A cat’s immune system is divided into two parts - innate and adaptive.
The innate immune system is the first line of defense and it is designed to keep all infections away. The cat’s skin, stomach acid, mucus in her respiratory system and chemicals in her saliva, special cells called monocytes which consume anything foreign, are all part of the innate immune system.
The adaptive immune system protects cats from specific infections such as viruses and bacteria. If the innate immune system is unable to destroy the infection, then the adaptive immune system will kick in to fight that infection.
If the cat’s immune system is strong then her body will successfully fight off that infection. The adaptive immune system also has a memory so if the cat is exposed to the same virus again then the response from the immune system is faster and stronger to prevent any illness.
Active immunity is what lasts through the whole life of the cat, but Passive immunity is present only for a short time in the beginning few months of a cat’s life. This is because when the cat is nursing, she’s getting the immunity through her mother’s milk. So this immunity cannot be replenished, so once the passive immunity antibodies are used up to fight any disease they are not replaced.
Compromised immune system is when
A healthy cat will have a healthy immune system, so you should ensure that the injections from early age are all given at the right time. Medicines should always be given as and when required after consulting with vet. And lastly, a healthy diet will also help in keeping the immune system in a good condition.