B cell and DC activation early after immunization
To investigate the early activation of B cells by the immunogen, mouse lymphocytes from inguinal lymph nodes were analyzed on the 3rd, 6th and 9thdays after the first immunization. As shown in Fig. 4A-B, on the 3rd and 6th days (D3 and D6) after the first immunization, the immune group showed a variable increase in the percentage of CD19+ CD40+double-positive cells in the inguinal lymph nodes, with values differing significantly from those of the control group. In addition, ZI-△-PA-GEM caused the strongest activation, with greatest significant differences compared to the control group (Fig. 4A, D3 and D6).
Next, the activation of DCs was analyzed by detecting the proportion of CD11c+ MHC II+ cells (Fig. 4C-D). On the 3rd day, there was slight activation of DCs, but there was no significant difference among the groups. On the 6th and 9th days after the first immunization, the immune groups had an increased percentage of CD11c+ MHC II+ double-positive cells. On the 9th day, the activation levels of some groups decreased, but the ZI-△-PA-GEM group still showed significant differences from the control group.