Table 1.
Designation and properties of cell strains used in this investigation
| Patient | UDS,* % | ED50,† J/m2 | Amino acid changes in XPD protein‡ | Susceptibility§ | Cancer- prone¶ |
|---|---|---|---|---|---|
| N46 | 100 | 49 | NA | − | − |
| N47 | 100 | 42 | NA | − | − |
| N50 | 100 | 43 | NA | − | − |
| XP67MA (D) | 36 | 20 | Q726am (20) | + | + |
| XP16BR (D) | 16 | 17.5 | R683W, R616P‖ | + | + |
| XP26VI (D) | 20 | 19 | ND | + | + |
| TTD4BR (21) | 100 | 49 | NA | − | − |
| TTD1BI (22) | 50 | 46 | Frameshift 730 (14) | − | − |
| TTD1BEL (12) | 15 | 49 | R722W, R616P (14) | − | − |
UDS, levels of unscheduled DNA synthesis (percent of normal cells) after UVC irradiation. Data were obtained from indicated published data or our own results.
ED50, mean UVB dose required for half-maximal suppression of IFN-γ-induced ICAM-1 mRNA expression, as calculated from three independent experiments for each cell strain. Standard deviations of each ED50 given in this table were <15%.
Results of mutation analysis of the XPD gene in patients. NA, not applicable—no DNA repair defect; ND, not determined.
Susceptible to UVB-radiation-induced suppression of IFN-γ-induced ICAM-1 mRNA expression. Cell strains N46, N47, and N50 were regarded as normal. Cells were defined as susceptible if their ED50 was not within the 95% confidence interval of ED50 calculated from normal cells (35.5–53.9 J/m2). If cells revealed an ED50 within the 95% confidence interval of ED50 calculated from normal cells (N46, N47, N50), cells were defined as normal.
Cancer-prone, personal history of malignant skin tumors during childhood and early adolescence.
Unpublished data of B. C. Broughton and A.R.L.