We've got to get beyond the knee-jerk reaction that LASIK isn't appropriate for any patient under 18 years of age, said Davidorf. The subtext is that Hahn wanted to get rid of the embarrassment of airport officials' knee-jerk reaction that it's OK to snub the Valley by trampling on one of its beloved traditions.
Natural killer cells, or NK cells, are a component of the innate immune system which 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..
The immune system is the body's defense against infectious organisms and other invaders. Through a series of steps called the immune response, the immune system attacks organisms and substances that invade body systems and cause disease. The immune system is made up of a network of cells, tissues, and organs that work together to protect the body. One of the important cells involved are white blood cells, also called leukocytes, which come in two basic types that combine to seek out and destroy disease-causing organisms or substances.