Dendritic cells in cattle: phenotype and function

Dendritic cells are professional antigen presenting cells derived from the bone marrow and distributed throughout body tissues where they are located in sites that are suitable for antigen uptake. They are central to the indu ction of immune responses in naive animals and thus have become targets in strategies that are aimed at modulating resistance to infection. Studies in cattle have shown that the dendritic cells are phenotypically heterogeneou s and that the different phenotypes have different biological properties. T he molecular basis for this variation has begun to be investigated and has led to the identification of a member of the SIRP alpha family of signal re gulatory proteins (MyD1) on a subset of dendritic cells in afferent lymph. Uptake of antigen by cattle dendritic cells is by a number of mechanisms th at can involve endocytosis via clathrin coated pits or via caveolae as well as macropinocytosis. (C) 1999 Elsevier Science B.V. All rights reserved.