How does immunity work?

The immune system comprises a wide range of organs, tissues, cells, and microorganisms that work in synergy to prevent pathogens from causing harm to you.

Learning how your immune system works equips you with the knowledge to help support your immunity. In this article, we will cover some of the basics.

Physical barriers

The first line of defence includes physical barriers, such as the skin and mucous membranes, which act as a physical barrier to pathogens. The skin's outermost layer is relatively impermeable, meaning pathogens are unable to pass through it and enter the bloodstream.

Mucous membranes, which line the respiratory and digestive tracts in the body, capture and expel pathogens through mechanisms like coughing and sneezing. These barriers produce antimicrobial substances like mucus and stomach acid to kill or inhibit pathogens.

Innate vs. acquired immunity

The immune system can be split into two parts -  innate and acquired immunity.

Innate immunity is what you're born with. In other words, it's there from infantile years and sticks with you for the rest of your life. The innate immune system is non-specific, meaning it doesn't work against a specific pathogen but, instead, attacks anything that the body perceives as foreign.

White blood cells recognize pathogens and cause inflammation in the area to recruit even more immune-killing cells to the area.

Acquired immunity is something you acquire over time with exposure to various pathogens. When your body is exposed to a harmful strain of bacteria, a nasty virus, or a particular type of fungus, it activates a range of different cells, including:

• T cells - conduct cell-mediated immunity when they recognize specific antigens on infected body cells or pathogens. Helper T cells stimulate other immune cells and coordinate the immune response.
• B cells - responsible for humoral immunity. B cells produce antibodies, proteins that target specific pathogenic antigens and tag them. This tag signals to other immune cells to destroy the pathogens. Memory B cells ‘remember' the specific antigens the body has come across previously to activate a faster response if the body gets infected with the same antigens again in the future.