Current chikungunya antibody prevalence and titers are likely to differ based on exposure rates before the 2006 reemergence. For vaccine usage, such data are of immense importance. This study addresses age-stratified IgG titers and its subtypes in Pune, India, endemic for the disease. One hundred seventy serum pools (791 individuals with prior chikungunya exposure, age stratified) from exposed and 15 samples from acute disease phase were screened. Inactivated chikungunya virus (CHIKV)–based indirect ELISA was used to determine anti–CHIKV-IgG and its subtypes. Neutralizing antibody titers (plaque reduction neutralization test [PRNT]) were compared with binding antibody titers (ELISA). Anti–CHIKV-IgG titers along with IgG1 and IgG4 increased till the age-group of 11–15 years and remained comparable thereafter till > 65 years. IgG1 was the predominant IgG subtype detected in all the pools, whereas IgG4 was present in 151/170 pools. Strong correlation of IgG1 was obtained with CHIKV–PRNT50 titers. None of the sample had anti–CHIKV-IgG2, whereas five pools had IgG3 antibody. In the acute-phase serum sample, IgG1 was present in all the samples, whereas IgG4 was present in 8/15 samples. IgG4 was predominant in four samples. During acute phase and at different times postinfection, IgG1 circulated in high titers followed by IgG4. Higher antibody titers in adults reflect reexposures. The data will prove useful in assessing immune response to CHIKV vaccine.
Address correspondence to Vidya A. Arankalle, Department of Communicable Diseases, Interactive Research School for Health Affairs (IRSHA), Bharati Vidyapeeth (Deemed to be University), Katraj-Dhankawadi, Pune 411043, India. E-mail: email@example.com
Disclosure: Samples from the study “Establishment of a novel Electronic Surveillance System for DENV in Pune: an initiative for Smart Cities Mission” funded by Indian Council of Medical Research, Government of India, New Delhi, were used in this study.