How to increase increase immune system?

Exercise ? At this point in time we have no magic answers to increase our immune system, but the latest data points to exercise, staying upbeat (avoiding depression) and perhaps vitamin d.
Be healthy! There are so many ways to increase your immune system. Excersise, eat fruits vegetables, drinking tea has antioxidants vitamins such a c and zinc have beneficial immune factors, proper sleep and avoidance of stress all will lead to a healthy you.