Immunology Flashcards
What are the functions of complements?
Complements are proteins that:
a) Activate inflammatory pathways
b) Recruit phagocytes
c) Opsonisation of pathogens
d) Remove immune complexes
e) Lysis of certain pathogens, such as through MAC formation
What are cytokines?
Cytokines are small proteins released by cells:
a) signalling molecules which induce response by binding to receptor
b) can have effect on cell behaviour that releases cytokines
Name the atypical TB condition named MAC. What is the CD4 count when infected with this condition?
Mycobacterium Avium Complex infection. When CD4 count is less than 100
Define primary and secondary prophylaxis
Primary prophylaxis: Measures to avoid first occurence of infections
Secondary prophylaxis: Measures to maintain treatment and prevent recurrence of infection
How are macrophages and monocytes related to each other?
Blood monocytes will mature into macrophages upon entering tissues.
What are macrophages and monocytes known as collectively?
Mononuclear phagocytes
Which complement receptor is found on erythrocytes?
What is the function of this receptor?
CR1.
Binds to soluble immune complexes coated with C3b for transport to spleen.
What are the 3 types of complement receptors?
- Receptors on phagocytic cells: CR1, CR3, CR4: Recognises C3b bound on bacteria
- Receptors on erythrocytes: CR1: Binds to soluble immune complexes coated with C3b for transport to spleen
- Receptors on B cells: CR1, CR2: Recognises C3b breakdown products in association with antigens (CR2 is part of the B cell co-receptor complex)
What are the effects that can be elicited by C3a and C5a?
Can cause inflammation and phagocyte recruitment
C5 - C9 deficiency leads to?
Recurrent Meningococcal infection
MHC I is involved in infections that occur inside/outside the cell? How about MHC II?
MHC I is involved in infections that occur inside the cell.
MHC II is involved in infections outside the cell.
What is the effect of CD59 on MAC formation?
CD59 prevents the final assembly of MAC at the C8 to C9 stage.
What condition is observed from mutation of Factor H?
Age-related macular degeneration
Name the condition resulting from deficiency of C1 inhibitor
Hereditary Angioedema (No urticaria, usually asymptomatic until puberty)
What do red cells lack in Paroxysmal Nocturnal Haemaglobinuria? What is the consequence?
CD55 and CD59. Red cells become susceptible to complement lysis.
What condition results from C5 - C9 complement deficiency?
Recurrent Meningococcal infection
What condition results form C3 complement deficiency?
Recurrent pyogenic infections
Most T cell development takes place in the cortex or medulla?
Cortex
What type of T cells does thymic medulla only contains?
Mature single-positive T cells
Where were MHC Class I molecules synthesised in? What molecule do they bind to after synthesis?
ER lumen. Binds to TAP
In T cell development, which one occurs first: double negative or double positive?
Double negative first
Which region of T Cell Receptor binds to antigen?
CDR3 region of T cell receptor
What are TAP 1 and 2 involved in?
TAP1/2 are transporters associated with antigen processing. They help transport peptide antigen to ER lumen.
Where are the invasions leading to MHC I or MHC II activation?
MHC I activation: when there is something wrong inside the cell.
MHC II activation: when there is something wrong outside the cell.
Which MHC molecule is bounded by invariant chain initially?
MHC II
How many signals are there in T cell activation. Elaborate on what happens in each signal.
2 signals in T cell activation.
1st signal: TCR + CD4/CD8 with MHC + peptide Ag
2nd signal: Must be from the same cell. CD28 and CD80/86 upregulated in the presence of danger signals
