Cytotoxic activity of calicheamicin immunoconjugates against human B-lymphoma cell lines in vitro
. | IC50 = pM (CalichDMH equivalents) . | . | . | ||
|---|---|---|---|---|---|
| . | Conjugated CalichDMH . | . | . | ||
| Human tumor cell line . | CD22-targeted CMC-544 . | CD33-targeted CMA-676 . | Unconjugated untargeted CalichDMH . | ||
| CD22+ RL | 6 | 627 | 234 | ||
| CD22+ Daudi | 21 | 1886 | 260 | ||
| CD22+ Raji | 300 | 2800 | 460 | ||
| CD22+ Ramos | 200 | 1110 | 700 | ||
| CD33+ HL-60 | 2500 | < 200 | 750 | ||
. | IC50 = pM (CalichDMH equivalents) . | . | . | ||
|---|---|---|---|---|---|
| . | Conjugated CalichDMH . | . | . | ||
| Human tumor cell line . | CD22-targeted CMC-544 . | CD33-targeted CMA-676 . | Unconjugated untargeted CalichDMH . | ||
| CD22+ RL | 6 | 627 | 234 | ||
| CD22+ Daudi | 21 | 1886 | 260 | ||
| CD22+ Raji | 300 | 2800 | 460 | ||
| CD22+ Ramos | 200 | 1110 | 700 | ||
| CD33+ HL-60 | 2500 | < 200 | 750 | ||
Human B-lymphoma cells were cultured for 96 hours in the presence of various concentrations of CMC-544, CMA-676, or unconjugated CalichDMH after which the viable cell number in each culture was enumerated by their exclusion of propidium iodide and detected by flow cytometry. Unconjugated anti-CD22 mAb G5/44 up to 1 μM had no effect on the growth of these B-cell lines. Results are IC50 values expressed in pM CalichDMH equivalents.