title: Blood kinetics, tissue distribution, and radioimaging of anti-common chronic lymphatic leukemia antigen (cCLLa) monoclonal antibody CLL2 in mice transplanted with cCLLa-bearing human leukemia cells.
abstract: The blood kinetics and biodistribution of anti-common chronic lymphatic leukemia antigen (cCLLa) monoclonal antibody (MoAb) CLL2 were assessed in mice bearing cCLLa+ tumors. The cCLLa is a 69-Kd glycoprotein antigen expressed selectively by malignant B cells in human CLL, hairy cell leukemia (HCL), and prolymphocytic leukemia. Immunoreactive 125I-CLL2 (5 micrograms/mouse, specific activity 4.3 microCi/micrograms) was injected intravenously in mice bearing HCL-derived EH xenografts, and blood kinetics and biodistribution were ascertained up to 16 days postinjection. Radioimages were also obtained up to 72 hours after injecting 10 micrograms/mouse (specific activity 50.1 microCi/micrograms) of 125I-CLL2. Distinct 125I-CLL2 blood kinetics were observed in EH engrafted compared with tumor-free mice including: a longer 125I-CLL2 T 1/2 (153 hours v 72 hours), and a considerably greater blood clearance (173 mg/h v 54.7 mg/h) with biexponential rather than monoexponential configuration; and a greater volume of antibody distribution (31,483 mg v 5,729 mg). These data suggest more rapid tissue uptake by grafted tumours. Preferential 125I-CLL2 uptake by EH tumours relative to normal tissues was observed beginning 24 hours postinjection (mean ratio, 4.2) with average peak tumor 125I-CLL2 levels of 428.7 pg/mg. 125I-CLL2 uptake selectivity by EH tumor cells was also supported by: (1) negligible 125I-CLL2 uptake by cCLLa- Molt-4 xenografts (average 29.1 pg/mg 24 hours postinjection); (2) background uptake of cCLLa-irrelevant MoAb 131I-LEU1 by CD5- EH xenografts (average 31.4 pg/mg 48 hours postinjection); and (3) by scintigraphy. The EH xenograft mouse model might be useful to ascertain preclinically the anti-tumor effect of anti-cCLLa MoAbs and of their conjugated derivatives.
authors.affiliation: Cancer Immunology Research, Veterans Administration Medical Center, Augusta, GA 30910.
authors.forename: G B
authors.initials: GB
authors.lastname: Faguet
authors.forename: J F
authors.initials: JF
authors.lastname: Agee
authors.forename: J T
authors.initials: JT
authors.lastname: DiPiro
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D000951:Antigens, Neoplasm / Q000032:analysis*; D014408:Biomarkers, Tumor / Q000032:analysis*; D002460:Cell Line; D006801:Humans; D007457:Iodine Radioisotopes; D007700:Kinetics; D007943:Leukemia, Hairy Cell / Q000276:immunology*; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D014018:Tissue Distribution; D014183:Transplantation, Heterologous
chemical_list: D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D007457:Iodine Radioisotopes; C058497:common chronic lymphatic leukemia antigen gp69, human