The immune system refers to all of the cells, tissues, organs and processes that protect an organism from invasion by pathogens. Viruses, bacteria, parasites, and some toxins are some of pathogens that the immune system is involved in eliminating from the body.

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Articles relating to the study of the immune system, including medical specialties and techniques, as well as manipulations of the immune system (such as vaccination), can be found in Category:Immunology.

Pages in this category should be moved to subcategories where applicable. This category may require frequent maintenance to avoid becoming too large. It should directly contain very few, if any, pages and should mainly contain subcategories.