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Open Access Research

Altering α-dystroglycan receptor affinity of LCMV pseudotyped lentivirus yields unique cell and tissue tropism

Douglas E Dylla12, Litao Xie2, Daniel E Michele4, Stefan Kunz5 and Paul B McCray123*

Author Affiliations

1 Genetics Ph.D. Program, Program in Gene Therapy, 240 EMRB, The University of Iowa Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, IA 52242 USA

2 Department of Pediatrics, 240 EMRB, The University of Iowa Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, IA 52242 USA

3 Microbiology, 240 EMRB, The University of Iowa Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, IA 52242 USA

4 Molecular and Integrative Physiology, University of Michigan, 7771 Med Sci II, Ann Arbor, MI 48109, USA

5 Institute of Microbiology, University Hospital Center and University of Lausanne, CH-1011, Lausanne, Switzerland

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Genetic Vaccines and Therapy 2011, 9:8  doi:10.1186/1479-0556-9-8

Published: 8 April 2011

Abstract

Background

The envelope glycoprotein of lymphocytic choriomeningitis virus (LCMV) can efficiently pseudotype lentiviral vectors. Some strains of LCMV exploit high affinity interactions with α-dystroglycan (α-DG) to bind to cell surfaces and subsequently fuse in low pH endosomes. LCMV strains with low α-DG affinity utilize an unknown receptor and display unique tissue tropisms. We pseudotyped non-primate feline immunodeficiency virus (FIV) vectors using LCMV derived glycoproteins with high or low affinity to α-DG and evaluated their properties in vitro and in vivo.

Methods

We pseudotyped FIV with the LCMV WE54 strain envelope glycoprotein and also engineered a point mutation in the WE54 envelope glycoprotein (L260F) to diminish α-DG affinity and direct binding to alternate receptors. We hypothesized that this change would alter in vivo tissue tropism and enhance gene transfer to neonatal animals.

Results

In mice, hepatic α- and β-DG expression was greatest at the late gestational and neonatal time points. When displayed on the surface of the FIV lentivirus the WE54 L260F mutant glycoprotein bound weakly to immobilized α-DG. Additionally, LCMV WE54 pseudotyped FIV vector transduction was neutralized by pre-incubation with soluble α-DG, while the mutant glycoprotein pseudotyped vector was not. In vivo gene transfer in adult mice with either envelope yielded low transduction efficiencies in hepatocytes following intravenous delivery. In marked contrast, neonatal gene transfer with the LCMV envelopes, and notably with the FIV-L260F vector, conferred abundant liver and lower level cardiomyocyte transduction as detected by luciferase assays, bioluminescent imaging, and β-galactosidase staining.

Conclusions

These results suggest that a developmentally regulated receptor for LCMV is expressed abundantly in neonatal mice. LCMV pseudotyped vectors may have applications for neonatal gene transfer.

Abbreviations

Armstrong 53b (Arm53b); baculovirus Autographa californica GP64 (GP64); charge-coupled device (CCD); dystroglycan (DG); feline immunodeficiency virus (FIV); glycoprotein precursor (GP-C); firefly luciferase (Luc); lymphocytic choriomeningitis virus (LCMV); nuclear targeted β-galactosidase (ntLacZ); optical density (OD); PBS/0.1% (w/v) Tween-20 (PBST); relative light units (RLU); Rous sarcoma virus (RSV); transducing units per milliliter (TU/ml); vesicular stomatitis virus (VSV-G); wheat germ agglutinin (WGA); 50% reduction in binding (C50).