The adjuvanticity of gamma inulin

Abstract

Gamma-inulin (g-IN) is a polymorph identified as the active component of inulin preparations that specifically activates the alternative pathway of complement (APC). The APC is central to many leucocyte functions, including B cell activation. We show here that g-IN, when formulated as a pure, endotoxin-free, fine suspension insoluble at 37°C and given at 50–100 g per mouse, is a potent adjuvant for both humoral and cell-mediated responses to a variety of antigens. g-IN increased secondary IgG responses five- to 28-fold (P P P < 0001), a deduced but not proven boost to cytotoxic T cell-mediated immunity. Unpublished work has shown that g-IN has no adverse effects at adjuvant-active doses. g-IN is thus a promising new vaccine adjuvant. It also has a potential for antitumour therapy, and is a specific reagent for expioring the role of complement in vivo.