Bioactivity of electric field-pulsed human recombinant interleukin-2 and its encapsulation into erythrocyte carriers.
The molecular integrity of human recombinant interleukin-2 (rIL-2), as measured by size exclusion chromatography, was not altered when exposed to high electrical field intensities. In addition, the biological activity was unaffected, as evidenced by the ability of the rIL-2 to stimulate the proliferation (by cell growth assays and tritiated thymidine uptake) and differentiation (by cytotoxicity assay) of human lymphocytes into killer cells. Electroporation conditions chosen for the loading of rIL-2, based upon those which provided for good recovery of carriers and minimal hemoglobin release, involved a lower field intensity (i.e., 6 kV/cm instead of 7 or 8 kV/cm) and multiple pulses (eight pulses, 5 microseconds) rather than a single pulse (40 microseconds). Human erythrocyte carriers consistently encapsulated 5-7.5% of the rIL-2 by electroporation (6 kV/cm, eight pulses, 5 microseconds duration). A rIL-2 concentration of 600,000 U/ml surrounding the erythrocytes during loading resulted in ca. 245,000 U/ml carriers, which represents a therapeutically significant quantity. Thus, rIL-2 shows potential as an encapsulated agent for slow release in the erythrocyte carrier system.
Mitchell
D H
DH
Department of Surgery, University of Colorado Health Sciences Center, Denver 80262.
James
G T
GT
Kruse
C A
CA
D001709:Biotechnology; D003602:Cytotoxicity, Immunologic; D004560:Electricity; D004912:Erythrocytes; D006801:Humans; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000008:administration & dosage*; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000276:immunology; D014677:Pharmaceutical Vehicles
D007376:Interleukin-2; D014677:Pharmaceutical Vehicles