International Journal of Microbiology and Immunology Research Vol. 2(3), pp. 033-040, May 2014 ISSN 2327-7769 ©2014 Academe Research Journals

Full Length Research Paper

Neutralizing human single-chain antibodies against Herpes Simplex Virus type 1 glycoprotein D from a phage display library

Foroogh Nejatollahi^1,2*, Vahid Bagheri^2,3, Mohammad Motamedifar^1,4 and Bahareh Moazen³

¹Shiraz HIV/AIDS Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.

²Recombinant Antibody Laboratory, Department of Immunology, Shiraz University of Medical Sciences, Shiraz, Iran.

³Student Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran.

⁴Department of Bacteriology and Virology, Shiraz University of Medical Sciences, Shiraz, Iran.

*Corresponding author. E-mail: nejatollaf@sums.ac.ir. Tel: (+)989171039033. Fax: (+) 987112351575.

Accepted 9 May, 2014

Abstract

Among the 12 glycoproteins of the Herpes simplex virus type 1 envelope (HSV-1), glycoprotein D (gD) plays a critical role in the entry of the virus into target cells and cell-to-cell spread. gD is an attractive target for molecular intervention and monoclonal antibodies to this glycoprotein has decreased the severity of experimental HSV-1 infection in animal studies. Single chain antibodies which are produced by antibody engineering are small high affinity recombinant antibodies with growing clinical importance especially when viral antigens have been used for targeted therapy. Here we report neutralizing single-chain fragment variable (scFv) antibodies against HSV-1 gD from a phage-display non-immune human scFv library. The phage antibody was panned against amino acid residues 12-21 derived from the N-terminal part of gD. Two scFvs, scFv-gD₁ and scFv-gD₂, with frequencies of 25% and 20% were isolated among scFv clones using PCR and MvaI fingerprinting. Phage ELISA analysis demonstrated high reactivity of scFv-gD₁ and scFv-gD₂ with the gD peptide. In neutralization assay, scFv-gD₂ exhibited neutralizing effect of 76%. Sequence analysis of scFv-gD₂ revealed the amino acid specific changes in FR1 region of heavy chain and FR1 and JL3 regions of light chain of antibody molecule. Also the sequence GADTAMAG in CDR3 region represented the specificity of the selected antibody. The results suggest that the specific neutralizing scFv-gD₂ can be considered as a new alternative in the prophylaxis and treatment of HSV-1 infections.

Key words: Herpes simplex virus type 1, glycoprotein D, single-chain antibody, neutralizing antibody, immunotherapy.