Mod3: Immunity

Question 1

Normal function of T-lymphocytes differ from B-lymphocytres how

Answer 1

B cells produce antibodies, form recognizable complexes for immune system
T cells- recognizes antigen outside of cell, can attack

Question 2

Humoral immunity function
Stimulated by
Provides protection against (5)

Answer 2

B-cells stimulated by IL4

Provides immunity against viral, toxin diseases, pneumococci, meningococcal, haemophilus diseases

Question 3

Cell mediated immunity

Answer 3

T-cells
Against intracellular bacteria/viruses
Defense w CA, fungal, parasitic infections
Responsible for organ transplant rejection

Question 4

Active acquired immunity

Answer 4

Produced by host after exposure to antigen or immunization

slower acting, long lived, improves w repeat exposure

Question 5

Passive acquired immunity

Answer 5

Acquired via the transfer of antibodies, or T-cells to the recipient

Natural-fetus
Artificial-immediate,2 wks, tb,rabies,tetanus,hepatitis,snake bite

Question 6

Self antigen
Production of
Tolerable?
Regulated by

Answer 6

Immunogens=immune response=production of antibodies/Tcells
Most can tolerate own Tcells
Regulated by T regulatory cells

Question 7

B-lymphocyte

IgA

Answer 7

Main ig in secretions and mucous membranes

Prevents attachment of microorganisms to mucous membrane

Question 8

B-lymphocyte

IgM

Answer 8

Produced early in primary immune response

High level=recent infection

Question 9

B-lymphocyte IgG

Answer 9

Binds with viruses, bacteria, toxins
Activates complement and binds to macrophages
Primary antigen in secondary response
Crosses placenta
Provide long lasting immunity

Question 10

B-Lymphocyte IgE

Answer 10

Binds to mast cells, eosinophils and basophils

Involved in parasitic and hypersensitive rxn’s

Question 11

T-lymphocytes: T-cytotoxic cells

Killer T, CD8, T8 cells

Answer 11

Kill virus infected, tumor, and allograft cells directly thru release of cytotoxic chemicals destroying membrane or =apoptosis

Question 12

T-lymphocytes

NK Killer

Answer 12

Contain granules that recognize, attack and kill virus infected or cancerous cells
Inhibitory/activation receptors allow differentiation infected/normal cells
Produces cytokines that kill

Question 13

T-lymphocytes
T-helper

TH1,TH2

Answer 13

Secretes cytokines stimulating differentiation of B to plasma cells
Activate macrophages(B-cells, Cytotoxic Tcells + other CD4 cells)
Release lymphokines=begins inflammatory process 
Mediate delayed hypersensitivity rxn’s

Question 14

How do B lymphocytes recognize and process antigens

Answer 14

Bcell receptor on surface recognize antigen
L4 -> B-cells into plasma cells= antibodies/memory B-cells
antibodies bind to antigen =antigen-antibody complexes
Memory B-cells act during secondaryresponse

Question 15

How do T lymphocytes recognize and process antigens

Answer 15

Antigen enters->Macrophage (or other APC) engulfs antigen ->antigen
expressed on MHC class II -> secretes IL 1 to attract CD4 cells ->presents it to CD4-cells ->CD4 differentiates into Th1 and Th2->Th1 releases IL2 -> activated cytotoxic T-cells (Tc) ->Tc receptor connects with MHC class I receptor on invader-> cytotoxic chemicals released ->invader killed
Th2 releases IL4 → activates the humoral immune system

Question 16

Purpose and process of primary immune response

Answer 16

Response in 5-7 days
Bcell differentiation, clonal selection,processing/presenting antigens, Bcell TH cell interaction must occur
^igM initial then ^igG in second

Question 17

Purpose and process of secondary immune response (2nd exposure)

Answer 17

anamnestic immune response. IgM levels rise during this response, but IgG levels rise much more than in a primary immune response

Question 18

Age related changes in immune system

Answer 18

60+ decreased T- cell activity
vThymus size= vT-cell differentiation
T-cell numbers do not decrease. 
B-cells produce less antibodies 
vAmount of circulating memory B-cells
^circulation of autoantibodies

Question 19

Fetal immune function

Answer 19

vPhagocytic activity, antibody production, complement activity
last trimester-fetus can mount a primary immune response and produce IgM antibodies but they are unable to produce a significant amount of IgG antibodies
unable to produce IgA antibodies.
mother’s antibodies are transported across the placenta and provide protection

Question 20

Neonatal immune function

Answer 20

At birth IgG levels in the umbilical cord blood is near adult levels but then drops off after the cord is cut. Antibody levels reach a minimum point at 5-6 months post birth
Cause recurrent resp infections

Question 21

Antigen presenting cells

Answer 21

B-lymphocytes

macrophages, dendriticncells

Question 22

Allergens

Answer 22

Antigens=allergic response

Question 23

Antibodies

Answer 23

Immunoglobulin Yshaped

Coats pathogen->forms antibody complex->activates complement cascade

Question 24

T cells differentiated by

Answer 24

expression of antigen on their cell “cluster of differentiation”