midterm revision - part 2 , Adaptive Immunity Flashcards
Immunoglobulin = antibody consists of ?
- 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
Which antibody class are held together by J chains?
1) IgM (Pentamer)
2) IgA (dimer)
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)
IgE
What is the Physiological role of IgE?
Protection against parasitic heminths (worms) and protozoa
Explain how Adaptive immunity through IgE works
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
———- produced by epi cells in skin/respiraotry / gut and urogenital tract, provide strong defence barriers against pathogens from entering the body
AMPs - antimicrobial peptides (innate immunity component)
What are the main types of AMPs
α- and β-defensis, cathelicidins, histatins
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
??
IgA
Fxn of IgD heavy chain
Naive B cell antigen receptor
(Unknown fxn)
Fxn of IgM heavy chain
1) Complemt activation (classical pathway)
2) Neutralization
3) Naive B cell antigen receptor
Fxn of IgG Heavy chain
1) Complement activation (classical pathway)
2) Opsonization
3) Neutralization
4) ADCC (Antibody-dependent cell-mediated cytotoxicity)
5) Placental transport
Fxn of IgA Heavy chain
Neutralization
*dimer
Fxn of IgE Heavy chain
Mast cell degranulation
which antibody class determines the presence of infection in a neonate/ fetus ?
IgM (as it does not corss materal placenta)
The type of heavy chain determines the ——– of the antibody
Class
types: α ,γ,δ,ε,μ
Each heavy-chain constant region is referred to as an ————–
Isotype
*the isotype of the heavy chains of a given antibody molecule determines its class
which Immunoglobulin marker is used in DNA paternity testing?
Allotypes
———– : cellular immune response in which the local accumulation of mononuclear pahgocytes is a key component
Granuloma
Note:
- Granulomas can present as caseating/ non-caseating depending on the degree of cellular activity and chronicity of the response
What cause Caseating/ non-caseating Granulomas + Give examples
Caseating –> Infections (e.g., Tbc)
Non-Caseating –> Inflammatory disease (e.g., Wegner’s granulomatosis, sarcoidosis, Rheumatoid arthritis, Crohn’s disease)
compontents of Granulomas
Epitheloid, macrophages, giant cells
Giant cells: multinucleated cells resulting from the fusion of mf
Cytokines associated with granuloma formation and granuloma maintenance
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)
Deficiency in IL-12 Receptor and IFN-γ
Receptor result in enhanced susceptibility to
intracellular pathogens such as ?
Mycobacterium tuberculosis (Tbc)
Clonal selection and clonal expansion take place in ———————– upon binding to antigen
peripheral lymphoid organs
fxn of IFN-α , IFN-β
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)
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
IFNs (IFN-γ) , TNF and IL-12
*Proinflammatory cytokines
Virus elimination is accomplished by virus specific ——- and neutralizing antibodies
CD8+ T cells (MHC class I)
ΜΗC class Ι presents [intracellular/extracelluar] antigen peptides to CD8+ T cells
intracelluar
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 ??
Giardia lamblia
fx of Fab vs Fc regoin of antibodies
Fab–> Mediates antigen recognition
Fc region of the antigen-antibody–> binds to C1q or Fc receptors -mediate effector fxns
the 2 functions of Antibodies
1) specific Antigen recognition and binding (V region, Fab, B cell receptors)
2) Activation of effector mechanisms for antigen-pathogen eradications (C region ,Fc)
