Wednesday, March 18, 2009

Dendritic Cells to the Rescue

photo by burning image

Dendritic cells (DCs) are immune cells in the body which collect antigens in tissues, process the antigen, and then present the antigen to other immune cells, such as T cells, mounting an immune response. Put more simply, DCs are always on the look out for those bad guys that invade our bodies, like viruses. Once DCs capture these pathogens, they transport them to other cells which can fight against the invader.

Several types of DCs exist, including ones that lie in the dermis (layer of skin below the epidermis), termed “dermal dendritic cells” (DDCs). Upon visualizing the behavior of DDCs under normal conditions, they appear to be highly motile and actively crawl through spaces within the dermis. To see how DDCs would react upon introduction of a pathogen, researchers injected skin with the protozoan parasite Leishmania. This parasite is transmitted by sand flies which bite individuals, depositing the parasite into the dermis, causing cutaneous leishmaniasis. When DDCs encountered the parasite, their behavior and morphology changed rapidly- they became stationary and extended long, motile pseudopods capable of reaching out to and engulfing the pathogens. In fact, multiple parasites were incorporated into small compartments within the DDC. This shows how DDCs quickly respond to “danger signals”, allowing for the initiation of an immune response. So thank your DCs for slowing down every now and then and taking care of your unwelcome guests!

Reference: Ng LG, Hsu A, Mandell MA, Roediger B, Hoeller C, et al. (2008) Migratory dermal dendritic cells act as rapid sensors of protozoan parasites. PLoS Pathog 4(11): e1000222. doi:10.1371/ journal.ppat.100022 2

1 comment:

  1. Hello,

    Thank you so much for sharing it. Dendritic cells are important antigen presenting cells of the immune system that induce and modulate immune responses. They interact with T and B lymphocytes as well as with natural killer cells to promote activation and differentiation of these cells...

    Contract Research