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Bovine Antibody Genetics, Structure and Antigenization for Disease Prevention

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Title: Bovine Antibody Genetics, Structure and Antigenization for Disease Prevention
Author: Pasman, Yfke
Department: Department of Molecular and Cellular Biology
Program: Molecular and Cellular Biology
Advisor: Kaushik, Azad K.
Abstract: Cattle provide a suitable model for studying neonatal immunity since the fetus develops without exposure to maternal immunoglobulins. In bovine neonate, a significant shift in total transcriptome occurs within the first week of life. Pathway analysis showed 110 significantly differentially expressed immunity-related genes at birth (e.g., complement, defensins, cytokines). Development of bovine neonatal humoral immunity revealed differentially expressed immunoglobulin genes over time encoding heavy and light chain constant domains e.g. higher immunoglobulin kappa light chain gene expression in calf as compared to adult. Furthermore it showed preferred expression of 3' heavy chain variable gene IGHV1S1(BF4E9), and longest heavy chain diversity gene IGHD2 at birth known to encode immunoglobulins with exceptionally long CDR3H indicating their importance in the development of bovine humoral immunity. Analysis of the contributions of VH and VL domains to antibody function revealed fine differences with regard to antigen recognition and virus neutralization functions. The variable-heavy domain alone of polyspecific IgM with an exceptionally long CDR3H (FdVH1H12) is capable of recognizing multiple antigens, unlike variable-light domain (FdVL1H12). By contrast, both variable heavy (FdVH073) and light (FdVL074) domains of a monospecific IgG recognize antigen but it is enhanced by VH+VL pairing. Further, both VH and VL domains (scFv3-18L) are required for virus (bovine herpes virus-1; BoHV-1) neutralization. Thus, differences exists with regard to VH and VL domains of an antibody in antigen recognition and virus neutralization functions. A 32-kDa BoHV-1 gC envelope glycoprotein was identified to have a B-epitope recognized by a bovine antibody fragment containing the variable domains of the heavy and light chain connected with a flexible amino-acid Linker (scFv3-18L). A 156 amino- acid long gC fragment (antigen gC156) was grafted into the exceptionally long CDR3H of bovine antibody fragment (scFv1H12) and expressed in Pichia pastoris. The gC156 was also expressed separately. The antigenized gC156scFv1H12 sustained gC156 conformation, similar to native gC, as it was recognized by anti-BoHV-1 scFv3-18L. gC156scFv1H12 induced a higher antibody response as compared to gC156 in calves upon immunization. Antigenization of bovine scFv with exceptionally long CDR3H capable of sustaining conformational B-epitope and inducing desired immune response provides a novel approach to developing vaccines.
Date: 2015-11
Rights: Attribution-NonCommercial-NoDerivs 2.5 Canada

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Attribution-NonCommercial-NoDerivs 2.5 Canada Except where otherwise noted, this item's license is described as Attribution-NonCommercial-NoDerivs 2.5 Canada