Figure 7.

IL-6 is crucial for LNP-induced GC reactions

(A) BALB/c mice received a single IM immunization with 10 μg rHA adjuvanted with eLNP or AddaVax. IL-6 levels were determined by ELISA in dLN lysates at various times after immunization.

(B) BALB/c mice received anti-IL-6 or isotype mAb 1 day prior to and every other day after a single IM immunization with 10 μg rHA + eLNP. Tfh cell (CD4⁺B220⁻CD44^hiCD62L⁻PD-1⁺CXCR5⁺) percentages and absolute numbers were analyzed in dLNs 5 days after immunization.

(C–F) Il6^−/− and control mice received a single IM immunization with 30 μg PR8 HA mRNA-LNP or 30 μg rHA + eLNP. Twelve days later, Tfh and GC B cell responses were examined in dLNs by flow cytometry.

(C and D) Tfh cell (CD4⁺B220⁻CD44^hiCD62L⁻Bcl6⁺CXCR5⁺) representative flow cytometry (C) and percentages and absolute numbers (D).

(E and F) GC B cell (CD3⁻CD19⁺FAS⁺GL7⁺, top panel) and antigen-specific GC B cell (RBD⁻HA⁺, bottom panel) representative flow cytometry (E) and percentages and absolute numbers (F).

In (A)–(F), n = 6–7 mice/group. Data were combined from two independent experiments. In (B), (D), and (F), symbols represent individual animals. Data are shown as mean + SEM. Statistical analysis: unpaired two-tailed Mann-Whitney U test was conducted. ^∗p ≤ 0.05, ^∗∗p ≤ 0.01, ^∗∗∗p ≤ 0.001, ^∗∗∗∗p ≤ 0.0001. See also Figure S7.