Adjuvant effect of gamma-inulin is mediated by C3 fragments deposited on antigen-presenting cells.
The adjuvant effect of gamma-inulin, a strong activator of the alternative complement pathway, is well-known, but its exact mechanism is not revealed yet. Here, we show that macrophages, isolated from the peritoneal cavity of gamma-inulin-injected mice and used as antigen-presenting cells, enhance the proliferation of antigen-specific T-cells up to 2.5-fold when compared with macrophages of non-treated animals. This effect is abrogated by the presence of anti-C3 F(ab')2 fragments and by prior decomplementation of the donor animals with CVF. It is demonstrated that treatment of mice with the adjuvant results in deposition of C3-fragments onto the surface of peritoneal macrophages, as does in vitro incubation of the cells with gamma-inulin in the presence of fresh autologous serum. Prior incubation of macrophages with gamma-inulin plus serum in vitro enhances subsequent C3 production. Because it has been shown earlier that CR1/2 expressed on activated T-cells and interacting with covalently bound C3-fragments plays an important role in the augmentation of the adaptive response, our present results reveal a mechanism that contributes to the adjuvant effect of gamma-inulin and point to a further link between innate and adaptive immunity.
Kerekes
K
K
Department of Immunology, Eötvös Loránd University, Göd, Hungary.
Cooper
P D
PD
Prechl
J
J
Józsi
M
M
Bajtay
Z
Z
Erdei
A
A
D000818:Animals; D017951:Antigen Presentation / Q000276:immunology*; D003176:Complement C3 / Q000276:immunology*; D007444:Inulin / Q000276:immunology*; D008213:Lymphocyte Activation; D017737:Macrophages, Peritoneal / Q000276:immunology*; D051379:Mice; D013601:T-Lymphocytes / Q000276:immunology
D003176:Complement C3; D007444:Inulin