Antigen-presenting cells professional

Parallel to orchestrating acute inflammatory processes by providing an optimal milieu of cytokines, mediators, and adhesion molecules in order to recruit and activate effector cells to the site of infection, dendritic cells also setve as professional antigen-presenting cells for cells of the adaptive immune system ( antigen presentation ... 

In the specialized environment of secondary lymphoid tissues such as lymph nodes or spleen, dendritic cells provide the requirements for naive T-lymphocytes to become activated and to proliferate. The professional antigen-presenting cells present peptides in MHC II, express costimulatory molecules, and release cytokines into the immunological synapse, which is formed by the antigen-presenting cell and the naive T-lymphocyte. Thus, cells of innate immunity initiate and facilitate the activation of naive lymphocytes, and it is easily conceivable that their cytokines and adhesion molecules will instruct the naive T-lymphocyte during activation and differentiation to T-effector cells. 

Dendritic cells (DCs) are functionally classified into myeloid (MDCs) and plasma-cytoid DCs (PDCs), both of which are potent professional antigen presenting cells (APC) but vary in the expression of a number of surface molecules. They also exhibit differences in their susceptibility to various strains of HIV-1 (Lore et al. 2005 Smed-Sorensen et al. 2005). Their role in the dissemination of HIV-1 is of... 

Dendritic cells (DCs) are bone marrow-derived professional antigen-presenting cells (APCs) (1). The function of DCs depends on their maturation stages progenitors in the bone marrow, precursors in the blood, immature DCs in peripheral tissues, antigen-transporting DCs in the afferent lymphatics, and... 

The activation of a T-cell response and subsequent efficacy of DNA vaccines is ultimately determined by professional antigen presenting cells, such as macrophages, dendritic cells, and Langerhans cells (Corr et al., 1996 Doe et al., 1996 Iwasaki et al., 1997 Ulmer et al., 1996). It follows that successful DNA vaccination strategies should seek to target DNA... 

We also addressed IRIV effects on antigen-presenting cells (APC). We investigated IRIV effects on DC, some of the most effective professional APC. 

The class II proteins are produced mainly within specific cells, known as antigen-presenting cells (APC). Their role is to prepare antigens derived from the pathogens in such a way that they can interact with the T-helper cell receptor. Since this is their only role, they are sometimes called professional antigen-presenting cells , i.e. other immune cells can also present peptides to T-helper cells (e.g. macrophages, B-lymphocytes) but this is not their prime role. The professional APCs are also known as dendritic cells. 

The professional antigen-presenting cells patrol tissues throughout the body, especially in areas where pathogens... 

Recent advances in understanding how immune responses are generated allows a particularly interesting approach using cytokines, co-stimulatory molecules, and professional antigen-presenting cells (e.g., dendritic cells) to enhance or otherwise modify vaccine responses [43 5], It is hkely that one or more of these adjuvant and delivery systems will be incorporated in the design of future vaccines. 

Cytokines have been under clinical investigation as adjuvants to vaccines, and IFNs and IL-2 have shown some positive effects in the response of human subjects to hepatitis vaccine. IL-12 and GM-CSF have also shown adjuvant effects with vaccines. GM-CSF is of particular interest because it promotes recruitment of professional antigen-presenting cells such as the dendritic cells required for priming naive antigen-specific T-lymphocyte responses. There are some claims that GM-CSF can itself stimulate an antitumor immune response, resulting in tumor regression in melanoma and prostate cancer. 

Antigen-presenting cells (APCs) are a heterogeneous population of cells with extraordinary immunostimulatory capacity. Some play an important role in the induction of the function of T helper cells and some communicate with other lymphocytes. Cytokines can render the ability to present antigens to various cell types. This results in the expression of MHC class II molecules, which are sometimes lacking on some cells such as endothelial cells. The different types of APCs include macrophages, dendritic cells, B cells and interdigitating cells. APCs are mostly derived from bone marrow and are distributed in lymphoid tissues and in the skin. These three types of major APCs are also called professional APCs. 

Fitzmaurice, C.J., Brown, L.E., Kronin, K., and Jackson, D.C. (2000) The geometry of synthetic peptide-based immunogens affects the efficiency of T cell stimulation by professional antigen-presenting cells. Int. Immunol. 12, 527-535. 

MHC class n molecules are only expressed on professional antigen-presenting cells. The peptides presented by class II molecules are derived from extracellular proteins (not cytosohc as in class I) hence the MHC class Il-dependent pathway of antigen presentation is called the endocytic or exogenous pathway. 

Infiammation. During an inflammatory response an immunostimulatory environment is created by the release of cytokines which recruit and activate professional antigen-presenting cells and provide support for T-cefl activation, rather than anergy. As a result, autoreactive T-cells which were anergic or ignorant might become activated. 

C.-F. Hung and T.C. Wu, Improving DNA vaccine potency via modification of professional antigen presenting cells, Curr. Opin. Mol. Therapeutics 2003, 5, 20-24. 

---