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MF59- and Al(OH)3-Adjuvanted Staphylococcus aureus (4C-Staph) Vaccines Induce Sustained Protective Humoral and Cellular Immune Responses, with a Critical Role for Effector CD4 T Cells at Low Antibody Titers.

Monaci E, Mancini F, Lofano G, Bacconi M, Tavarini S, Sammicheli C, Arcidiacono L, Giraldi M, Galletti B, Rossi Paccani S, Torre A, Fontana MR, Grandi G, de Gregorio E, Bensi G, Chiarot E, Nuti S, Bagnoli F, Soldaini E, Bertholet S - Front Immunol (2015)

Bottom Line: Due to the increasing antibiotic resistance, the development of an effective vaccine against S. aureus is needed.However, the role of CD4 T cells seemed more evident in the presence of low-antibody responses.This study provides preclinical data further supporting the use of the adjuvanted 4C-Staph vaccines against S. aureus diseases, and provides critical insights on the correlates of protective immunity necessary to combat this pathogen.

View Article: PubMed Central - PubMed

Affiliation: Research Center, Novartis Vaccines and Diagnostics S.r.l. , Siena , Italy.

ABSTRACT
Staphylococcus aureus (S. aureus) is an important opportunistic pathogen that may cause invasive life-threatening infections, like sepsis and pneumonia. Due to the increasing antibiotic resistance, the development of an effective vaccine against S. aureus is needed. Although a correlate of protection against staphylococcal diseases is not yet established, several findings suggest that both antibodies and CD4 T cells might contribute to optimal immunity. In this study, we show that adjuvanting a multivalent vaccine (4C-Staph) with MF59, an oil-in-water emulsion licensed in human vaccines, further potentiated antigen-specific IgG titers and CD4 T-cell responses compared to alum and conferred protection in the peritonitis model of S. aureus infection. Moreover, we showed that MF59- and alum-adjuvanted 4C-Staph vaccines induced persistent antigen-specific humoral and T-cell responses, and protected mice from infection up to 4 months after immunization. Furthermore, 4C-Staph formulated with MF59 was used to investigate which immune compartment is involved in vaccine-induced protection. Using CD4 T cell-depleted mice or B cell-deficient mice, we demonstrated that both T and B-cell responses contributed to 4C-Staph vaccine-mediated protective immunity. However, the role of CD4 T cells seemed more evident in the presence of low-antibody responses. This study provides preclinical data further supporting the use of the adjuvanted 4C-Staph vaccines against S. aureus diseases, and provides critical insights on the correlates of protective immunity necessary to combat this pathogen.

No MeSH data available.


Related in: MedlinePlus

4C-Staph formulations induced antigen-specific CD4 T cells. Splenocytes from individual mice were stimulated in vitro with 4C-Staph antigens and Edu, IFN-γ, IL-4, IL-13, IL-17, IL-2, and/or TNF positive CD4+CD44hi T cells were identified by flow cytometry using the gating strategy shown in Figure S1 in Supplementary Material. (A) Number of Edu+ proliferating CD4 T cells. (B,C) Frequency of cytokine+ CD4 T cells in response to stimulation with (B) all 4C-Staph antigens, or (C) with each single antigen (n = 10–18). (D) Pie charts representing polyfunctional CD4 CD44hi T cells. (E) Frequencies of CD4 T cells expressing one or more cytokines. Graphs represent the merge of two separate experiments, n = 10. Graphs show mean ± SD. Data were analyzed using one-way ANOVA and Tukey’s multiple comparison test, p < 0.05, *4C-Staph formulation versus its respective formulation without 4C-Staph; #adjuvanted-4C-Staph versus 4C-Staph alone; $4C-Staph/MF59 versus 4C-Staph/alum.
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Figure 3: 4C-Staph formulations induced antigen-specific CD4 T cells. Splenocytes from individual mice were stimulated in vitro with 4C-Staph antigens and Edu, IFN-γ, IL-4, IL-13, IL-17, IL-2, and/or TNF positive CD4+CD44hi T cells were identified by flow cytometry using the gating strategy shown in Figure S1 in Supplementary Material. (A) Number of Edu+ proliferating CD4 T cells. (B,C) Frequency of cytokine+ CD4 T cells in response to stimulation with (B) all 4C-Staph antigens, or (C) with each single antigen (n = 10–18). (D) Pie charts representing polyfunctional CD4 CD44hi T cells. (E) Frequencies of CD4 T cells expressing one or more cytokines. Graphs represent the merge of two separate experiments, n = 10. Graphs show mean ± SD. Data were analyzed using one-way ANOVA and Tukey’s multiple comparison test, p < 0.05, *4C-Staph formulation versus its respective formulation without 4C-Staph; #adjuvanted-4C-Staph versus 4C-Staph alone; $4C-Staph/MF59 versus 4C-Staph/alum.

Mentions: 4C-Staph-specific Edu+ proliferating CD4 T cells were observed after one immunization in 4C-Staph/MF59 and after two immunizations in 4C-Staph/MF59 and 4C-Staph/alum groups (Figure 3A). In addition, 4C-Staph-specific cytokine+ CD4 T cells were detected after one immunization in adjuvanted and non-adjuvanted 4C-Staph-immunized mice, even though to a lesser extent in mice that received non-adjuvanted 4C-Staph antigens and were boosted by the second immunization (Figure 3B). The highest frequency of total cytokine+ CD4 T cells was observed in 4C-Staph/MF59-immunized mice, 2 weeks after the second immunizations, followed by 4C-Staph/alum and 4C-Staph. Most of the cytokine+ CD4 T cells were reactive to HlaH35L and EsxAB and to a lesser extent to FhuD2 and Csa1A (Figure 3C). When looking at the quality of the CD4 T-cell response, boolean gate analyses of the different cytokines (IL-2, TNF, IFN-γ, IL-17, and IL-4/IL-13) evidenced that, after one immunization, 4C-Staph/MF59 induced the highest number of IFN-γ+ (Th1) and IL-17+ (Th17) CD4 T cells, with frequencies of 0.146 and 0.152% of total CD4+CD44high T cells, respectively, compared to 4C-Staph/alum (0.103% for both IFN-γ and IL-17) and 4C-Staph (0.046 and 0.049%, respectively) (Figure 3D). Frequencies of IL-2+, TNF+, and IL-2+TNF+ (Th0) CD4 T cells were also higher in the 4C-Staph/MF59 group compared to the other two groups, while 4C-Staph/alum induced the highest frequencies of IL-4/13+ (Th2) CD4 T cells, followed by 4C-Staph/MF59 and 4C-Staph. Two weeks after the second immunization, the magnitude of Th0, Th1, and Th2 CD4 T-cell responses increased in all three groups of vaccination, while Th17 decreased. 4C-Staph/MF59 induced the highest frequency of Th0, Th1, and Th17 combined (1.152%), followed by 4C-Staph (0.682%) and 4C-Staph/alum (0.339%). No significant differences in the proportion of CD4 T cells producing more than one cytokine were observed among 4C-Staph/MF59, 4C-Staph/alum, and 4C-Staph (Figure 3E).


MF59- and Al(OH)3-Adjuvanted Staphylococcus aureus (4C-Staph) Vaccines Induce Sustained Protective Humoral and Cellular Immune Responses, with a Critical Role for Effector CD4 T Cells at Low Antibody Titers.

Monaci E, Mancini F, Lofano G, Bacconi M, Tavarini S, Sammicheli C, Arcidiacono L, Giraldi M, Galletti B, Rossi Paccani S, Torre A, Fontana MR, Grandi G, de Gregorio E, Bensi G, Chiarot E, Nuti S, Bagnoli F, Soldaini E, Bertholet S - Front Immunol (2015)

4C-Staph formulations induced antigen-specific CD4 T cells. Splenocytes from individual mice were stimulated in vitro with 4C-Staph antigens and Edu, IFN-γ, IL-4, IL-13, IL-17, IL-2, and/or TNF positive CD4+CD44hi T cells were identified by flow cytometry using the gating strategy shown in Figure S1 in Supplementary Material. (A) Number of Edu+ proliferating CD4 T cells. (B,C) Frequency of cytokine+ CD4 T cells in response to stimulation with (B) all 4C-Staph antigens, or (C) with each single antigen (n = 10–18). (D) Pie charts representing polyfunctional CD4 CD44hi T cells. (E) Frequencies of CD4 T cells expressing one or more cytokines. Graphs represent the merge of two separate experiments, n = 10. Graphs show mean ± SD. Data were analyzed using one-way ANOVA and Tukey’s multiple comparison test, p < 0.05, *4C-Staph formulation versus its respective formulation without 4C-Staph; #adjuvanted-4C-Staph versus 4C-Staph alone; $4C-Staph/MF59 versus 4C-Staph/alum.
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Related In: Results  -  Collection

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Figure 3: 4C-Staph formulations induced antigen-specific CD4 T cells. Splenocytes from individual mice were stimulated in vitro with 4C-Staph antigens and Edu, IFN-γ, IL-4, IL-13, IL-17, IL-2, and/or TNF positive CD4+CD44hi T cells were identified by flow cytometry using the gating strategy shown in Figure S1 in Supplementary Material. (A) Number of Edu+ proliferating CD4 T cells. (B,C) Frequency of cytokine+ CD4 T cells in response to stimulation with (B) all 4C-Staph antigens, or (C) with each single antigen (n = 10–18). (D) Pie charts representing polyfunctional CD4 CD44hi T cells. (E) Frequencies of CD4 T cells expressing one or more cytokines. Graphs represent the merge of two separate experiments, n = 10. Graphs show mean ± SD. Data were analyzed using one-way ANOVA and Tukey’s multiple comparison test, p < 0.05, *4C-Staph formulation versus its respective formulation without 4C-Staph; #adjuvanted-4C-Staph versus 4C-Staph alone; $4C-Staph/MF59 versus 4C-Staph/alum.
Mentions: 4C-Staph-specific Edu+ proliferating CD4 T cells were observed after one immunization in 4C-Staph/MF59 and after two immunizations in 4C-Staph/MF59 and 4C-Staph/alum groups (Figure 3A). In addition, 4C-Staph-specific cytokine+ CD4 T cells were detected after one immunization in adjuvanted and non-adjuvanted 4C-Staph-immunized mice, even though to a lesser extent in mice that received non-adjuvanted 4C-Staph antigens and were boosted by the second immunization (Figure 3B). The highest frequency of total cytokine+ CD4 T cells was observed in 4C-Staph/MF59-immunized mice, 2 weeks after the second immunizations, followed by 4C-Staph/alum and 4C-Staph. Most of the cytokine+ CD4 T cells were reactive to HlaH35L and EsxAB and to a lesser extent to FhuD2 and Csa1A (Figure 3C). When looking at the quality of the CD4 T-cell response, boolean gate analyses of the different cytokines (IL-2, TNF, IFN-γ, IL-17, and IL-4/IL-13) evidenced that, after one immunization, 4C-Staph/MF59 induced the highest number of IFN-γ+ (Th1) and IL-17+ (Th17) CD4 T cells, with frequencies of 0.146 and 0.152% of total CD4+CD44high T cells, respectively, compared to 4C-Staph/alum (0.103% for both IFN-γ and IL-17) and 4C-Staph (0.046 and 0.049%, respectively) (Figure 3D). Frequencies of IL-2+, TNF+, and IL-2+TNF+ (Th0) CD4 T cells were also higher in the 4C-Staph/MF59 group compared to the other two groups, while 4C-Staph/alum induced the highest frequencies of IL-4/13+ (Th2) CD4 T cells, followed by 4C-Staph/MF59 and 4C-Staph. Two weeks after the second immunization, the magnitude of Th0, Th1, and Th2 CD4 T-cell responses increased in all three groups of vaccination, while Th17 decreased. 4C-Staph/MF59 induced the highest frequency of Th0, Th1, and Th17 combined (1.152%), followed by 4C-Staph (0.682%) and 4C-Staph/alum (0.339%). No significant differences in the proportion of CD4 T cells producing more than one cytokine were observed among 4C-Staph/MF59, 4C-Staph/alum, and 4C-Staph (Figure 3E).

Bottom Line: Due to the increasing antibiotic resistance, the development of an effective vaccine against S. aureus is needed.However, the role of CD4 T cells seemed more evident in the presence of low-antibody responses.This study provides preclinical data further supporting the use of the adjuvanted 4C-Staph vaccines against S. aureus diseases, and provides critical insights on the correlates of protective immunity necessary to combat this pathogen.

View Article: PubMed Central - PubMed

Affiliation: Research Center, Novartis Vaccines and Diagnostics S.r.l. , Siena , Italy.

ABSTRACT
Staphylococcus aureus (S. aureus) is an important opportunistic pathogen that may cause invasive life-threatening infections, like sepsis and pneumonia. Due to the increasing antibiotic resistance, the development of an effective vaccine against S. aureus is needed. Although a correlate of protection against staphylococcal diseases is not yet established, several findings suggest that both antibodies and CD4 T cells might contribute to optimal immunity. In this study, we show that adjuvanting a multivalent vaccine (4C-Staph) with MF59, an oil-in-water emulsion licensed in human vaccines, further potentiated antigen-specific IgG titers and CD4 T-cell responses compared to alum and conferred protection in the peritonitis model of S. aureus infection. Moreover, we showed that MF59- and alum-adjuvanted 4C-Staph vaccines induced persistent antigen-specific humoral and T-cell responses, and protected mice from infection up to 4 months after immunization. Furthermore, 4C-Staph formulated with MF59 was used to investigate which immune compartment is involved in vaccine-induced protection. Using CD4 T cell-depleted mice or B cell-deficient mice, we demonstrated that both T and B-cell responses contributed to 4C-Staph vaccine-mediated protective immunity. However, the role of CD4 T cells seemed more evident in the presence of low-antibody responses. This study provides preclinical data further supporting the use of the adjuvanted 4C-Staph vaccines against S. aureus diseases, and provides critical insights on the correlates of protective immunity necessary to combat this pathogen.

No MeSH data available.


Related in: MedlinePlus