If you are experiencing pain on top of your foot, you should consider seeing your doctor as soon as possible. Pain in this location is not normal, and usually indicates a more serious problem. Catching conditions and injuries such as stress fractures in their early stages is vital to successful treatment.
Natural killer cell: A cell that can react against and destroy another cell without prior sensitization to it. Abbreviated NK cell. NK cells are part of our first line of defense against cancer cells and virus-infected cells. NK cells are small lymphocytes that originate in the bone marrow and develop without the influence of the thymus. An NK cell attaches to a target cell, releases chemicals that breach its cell wall, and causes it to lyse (break up).
The innate immune system, also known as the nonspecific immune system, is an important subsystem of the overall immune system that comprises the cells and mechanisms that defend the host from infection by other organisms.atural killer cells, or NK cells, are a component of the innate immune system that does not directly attack invading microbes. Rather, NK cells destroy compromised host cells, such as tumor cells or virus-infected cells, recognizing such cells by a condition known as missing self..