M. Bevan showed in the mid-seventies that cytotoxic T lymphocyte (CTL) responses may be initiated by antigen-presenting cells that do not express the antigens themselves (1). He called this process cross-priming. The antigen-presenting cells involved in cross-priming must therefore inter-nalize and present antigens to CD8 ϩ T cells in the context of MHC class I molecules. This process is often ...

Dendritic cells are considered the most influential antigen presenting cells in the body because of their unique role in initiating immunity against threatening antigens. Recent studies addressing the consequences of self-antigen presentation by dendritic cells revealed the unexpected ability of these antigen presenting cells to inhibit T cell-mediated autoimmune diseases. The specific mechanis...

Bone marrow–derived antigen-presenting cells (APCs) play a central role in the induction of tolerance to tumor antigens expressed by B-cell lymphomas. Here we show that in vivo disruption of this APCmediated tolerogenic mechanism unveils an intrinsic ability of malignant B cells to efficiently present tumor antigens to antigen-specific CD4 T cells, resulting in a strong antitumor effect. This i...

We have produced a panel of islet-specific T-cell clones from nonobese diabetic (NOD) mice. These clones proliferate and make interleukin 2 in an antigen-specific manner in response to NOD antigen-presenting cells and islet cells. Most of the clones respond to islet-cell antigen from different mouse strains but only in the presence of antigen-presenting cells bearing the class II major histocom...

Bone marrow-derived antigen-presenting cells (APCs) play a central role in the induction of tolerance to tumor antigens expressed by B-cell lymphomas. Here we show that in vivo disruption of this APC-mediated tolerogenic mechanism unveils an intrinsic ability of malignant B cells to efficiently present tumor antigens to antigen-specific CD4+ T cells, resulting in a strong antitumor effect. This...

Because eosinophils recruited into the airways in allergic diseases are exposed to inhaled allergens, we evaluated whether eosinophils within the endobronchial lumen can function in vivo as antigen-presenting cells for inhaled antigens. We recovered eosinophils from the airways after aerosol antigen challenge in sensitized mice or from the peritoneal cavities of IL-5 transgenic mice and fluores...

T helper type 2 (TH2)-mediated immune responses are induced after infection with multicellular parasites and can be triggered by a variety of allergens. The mechanisms of induction and the antigen-presenting cells involved in the activation of TH2 responses remain poorly defined, and the innate immune sensing pathways activated by parasites and allergens are largely unknown. Basophils are requi...

A Salmonella enterica serovar Typhimurium aroA-deficient delivery system was used to target the immunosuppressive protein Salp15 to antigen-presenting cells. In vitro and in vivo infections with Salp15-containing Salmonella resulted in an impaired CD4(+)-T-cell activation, suggesting that the protein was produced by antigen-presenting cells in a physiologically active form.

The immune response is how your body recognizes and defends itself against bacteria, viruses, substances that appear foreign harmful. Innate, or nonspecific, immunity the defense system with which you were born. It protects all antigens. Innate involves barriers keep harmful materials from entering body. An antigen-presenting cell (APC) a displays antigen bound by major histocompatibility compl...

The betaherpesvirus human cytomegalovirus (HCMV) encodes several molecules that block antigen presentation by the major histocompatibility complex (MHC) proteins. Humans also possess one other family of antigen-presenting molecules, the CD1 family; however, the effect of HCMV on CD1 expression is unknown. The majority of CD1 molecules are classified on the basis of homology as group 1 CD1 and a...