Host Defense II Microbiology

First line of defense

any barrier that blocks invasion at the portal of entry

Second line of defense

Also called innate immunity, Internal system of protective cells, fluids, and processes that includes inflammation and phagocytosis

Third line of defense

White blood cells specifically adapted to individual invaders

Examples of first line of defense includes

physical barriers, microbiota barriers, chemical barriers

Examples of second line of defense includes

Phagocytosis, inflammation, fever, antimicrobial products

Examples of third line of defense includes

B cells, T cells (produced by lymphocytes)

Antigen

Any cell, particle, or chemical that induces a specific immune response by B cells or T cells and can stimulate resistance to an infection or a toxin. See immunogen.

self

Natural markers of the body that are recognized by the immune system.

nonself

Molecules recognized by the immune system as containing foreign markers, indicating a need for immune response.

Another word for antigen is

markers

pathogen-associated molecular patterns (PAMPs)

Molecules on the surfaces of many types of microbes that are not present on host cells that mark the microbes as foreign.

pattern recognition receptors (PRRs)

Molecules on the surface of host defense cells that recognize pathogen-associated molecular patterns on microbes.

What encompasses the study of all features of the body’s second and third lines of defense

Immunology

Immune cells that become specialized during a specific host defense against a pathogen.

lymphocytes

Stimulate nonspecific response by Innate Immune system

PAMPs

Stimulate specific response by

adaptive immune system

Antigens