Recombinant dimeric small immunoproteins neutralize transmissible gastroenteritis virus infectivity efficiently in vitro and confer passive immunity in vivo.
Small immunoproteins (SIPs) are single-chain molecules comprising the variable regions of an antibody assembled in a single polypeptide (scFv) and joined to the immunoglobulin heavy-chain dimerizing domain. To investigate the potential of these molecules to provide protection against enteric infections when supplied orally, SIPs were generated against Transmissible gastroenteritis virus (TGEV), a highly pathogenic porcine virus. Different variants of TGEV-specific SIPs were created, of epsilon and alpha isotypes, by exploiting the dimerizing domains epsilonCH4 and alphaCH3 of human and swine origin. Transfected cells secreted these recombinant mini-antibodies efficiently, mainly as dimers stabilized covalently by inter-chain disulphide bridges. The specificity and functionality of the recombinant TGEV-specific SIPs were determined by in vitro binding, neutralization and infection-interference assays. The neutralization indices of the TGEV-specific SIPs were all very similar to that of the original TGEV-specific mAb, thus confirming that the immunological properties have been preserved in the recombinant SIPs. In vivo protection experiments on newborn piglets have, in addition, demonstrated a strong reduction of virus titre in infected tissues of animals treated orally with TGEV-specific SIPs. It has therefore been demonstrated that it is possible to confer passive immunization to newborn pigs by feeding them with recombinant SIPs.
Bestagno
Marco
M
International Centre for Genetic Engineering and Biotechnology, AREA Science Park, Padriciano 99, 34012 Trieste, Italy.
Sola
Isabel
I
Department of Molecular and Cell Biology, Centro Nacional de Biotecnologia, Consejo Superior de Investigaciones Cientificas, Campus Univ. Autonoma Madrid, Darwin 3, Cantoblanco, 28049 Madrid, Spain.
Dallegno
Eliana
E
International Centre for Genetic Engineering and Biotechnology, AREA Science Park, Padriciano 99, 34012 Trieste, Italy.
Sabella
Patricia
P
Fort-Dodge Veterinaria SA, Department of Research and Development, Vall de Bianya, 17813 Girona, Spain.
Poggianella
Monica
M
International Centre for Genetic Engineering and Biotechnology, AREA Science Park, Padriciano 99, 34012 Trieste, Italy.
Plana-Durán
Juan
J
Fort-Dodge Veterinaria SA, Department of Research and Development, Vall de Bianya, 17813 Girona, Spain.
Enjuanes
Luis
L
Department of Molecular and Cell Biology, Centro Nacional de Biotecnologia, Consejo Superior de Investigaciones Cientificas, Campus Univ. Autonoma Madrid, Darwin 3, Cantoblanco, 28049 Madrid, Spain.
Burrone
Oscar R
OR
International Centre for Genetic Engineering and Biotechnology, AREA Science Park, Padriciano 99, 34012 Trieste, Italy.
D000818:Animals; D000831:Animals, Newborn / Q000276:immunology / Q000821:virology*; D000914:Antibodies, Viral / Q000096:biosynthesis / Q000276:immunology*; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D019281:Dimerization; D005761:Gastroenteritis, Transmissible, of Swine / Q000517:prevention & control*; D007162:Immunoproteins / Q000008:administration & dosage* / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000276:immunology; D013552:Swine; D005760:Transmissible gastroenteritis virus / Q000276:immunology*
D000914:Antibodies, Viral; D007162:Immunoproteins; D011994:Recombinant Proteins