Obtaining and characterizing of single domain antibodies derived from camelids (nanoantibodies or vhh) against foot-and-mouth disease virus for diagnostic application.

BOZZO JOAQUIN; GRIPPO VANINA; MARCHESE FLORENCIA; MATTION, NORA

Congreso; LXII Reunión anual de la Sociedad argentina de Investigación Clínica (SAIC); 2017

SAIC

Foot-and-Mouth Disease (FMD) is a viral disease of livestock with seriouseconomic repercussions. Development of innovative diagnostic methods for theFMD control is of concern due to the susceptibility of species of economicinterest. Camelids present heavy chain only antibodies (IgG 2 and 3), so thevariable domain consists of a single domain (VHH or Nanoantibody). Theseantibodies represent a novel tool with unique characteristics conferring greatpotential in the development of new more sensitive diagnostic methods. For thisreason, the present work aimed to obtain and preliminary characterize VHHspecific against FMDV for its application in the diagnostic innovation.Two llamas (Lama glama) were immunized with the strains O1/Campos,A24/Cruzeiro (A24), A/Arg/2001 (A2001) and C3/Indaial (C3). Humoral immuneresponse (total IgG and subtype titers) was assessed throughout theimmunization schedule obtaining high levels of heavy chain-only antibodiesagainst the 4 serotypes by ELISA. Serum reactivity against viral proteins wasconfirmed in Western Blot. Two Nanoantibody libraries were constructedstarting from llama peripheral blood and VHH against O1C strain were selectedby Phage Display. Even more, 119 out of 182 selected clones recognized the 4serotypes in ELISA. From these clones, 17 which showed very high reactivity inELISA were selected for diversity analysis by enzymatic digestion. As a result, itwas shown that 16 out of 17 clones presented different fingerprinting pattern.In conclusion, two VHH libraries were constructed from immunized llama withthe O1C, A24, A2001 and C3 strains. Both llamas had a high immune responseand their sera were able to recognize the 4 FMDV serotypes. Furthermore, thetwo llamas had high levels of heavy chain only antibodies, mainly IgG3 subtype.At least 16 different cross-reactive Nanoantibodies were obtained against the 4strains. Thus, these antibodies represent a potential tool for diagnosticinnovation of FMDV