Naive T cells are stimulated by antigen-presenting dendritic cells (DCs) in secondary lymphoid organs, but whether other types of cell participate in T cell priming is unclear. Here we show in mice that natural killer (NK) cells, which are normally excluded from lymph nodes, are rapidly recruited in a CCR7-independent, CXCR3-dependent manner to lymph nodes on stimulation by the injection of mature DCs. Recruitment of NK cells is also induced by some, but not all, adjuvants and correlates with the induction of T helper cell type 1 (T(H)1) responses. NK cell depletion and reconstitution experiments show that NK cells provide an early source of interferon-gamma (IFN-gamma) that is necessary for T(H)1 polarization. Taken together, our results identify an induced pathway of NK cell migration in antigen-stimulated lymph nodes and a mechanism by which some adjuvants may facilitate T(H)1 responses.

A subclone of the human colon adenocarci-

Uric acid released from dying cells has been shown recently to act as a danger signal for the immune system, stimulating dendritic cell maturation and enhancing T-cell responses to foreign antigens. Stimulation of dendritic cell maturation by uric acid has been proposed as a mechanism by which the immune system could generate responses against tumors. We show here that uric acid levels are elevated in tumors undergoing immune rejection and that the inhibition of uric acid production, by systemic administration of allopurinol, or the removal of uric acid, by administration of uricase, delayed tumor immune rejection, whereas subcutaneous administration of crystalline uric acid enhanced the rejection process.

No abstract

No abstract