Development and evaluation of a recombinant-glycoprotein-based latex agglutination test for rabies virus antibody assessment

Abstract

The measurement of neutralizing antibodies induced by the glycoprotein of rabies virus is indispensable for assessing the level of neutralizing antibodies in animals or humans. A rapid fluorescent focus inhibition test (RFFIT) has been approved by WHO and is the most widely used method to measure the virus-neutralizing antibody content in serum, but a rapid test system would be of great value to screen large numbers of serum samples. To develop and evaluate a latex agglutination test (LAT) for measuring rabies virus antibodies, a recombinant glycoprotein was expressed in an insect cell system and purified, and the protein was coated onto latex beads at concentrations of 0.1, 0.25, 0.5, 0.75, and 1 mg/ml to find out the optimal concentration for coating latex beads. It was found that 0.5 mg/ml of recombinant protein was optimal for coating latex beads, and this concentration was used to sensitize the latex beads for screening of dog serum samples. Grading of LAT results was done with standard reference serum with known antibody titers. A total of 228 serum samples were tested, out of which 145 samples were positive by both RFFIT and LAT, and the specificity was found to be 100 %. In RFFIT, 151 samples were positive, the sensitivity was found to be 96.03 %, and the accuracy/concordance was found to be 97.39 %. A rapid field test-a latex agglutination test (LAT)-was developed and evaluated for rabies virus antibody assessment using recombinant glycoprotein of rabies virus expressed in an insect cell system.

Mini review on Potency Evaluation of Rabies Vaccine preparations

“…A percentage of 97% of monoclonal antibodies recognize antigenic sites [15]. Rabies virus antigenic sites play an important role in the disease pathogenies [16,17,18]. In addition, it is discovered that to sustain viral pathogenicity, the expression of viral proteins and conservancy of many viral elements must be maintained [18], especially G protein must be controlled.…”

“…About twenty-four thousand die due to rabies in Africa annually and dogs are the main reason for infection transmission [1]. Fortunately, it is a vaccine-preventable disease [4] and the most important way to prevent is vaccination of both pets and people [16]. The rabies vaccine is a type of inactivated virus vaccine that is prepared either in human diploid cell culture [HDCV] or in purified chick embryo cell culture [PCEC] [5].…”

Review on Rabies and Vaccines

“…During infection and vaccination, the glycoprotein plays a major role as an antigenic stimulant and induces neutralizing antibodies (Jemima et al, 2014). Several studies have confirmed that glycoprotein gives protection against rabies.…”

Rabies, a Vaccine Preventable Disease: Current Status, Epidemiology, Pathogenesis, Prevention and Control With Special Reference to India

“…2014 A rapid field test latex agglutination test (LAT) was developed for measuring RABV antibodies using recombinant glycoprotein expressed in an insect cell system. Jemima et al (2014) 14. 2014…”