Expression of HM1.24 and the Sensitivity to Humanized Anti-HM1.24 MoAb of Neoplastic Myeloma Cells
Target Cells . | HM1.24 Expression (MSFI) . | Cytotoxicity (%) . | |
---|---|---|---|
Control Human IgG . | Humanized Anti-HM1.24 . | ||
ARH-77 | 43 | 2 | 44 |
IM-9 | 38 | 6 | 61 |
RPMI 8226 | 36 | 0 | 37 |
Ramos | 33 | 0 | 33 |
U 266 | 30 | 38* | 59 |
HS-Sultan | 21 | 0 | 31 |
Daudi | 12 | 0 | 11 |
Patient no. 1 | 34 | 4 | 29 |
1† | 25† | ||
Patient no. 2 | 33 | 0 | 21 |
0† | 27† | ||
Patient no. 3 | 30 | 0 | 16 |
Patient no. 4 | 30 | 7 | 32 |
CHO-1 | 50‡ | 5 | 38 |
CHO-2 | 20‡ | 11 | 28 |
CHO-3 | 5‡ | 7 | 8 |
CHO-4 | 1‡ | 0 | 1 |
HEL | 11-153 | 6 | 6 |
Target Cells . | HM1.24 Expression (MSFI) . | Cytotoxicity (%) . | |
---|---|---|---|
Control Human IgG . | Humanized Anti-HM1.24 . | ||
ARH-77 | 43 | 2 | 44 |
IM-9 | 38 | 6 | 61 |
RPMI 8226 | 36 | 0 | 37 |
Ramos | 33 | 0 | 33 |
U 266 | 30 | 38* | 59 |
HS-Sultan | 21 | 0 | 31 |
Daudi | 12 | 0 | 11 |
Patient no. 1 | 34 | 4 | 29 |
1† | 25† | ||
Patient no. 2 | 33 | 0 | 21 |
0† | 27† | ||
Patient no. 3 | 30 | 0 | 16 |
Patient no. 4 | 30 | 7 | 32 |
CHO-1 | 50‡ | 5 | 38 |
CHO-2 | 20‡ | 11 | 28 |
CHO-3 | 5‡ | 7 | 8 |
CHO-4 | 1‡ | 0 | 1 |
HEL | 11-153 | 6 | 6 |
HM1.24 expression was examined by flow cytometry. Cytotoxicity against tumor cells was determined by a 4-hour 51Cr-release assay using normal human PBMCs as effector cells at an E/T ratio of 50 in the presence of 1 μg/mL control human IgG or humanized anti-HM1.24 MoAb. Data represent the mean value of three independent experiments. The standard error of cytotoxicity was <10% in all target cells.
U266 is NK-sensitive.
Autologous PBMCs were used as effector cells.
CHO transformants expressing different levels of HM1.24 antigen were used.
HEL does not express HM1.24 antigen.