The body's greatest exposure to the outside world is through the lining of the intestines. These cover more than 2000 square feet! It is also very thin - many times thinner than a single sheet of tissue paper. This is so that the body can absorb nutrients.
A special type of white blood cell (intraepithelial lymphocytes) maintains this lining and act as a defence against pathogens including viruses. These white blood cells have receptors that activate them and spring them into action, like an army, defending your body from pathogens and viruses.
It turns out that BROCCOLI contains the KEY to activate these receptors! In short, drinking broccoli sprout juice provides a concentrated form of these keys that will RALLY your IMMUNE SYSTEM FOOT SOLDIERS.
(See Esser C. Biology and function of the aryl hydrocarbon receptor and Veldhoen M. Direct interactions between intestinal immune cells and the diet.)