How Do Dogs’ Immune Systems Work?
Animals have an internal defense mechanism against external pathogens, such as viruses, bacteria, protozoa, parasites… The dog’s immune system works like ours and, when there is an aggression, it responds by preventing the pathogen from spreading through the body.
The first antibodies
When puppies are born , they receive their first antibodies from colostrum, the mother’s first milk. These antibodies will protect the puppy for the first few weeks of life as the immune system develops.
What makes up the dog’s immune system?
The immune system is made up of organs, tissues, cells and small molecules that act together against infectious agents.
Lymph nodes and lymph
Lymph is similar to blood plasma formed to collect excess interstitial fluid, proteins, fats and white blood cells. Lymph circulates through the lymph ducts.
The lymph nodes (submandibular, pre-scapular, axillary, inguinal and popliteal in dogs) are responsible for purifying it for recirculation in the veins.
the spleen
The spleen is an organ that intervenes directly in the animal’s immune system: it is responsible for filtering the blood, destroying old blood cells and producing new cells.
Immune Cells
There are different types of immune cells. All have a common origin, but each type specializes in a specific task. The joint action of all these cells is capable of fighting a disease.
- Lymphocytes. Lymphocytes produce antibodies, small proteins capable of binding to an antigen, that is, to the infectious agent.
- Macrophages. These cells phagocyte, that is, they ingest the invading microorganism and, once inside, they destroy it. Macrophages, in addition, are responsible for producing substances that attract other cells of the immune system to treat the infection.
- Dendritic cells. They are similar to macrophages, with many branches; they also phagocytose the microorganism and expose a part of it on its surface for other immune cells to destroy.
- Neutrophils. They are the first cells to appear at the site of infection and are very abundant.
- Basophils and eosinophils. These cells participate in inflammatory, allergic and parasite attack processes. Your percentage is very small.
How do dogs’ immune systems act against an attack?
The immune system of dogs, like that of other mammals, develops as the body is exposed to antigens.
Faced with a pathogen, there are a series of barriers that prevent its entry and reproduction. These barriers are:
- Primary barriers : the skin and mucous secretions.
- Secondary barriers : these are the cells that make up our immune system and prevent the pathogen from spreading through the body after overcoming the primary barriers.
In the first months of life, the puppy has innate immunity, an immune system that responds immediately to the invasion of pathogenic microorganisms, but that does not carry learning or keeps memory.
The cells that make up this initial immunity recognize a series of antigens and respond more generally. As the puppy grows and is exposed to new antigens, it develops acquired immunity.
The immune system retains memory of encounters and is more effective against future invasions by the same pathogen.
Vaccines follow this principle, because with them we can “teach” the immune system to fight certain diseases, presenting the weakened pathogen to the immune cells or some of its parts. This presentation is enough to provoke a response.
Vaccines are a safe method of immunizing dogs against serious illnesses such as parvovirus, hepatitis, distemper or leishmaniasis.
Therefore, it is best to start when they are puppies and apply all the vaccines and subsequent doses to increase effectiveness and strengthen your dog’s immune system.
