Responding To Antigens

Question 1

Antigen

Answer 1

Are molecules or parts of molecules that interact with the receptors of lymphocytes and with antibodies and thus initiates an immune response.

Question 2

Non-self antigens

Answer 2

Antigens that do not belong to an organism’s own cells.

Question 3

Self antigens

Answer 3

An organism’s own antigens, which are normally don’t initiate a immune response.

Question 4

Allergen

Answer 4

An antigen that elicits an allergic response.

Question 5

Immunogens

Answer 5

Antigens that elicit an immune response.

Question 6

Antibodies

Answer 6

Proteins produced by b lymphocytes that bind to specific antigens.

Question 7

Pathogen

Answer 7

Agent that causes diseases in organisms

Question 8

Cellular pathogens

Answer 8

Bacteria, fungi, oomycetes, worms, Arthropods.

Question 9

Non-cellular pathogens

Answer 9

Viruses, viroids and prions

Question 10

Physical barriers in animals

Answer 10

Intact skin, epithelial cells in respiratory and gastrointestinal tracts, mucus and cilia.

Question 11

Chemical barriers in plants

Answer 11

Tannins, caffeine, defensins.

Question 12

Physical barriers in plants

Answer 12

Thicker cuticle, thick layer of bark, orientation of leaves, stomata closing.

Question 13

Microbiological barriers

Answer 13

Normal flora found on the skin, mouth, nose, throat and gastrointestinal tract. The presence of normal flora compete with invading bacteria for resources and space, and produce chemicals that reduce environment of the micro- environment.

Question 14

Macrophages

Answer 14

A type of leukocyte that is responsible for engulfing and digesting foreign matter in the body, as well as damaged cells and the remnants of apoptosis.

Question 15

Dendritic cells

Answer 15

A type of apc.

Question 16

Antigen-presenting cell

Answer 16

A cell that uses mhc-11 on it surface to present foreign antigens to helper t lymphocytes to elicit an adaptive immune response.

Question 17

Complement proteins

Answer 17

Proteins that kill foreign cells by lysis and are activated in response to antigen-antibody complexes.

Question 18

Neutrophils

Answer 18

Phagocyte

Question 19

Mast cells

Answer 19

Play a role in inflammation by releasing histamines which cause blood to dilate.

Question 20

Cytokine examples

Answer 20

Interferons: produced by virus-infected cells and inhibit viral replication by resulting in transcription of antiviral genes and expression of antiviral proteins.
Chemokines: attract white blood cells to the site of infection.

Question 21

Inflammation

Answer 21

Accumulation of fluid, plasma proteins and leukocytes that occurs when tissue is damaged/ infected. Results in sweeping, heat, pain, renews and loss of function of tissues.

Question 22

Fever

Answer 22

Increase in body temperature that results in the hypothalamus of the brain being set to a higher level by inflammatory cytokines.

Question 23

Inflammation steps

Answer 23

1. Pathogens breach first line of defence.
2. Injured cells release cytokines that attract neutrophils and mast cells that release histamines (blood vessel dilation -> leukocytes and proteins enter infected tissue),platelets close up the wound by releasing clotting factors.
3. Neutrophils migrate towards cytokines and are activated causing recruitment of phagocytes -> factors are secreted killing and degrading pathogens.
4. Macrophages are activated and secrete cytokines, along with neutrophils debris at the site of infection phagocyte debris.
5. Inflammatory response continues until the pathogen is eliminated and wound is healed.

Question 24

Lymphatic system

Answer 24

Body system transports immune cells (apc) throughout the body, where antigen recognition by lymphocytes occurs.

Question 25

Primary lymphoid tissues

Answer 25

Bone marrow and thymus

Question 26

Secondary lymphoid tissues

Answer 26

Lymph nodes, spleen, tonsils, adenoids and the appendix.

Question 27

B lymphocytes

Answer 27

Lymphocytes that when stimulated produce large quantities of antibodies specific to an antigen. They are responsible for humoral immunity and include both memory and plasma cells.

Question 28

T helper

Answer 28

Bind to antigen mhc-11 complexes on apc and activate b lymphocytes to secrete antibodies, macrophages to phagocytose and cytotoxic T cells to kill infected cells.

Question 29

Cytotoxic T cells

Answer 29

T lymphocyte that is stimulated by cytokines to bind to antigen mhc-1 complexes on infected host cells and release cytotoxic compounds to destroy the infected cells.

Question 30

Memory cells

Answer 30

Activated against specific antigen that remain in the lymphoid tissues for a long time, and permit a faster and more effective secondary response if the same antigen is encountered again.