Secretion capacity of BM plasma cells generated in response to the CpG-adjuvanted PS3- and PS3TT-conjugated vaccine. Seven- to 10-week-old mice (10 per group) were immunized with PS3 and injected 2 days later with CpG1668 or twice with PS3TT at a 21-day interval. Two weeks after immunization, CD138⁺ BM cells were enriched by positive selection and seeded both in ELISPOT plates for 24 hours (to assess the number of PS3-specific IgM and IgG ASCs) and in cell culture plates for 5 days (to assess the level of PS3-specific IgM and IgG secretions). (A) Secretion capacity of BM plasma cells expressed as the mean of the titer/ASCs of triplicate determinations for both type of immunizations. One of 2 representative experiments is shown. (B) Photos of ELISPOT wells showing the difference of spot size generated after immunization with CpG-adjuvanted PS3 or PS3TT.