A chimeric Lym-1/interleukin 2 fusion protein for increasing tumor vascular permeability and enhancing antibody uptake.
A murine antihuman B-cell monoclonal antibody, Lym-1, has shown considerable promise for the treatment of human malignant lymphomas. To enhance its clinical potential, a genetically engineered fusion protein consisting of a chimeric Lym-1 (chLym-1) and interleukin 2 (IL-2) was tested for mediating cytotoxicity, increasing vasopermeability, and enhancing antibody uptake in human malignant lymphomas. The chLym-1/IL-2 fusion protein, which was expressed initially in a baculovirus system and more recently in the glutamine synthetase gene amplification system, was shown to be processed and assembled into a normal immunoglobulin monomer with two IL-2 molecules per antibody. It was found to be equivalent to the chLym-1 antibody in antigen-binding specificity and relative affinity. In addition, it maintains IL-2 cytokine activity as demonstrated by support of T-cell proliferation. Moreover, in antibody-dependent cellular cytotoxicity assays against Raji target cells, chLym-1/IL-2 had approximately 2-fold and 4-fold higher cytotoxicity than chLym-1 and murine Lym-1, respectively. Used as a pretreatment, chLym-1/IL-2 enhances the uptake of chLym-1 at the tumor site by altering the permeability of tumor vessels producing tumor:normal organ ratios of 420:1 for blood and 1708:1 for muscle at 3 days. The in vitro and in vivo activities of chLym-1/IL-2, therefore, suggest that this genetically engineered antibody fusion protein may represent a new immunotherapeutic reagent for the treatment of human malignant lymphomas.
Hu
P
P
Department of Pathology, University of Southern California School of Medicine, Los Angeles 90033, USA.
Hornick
J L
JL
Glasky
M S
MS
Yun
A
A
Milkie
M N
MN
Khawli
L A
LA
Anderson
P M
PM
Epstein
A L
AL
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology*; D000920:Antibody-Dependent Cell Cytotoxicity; D001483:Base Sequence; D002199:Capillary Permeability / Q000187:drug effects*; D006801:Humans; D018796:Immunoconjugates / Q000494:pharmacology*; D007376:Interleukin-2 / Q000378:metabolism / Q000494:pharmacology*; D008223:Lymphoma / Q000628:therapy; D051379:Mice; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology*; D014018:Tissue Distribution
D000911:Antibodies, Monoclonal; D018796:Immunoconjugates; D007376:Interleukin-2; D011993:Recombinant Fusion Proteins