What Is Mucosal Immunology?

Mucosal immunology represents a branch of biomedicine that studies toxins entering the body through the respiratory, gastrointestinal, or reproductive tract. These cavities provide pathways where viruses, bacteria, or harmful pathogens enter the body from the outside environment. Mucus found in these tracts represents the first line of defense as part of the human immune system by creating barriers to toxic substances.

Researchers involved in mucosal immunology study how mucus membranes trap foreign substances called antigens and send messages to lymph nodes to begin attacking these invaders. Scientists working in this branch of bioscience hope to discover new medicines and vaccines that improve the functioning of the immune system to fight illness and cure disease. They also research how these mucus membranes are breached by specific viruses, bacteria, or chemicals.

An example of the body’s mucosal immunology response occurs through coughing or sneezing, when tiny hairs called cilia trap antigens in the respiratory system. Diarrhea or vomiting typically occurs when gastrointestinal antibodies attempt to rid the body of harmful substances that enter the body from food or beverages. Tears, urine, sweat, and vaginal secretions also are part of the mucosal immunology system.

The human body produces immune cells called lymphocytes in bone marrow to attack different types of antigens, with the highest concentration of lymphocytes found in mucus. When these cells mature, they enter the bloodstream, lymph nodes, and spleen. These lymphocytes trigger the secretion of antibodies to destroy antigens and protect mucous membranes as part of a complex defense system against illness.

Mucous membranes are rich in dendritic cells, which are innate immune cells that can distinguish between benign and harmful substances that enter the body. If a bacterium or virus invades, dendritic cells stimulate production of white blood cells, or T cells, to attack the foreign antigen. B cells, considered helper cells, also become activated and bind to specific antigens. During this process, memory cells are also created that can activate a rapid response if the same foreign substance attacks the body again. Vaccines work by creating memory cells to protect against disease.

If the immune system malfunctions, antibodies attack healthy cells along with foreign invaders, leading to autoimmune diseases such as lupus, arthritis, multiple sclerosis, and allergies. The study of mucosal immunology looks at how antigens pass through mucus barriers and produce antibodies that destroy healthy tissue. This field of medicine also researches ways to strengthen the immune system and develop new vaccines to create memory cells.