High persistence rate of hepatitis B virus in a hydrodynamic injection-based transfection model in C3H/HeN mice

Figure 4 Hepatitis B surface antigen-specific T cell responses are impaired in hydrodynamically injected C3H/HeN mice. A: Regime of immunization: hydrodynamically injected C3H/HeN mice (n = 3) and C57BL/6 mice (n = 3) were subcutaneously injected with 5 μg HBsAg protein formulated in CFA at 10, 12, and 14 wk after HI. Age-matched C3H/HeN naïve mice (n = 3) and C57BL/6 naïve mice (n = 3) were subcutaneously injected with 5 μg HBsAg protein formulated in CFA three times at a 2-wk interval. Magnitudes of the total T cell responses were analyzed by IFN-γ ELISPOT two weeks after the final vaccination; B: Frequencies of IFN-γ producing T cells in C3H/HeN and C57BL/6 mice (both hydrodynamically injected ones and controls, n = 3 each group) after HBsAg stimulation. While hydrodynamically injected C3H/HeN mice showed almost zero in the frequency of IFN-γ positive cells, the other groups did show IFN-γ positive cells; C: Spot sizes of IFN-γ producing T cells in C3H/HeN and C57BL/6 mice (both hydrodynamically injected ones and controls, n = 3 each group) after HBsAg stimulation. Hydrodynamically injected C57BL/6 and control (ctrl) mice were significantly larger than hydrodynamically injected C3H/HeN mice [^aP < 0.05, C57BL/6 HI vs C3H/HeN HI mice; ^bP < 0.01 control (ctrl) mice vs C3H/HeN HI mice, respectively]; D: IFN-γ producing T cell spot in C3H/HeN and C57BL/6 mice (both hydrodynamically injected ones and controls, n = 3 each group) after PMA + ionomysin stimulation; left: bar chart of frequencies of IFN-γ producing T cells. Hydrodynamically injected C57BL/6 mice were significantly higher than hydrodynamically injected C3H/HeN mice (^dP < 0.01, C57BL/6 HI vs C3H/HeN HI mice), and C3H/HeN mice (^cP < 0.05, C57BL/6 HI vs C3H/HeN); right: Images of ELISOPT. HI: Hydrodynamic injection; CFA: Complete Freund’s adjuvant; IFN: Interferon; HBsAg: Hepatitis B surface antigen.