midterm revision - part 2 , Adaptive Immunity

Question 1

Immunoglobulin = antibody consists of ?

Answer 1

• Two identical heavy (H) chains (Variable and contant regoins) (μ,γ,δ,ε, or α)
• Τwo identical light (L) chains (Variable and constant regoins) (κ or λ)
• held together by disulfide covalent bonds

Question 2

Which antibody class are held together by J chains?

Answer 2

1) IgM (Pentamer)
2) IgA (dimer)

Question 3

Which Antibody class is known for its role in Allergy and asthma?
Has potent effects where it binds to Fc receptors leading to degranulation of Eosinophils/ basophils/ mast cells –> releasing Histamine (destroys large pathogens)

Answer 3

IgE

Question 4

What is the Physiological role of IgE?

Answer 4

Protection against parasitic heminths (worms) and protozoa

Question 5

Explain how Adaptive immunity through IgE works

Answer 5

FcεRs expressed by mast cells (basophiles/ eosinophils) bind to IgE-antigen complexes –> triggers degranualtion of mast cells –> release of Histamine, proteases and other inflammatory mediators

* IgE “kills” large parasites

Question 6

———- produced by epi cells in skin/respiraotry / gut and urogenital tract, provide strong defence barriers against pathogens from entering the body

Answer 6

AMPs - antimicrobial peptides (innate immunity component)

Question 7

What are the main types of AMPs

Answer 7

α- and β-defensis, cathelicidins, histatins

Question 8

Which antibody class is:
1) A dimer Held togeher by J chains
2) Major protective defense of mucosal surfaces of the body
3) Effective at neutralizing toxins and pathogens

??

Answer 8

IgA

Question 9

Fxn of IgD heavy chain

Answer 9

Naive B cell antigen receptor
(Unknown fxn)

Question 10

Fxn of IgM heavy chain

Answer 10

1) Complemt activation (classical pathway)
2) Neutralization
3) Naive B cell antigen receptor

Question 11

Fxn of IgG Heavy chain

Answer 11

1) Complement activation (classical pathway)
2) Opsonization
3) Neutralization
4) ADCC (Antibody-dependent cell-mediated cytotoxicity)
5) Placental transport

Question 12

Fxn of IgA Heavy chain

Answer 12

Neutralization

*dimer

Question 13

Fxn of IgE Heavy chain

Answer 13

Mast cell degranulation

Question 14

which antibody class determines the presence of infection in a neonate/ fetus ?

Answer 14

IgM (as it does not corss materal placenta)

Question 15

The type of heavy chain determines the ——– of the antibody

Answer 15

Class

types: α ,γ,δ,ε,μ

Question 16

Each heavy-chain constant region is referred to as an ————–

Answer 16

Isotype
*the isotype of the heavy chains of a given antibody molecule determines its class

Question 17

which Immunoglobulin marker is used in DNA paternity testing?

Answer 17

Allotypes

Question 18

———– : cellular immune response in which the local accumulation of mononuclear pahgocytes is a key component

Answer 18

Granuloma

Note:
- Granulomas can present as caseating/ non-caseating depending on the degree of cellular activity and chronicity of the response

Question 19

What cause Caseating/ non-caseating Granulomas + Give examples

Answer 19

Caseating –> Infections (e.g., Tbc)
Non-Caseating –> Inflammatory disease (e.g., Wegner’s granulomatosis, sarcoidosis, Rheumatoid arthritis, Crohn’s disease)

Question 20

compontents of Granulomas

Answer 20

Epitheloid, macrophages, giant cells

Giant cells: multinucleated cells resulting from the fusion of mf

Question 21

Cytokines associated with granuloma formation and granuloma maintenance

Answer 21

TNF and IL-12 (proinflammatory cytokines produced by activated macrophages -> aid granuloma formation)
* IL-12 acts on T-helper cells activating them further to produce –> IFN-γ (maintains granuloma)

Question 22

Deficiency in IL-12 Receptor and IFN-γ
Receptor result in enhanced susceptibility to
intracellular pathogens such as ?

Answer 22

Mycobacterium tuberculosis (Tbc)

Question 23

Clonal selection and clonal expansion take place in ———————– upon binding to antigen

Answer 23

peripheral lymphoid organs

Question 24

fxn of IFN-α , IFN-β

Answer 24

1) Induce resistance to viral replication in all cells
2) Increase MHC I (CD8+ Tcells) expression and antigen presentation in all cells –> lysis
3) Activate DCs and macrophages (produce TNF, IL-12)
4) Activate NK cells (CD16)

Question 25

During the Immune defense against viral infections —-,—– and ——— appear first followed by a wave of NK
cells, which together control viral replication but cannot eliminate the virus

Answer 25

IFNs (IFN-γ) , TNF and IL-12

*Proinflammatory cytokines

Question 26

Virus elimination is accomplished by virus specific ——- and neutralizing antibodies

Answer 26

CD8+ T cells (MHC class I)

Question 27

ΜΗC class Ι presents [intracellular/extracelluar] antigen peptides to CD8+ T cells

Answer 27

intracelluar

Question 28

Selective IgA deficiency:
- Absent or very low IgA levels,
- normal levels of IgM and IgG

individuals present are normally asymptomatic but recurrent bacterial and viral infections of the respiratory and GI tract and genitourinary tract can occur in some patients

Causative agent ??

Answer 28

Giardia lamblia

Question 29

fx of Fab vs Fc regoin of antibodies

Answer 29

Fab–> Mediates antigen recognition
Fc region of the antigen-antibody–> binds to C1q or Fc receptors -mediate effector fxns

Question 30

the 2 functions of Antibodies

Answer 30

1) specific Antigen recognition and binding (V region, Fab, B cell receptors)
2) Activation of effector mechanisms for antigen-pathogen eradications (C region ,Fc)