Immunology Lecture 2. Flashcards Preview

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Flashcards in Immunology Lecture 2. Deck (21):
1

What is antibody?

activity/clumping against antigen

2

Which immunoglobulin is most common in the blood?

IgG

3

Which immunoglobulin is first one made in an immune response?

IgM

4

Which is the largest immunoglobulin by mass?

IgM

5

Which immunoglobulin has the longest half life?

IgG (most stable)

6

Which immunoglobulin has the shortest half-life/lowest serum level and why?

IgE - sticks to cells very quickly - does not need bound antigen to bind to cells

7

Which immunoglobulin activates the complement system?

IgM (most potent)

8

Which immunoglobulin can transport across the placenta?

IgG (baby has mother’s profile of IgGs)

9

Which immunoglobulin can transport across epithelium?

IgA (as a dimer) - in secretions

10

How do IgG and IgE differ?

IgG needs bound antigen to bind to cells, IgE does not (very sticky)

11

What are the main functions of IgG?

toxin neutralizing (tetanus!), agglutinating, opsonizing, bacteriolytic

12

Why does IgM require complement for opsonization?

immune cells do not have IgM

13

What is the secretory piece of IgA?

T-piece - resists acid hydrolysis

14

What form is IgM predominately found?

pentamer - held together by J chain and disulfide bonds

15

What form is IgA predominately found?

dimer - has j chain between - highly glycosylated

16

What is the function of IgD?

co-expressed with IgM on surface of B-lymphocytes, associated with some tumor cells

17

What is the function of IgE?

Immediate hypersensitivity (allergies) - fixes to mast cells BEFORE antigen is bound - cross linking causes release of histamine from mast cell - used to be used to clear parasites

18

What is the structure of IgE

similar to IgM

19

What did we find by proteolytically degrading immunoglobulins?

constant region is crystallizable and binds to Fc receptor, variable region can’t crystalize, binds only antigen

20

What are hypervariable regions?

provide the sequence of the very specific antigen binding site

21

How many hypervariable regions per antibody?

three - spread out linearly, but close together in space