7 - Generation of Humoral Effector Mechanism

Question 1

What are the mitogens use for?

Answer 1

Assess lymphocytes function

Question 2

Features of the thymus-independent antigens

Answer 2

Direct stimulates BL (no peptides antigens)
Only induce IgM secretion
No memory produce

Question 3

Principal feature of thymus-dependent antigens

Answer 3

Response for them need BL and TH cell conjugates
Peptides presented through MHC II to TH by BL
Class switching, memory and plasma cell (ab secretion)

Question 4

What is the agglutination? What type of immunoglobulin cleaving do you use to agglutinate?

Answer 4

• Bridging a particulate Ag (RBC, latex beads) by divalent F(ab’)2 or by IgG ▶️ precipitation of soluble Ag
• pepsin cleavage

Question 5

Advantages and disadvantages of pentameric IgM?

Answer 5

• trap early antigens
• most effective in activating complement
• it’s not an opsonin
• not mediate ADCC

*highest avidity

Question 6

Clinical use of IgM

Answer 6

Measure of primary response (acute infection)

Question 7

What is the function of secretory component of the IgA dimer at mucosal surfaces?

Answer 7

Protect IgA of the aggressive environment (enzyme degradation)

Question 8

Cause of X-linked hyper-IgM syndrome. Symptoms or presentation.

Answer 8

Defect CD40L
Children ⬆️ risk of infection - recurrent respiratory tract infections (pneumocystis jirovecii)

*absence of adequate activation of BL to do switch class ▶️ ⬆️⬆️ IgM

Question 9

Cytokines that stimulate switch to IgE. Functions of it.

Answer 9

IL-4, IL-13
Bind to FcE receptor (basophils, mast cells)
Protection against parasites (helmintic)
Mediates type I hypersensibility allergic reaction

Question 10

Functions and cytokines that stimulate switch of IgA.

Answer 10

IL-5, TGFB

Blocks binding of toxins or adhesive microbial components to the surface respiratory, digestive and urinary tract mucosa

Question 11

Type of infections with most risk and frequency in patients with B-cell deficiencies. Why?

Answer 11

Recurrent pyogenic infections

Absence Ig for opsonization, complement (+), ADCC of extracellular pathogens

Question 12

Activation of alternative pathway of complement

Answer 12

Interaction with microbial surfaces

*LPS of cell envelope of gram (-) bacteria, bacterial polysaccharides. Ex; endotoxins.

Question 13

Activation of classical complement pathway.

Answer 13

Antigen-antibody complexes

*IgM most efficient to activate complement

Question 14

Most important chemotactic factor of the complement

Answer 14

C5a

Question 15

Anaphylatoxins of the complement. How does it work?

Answer 15

C3a, C4a, C5a

Degranulation of mast cells and basophils ▶️ ⬆️ histamine

Question 16

Functions of C3b

Answer 16

Opsonization

Clearance of immune complexes

Question 17

What age do the IgA and IgE begin to be produced?

Answer 17

From one to two years after birth ▶️ IgA

Until second year after birth ▶️ IgE

Question 18

Which classes of Ig are affected if J chain is absence?

Answer 18

IgA, IgM

*they need J chain to make dimer and pentamer respectively and accomplish their functions

Question 19

Major Ig of the blood

Answer 19

IgG