Fig 1.

PfMSP-1₁₉-specific B cell responses in mice is short-lived. Mice (n = 10) were immunized subcutaneously and boosted with 20 μg of PfMSP-1₁₉ emulsified in CFA/IFA at the base of the tail on days 0, 30, and 90. Age- and sex-matched control mice were immunized with adjuvant alone. (A and B) Anti-PfMSP-1₁₉ total IgG and IgG isotype Ab titers in mice were determined by ELISA. Results are shown as mean ± SD (n > 6). (C) Splenocytes and bone marrow cells were recovered from PfMSP-1₁₉-primed or adjuvant-treated control mice at different days postimmunization and were stained for B220 versus CD138 for fluorescence-activated cell sorter analysis. Contour plots represent live cells gated according to forward and side scatter profiles. Gates were set to show the percentages of plasma cells (B220⁻ CD138⁺). (D) Cell suspensions of spleen and bone marrow were prepared from individual mice, and an ELISPOT assay was used to enumerate the number of PfMSP-1₁₉-specific IgG-producing ASCs. The values are geometric means ± SD values of three to four mice per time point. Experiments are representative of three repeats. **, P < 0.001; ***, P < 0.005 (statistically significant difference in ex vivo ASC response between spleen and bone marrow).