The effects of crude antigen of Caenorhabditis elegans on the interaction between dendritic cells and CD4+ T cells of mice

Abstract

Helminth infections have been known to modulate the immune response of the host and several helminth-derived molecules were suggested to have protective effects against allergic diseases and autoimmune diseases. In the previous study, crude extracts of Caenorhabditis elegans (CEC) have been shown to suppress airway inflammation in a murine asthma model. The present study was undertaken to investigate the effects of CEC on the interaction between bone marrow-derived dendritic cells (BMDCs) and CD4+ T helper cells of mice. CEC treatment on BMDCs markedly attenuated the expression of MHC class II molecules and co-stimulatory molecules including CD80, CD86, and CD40 compared to BMDCs stimulated by LPS alone (P<0.01). Production of pro-inflammatory cytokines including IL-12p70, IL-6 and TNF-α, was significantly decreased and that of an anti-inflammatory cytokine, IL-10, was elevated by stimulation of BMDCs with CEC and LPS than those stimulated by LPS alone (P<0.05). Moreover, LPS+CEC-pulsed BMDCs suppressed proliferation of CD4+ T cells. CD4+ T cells cultured with LPS+CEC-pulsed BMDCs produced significantly higher amounts of Th1 cytokine, interferon-γ (IFN-γ), and lower Th2 cytokines including IL-4, IL-5 and IL-13 compared with those with LPS-pulsed BMDCs (P<0.05). Taken together, the present results suggest that CEC activates BMDCs and induces naïve CD4+ T cells to differentiate into Th1 cells and also suppresses the proliferation of CD4+ T cells. Therefore, CEC may modulate the immune response of hosts by interacting with BMDCs, resulting in the differentiation of naïve T cells to Th1 cells.