Humoral Effector

Question 1

What is antigenic shift?

Answer 1

Antigenic shift is a type of immune evasion, it is done by mutation of epitopes so that antibodies can no longer bind, antibodies are very specific so small mutations can have large impacts on their ability to bind

Question 2

What is a hapten?

Answer 2

A hapten is a small antigen bound to a larger molecule, example is for drugs which are normally small molecules, they will bind them with albumin, altering this protein and how the drug is large enough to be recognized.

-Higher molecular weight substances are more immunogenic (>10kDa)

Question 3

Where are plasma cells concentrated in the body?

Answer 3

In the Bone marrow, and in the medualla of the Lymph Nodes.

-antibodies are transported by the blood

Question 4

What do antibodies do? list of 7

Answer 4

1. neutralize microbes and toxins (IgM, IgG, IgA)
2. Opsonophagocytosis (IgM, IgG)
3. Anti-body dependent cellular toxicitgy (IgG)
4. Eosinophil/mast-cell mediated responses (IgE)
5. Complement (IgM, IgG)
6. Protect mucosal surfaces (IgM, IgA)
7. protect neonates (IgG)

Question 5

What antibodies neutralize microbes/toxins?

Answer 5

IgM, IgG, IgA

• they bind viruses and prevent attachment to cells
• bind toxins and prevent toxin from binding to receptor on cells

Question 6

What antibodies are used for opsonophagocytosis?

Answer 6

IgM, and IgG

• they coat the microbe with antibody or complement
• IgG-Ag complexes or complement bind macrophages and neutorphils via Fc-gamma-receptor or complement receptors
• induces phagocytosis and ROS, NO, and proteolytic enzymes
• This is the major mechanism for encapsulated bacters (spleen is the major site for phagocytes)

Question 7

What antibodies are used in ADCC (antibody-dependent cellular cytotoxicity)?

Answer 7

IgG

• IgG-Ag complexes bind Fc-gamma-R on NK cells, and then NK cells release perforin and granzyme B
• overstimulation of Fc-gamma-receptor can overwhelm the inhibitory signaling of MHC with NK cells

Question 8

What antibodies are used with eosinophils and mast cells? What recruits eosinophils?

Answer 8

IgE, it binds with high affinity to Fc-epsilon-receptor and causes the eosinophils and mast cells to degranulate.

IL-5 recruits and activates eosinophils, effective for helminths, contribute to asthma

Question 9

What antibodies are used in mucosal immunity?

Answer 9

IgA and IgM

-IgA production is induced by TGF-beta produced in mucosal-associated lymphoid tissue (MALT)

Question 10

What cell transports antigens across the epithelium? What is peyer’s patch?

Answer 10

• this is all within the mesenteric lymph node
• The M cell transports antigens across the epithelium
• Peyer’s patch is essenstially a small lymph node

Question 11

Parenteral vs. Oral Vaccine for Polio?

Answer 11

Pareenteral is intramuscular and induces IgG which neutrolizes the virus in the blood and permits a carrier state

The oral vaccine induces secretaroy IgA and neutralizes virus in the GI tract, it will also block viral entry and replication in the gut and does not permit a carrier state

Question 12

What antibodies are involved in Fetal and neonatal immunity?

Answer 12

FcRn binds with free IgG and transports IgG across the placent.

-side note: normally Fc receptors bind ag-ab complexes, but in this case it only need to bind IgG, another example of this is Fc-epsilon receptor binding IgE (like with eosinophils)

Question 13

When should you test a newborn for antibodies?

Answer 13

6 months after because before that they will still have IgG from their mother

Transient Hypogammaglobulinemia of incancy is normal