Antigen-specific B memory cell responses to lipopolysaccharide (LPS) and invasion plasmid antigen (Ipa) B elicited in volunteers vaccinated with live- attenuated Shigella flexneri 2a vaccine candidates

摘要

We evaluated B memory responses in healthy adult volunteers who received one oral dose of live-attenuated Shigella flexneri 2a vaccine. LPS- specific B sub(M) cells increased from a median of 0 at baseline to 20 spot forming cells (SFC)/10 super(6) expanded cells following vaccination (p = 0.008). A strong correlation was found between post-vaccination anti-LPS B sub(M) cell counts and peak serum anti-LPS IgG titers (rs = 0.95, p = 0.0003). Increases in B sub(M) specific for IpaB approaching significance were also observed. In sum, oral vaccination with live-attenuated S. flexneri 2a elicits B sub(M) cells to LPS and IpaB, suggesting that B sub(M) responses to Shigella antigens should be further studied as a suitable surrogate of protection in shigellosis.