A cell usually has many things on display at its surface. Most of these are receptors. Having receptors is a way by which cells communicate with other cells (see Nov 4 post “cells talk”). However, there are some cells that are “professional display artists.” These cells “make a living” by displaying bits and pieces of foreign antigen on there cell surface. I’m talking here about the “antigen presenting cells” or APCs.
APCs “eat” foreign antigens and process these in their lysosomes (see Nov 19 post “phagocytosis”). Then they display bits and pieces of these foreign antigens on their cell surface so they can attract circulating T lymphocytes. It’s their way of telling the T lymphocytes that a foreign substance is present in the body. When the two meet, they then “kiss” through the displayed antigen and the T lymphocyte receptor. After the “kiss” the T lymphocyte becomes activated and then sets the immune response rolling. The continuation of this story will be the subject of another post.
So in the cellular world, display, tell and kiss (not display, kiss and tell) is the way to go to get things moving.