BIOC Unit 11 'immunity'

1) non specific external

2) non specific internal

3) specific immune response

what are the three basic lines of defense against disease?

First line of defense

non specific external; prevents microbes from entering the body, skin, mucous membranes, tears

second line of defense

non specific internal; microbes breach non specific external barriers, broad internal responses to microbe infection, PHAGOCYTIC WHITE BLOOD CELLS, INFLAMMATION, FEVER, HYDROCHLORIC ACID IN STOMACH, BLOOD CLOTTING

third line of defense

specific immune response; immune cells selectively destroy specific invading microbes and toxins, invaders are “remembered” allowing for a rapid future response to invasion

antibacterial enzymes; ex: lysosomes

what does mucus contain?

in the interstitial fluid

where do macrophages wander?

elevates body temperature, increase cell activity, provides stress to invader

what do fevers do?

1st step of inflammatory response

tissue damage carries bacteria into wound

2nd step of inflammatory response 

wounded cells release chemicals that stimulate mast cells

3rd step of inflammatory response 

mast cells release histamine

4th step of inflammatory response 

histamine increases capillary blood flow and permeability

5th step of inflammatory response 

phagocytes leave capillaries and ingest bacteria and dead cells

increases blood flow (heat)

what does widening the capillary do?

fluid ( containing WBCs) release into tissues

what does increased permeability of the capillary do?

a white blood cell

what is a leukocyte?

phagocytes

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

Lymphocytes

A lymphocyte is a type of white blood cell that plays a key role in the immune system. They are responsible for recognizing and attacking foreign substances such as viruses, bacteria, and cancer cells. There are two main types of lymphocytes: B cells and T cells.

phagocytes and lymphocytes

what are the two types of white blood cells?

antigen

anything the body recognizes as foreign

antibody

globular glycoproteins (y-shaped) that act against specific antigens

* made of 2 heavy chains and 2 light **peptide** chains
* both chains have constant and variable regions
* each type is unique to the B cell that makes them
* connected by a “hinge region” - disulfide bond

surface antigens

what establishes your body to distinguish between “self” and “non-self”

neutrophils and macrophages

what do phagocytes consist of?

bone marrow

where are phagocytes stores/produced?

neutrophils

* 60% of WBCs in blood are Neutrophils
* short lived
* released in large #s during infections

macrophages

* larger than neutrophils
* in lungs, liver, kidney, and lymph nodes
* travel in blood as monocytes but develop into macrophages when settle in organs
* remove foreign matter
* long lived
* cut up pathogens to present their antigens to lymphocytes

histamine

chemical compound that is released by cells in response to injury, inflammation, or allergic reactions. It causes the dilation of blood vessels and the contraction of smooth muscle, leading to symptoms such as itching, swelling, and increased mucus production.

chemotaxis

the movement of an organism or a cell towards or away from a chemical stimulus. It is a biological process that allows cells to detect and respond to chemical gradients in their environment.

B cells

(bone marrow made cell) secrete antibodies that attack antigens

T cells

(thymus made cell) attack antigens infected with pathogens

thymus

The thymus is a specialized organ of the immune system located in the upper chest behind the sternum. It plays a crucial role in the development and maturation of T cells, which are important for immune defense against infections and cancer.

hinge region

disulfide bridge between heavy chains of a antibody

epitope/antigenic determinants

molecules to which antibodies bind (its part of the antigen)

the specific part of an antigen that is recognized and bound by an antibody or T cell receptor during an immune response. It is usually a small, accessible portion of a larger protein or polysaccharide molecule.

paratope

A paratope is the part of an antibody molecule that binds to an antigen. It is located on the variable region of the antibody's heavy and light chains.

humoral response

clonal selection musters defensive forces against specific antigens

* clonal selection
* mitosis

1) attached B cell antibodies bind to invading antigen in the blood

2) bound B cell divides rapidly (mitosis) forming many identical copies (clonal selection)

3) B cell clones differentiate to form memory B cells (long lived) and plasma cells (short lived)

clonal selection

a specific antigen selectively binds to and activates only those lymphocytes (B or T cells) that have receptors capable of recognizing the antigen. These activated lymphocytes then undergo clonal expansion, producing a large number of identical cells that can recognize and respond to the antigen. This process is a key mechanism of the adaptive immune response.

memory B cells

saved to fight future infection

plasma cells

mass-produce the specific antibody into the blood

Cell-mediated immunity

**HELPER T CELLS**

* bind to antigens presented by a macrophage that consumed them (APC)
* APC displays a foreign antigen and one of the bodies own self proteins to a helper T cell

Antigen presenting cell

what does APC mean?

cytokine

**helper T cells** produce this to stimulate T cell division and differentiation to form memory T cells and cytotoxic T cells

* will also stimulate division of B cells (humoral response) that are bound to an antigen

cytotoxic T cells

* bind directly to cancerous or virally-infected cells
* release proteins that poke holes in cancer/infected cell membrane, killing the cell (apoptosis)

immunoglobulins

also known as antibodies, are proteins produced by the immune system in response to the presence of foreign substances, such as bacteria or viruses. They recognize and bind to specific antigens on the surface of these substances, marking them for destruction by other immune cells. IgG

(antibody jobs) neutralizers

combine with viruses to prevent entering or damaging cells

(antibody jobs) attachers

they attach to flagella of bacteria to make them less active so they get phagocytoses

(antibody jobs) agglutination

clumps bacteria to slow down spread

(antibody jobs) hole punchers /complementary

causes cells to lyse

(antibody jobs) coats the surface

of bacteria for easier endocytosis

(antibody jobs) antitoxins

blocks toxins from bacteria (cholera, diphtheria, tetanus

monoclonal antibodies (Mabs)

B cell clones that secrete identical antibodies, can undergo mitosis and produce antibodies, a type of hybridoma

Treatment for the rabies virus

injecting purified antibodies (using MABs)

treatment of breast cancer

**Herceptin** (trastuzumab) is a MAB used to treat breast caner, it recognizes receptor proteins on the surface of caner cells and bind to them allowing the immune system to identify and destroy them.

overcoming autoimmune response with mabs by

* genetically modifying the antibody polypeptide chains so that the amino acid sequences are now human not animal
* altering the type and position of the sugar groups (antibodies are glycoproteins) attached to the heavy polypeptide chains to reflect those found on human

Interleukin-1 is a cytokine that plays a key role in the regulation of immune and inflammatory responses. It is involved in the activation of T cells, B cells, and natural killer cells, as well as the production of other cytokines and chemokines. Additionally, interleukin-1 is involved in the regulation of fever and the acute phase response.

what does **interleukin-1** do?

Interleukin-2 is a cytokine that plays a key role in the regulation of the immune system. It stimulates the growth and proliferation of T cells, which are important for the body's defense against infections and cancer.

what does **interleukin-2** do? 

colostrum

thick, yellowish liquid produced from mommy milk for 4-5 days after birth, contains IgA, an antibody for gut health.

hybridoma

a cell resulting from the fusion of a cancerous B-cell with a non-cancerous myeloma cell. It is capable of producing large amounts of a single type of antibody, which can be used for research, diagnosis, and therapy.

trastuzumabm, ipilimumab, inflixmab, rituximab

what are successful MABs drugs?

trastuzumabm/herceptin

great cancer treatment by binding receptor proteins of antigen,