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)**