A) allelic- or (B) locus-specific HLA class I
antigen down-regulation due to defects in the regulatory mechanisms
controlling HLA class I antigen expression.
Tab. 5.4 Allele-specific down-regulation or loss
Tumor cell line Tumor type Molecular alterations References
LS411 colorectal carcinoma chromosomal breakpoint in HLA A11 153
CC11 cervical carcinoma G ? T in exon 2 of HLA A24 156
CSCC7 TGGG insertion at codon 32 in exon 2
of HLA-B15
808 CAG ? TAG in exon 3 of HLA-A2 157
778 G ? C at the 3' acceptor site of intron 1
of HLA-A2
157
624MEL28 melanoma base substitution at the 5' donor site
of intron 2 of HLA-A2 158
5.6
MHC Class I Alterations: Impact on Immune Responses and Clinical Relevance
The functional significance of the MHC class Ialterations described above will be
discussed in this section. The loss of MHC class Isurface expression causes escape
from specific T cell-mediated antitumor responses directed against TAAs restricted
by particular MHC class Imolecules. The relevance of the down-regulation of MHC
class Isurface expression which directly correlates with the inadequate presentation