Natural killer cells mediated antibody dependent cellular cytotoxicity response in acute and recovery phases of chikungunya

Abstract Background Neutralizing antibody is reported to correlate with protection from symptomatic chikungunya disease. In addition to direct virus neutralization, virus-specific antibodies can also protect through antibody effector functions via antibody-dependent cellular cytotoxicity (ADCC) mechanism. Methods We have assessed NK cell-mediated chikungunya virus (CHIKV) specific ADCC response in 56 acute, 56 prolonged, 44 chronic chikungunya arthritis patients, 23 recovered individuals from chikungunya (CHIK) & 50 healthy controls using a flow cytometry-based antibody-dependent heterologous NK cell activation assay with ADCC surrogate markers CD107a & IFN-γ. Results Persistent ADCC response in recovered individuals spanning over a duration of 3 months to 18 years post-infection and progressive decline in ADCC response in chronic chikungunya arthritis patients over the period of time were observed. ADCC response correlated with lower plasma viral load in acute patients ( p =0.022, r=-0.709). Recovered individuals elucidated a positive correlation between ADCC response and plasma anti-CHIKV IgG and IgG3 antibody levels (IgG: r=0.4503, IgG3: r=0.4583, p -value