The flu is a subject of concern for many Americans each year. Your immune system is perfectly capable of maintaining a highly effective response against any never-before-seen virus. This article explains how your immune system does this, what nutrients can help, what forms of stress handicap this capability, and how to help prevent the cytokine storm that would be associated with a severe flu episode. Perception 101 Various foot soldiers of your immune system, called innate immunity, come into contact with any viral invader. During this front line scuffle the invader is broken down into pieces. The invader’s unique look, called an antigen, is then presented to cells of your higher powered, cell mediated immune response, called adaptive immunity. The perception part of your immune system’s operation is based on antigen presentation. You have three main types of antigen presenting immune cells: macrophages, B lymphocytes, and dendritic cells. Macrophages and B lymphocytes can only present antigens to memory related immune cells. Therefore, they do not initially help your higher powered forces respond to a new type of virus, such as the current swine flu. This is the main reason why previous experience has some advantages. It is also why the vaccination theory has some utility. If your immune system has experience with a previous exposure, then a greater number and type of immune cells can participate in the initial immune response. This increases the potential for a more robust immune response. Dendritic cells are the most important antigen presenting immune cells. This is especially true when the invader is a new variety. Dentritic cells present antigen to naive T cells, the type of T cells that activate the higher powered immune response when it is a new type of invader. Dendritic cells are in your skin and on the inner part of the mucosal linings of your nose, lungs, stomach, and intestines. They constantly take samples of whatever you come into contact with. If they recognize a viral enemy, they help call ground troops to the scene for immediate front line action (innate immunity). They present the antigen of the enemy to your higher powered immune response (adaptive immunity) so that you can mount a highly aggressive immune response targeted for the specific enemy. Most of this dendritic cell activity takes place on barriers that separate your internal body from the outside world. When your immune system is working well, the virus does not breech these barriers and enter your body. You do not feel sick, even though you may be mounting an immune response. During a typical flu season, there is an extremely high probability that you will be exposed to the flu. The odds of whether or not you actually get sick depends in part on how well your dendritic cells do their job. You don’t have to actually get sick or be vaccinated in order to develop a memory enhanced immune response for a future flu encounter. If your immune system is successfully defending you from exposure to any current flu, which will be the case for many, then your memory related immune cells will become “trained” and be prepared for the same invader in future years. Read more here.