Immune System pt 2

Question 1

what are the features of specific immune response

Answer 1

• specificity
• diversity
• memory
• self-tolerance

Question 2

what are the specific defense mechanisms

Answer 2

humoral and cell-mediated immunity

Question 3

describe humoral immunity

Answer 3

• B cell mediated
• B cells turn to plasma cells to secrete antibodies
• able to defend against bacteria, toxins, viruses in body fluids

Question 4

describe cell-mediated immunity

Answer 4

• T cell mediated
• T cells turn to active cytotoxic T cells to bind and kill abnormal body cells
• defend against bacteria and viruses hidden in infected body cells
• part of rxn to transplants and cancer cells

Question 5

describe how specificity occurs in immune responses

Answer 5

• B and T cells bind and respond to antigens (each antigen has unique structure w/ epitopes [recognition sites])
• B and T cells recognize certain antigens thru antigen receptors on surface
• interacts/activates only lymphocytes w/ receptors specific for antigens on invader

Question 6

draw out the antibody structure and include a separate structure for the antigen attaching to a specific antibody

Answer 6

….

Question 7

describe B cell antigen receptors

Answer 7

• similar to antibody molecules except that they’re bound to membrane
• AKA membrane antibodies

Question 8

describe T cell receptors

Answer 8

• same protein family as antibodies but are different in structure and are never secreted
• act only as cell surface receptors for antigen

Question 9

describe how diversity plays a role in specific immune responses

Answer 9

• = capacity to recognize and respond to millions of dif antigens
• single B or T lymphocyte has ~100K antigen receptors all w/ same specificity
• each cell can detect a few million antigens that can enter body

Question 10

describe clonal selection

Answer 10

• a single lymphocyte expresses receptors specific to a distinct antigen
• required for immune response
• 2 types of clones result from lymphocyte differentiation (effector/plasma and memory B cells)

Question 11

describe effector/plasma cells

Answer 11

• combat same antigen that stimulated their production
• short-lived (4-7 day lifespan)
• secrete 2000 antibodies per second that bind to antigen
• antibodies circulate several weeks, binding to and marking antigens for destruction by phagocytosis and complement-mediated lysis

Question 12

describe memory B cells

Answer 12

• have membrane receptors specific for same antigen
• long-lived

Question 13

describe the relationship of chickenpox and shingles

Answer 13

• cp caused by varicella zoster virus
• virus can survive by travelling to dorsal root ganglia and remain dormant for years
• virus can reactivate and cause shingles due to age or stress (1 in 10)

Question 14

describe the importance of memory in specific immune responses

Answer 14

• first exposure to antigen = primary immune response
• symptoms of illness occur (10-17 days)
• antigen-selected B and T cells proliferate and differentiate into effector cells
• this leads to acquired immunity
• secondary immune response is faster than primary (2-7 days) and is more prolonged bc of clones of memory T and B cells
• serum antibody conc is higher in secondary response than primary esp over short amt of time

Question 15

describe self-tolerance in specific immune response

Answer 15

• B and T cells don’t attack normal cells
• programmed cell death (apoptosis) occurs w cells that have antigen receptors during development in bone marrow and thymus
• autoimmune diseases are caused by failure of self-tolerance

Question 16

describe the role of B lymphocytes in antibody production for humoral immunity

Answer 16

• B cell exposure to antigen triggers clonal selection which increases memory B and plasma cells
• antigens that trigger production of both types of cells are T-dependent antigens
• IL-2 secreted from helper T cells + T-dependent antigens lead to activation of B cells
• no memory for subsequent exposures

Question 17

describe antibody function in humoral immunity

Answer 17

• specific antigen binding which aids in inactivation or destruction of antigen
• tail involved in inactivation or destruction of antigen
• antigen-binding site recognizes and binds antigen

Question 18

what are the major classes of antibodies; what features do they have in common

Answer 18

• IgA, IgD, IgE, IgG, IgM;
• neutralizes and agglutinates antigen

Question 19

what are the roles of IgM in antigen disposal

Answer 19

• activates complement

Question 20

what are the roles of IgG in antigen disposal

Answer 20

• activates complement
• opsonizes antigen
• enhances NK cell activity

Question 21

what are the roles of IgE in antigen disposal

Answer 21

• binds to mast cells and basophils causing them to release histamine

Question 22

describe neutralization

Answer 22

antibodies block the activity of a pathogen

Question 23

describe agglutination

Answer 23

multiple pathogens are aggregated by antibody molecules

Question 24

describe opsonization

Answer 24

pathogens bound by antibodies are more efficiently engulfed by phagocytes

Question 25

describe complement activation

Answer 25

antibodies bound to pathogens activate the complement cascade resulting in lysis of cell

Question 26

describe enhanced NK cell activity

Answer 26

abnormal body cells that are bound by antibodies are recognized by NK cells and are subsequently lysed

Question 27

describe the roles of T cells in cell-mediated immunity

Answer 27

• helper T cells secrete cytokines that enhance activity of B cells and other T cells as well as enhance activity of macrophages and NK cells
• cytotoxic T cells kill virus-infected, abnormal, and bacteria cells including suppressor T cells which secrete cytokines that suppress activity of B cells and other T cells
• MHC molecules are unique to self (Class I and II) and T cells only recognize antigen when its associate with the MHC

Question 28

describe antigen presentation

Answer 28

MHC molecules binding antigen within the cell and transporting antigen to the surface where it can be recognized by T cells

Question 29

what is the main difference b/w cytotoxic and helper T cells

Answer 29

killing (cytotoxic) vs not killing (helper) antigen presenting cell

Question 30

what are the types of immunization

Answer 30

active and passive

Question 31

describe active immunity

Answer 31

• long-term immunity
• depends on immunized person’s immune system mounting a response

Question 32

describe passive immunity

Answer 32

• short-term immunity
• ready-made antibodies introduce into person; the person’s B cells don’t make antibodies

Question 33

describe how immunization works

Answer 33

• inactivated microorganism or harmless components of pathogen are part of immunization mechanism
• leads to a slow and weak primary immune response which makes antibodies (not needed) and memory cells (needed)
• the natural exposure to pathogen leads to a fast and strong secondary immune response which makes antibodies (needed) and memory cells

Question 34

describe plasma antibodies and RBC antigens in all 4 blood groups

Answer 34

A: anti-B and A antigen
B: anti-A and B antigen
AB: none and A&B antigens
O: anti-B&A and none

Question 35

if a blood receiver has anti-A antibodies and gets blood from a type A donor:

-what blood type and antibodies is the recipient?
- what antigens does the donor have?
- will there be agglutination or not?

Answer 35

• type B
• A antigens
• agglutination occurs bc antibodies and anitgens stick together