Article Figures & Data
Figures
- Fig. 1.
Magnitude and isotype profiles of serum antibody responses to i.m. immunization with inactivated PR8 virus in CD4+ T-cell-deficient and immunocompetent mice. CD4+ T-cell-deficient mice or C57BL/6 mice (16 weeks old) were immunized i.m. with 10 μg of inactivated PR8 virus per mouse. The mice were boosted with the same dose after 15 days. Con, unimmunized CD4+ T-cell-deficient mice (n = 5). CD4KO, CD4+ T-cell-deficient mice received inactivated PR8 virus (n = 5). C57B/6: C57BL/6 immunocompetent mice received inactivated PR8 virus (n = 5). Prime, samples were measured 15 days after first immunization. Boost, samples were measured 10 days after boost. Serum samples were assayed in 1:400 and 1:1,600 dilutions. Error bars in this and subsequent figures represent standard error.
- Fig. 2.
Antibody responses and isotype distribution of virus-specific IgG in mice immunized intraperitoneally. CD4+ T-cell-deficient mice (n = 5) were immunized i.p. with formalin-inactivated PR8 virus (10 μg/mouse) on day 0 and boosted on day 15. Serum samples were collected 15 days after priming and 10 days after boosting. Con, control, unimmunized CD4+ T-cell-deficient mice. Prime, after first immunization. Boost, after boost.
- Fig. 3.
Antibody responses and IgG isotype profile in CD8-depleted CD4+ T-cell-deficient C57BL/6 mice after immunization with inactivated PR8 virus. CD4+T-cell-deficient mice (n = 5) were depleted of CD8 T cells by i.p. injection of MAb. 2.43. These mice were then i.m. immunized with formalin-inactivated PR8 virus (10 μg/mouse) at day 0 and boosted at day 15 with the same dose. Pre, serum samples before immunization. Prime, serum samples taken at day 15 after first immunization. Boost, serum samples taken at day 10 after boost.
- Fig. 4.
Serum virus-neutralizing antibody titers in CD4+ T-cell-deficient C57BL/6 mice i.m. immunized with formalin-inactivated PR8 virus. CD4+ T-cell-deficient mice were immunized i.m. with formalin-inactivated PR8 virus (10 μg/mouse) at day 0 and boosted at day 15 with the same dose. Different dilutions of serum samples from immunized mice were mixed with approximately 100 PFU of PR8 virus and incubated for 1 h at room temperature. The mixtures were then used to infect a monolayer of MDCK cells, and a standard plaque reduction assay was performed. The neutralizing-antibody titer of the serum is considered the highest dilution that was found to reduce the number of plaques by 50% or more. ⧫, control, serum from unimmunized CD4+T-cell-deficient mice; ■, serum from CD4+T-cell-deficient C57BL/6 mice 15 days after priming; ▴, serum from CD4+ T-cell-deficient C57BL/6 mice 10 days after boosting.
- Fig. 5.
Protection of immunized CD4+T-cell-deficient mice against lethal PR8 virus challenge. CD4+ T-cell-deficient C57BL/6 mice i.m. immunized with inactivated PR8 virus were challenged intranasally with 10 times the LD50 of live PR8 virus under anesthesia 4 weeks after boost. (a) Control, unimmunized CD4+ T-cell-deficient C57BL/6 mice. (b) CD4+ T-cell-deficient C57BL/6 mice immunized with inactivated PR8 virus. (c) CD8 T-cell-depleted CD4+ T-cell-deficient C57BL/6 mice immunized with inactivated PR8 virus.
- Fig. 6.
Isotype profile of PR8 virus-specific antibody responses of T-cell-deficient mice. TCRβ−/− mice were i.m. immunized with formalin-inactivated PR8 virus (10 μg/mouse) at day 0 and boosted at day 15. Serum samples were obtained 15 days after priming and 10 days after boosting. Con, control, unimmunized TCRβ−/− mice; PR8, TCRβ−/− mice immunized with formalin-inactivated PR8 virus. Prime and Boost are defined in the legend to Fig. 1.
- Fig. 7.
Antibody responses and isotype distribution of virus-specific IgG in 6-week-old mice i.m. immunized with inactivated PR8 virus. Six-week-old mice (n = 4) were immunized intramuscularly with formalin-inactivated PR8 virus (10 μg/mouse) on day 0 and boosted on day 15. Serum samples were collected 10 days after boosting. Con, control, unimmunized CD4+ T-cell-deficient mice. Boost, serum samples after boost.
- Fig. 8.
Flow cytometry analysis of αβ T cells in CD4+ T-cell-deficient mice. Spleen cells from C57BL/6 mice or CD4+ T-cell-deficient mice were stained with anti-TCRβ, anti-CD8, and anti-CD4 MAbs (H57-FITC, 53-6.7-PerCP, and GK1.5-PE, respectively, from PharMingen and Beckton-Dickinson). Plots show TCRβ-gated cells. Samples were from (a) a 16-week-old C57BL/6 mouse, (b) a 6-month-old CD4+ T-cell-deficient mouse, and (c) a 6-week-old CD4+ T-cell-deficient mouse.
