CHAPTER 15: RECEPTORS and ANTIGENS

Question 1

B cell Receptor: Immunoglobulin

Answer 1

• B cells direct immunoglobulin synthesis

Question 2

Immunoglobulin

Answer 2

• large glycoprotein serve as specific receptors of B cells
• 2 heavy chains (Y), 2 light chains (L shape)
• Heavy have the variable antigen binding sites (part that is diff between each clone)
• 2 binding sites

Question 3

Receptor Development

Answer 3

• immunoglobulin genes on 3 different chr
• undiff lymphocytes 150 diff genes for L variable region
• 250 diff genes for H variable region

Question 4

VDJ Recomb

Answer 4

during development of the receptor, recomb causes selected V and D genes to be active, but once synthesized, the immunoglobulin is transported to cell membrane and inserted to act as a receptor

Question 5

T cell Receptors

Answer 5

• formed by recomb, variable and constant regions
• mimics ONE arm of an immunoglobulin (half of a BCR)
• ONE antigen binding site instead of 2
• DOES NOT get secreted

Question 6

B cell maturation

Answer 6

• bone marrow sites nurture lymphocyte stem cells and provide hormonal signals
• distinct B cells go to lymph nodes, spleen, and GALT

Question 7

T cell Maturation
- where do they mature
- where do they go after maturation
- classes?

Answer 7

• maturation in thymus and its hormones
• additional classes of T cells (CD8)
• mature T cells migrate to lymphoid organs

Question 8

CD8 vs CD4 T cells

Answer 8

CD8+= Killer T cells
CD4+= Helper T cells

Question 9

Antigen and Antigenicity

Answer 9

antigen: capable of binding to B or T cell
antigenicity: property of behaving as an antigen (foreignness, size, shape, accessibility)

Question 10

Immunogen

Answer 10

an antigen that induces an immune response
- WHOLE cells and viruses make good immunogens

Question 11

• what kinds of cells/viruses make good immunogens? poor immunogens?

Answer 11

good: WHOLE cells and viruses
poor: repetitive molecules or small simple molecules

Question 12

Antigen Characteristics

Answer 12

• perceived as foreign, not normally part of body
• large complex molecules over 10,000 MW are most antigenic

Question 13

Epitope

Answer 13

• antigenic determinant
• small molecular group recognized by lymphocytes

Question 14

Haptens

Answer 14

• small foreign molecules that consist ONLY of determinant group
• NOT antigenic unless attached to larger carrier

” size matters “

• hapten plus a carrier group = antibody formed in response

Question 15

Carrier group in haptens

Answer 15

• contributes to size of complex and enhances orientation of antigen

Question 16

Specialized Antigens: Alloantigens

Answer 16

• cell surface markers and molecules that occur in some members of same species but not in others
• responsible for blood transfusion/organ grafting NOT being compatible

Question 17

Superantigens (specialized)

Answer 17

• potent T cells stimulators that provoke an OVERWHELMING response
• rheumatic fever, scarlet fever, toxic shock

Question 18

Allergen

Answer 18

• antigen that evokes allergic reactions

Question 19

Autoantigens

Answer 19

• molecules on self-tissues for which tolerance is inadequate

” murder university did not work, B and T cannot differentiate between self and non self so we end up killing self molecules”
- can cause autoimmune diseases