Antibody kinetics following confirmed Shigella infection: A longitudinal study in Dhaka, Bangladesh

The study analyzed blood samples from 48 individuals with confirmed Shigella infection in Dhaka, Bangladesh during 2021-2022. Researchers measured IgG and IgA antibodies against five antigens at time points up to 180 days post-infection. IgA antibodies rose rapidly and returned to baseline levels within 2-3 months, while IgG remained elevated throughout 200 days. Children under five years showed lower baseline values and higher peaks, indicating primary infection, whereas older children had higher baseline values and lower peaks, suggesting prior exposure. IpaB antigen responses were elevated across all serotypes, while polysaccharide responses were serotype-restricted. The findings indicate that IgA marks recent infection and IgG reflects longer-term exposure to Shigella.