Measles virus glycoprotein-based lentiviral targeting vectors that avoid neutralizing antibodies

• Published in: PloS one Vol. 7; no. 10; p. e46667
• Main Authors: Kneissl, Sabrina, Abel, Tobias, Rasbach, Anke, Brynza, Julia, Schneider-Schaulies, Jürgen, Buchholz, Christian J
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 10.10.2012; Public Library of Science (PLoS)
• Subjects: Antibodies; Antibodies, Neutralizing - blood; Antibodies, Viral - blood; Binding sites; Biology; Biotechnology; Blood plasma; CD150 antigen; CD46 antigen; Clinical trials; Dilution; Encephalitis; Engineering; Epitopes; Expression vectors; Fusion protein; Gene expression; Gene therapy; Gene transfer; Genetic Therapy - methods; Genetic Vectors; Glycoproteins; Green Fluorescent Proteins - biosynthesis; Green Fluorescent Proteins - genetics; H protein; Health aspects; HEK293 Cells; Hemagglutinins; Hemagglutinins, Viral - genetics; Humans; Immunity; Immunoglobulins; Incorporation; Lectins; Lentivirus - genetics; Lentivirus - immunology; Lentivirus - physiology; Measles; Measles virus - genetics; Measles virus - immunology; Medical research; Medicine; Multiplicity of infection; Mutation; Neutralization; Neutralizing; Proteins; Receptors; Recognition; Recombinant Fusion Proteins - genetics; Transduction, Genetic; Vaccination; Vaccines; Vectors (Biology); Viral Fusion Proteins - genetics; Virus Internalization; Viruses; Germany
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0046667

Lentiviral vectors (LVs) are potent gene transfer vehicles frequently applied in research and recently also in clinical trials. Retargeting LV entry to cell types of interest is a key issue to improve gene transfer safety and efficacy. Recently, we have developed a targeting method for LVs by incorporating engineered measles virus (MV) glycoproteins, the hemagglutinin (H), responsible for receptor recognition, and the fusion protein into their envelope. The H protein displays a single-chain antibody (scFv) specific for the target receptor and is ablated for recognition of the MV receptors CD46 and SLAM by point mutations in its ectodomain. A potential hindrance to systemic administration in humans is pre-existing MV-specific immunity due to vaccination or natural infection. We compared transduction of targeting vectors and non-targeting vectors pseudotyped with MV glycoproteins unmodified in their ectodomains (MV-LV) in presence of α-MV antibody-positive human plasma. At plasma dilution 1:160 MV-LV was almost completely neutralized, whereas targeting vectors showed relative transduction efficiencies from 60% to 90%. Furthermore, at plasma dilution 1:80 an at least 4-times higher multiplicity of infection (MOI) of MV-LV had to be applied to obtain similar transduction efficiencies as with targeting vectors. Also when the vectors were normalized to their p24 values, targeting vectors showed partial protection against α-MV antibodies in human plasma. Furthermore, the monoclonal neutralizing antibody K71 with a putative epitope close to the receptor binding sites of H, did not neutralize the targeting vectors, but did neutralize MV-LV. The observed escape from neutralization may be due to the point mutations in the H ectodomain that might have destroyed antibody binding sites. Furthermore, scFv mediated cell entry via the target receptor may proceed in presence of α-MV antibodies interfering with entry via the natural MV receptors. These results are promising for in vivo applications of targeting vectors in humans.