Heat shock protein 70 from Trichinella spiralis induces protective immunity in BALB/c mice by activating dendritic cells

Trichinella spiralis heat shock protein 70 (Ts-Hsp70) is a protective antigen that induces partial protective immunity against T. spiralis infection in mice. To determine whether dendritic cells are involved in the mechanism responsible for the protection induced by Ts-Hsp70, mouse bone marrow-derived dendritic cells (DCs) were incubated with recombinant Ts-Hsp70 (rTs-Hsp70), and the DC-secreted cytokines and expressed surface markers were measured. The results demonstrated that rTs-Hsp70 activated DC maturation that was characterized by the secretion of IL-1β, IL-12p70, TNF-α, and IL-6 and the increased surface expression of CD11c, MHC II, CD40, CD80, and CD86. The rTs-Hsp70-activated DCs enabled the stimulation, proliferation and secretion of Th1/2 cytokines (i.e., INF-γ, IL-2, IL-4 and IL-6) in CD4⁺ T cells from T. spiralis-infected mice. The mice that received rTs-Hsp70-activated DCs exhibited a 38.4% reduction in muscle larvae upon larval challenge with T. spiralis compared to the group that received PBS-incubated DCs. This partial protection was correlated with Th1 and Th2 mixed anti-Ts-Hsp70-specific immune responses that included high titers of total IgG, IgG1 and IgG2a and increased levels of Th1/2 cytokines (i.e., IFN-γ, IL-2, IL-4, IL-6). These results indicate that the rTs-Hsp70-induced protective immunity was mediated by the activation of the DCs and that rTs-Hsp70-loaded DCs could be an alternative vaccine approach against trichinellosis.