Understanding Your Cat's Immune System
What Does the Feline Immune System Do?
What Makes Up a Cat's Immune System?
- bone marrow - Helps produce white blood cells
- intestines - Home to pro- and pre-biotics, friendly bacteria that help fight invaders
- liver - Helps educate white blood cells on how to attack pathogens
- lymph nodes - House large number of lymphocytes that attack pathogens - the immune system is actually considered to be part of the body's lymphatic system
- mouth - Certain chemicals in saliva are a first line of defense from many pathogens
- respiratory system - Mucus produced there is a first line of defense from many pathogens
- skin - The primary first line of defense for many pathogens
- spleen - Houses large amounts of lymphocytes that attack pathogens and filters antigens out of the bloodstream
- stomach - Both its acid and its mucous lining are first lines of defense from pathogens
- thymus gland - Helps produce mature white blood cells and teaches them how to do their job of defending the cat's body from invaders
- tonsils - One of the locations where NK lymphocytes mature
All these cells move throughout the body via the lymphatic system, which is a structure of vessels similar to the circulatory system for blood. A fluid known as lymph constantly washes the body's organs with the defensive cells.
A third type of lymphocyte is known as Natural Killer (NK) cells. These specifically attack cells infected with a virus, as well as cancer cells and microorganisms.
What Weakens a Cat's Immune System?
With kittens, if something prevents them from nursing on a mother cat within their first 24 hours of life, they will not receive the protection of antibodies from the colostrum in her milk. Kitten formulas can fill their tummies and help them grow, but they do not provide that key immune-boosting function. Within 18-24 hours after birth, the kittens begin to develop their own antibodies and no longer need the colostrum. See this recent post on Cat Blood Types for more on a condition known as Fading Kitten Syndrome that can occur with young kittens.
When something goes wrong in training the cells to recognize invaders, they may start to view the body's own cells as foreign and begin attacking them. This is an autoimmune disease. Sometimes drugs given to treat one thing can alter the body's red blood cells and make them appear foreign to the immune system.
Five common autoimmune diseases in cats are:
- Pemphigus foliaceous - causes pustules and lesions on the ears, nose, chin, and/or feet
- Myasthenia gravis - nerve disorder that can cause weakness, vocal changes, and problems with eating
- Autoimmune hemolytic anemia (AIHA) - causes the body to attack its own red blood cells; in cats this is usually triggered by a disease, drug or toxin
- Chronic progressive polyarthritis - inflammatory disease that causes arthritis symptoms in the cat's moving joints, with the immune system attacking the joint cartilage
- Systemic lupus erythematosis (SLE) - Persian, Siamese, and Himalayan cats are thought to be more susceptible to this autoimmune disease that causes lameness, loss of appetite, skin lesions or ulcers, kidney and liver problems.
How Can I Protect My Cat's Immune System?
Certain types of immune-boosting supplements may also be helpful. Ingredients that have been studied and found to be effective include the amino acid arginine, nucleotides, and salmon oil.
- Feline herpes, calicivirus, panleukopenia combination (FVRCP)
- Feline leukemia (FeLV)
Feline Immunodeficiency Virus (FIV) Feline Infectious Peritonitis (FIP) Bordatella Giardia Chlamydia