Use of genetically engineered lipid-tagged antibody to generate functional europium chelate-loaded liposomes. Application in fluoroimmunoassay.
Biosynthetically lipid-tagged single-chain antibody (Laukkanen et al., Protein Eng. 6 (1993) 449; Biochemistry 33 (1994) 11664) has been used to functionalize europium (Eu3+) chelate-loaded liposomes. The resulting Eu immunoliposomes displayed specific hapten-binding activity and little non-specific binding in time-resolved fluoroimmunoassay (TR-FIA). No loss of entrapped marker nor of binding activity was observed after storage of Eu immunoliposomes for 1 month at 4 degrees C. In comparison with Eu-labeled free single-chain antibody, Eu immunoliposomes produced a higher signal and provided increased sensitivity in a sandwich-type immunoassay. These results demonstrate the potential of Eu immunoliposomes as signal-amplifying reagents in TR-FIA.
Laukkanen
M L
ML
VTT Biotechnology and Food Research, Espoo, Finland.
Orellana
A
A
Keinänen
K
K
D000906:Antibodies / Q000737:chemistry*; D005063:Europium / Q000008:administration & dosage*; D005455:Fluorescent Antibody Technique; D005456:Fluorescent Dyes; D005818:Genetic Engineering; D006241:Haptens; D007128:Immunoglobulin Fragments / Q000737:chemistry*; D008055:Lipids; D008081:Liposomes; D004369:Pentetic Acid / Q000737:chemistry; D011994:Recombinant Proteins
D000906:Antibodies; D005456:Fluorescent Dyes; D006241:Haptens; D007128:Immunoglobulin Fragments; D008055:Lipids; D008081:Liposomes; D011994:Recombinant Proteins; C055966:immunoglobulin Fv; D005063:Europium; D004369:Pentetic Acid