Chemical guidance of T cells leads to immunologic memory and long-term immunity

WOW, they are really getting close now!!
Wonder what directs these "guided by chemical signals released from other cells"
Bet you can't guess yet.... lol... go ahead take a guess!!!
Chemical guidance of T cells leads to immunologic memory and long-term immunity: "Chemical guidance of T cells leads to immunologic memory and long-term immunity
In the latest issue of the journal Nature, scientists at the National Institute of Allergy and Infectious Diseases (NIAID) of the National Institutes of Health (NIH) describe a new understanding about how long-term immunity works--findings that may lead to new ways of thinking about how to enhance certain immune responses and how to improve vaccines.
Led by immunologist Ronald Germain, M.D., Ph.D., the scientists took videos through a microscope to document what happens inside the lymph nodes of a living mouse shortly after a vaccination. The videos reveal that the movement of a specific type of immune cell known as a CD8+ T cell, also called a cytotoxic T cell, is not random as was previously thought, but instead is guided by chemical signals released from other cells.
Scientists have long recognized the importance of understanding how CD8+ T cells move through the lymph nodes and become activated. Once active, CD8+ T cells roam throughout the body destroying cells infected with bacteria or viruses--a process known as cell-mediated immunity. When these CD8+ T cells encounter an infected cell, they unleash a torrent of substances that poke holes in the cell's membrane, chew up its proteins and ultimately cause it to die. They also produce molecules such as interferon-gamma that help activate other immune cells."