The immune system is your cat’s first line of defense against illness and disease. It is an intricate network of white blood cells, antibodies, and other substances that fight infection and protect your pet from invaders such as viruses, bacteria, allergies, arthritis, reproductive disorders, degenerative disorders, parasites, and toxins. The immune system includes the organs in which white blood cells are produced, including the thymus gland and bone marrow. It also includes the spleen, lymph nodes, and liver - organs that trap microorganisms and foreign substances and provide a place for immune system cells to interact (with each other and with foreign substances) and generate an immune response.
The immune system works by identifying and differentiating "self" from "non-self," which means identifying viruses, chemical agents, and foreign objects and protecting itself from attack. Substances that stimulate an immune response in a cat’s body are called antigens, which may be contained within or on bacteria, viruses, cancer cells, and other microorganisms. Antigens may also exist on their own as pollen or food molecules.
When a foreign invader enters the body, the immune system reacts in one of several ways. The white blood cells may attack the invader, antibodies may damage the invader directly, or alert white cells may mount an attack.
The daily stresses your pet encounters - along with the stress of aging - can suppress the immune system function. Other factors that can compromise your cat’s immune system include poor diet, environmental toxins, lack of exercise, and inadequate sleep.
To boost your pet’s immune system, ensure he or she is fed a healthy diet loaded with vitamins and minerals. Choose high-quality cat food and avoid cheap commercial pet foods with fillers or byproducts. Make sure your cat gets plenty of exercise and try to reduce stress that may compromise his or her immune system.