The immune system is the body’s natural defense against infection and disease. It is a complex network of cells, tissues, and organs that work together to protect the body from foreign invaders. The immune system is constantly on the lookout for anything that doesn’t belong in the body, such as bacteria, viruses, fungi, and parasites. When it detects something suspicious, it sends out an army of specialized cells to destroy the invader.
The immune system is made up of many different types of cells that all have different roles to play in protecting the body. The three main types of immune cells are: white blood cells (WBCs), antibodies, and antigens.
White blood cells are the first line of defense against infection. They circulate through the bloodstream looking for foreign invaders. When they find one, they engulf it and destroy it. There are several different types of WBCs, each with a specific role to play in fighting infections: neutrophils, eosinophils, basophils, lymphocytes, and monocytes/macrophages.
Antibodies are proteins produced by white blood cells that bind to specific antigens on invading microbes or toxins. This binding process flags the microbe or toxin for destruction by other parts of the immune system. Antibodies can also neutralize toxins before they can do any damage to host cells. Each antibody is specific to one particular antigen; this specificity allows the immune system to target only those microbes or toxins that pose a threat while leaving healthy cells unharmed.
Antigens are any substances that stimulate an immune response; they can be either harmful (such as viruses and bacteria) or harmless (such as food proteins). Once an antigen has been identified by a white blood cell, it will trigger the production of antibodies specific to that antigen; these antibodies will then circulate through the bloodstream looking for matching antigens on othercells or microbes so that they can bind to them and mark them for destruction by other parts ofthe immune system .
Immune System