How does the immune system identify and attack pathogens?

The immune system identifies pathogens through specific markers on their surface and attacks them using immune cells and antibodies.

The immune system is a complex network of cells, tissues, and organs that work together to defend the body against harmful invaders. These invaders, or pathogens, include bacteria, viruses, and other microorganisms that can cause disease. The immune system identifies these pathogens through specific markers, known as antigens, on their surface. These antigens are unique to each pathogen and allow the immune system to recognise and remember harmful invaders.

The immune response begins when a type of white blood cell called a macrophage encounters a pathogen. The macrophage engulfs the pathogen and presents its antigens on its surface. This process is known as antigen presentation. The presented antigens are then recognised by another type of white blood cell, the T cell. This recognition triggers the activation of the T cell, which then multiplies and produces other immune cells to fight the infection.

Some of these immune cells, known as B cells, produce antibodies. Antibodies are proteins that can bind to the antigens on the surface of the pathogen. This binding neutralises the pathogen and marks it for destruction by other immune cells. This process is known as opsonisation.

In addition to attacking the pathogen, the immune system also has a memory function. Some of the activated T and B cells become memory cells, which remain in the body long after the infection has been cleared. If the same pathogen invades the body again, these memory cells recognise the antigens and trigger a faster and stronger immune response. This is the basis of immunity and the principle behind vaccination.

In summary, the immune system identifies and attacks pathogens through a complex process involving antigen recognition, immune cell activation, antibody production, and memory cell formation. This process ensures that the body can defend itself against harmful invaders and remember them for future encounters.