What are the 4 main line of defense against invading organisms in our bodies?

The four main lines of defense against invading organisms in our bodies are:

1. Physical Barriers: The skin and mucous membranes serve as the first line of defense, preventing pathogens from entering the body.
2. Innate Immune Response: This includes non-specific immune responses such as inflammation and the activity of phagocytic cells that attack and destroy pathogens.
3. Adaptive Immune Response: This involves the activation of lymphocytes (B cells and T cells) that specifically target and remember pathogens for more effective responses in the future.
4. Microbiome: The beneficial microorganisms that inhabit our bodies help prevent the colonization of harmful pathogens by competing for resources and space.