Use of Polyclonal Antibody for the Diagnosis of Human African Trypanosomiasis

Abstract

Human African trypanosomiasis (HAT), commonly known as sleeping sickness is one of the neglected tropical diseases (NTDs), which is fatal if left untreated. Its diagnosis is a challenge since the signs and symptoms of the primary phase are not specific, the existing diagnostic methods have low sensitivity and specificity, and the available drugs have some toxicity. New, robust, and cost-effective techniques are needed for the early identification of parasites. This study aimed to assess the sensitivity and specificity of two different types of polyclonal antibodies against T. b. gambiense using antigen detection ELISA. Polyclonal antibodies against the expressed proteins Tbg I2 and Tbg I17 were produced using New Zealand white rabbits. The antibody titer measured was greater than 32 g/L after the 3rd immunization for the expressed protein Tbg I2. For the expressed protein Tbg I17, the antibody titer measured was greater than 32 g/L after the 4th immunization. The sensitivity and specificity of the Tbg I2 polyclonal antibody confirmed with Polymerase Chain Reaction (PCR) as gold standard were respectively 89.5% and 80.6%, while for the Tbg I17 polyclonal antibody, the sensitivity and specificity were respectively 92.1% and 88.9%. The area under the curve for the Tbg I2 polyclonal antibody was 0.90 ± 0.032, while for the Tbg I17 polyclonal antibody, the area under the curve was 0.92 ± 0.0. The Tbg I17 polyclonal antibody produced in New Zealand white rabbits has good sensitivity and good specificity; it can be successfully used in the diagnosis of HAT.