What are professional antigen presenting cells?
Well, professional antigen presenting cells are the cells in our body that run around eating up foreign proteins. What they do after they eat them is they chew them up and they display small pieces of everything they eat on their surface in association with our matrix compatibility antigens, the transplant antigens that are a problem in transplantation. By doing that, they basically allow T-cells to bump into them as they travel around the body or go to specific immune sites such as the spleen or the lymph nodes. T-cells then get to see these small fragments of anything they’ve eaten. If it turns out it is a foreign antigen they respond, and that is why they are called professional antigen presenting cells, because they kind of present the antigen to the T-cell. They are sort of delivery machines for the T-cell. They are frequently cells that elaborate the cytokines I spoke of that expand T-cells, so they are really the cells that make the decision on expanding T-cells, and we don’t re
