LNP-IL-21 induced HBV clearance in BPS-based persistence mouse
model
To investigate whether LNP-IL-21 had any therapeutic effects against HBV
persistence, BALB/c mice displaying persistently positive serum HBV
antigens up to 4 weeks post injection of BPS were subjected to two-dose
LNP-IL-21 injections, two weeks apart, or control LNP via tail vein.
Serum HBV markers and biochemical indexes were regularly measured every
2 weeks up to 8 weeks post injection of LNP (w.p.i.). As shown inFigure 2 A and C , LNP-IL-21 administration caused
HBsAg and HBeAg levels to decrease much more quickly compared to mice
(n = 6) receiving LNP injection, and become undetectable in all
LNP-IL-21-injected mice (n = 6) by 6 w.p.i., while both viral
markers persisted in 5 out of 6 LNP-injected mice. Meanwhile, all
LNP-IL-21-injected mice which had cleared serum HBsAg displayed HBsAb
seroconversion by 6 w.p.i. (Figure 2B ), indicating anti-HBsAg
humoral responses was involved in HBsAg clearance. Accordingly, HBV DNA
in pooled serum started to decrease following LNP-IL-21 injection and
dropped to detection limit level by 8 w.p.i., while it remained largely
unchanged in LNP-injected group (Figure 2D ). LNP-IL-21-injected
mice manifested ALT and IL-21 elevations at 3 w.p.i., which reverted to
normal levels by 6 and 8 w.p.i. respectively (Figure 2E-F ). In
contrast, no obvious changes in ALT or IL-levels were detected in
LNP-injected mice (Figure 2E-F ). Total bilirubin and creatine
kinase levels were generally normal in both two groups (Figure
S4 ).
In addition to serum HBV markers analyses, both intrahepatic HBV DNA and
capsids were assayed using Southern and Western blots to confirm true
clearance at 8 w.p.i. (Figure 3A) . As shown in Figure
3B , HBV replication intermediates, BPS replicons DNA or capsids were
undetectable in all LNP-IL-21-injected mice (n = 6) that had
cleared serum HBsAg, but persisted in 5 out of 6 LNP-injected mice.
Collectively, LNP-IL-21 efficiently and safely induced HBV clearance in
BPS-based persistence mouse model.