Chapter 43: The Immune System

Heavy chain rearrangement

*occur in B lymphocytes *variable regions are encoded by V, D, and J *steps 1. 1st DJ gene rearrangement 2. 2nd VDJ gene rearrangement

When do phagocytic cells leak out?

To head to the site of injury.

autoimmune disease

a condition in which the immune system mistakenly attacks itself, targeting the cells, tissues, and organs of a person's own body

immunodeficiency disorder

a condition that occurs when one or more parts of the immune system are deficient or missing

Phagocytes

a type of cell within the body capable of engulfing and absorbing bacteria and other small cells and particles.

viral neutralization

antibodies bind to certain proteins on the surface of a virus, thereb blocking the virsu's ability to infect a host cell

opsinization

coating of the foreign antigen with antibodies, sometimes bacteria have glycokalix that prevents binding of the bacteria (helps phagocytize the antigens that cannot be bound)

TLR3 recognizes

dsRNA viruses

Class 1 MHC molecules

found on almost all nucleated cells of the body; display peptide antigens to cytotoxic T cells

Do red blood cells have a nucleus?

nope

Phagocytosis

process in which extensions of cytoplasm surround and engulf large particles and take them into the cell

Interferons

proteins (cytokines) secreted by T cells and other cells to aid and regulate the immune response

MHC molecules

responsible for stimulating rejection of tissue grafts and organ transplants.

dendritic cells

specialized white blood cells that patrol the body searching for antigens that produce infections

Basophils

A circulating leukocyte that produces histamine.

active immunity

A form of acquired immunity in which the body produces its own antibodies against disease-causing antigens.

epitope

A small, accessible region of an antigen to which an antigen receptor or antibody binds; also called an antigenic determinant.

natural killer cells

A type of white blood cell that can kill tumor cells and virus-infected cells; an important component of innate immunity.

Neutrophils

A type of white blood cell that engulfs invading microbes and contributes to the nonspecific defenses of the body against disease.

The killing action of cytotoxic T cells on an infected host cell

An activated cytotoxic T cell releases molecules that make pores in an infected cell's membrane

hemocytes

Blood cells, primarily responsible for defense against disease and parasites.

T cells

Cells created in the thymus that produce substances that attack infected cells in the body.

B cells

Cells manufactured in the bone marrow that create antibodies for isolating and destroying invading bacteria and viruses.

passive immunity

the short-term immunity that results from the introduction of antibodies from another person or animal.

TLR5 recognizes

Flagellin (bacteria)

Macrophages

Found within the lymph nodes, they are phagocytes that destroy bacteria, cancer cells, and other foreign matter in the lymphatic stream.

secondary immune response

Immune response after the body has already been exposed to a specific antigen. Response is faster, of greater magnitude, and more prolonged.

primary immune response

Immune response the first time the body is exposed to a particular antigen. Does not peak until 10-17 days after exposure.

TLR4 recognizes

LPS of gram negative bacteria

RAG1 and RAG2

Necessary for somatic recombination of BCR (and TCR) genes Recognize recombination signal sequences (RSS's) and cut dsDNA Transiently expressed in Pro-B and Pre-B cells Presence of pre-BCR or BCR turns off gene expression for this

All cells except _____ have a class 1 MHC protein on the surface.

Red blood cells.

Why do red blood cells lose their nucleus as they mature?

The absence of a nucleus is an adaptation of the red blood cell for it's role. It allows the red blood cell to contain more haemoglobin (and, therefore, carry more oxygen molecules). It also allows the cell to have its distinctive bi-concave shape which aids diffusion - this shape would not be possible if the cell had a nucleus in the way.

humoral immune response

The branch of acquired immunity that involves the activation of B cells and that leads to the production of antibodies, which defend against bacteria and viruses in body fluids.

cell-mediated immune response

The branch of acquired immunity that involves the activation of cytotoxic T cells, which defend against infected cells.

Septic inflammation

The reaction caused by the decomposition of microorganisms

Lymphocytes

The two types of white blood cells that are part of the body's immune system: B lymphocytes form in the bone marrow and release antibodies that fight bacterial infections; T lymphocytes form in the thymus and other lymphatic tissue and attack cancer cells, viruses, and foreign substances.