title: Specific targeting to B cells by lipid-based nanoparticles conjugated with a novel CD22-ScFv.
abstract: The CD22 antigen is a viable target for therapeutic intervention for B-cell lymphomas. Several therapeutic anti-CD22 antibodies as well as an anti-CD22-based immunotoxin (HA22) are currently under investigation in clinical settings. Coupling of anti-CD22 reagents with a nano-drug delivery vehicle is projected to significantly improve treatment efficacies. Therefore, we generated a mutant of the targeting segment of HA22 (a CD22 scFv) to increase its soluble expression (mut-HA22), and conjugated it to the surface of sonicated liposomes to generate immunoliposomes (mut-HA22-liposomes). We examined liposome binding and uptake by CD22(+) B-lymphocytes (BJAB) by using calcein and/or rhodamine PE-labeled liposomes. We also tested the effect of targeting on cellular toxicity with doxorubicin-loaded liposomes. We report that: (i) Binding of mut-HA22-liposomes to BJAB cells was significantly greater than liposomes not conjugated with mut-HA22 (control liposomes), and mut-HA22-liposomes bind to and are taken in by BJAB cells in a dose and temperature-dependent manner, respectively; (ii) This binding occurred via the interaction with the cellular CD22 as pre-incubation of the cells with mut-HA22 blocked subsequent liposome binding; (iii) Intracellular localization of mut-HA22-liposomes at 37 degrees C but not at 4 degrees C indicated that our targeted liposomes were taken up through an energy dependent process via receptor-mediated endocytosis; and (iv) Mut-HA22-liposomes loaded with doxorubicin exhibited at least 2-3 fold more accumulation of doxorubicin in BJAB cells as compared to control liposomes. Moreover, these liposomes showed at least a 2-4 fold enhanced killing of BJAB or Raji cells (CD22(+)), but not SUP-T1 cells (CD22(-)). Taken together these data suggest that these 2nd-generation liposomes may serve as promising carriers for targeted drug delivery to treat patients suffering from B-cell lymphoma.
authors.affiliation: Center for Cancer Research Nanobiology Program, National Cancer Institute at Frederick, National Institutes of Health, Frederick, MD 21702-1201, USA.
authors.forename: Kristin
authors.initials: K
authors.lastname: Loomis
authors.forename: Brandon
authors.initials: B
authors.lastname: Smith
authors.forename: Yang
authors.initials: Y
authors.lastname: Feng
authors.forename: Himanshu
authors.initials: H
authors.lastname: Garg
authors.forename: Amichai
authors.initials: A
authors.lastname: Yavlovich
authors.forename: Ryan
authors.initials: R
authors.lastname: Campbell-Massa
authors.forename: Dimiter S
authors.initials: DS
authors.lastname: Dimitrov
authors.forename: Robert
authors.initials: R
authors.lastname: Blumenthal
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Xiao
authors.forename: Anu
authors.initials: A
authors.lastname: Puri
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000378:metabolism; D001402:B-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D002460:Cell Line; D002470:Cell Survival; D004317:Doxorubicin / Q000494:pharmacology; D005434:Flow Cytometry; D005456:Fluorescent Dyes; D006801:Humans; D008081:Liposomes / Q000097:blood / Q000378:metabolism; D053758:Nanoparticles; D010714:Phosphatidylethanolamines / Q000378:metabolism; D051918:Sialic Acid Binding Ig-like Lectin 2 / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D057127:Single-Chain Antibodies / Q000276:immunology*; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism
chemical_list: D005456:Fluorescent Dyes; D008081:Liposomes; D010714:Phosphatidylethanolamines; D051918:Sialic Acid Binding Ig-like Lectin 2; D057127:Single-Chain Antibodies; C038089:1,2-distearoylphosphatidylethanolamine; D015060:1,2-Dipalmitoylphosphatidylcholine; D004317:Doxorubicin