Lecture 47: Immune Responses to Microbes

Question 1

Describe the pathways of humoral immunity for protection against extracellular bacterial pathogens:

Answer 1

-

Question 2

Pasteur showed that chickens….
Erlich demonstrated that immune serum (antibody) was….
Metchnikoff identified that some forms of immunity required….

Answer 2

• Developed immunity to cholera
• Protective
• Cells, not serum or antibody

Question 3

CD4 T Helper Cells make…

Answer 3

• B cells (plasma cells)
• Mø cells
• CTL cells

Question 4

The real signal that starts the immune response come from the…

Answer 4

• APC (antigen presenting cells)

Question 5

Antibody mediated protection: We always start by secreting Ig_ molecules. It’s very important because….However it has a very short half life. So Ig_ becomes the next dominating molecule, they last a very long time. IgA is able to look a little bit like Ig_ in it’s monomeric form.

Answer 5

• IgM = pretty good at killing
• It has 10 surfaces that can recognise antigens
• IgG = all rounder for a very long time
• IgG
• Dimeric IgA is protected from mucosal degradation

Question 6

Antibody mediated mechanisms for antigen removal:

Binding of antibodies to antigens inactivates antigens by (3) (1)… (3) = ? (1) = ?

Answer 6

• Viral Neutralization
• Agglutination of antigen bearing particles
• Precipitation of soluble antigens
• Phagocytosis
• Activation of complement system and pore formation
• Cell Lysis

Question 7

Complement mediated lysis of Gram (-) bacteria:

Answer 7

• Complement attached to bacterial cell, creates pore
• Cell swells up because GRADIENTS + H2O + Sodium
• BOOM

Question 8

IgE protects against…

Answer 8

• Parasites
• Is a highly invasoactive molecule which changes mucous secretion but can act directly against parasites, does this in 2 ways
• Mast cells + eosinophils have IgE receptors
• When we produce IgE, they combine to these, in the tissues, these cells interact with parasites, firstly the histamine causes vasodilation, massive flow of fluids into the tissues, parasite is just spat out, if it’s in the body of the tissues, eosinophil makes mbp + ecp these are cytotoxic to parasites

Question 9

Control of Tb requires adaptive (T Cell) Immunity:

Answer 9

• After initial infection, adaptive immunity takes place

Question 10

Cells involved with the Cell Mediated Immunity to Acute Intracellular (Virus) Infection:

Answer 10

• APC –> CD4 + CD8 —-> CTL —> Virus-infected cell –> Apoptosis

Question 11

In the Cytotoxic T Cell we have….

Answer 11

• Perforin and Granzymes

- Granzymes activate apoptotic enzymes

Question 12

There are __ different defence pathways.

Answer 12

• 4