Figure 1. L-pampo is a potent adjuvant that enhances the production of OVA-specific antibodies and expands germinal center B cells upon tertiary immunization with OVA.

Naïve B6 mice were immunized with 100 μg of OVA alone or in combination with alum, polyI:C, Pam3, or L-pampo as adjuvants, followed by the same immunization 3 and 6 weeks after the first immunization. (a) Individual mouse sera were isolated at the indicated time points after the first immunization, and OVA-specific IgG levels were measured with an ELISA. (b) At the 7^th week, the indicated isotypes were measured with an ELISA. (c) The relative ratios of OVA-specific IgG2c to IgG1 were calculated as an indirect measure of T helper 1 (Th1) and Th2 type immune responses. (d) Seven weeks after the first immunization, splenocytes from each mouse were analyzed by flow cytometry. Representative FACS plots and the frequencies and numbers of germinal center B cells (gated as live B220⁺ CD19⁺ GL-7⁺ PNA⁺ lymphocytes) in the spleen of each mouse are shown. Data are represented as the mean ± SEM with each dot indicating one mouse (n = 5). The data are representative of two independent experiments. *p < 0.05; **p < 0.01; ***p < 0.001.