Determination of B cell epitopes and evaluation of antigen capture ELISA for the earlier diagnosis of CHIK virus using anti-rCHIK E1 rabbit antibodies.

Chikungunya fever caused by an alpha virus has been generally considered as self limiting and non fatal. Recent reports on Chikungunya infection indicate high mortality rates due to the severity of the viral infection. For the early diagnosis of CHIK virus, the incubation period required for the development of antibodies in the serum of patients was a constraint for antigen based ELISA. The results of the present study demonstrates the development and evaluation of the antigen capture ELISA using recombinant anti-CHIK rabbit antibodies and anti-CHIK human antibody for more specific and rapid detection of CHIK viral antigen. A comprehensive bioinformatics analysis of the amino acid sequence of CHIK E1 protein was done for determining the antigenic residues, predominant B cell epitopes and their properties. Rabbit antibodies against recombinant CHIK E1 antigen was developed and purified. Antigen capture ELISA was done in 104 CHIK patient serum samples using anti-rCHIK E1 rabbit antibodies and anti-CHIK human antibodies. The highest rate of sensitivity (96%) and specificity (100%) was observed in the assay data and it highlights the accuracy of the test as a clinical diagnostic tool. No cross reactivity was observed with samples of dengue patients. Apart from the development and evaluation of the ELISA test, the dominant epitopes identified in the recombinant CHIK E1 protein sequence can be exploited for the development of a subunit Chikungunya vaccine.