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IL-33 released by alum is responsible for early cytokine production and has adjuvant properties.

Rose WA, Okragly AJ, Patel CN, Benschop RJ - Sci Rep (2015)

Bottom Line: Alum can induce the release of endogenous danger signals via cellular necrosis which elicits inflammation-associated cytokines resulting in humoral immunity.Furthermore, IL-33 itself functions as an adjuvant that, while only inducing a marginal primary response, facilitates a robust secondary response comparable to that observed with alum.Our results provide novel insights into the mechanism of action behind alum-induced cytokine responses and show that IL-33 is sufficient to provide a robust secondary antibody response independently of alum.

View Article: PubMed Central - PubMed

Affiliation: Biotechnology Discovery Research, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, 46285.

ABSTRACT
Human vaccines have used aluminium-based adjuvants (alum) for >80 years despite incomplete understanding of how alum enhances the immune response. Alum can induce the release of endogenous danger signals via cellular necrosis which elicits inflammation-associated cytokines resulting in humoral immunity. IL-33 is proposed to be one such danger signal that is released from necrotic cells. Therefore, we investigated whether there is a role for IL-33 in the adjuvant activity of alum. We show that alum-induced cellular necrosis results in elevated levels of IL-33 following injection in vivo. Alum and IL-33 induce similar increases in IL-5, KC, MCP-1, MIP-1α and MIP-1β; many of which are dependent on IL-33 as shown in IL-33 knockout mice or by using an IL-33-neutralizing recombinant ST2 receptor. Furthermore, IL-33 itself functions as an adjuvant that, while only inducing a marginal primary response, facilitates a robust secondary response comparable to that observed with alum. However, IL-33 is not absolutely required for alum-induced antibody responses since alum mediates similar humoral responses in IL-33 knockout and wild-type mice. Our results provide novel insights into the mechanism of action behind alum-induced cytokine responses and show that IL-33 is sufficient to provide a robust secondary antibody response independently of alum.

No MeSH data available.


Related in: MedlinePlus

IL-33 mediates different antibody response kinetics than alum.(a) C57BL/6 mice (n = 5 mice/group) were injected i.p. with PBS, alum mixed with PBS at 1:2 ratio, or IL-33 in combination with NP-CGG then boosted i.p. on day 14 with PBS/NP-CGG. Antigen specific IgM, IgG1 and IgE serum titers were quantified via ELISA. Data are representative of four independent experiments. **p < 0.01 and ***p < 0.001 IL-33 compared to alum groups (Two-way ANOVA with Bonferroni multiple comparison test). (b) Spleens were harvested on days 10 and 21 post-immunization from mice treated as in (a). Representative brightfield images (200x magnification) of B220+ follicles (blue) and GCs (brown; indicated with black arrows) were captured from stained cryopreserved sections of spleens from each group. (c) The numbers of GC and B220+ follicles were quantified from sections (n = 8 sections/mouse and 5 mice/group) in (b) to calculate the ratio of GCs per B220+ follicle. Data are representative of at least two independent experiments. ***p < 0.001 (One-way ANOVA with Tukey’s multiple comparison test).
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f5: IL-33 mediates different antibody response kinetics than alum.(a) C57BL/6 mice (n = 5 mice/group) were injected i.p. with PBS, alum mixed with PBS at 1:2 ratio, or IL-33 in combination with NP-CGG then boosted i.p. on day 14 with PBS/NP-CGG. Antigen specific IgM, IgG1 and IgE serum titers were quantified via ELISA. Data are representative of four independent experiments. **p < 0.01 and ***p < 0.001 IL-33 compared to alum groups (Two-way ANOVA with Bonferroni multiple comparison test). (b) Spleens were harvested on days 10 and 21 post-immunization from mice treated as in (a). Representative brightfield images (200x magnification) of B220+ follicles (blue) and GCs (brown; indicated with black arrows) were captured from stained cryopreserved sections of spleens from each group. (c) The numbers of GC and B220+ follicles were quantified from sections (n = 8 sections/mouse and 5 mice/group) in (b) to calculate the ratio of GCs per B220+ follicle. Data are representative of at least two independent experiments. ***p < 0.001 (One-way ANOVA with Tukey’s multiple comparison test).

Mentions: To evaluate the potential role of IL-33 in driving the adjuvant activity of alum we compared the kinetic antibody response to NP induced by either IL-33 or alum. Both alum and IL-33 injected mice showed significantly increased IgM titers on day 5 compared to PBS controls; however the alum-induced IgM titers were significantly greater than the IL-33-induced titers (Fig. 5a). Following antigen boost, IgM titers in the IL-33 injected mice continued to increase on days 17 and 21, while they decreased in alum injected mice. Although IgG1 titers induced by alum were significantly greater than those induced by IL-33 on days 10 and 17, by day 21 the IL-33-induced IgG1 titers reached the level of those induced by alum. The kinetics of the IgE response was similar to IgM. Alum-induced IgE responses peaked on day 10 while IL-33-induced responses peaked on day 17 following the boost. The results indicate that IL-33 induced a delayed antibody response profile compared to alum during primary and secondary response.


IL-33 released by alum is responsible for early cytokine production and has adjuvant properties.

Rose WA, Okragly AJ, Patel CN, Benschop RJ - Sci Rep (2015)

IL-33 mediates different antibody response kinetics than alum.(a) C57BL/6 mice (n = 5 mice/group) were injected i.p. with PBS, alum mixed with PBS at 1:2 ratio, or IL-33 in combination with NP-CGG then boosted i.p. on day 14 with PBS/NP-CGG. Antigen specific IgM, IgG1 and IgE serum titers were quantified via ELISA. Data are representative of four independent experiments. **p < 0.01 and ***p < 0.001 IL-33 compared to alum groups (Two-way ANOVA with Bonferroni multiple comparison test). (b) Spleens were harvested on days 10 and 21 post-immunization from mice treated as in (a). Representative brightfield images (200x magnification) of B220+ follicles (blue) and GCs (brown; indicated with black arrows) were captured from stained cryopreserved sections of spleens from each group. (c) The numbers of GC and B220+ follicles were quantified from sections (n = 8 sections/mouse and 5 mice/group) in (b) to calculate the ratio of GCs per B220+ follicle. Data are representative of at least two independent experiments. ***p < 0.001 (One-way ANOVA with Tukey’s multiple comparison test).
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Related In: Results  -  Collection

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f5: IL-33 mediates different antibody response kinetics than alum.(a) C57BL/6 mice (n = 5 mice/group) were injected i.p. with PBS, alum mixed with PBS at 1:2 ratio, or IL-33 in combination with NP-CGG then boosted i.p. on day 14 with PBS/NP-CGG. Antigen specific IgM, IgG1 and IgE serum titers were quantified via ELISA. Data are representative of four independent experiments. **p < 0.01 and ***p < 0.001 IL-33 compared to alum groups (Two-way ANOVA with Bonferroni multiple comparison test). (b) Spleens were harvested on days 10 and 21 post-immunization from mice treated as in (a). Representative brightfield images (200x magnification) of B220+ follicles (blue) and GCs (brown; indicated with black arrows) were captured from stained cryopreserved sections of spleens from each group. (c) The numbers of GC and B220+ follicles were quantified from sections (n = 8 sections/mouse and 5 mice/group) in (b) to calculate the ratio of GCs per B220+ follicle. Data are representative of at least two independent experiments. ***p < 0.001 (One-way ANOVA with Tukey’s multiple comparison test).
Mentions: To evaluate the potential role of IL-33 in driving the adjuvant activity of alum we compared the kinetic antibody response to NP induced by either IL-33 or alum. Both alum and IL-33 injected mice showed significantly increased IgM titers on day 5 compared to PBS controls; however the alum-induced IgM titers were significantly greater than the IL-33-induced titers (Fig. 5a). Following antigen boost, IgM titers in the IL-33 injected mice continued to increase on days 17 and 21, while they decreased in alum injected mice. Although IgG1 titers induced by alum were significantly greater than those induced by IL-33 on days 10 and 17, by day 21 the IL-33-induced IgG1 titers reached the level of those induced by alum. The kinetics of the IgE response was similar to IgM. Alum-induced IgE responses peaked on day 10 while IL-33-induced responses peaked on day 17 following the boost. The results indicate that IL-33 induced a delayed antibody response profile compared to alum during primary and secondary response.

Bottom Line: Alum can induce the release of endogenous danger signals via cellular necrosis which elicits inflammation-associated cytokines resulting in humoral immunity.Furthermore, IL-33 itself functions as an adjuvant that, while only inducing a marginal primary response, facilitates a robust secondary response comparable to that observed with alum.Our results provide novel insights into the mechanism of action behind alum-induced cytokine responses and show that IL-33 is sufficient to provide a robust secondary antibody response independently of alum.

View Article: PubMed Central - PubMed

Affiliation: Biotechnology Discovery Research, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, 46285.

ABSTRACT
Human vaccines have used aluminium-based adjuvants (alum) for >80 years despite incomplete understanding of how alum enhances the immune response. Alum can induce the release of endogenous danger signals via cellular necrosis which elicits inflammation-associated cytokines resulting in humoral immunity. IL-33 is proposed to be one such danger signal that is released from necrotic cells. Therefore, we investigated whether there is a role for IL-33 in the adjuvant activity of alum. We show that alum-induced cellular necrosis results in elevated levels of IL-33 following injection in vivo. Alum and IL-33 induce similar increases in IL-5, KC, MCP-1, MIP-1α and MIP-1β; many of which are dependent on IL-33 as shown in IL-33 knockout mice or by using an IL-33-neutralizing recombinant ST2 receptor. Furthermore, IL-33 itself functions as an adjuvant that, while only inducing a marginal primary response, facilitates a robust secondary response comparable to that observed with alum. However, IL-33 is not absolutely required for alum-induced antibody responses since alum mediates similar humoral responses in IL-33 knockout and wild-type mice. Our results provide novel insights into the mechanism of action behind alum-induced cytokine responses and show that IL-33 is sufficient to provide a robust secondary antibody response independently of alum.

No MeSH data available.


Related in: MedlinePlus