A properly functioning immune system is critical for health. The immune system protects against infection by micro-organisms like viruses and bacteria. We generally think of immunity as a finely orchestrated interaction of immune cells like T cells and B cells along with their signaling molecules. This is the glamorous part of the immune system known as adaptive immunity. Adaptive immunity is able to specifically target identified micro-organisms like the parvovirus that affects dogs.

The other part of the immune system is known as innate immunity. It involves the physical barriers like the skin and mucous membranes along with effects of urine, mucus and other secretions. Innate immunity also involves white blood cells like neutrophils and macrophages that are involved in inflammation and have nonspecific, destructive effects on micro-organisms. Interestingly, there is a mosaic of micro-organisms that normally inhabit all body surfaces. This normal flora (microbiome) interfaces with innate immunity and adaptive immunity. The microbiome also contributes to protection by suppressing certain pathogens.

Innate immunity is important and is often neglected when defining an immune support plan. Since it compriseds the barriers like skin, secretions and fluids, and certain white blood cells, support should focus on those areas.

The barriers are designed to physically prevent micro-organisms from entering deeper and causing infection. Beyond the barrier function, each of these tissues have additional features that improve its protective ability. For example, the skin has antimicrobial secretions, the respiratory tract produces mucus, the digestive tract produces mucus and is bathed at certain points by stomach acid, bile and pancreatic fluid. All of these influence micro-organisms in different ways. Tears help to flush micro-organisms away from the eyes and contain enzymes like lysozyme, IgA antibodies and other substances that kill or reduce the ability of micro-organisms to cause an infection. Urine pH, ribonuclease 7 and other substances contained in urine inhibit bacteria. Mucus from the nose and respiratory tract contain lysozyme and lactoferrin in addition to its ability to trap micro-organisms that can be removed by sneezing, coughing and the sweeping action of cilia in the trachea. The skin secretes antimicrobial peptides that also trigger wider immune reactions when micro-organisms invade into the skin. Secretions of acid and pepsin in the stomach provide antimicrobial effects. Pancreatic fluid and bile have antimicrobial properties and along with gastric secretions, influence the micro-organism diversity in the digestive tract.

Immune support has generally focused on support of adaptive immunity. However, some chronic infectious problems can be reduced or controlled by focusing supportive care on the innate immunity. For example, managing urinary tract infections has long been known to benefit by controlling urine pH. Additional urinary tract support would include nutrients like vitamin A and C for support of the tissue lining the urinary bladder and urethra. Nutriceuticals like chondroitin can be used to improve the protective layer inside the urinary bladder. Other support focuses on the kidney as a way to improve urine quality. Use of probiotics has also shown benefits.

In a similar manner, improving the health and function of the mucous membrane lining the respiratory tract can enhance its barrier function and reduce the ability of micro-organisms to invade or trigger inflammation. Vitamins A and C can be beneficial. Reducing the inflammatory component that contributes to chronic reactive airway disease through adrenal support can play an important role. Control of dental disease and improvements in the oral microbiome can be valuable in certain situations.

Supporting the digestive tract innate immunity can be accomplished by careful evaluation of the underlying problem and then selecting the appropriate focus. For example, glutamine, an amino acid, is vital for the cells lining the small intestine. Short chain fatty acids are important for the lining of the large intestine. Short chain fatty acids are produced by bacterial fermentation of soluble fiber in the intestine. This process requires appropriate intestinal microbiome and can benefit from probiotic supplementation.

Innate immunity is an important part of the immune system. Its support can play an important role in managing chronic and stubborn infections. If you have questions about supporting your pet’s innate immunity, contact your veterinarian.

Ron Carsten, DVM, PhD, CVA, CCRT was one of the first veterinarians in Colorado to use the integrative approach, has lectured widely to veterinarians, and has been a pioneer in the therapeutic use of food concentrates to manage clinical problems. He is also the founder of Colorado Animal Rescue (CARE). In addition to his Doctor of Veterinary Medicine, he holds a PhD in Cell and Molecular Biology and is a Certified Veterinary Acupuncturist and Certified Canine Rehabilitation Therapist. He practices integrative veterinary medicine in Glenwood Springs.