THE non-structural polyprotein 3ABC of foot-and-mouth disease virus as a diagnostic antigen in ELISA to differentiate infected from vaccinated cattle

Abstract

A diagnostic assay to differentiate antibodies induced by foot-and-mouth disease virus (FMDV) infection from those induced by vaccination was developed. The test is an indirect-trapping ELISA which uses a monoclonal antibody to trap the non-structural 3ABC-FMDV polypeptide expressed in E. coli. Experimental and field sera from naive, vaccinated and infected cattle were examined. Using the established threshold of 0.20 optical density units, the sensitivity of the assay was 100%, as all the experimental post-infection sera (n degree = 137) gave values greater than this threshold, irrespective of the FMDV serotype used for the infection. In contrast, more than 99% of sera from vaccinated animals were negative (225 out of 228 primo-vaccinates and 159 out of 159 multi-vaccinates). A high degree of specificity was also confirmed by the finding that 99.5% (442 out of 444) of sera from naive animals gave negative results. Serum conversion against 3ABC was first detected 8 days post-infection and demonstrable levels of 3ABC specific antibodies were detectable at least 1 year post-infection. The described 3ABC-ELISA is safe, cheap and also easy to perform in large scale serological surveys. The high specificity and sensitivity makes this test an ideal tool for FMD eradication campaigns and control programs.

Foot-and-mouth disease (FMD) prevalence and exposure factors associated with seropositivity of cattle in north-central, Nigeria

“…However, recent sampling conducted between 2007 and 2009 have indicated that despite the endemicity of FMD in Nigeria with its attendant production losses in livestock, very little is known about the epidemiology of FMD in Nigeria (Fasina et al, 2013). The prevalence of FMD can be determined serologically by measuring the antibody level to the 3ABC nonstructural protein (NSP) (De Diego et al, 1997). The objectives of this study were to determine the seroprevalence of FMD and to identify the risk factors associated with seropositivity of FMD in cattle from the north-central Nigeria.…”

Development of a Peptide-Based Immunochromatographic Strip for Differentiation of Serotype OFoot-and-Mouth Disease Virus—Infected Pigs from Vaccinated Pigs

“…7 In such endemic areas, it is important to identify animals, whether vaccinated or not, in which replication of Footand-mouth disease virus (FMDV; order Picornavirales, family Picornaviridae, genus Aphthovirus) has taken place to eliminate potentially infective animals. 2,3,11 Recently, a number of in-house and commercial tests to identify infection within vaccinated livestock (i.e., the presence of viral carrier animals) were developed and evaluated. 4,10,12 These methods are theoretically based on the assumption that semi-purified, inactivated FMDV vaccines mainly consist of capsid (structural) proteins, and so they are less likely to elicit production of antibodies against nonstructural proteins (NSP).…”

“…An antibody response against NSPs is only related to in vivo virus activity. 3,8 However, the NSPs used in these test procedures were primarily produced in expression systems by using either bacteria or baculovirus, and nonspecific reactions can be caused by the presence of antibodies in test animals against these expression vector antigens. 14,15 More recently, synthetic peptides that contained B-cell epitopes of FMDV NSP have been used.…”

“…They can be used to survey large numbers of sera to estimate the level of subclinical viral infection and to detect early incursion of FMDV into an animal population, regardless of serotype of the virus involved. 3,8,15 But ELISAs require specialized equipment and technical expertise, thus suspect samples must be transported to a laboratory for testing. The availability of a specific, simple, inexpensive, and disposable test that would be capable of providing results within minutes of taking a clinical sample and that could be used on suspect premises by a veterinarian would help to mitigate the spread of any infection.…”

Novel Purification Method for Recombinant 3AB1 Nonstructural Protein of Foot-and-Mouth Disease Virus for Use in Differentiation between Infected and Vaccinated Animals

“…Several strategies have been applied to obtain antigen preparations of 3AB 123 and 3ABC, including their expression in Escherichia coli 1,2,5,7 or Baculovirus, 6,12 and the use of a synthetic peptide. 9 In addition, 1 group of workers have produced a recombinant form of 3AB1 associated with Glutathione S-transferase in a prokaryotic expression system, but the protein yield was very low in concentration.…”