Lymphocytes

Question 1

HLA subtypes associated with disease

A3

Answer 1

Hemochromatosis

(iron overload)

Question 2

HLA subtypes associated with disease

B27

(PAIR)

Answer 2

Seronegative arthopathies

• Psoriatic arhtritis
• Ankylosing Spondylitis
• Arthritis of Inflammatory bowel disease
• Reactive arthritis (formerly Reiter syndrome)

Question 3

HLA subtypes associated with disease

DQ2/DQ8

Answer 3

Celiac disease

Question 4

HLA subtypes associated with disease

DR2

(4 things)

Answer 4

• Multiple Sclerosis
• Hay fever
• SLE
• Goodpasture syndrome

Question 5

HLA subtypes associated with disease

DR3

(3 things DSG)

Answer 5

• Diabetes mellitus type 1
• SLE
• Graves disease

Question 6

HLA subtypes associated with disease

DR4

(2 things)

Answer 6

there are 4 walls in a rheum (room)

• Rhumatoid arthritis
• diabetes mellitus type 1

Question 7

HLA subtypes associated with disease

DR5

Answer 7

• Prenicious anemia (vit B₁₂ def)
• Hashimoto thyroiditis

Question 8

What stimulates the helper T cell in becoming

• Th₁ cell
• Th₂ cell
• Th₁₇ cell
• T_reg cell

Answer 8

• Th₁ cell: IL-12
• Th₂ cell: IL-4
• Th₁₇cell: IL-6 + TGF-Beta
• T_reg cell: TGF-Beta

Question 9

T-cell: Positive selection

• where does it occur
• What happens

Answer 9

• where does it occur
  
  • Thymic cortex
• What happens
  
  • T cells expressing TCRs capable of binding surface self MHC molecules survive.
  • Not so high affinity for self

Question 10

T-cell: Negative selection

• where does it occur
• What happens

Answer 10

• Where does it occur
  
  • Medulla
• What happens
  
  • T cells expressing TCRS with high affinity for self antigens undergo apotosis

Question 11

Immunoglobulin isotypes

• What is found on their surfaces
• where do they differentiate

Answer 11

• What is found on their surfaces
  
  • Mature B lymphoctyes express IgM and IgD on their surface
• Where do they differentiate
  
  • Differentiate in germinal centers of lymph nodes by isotype switching (gene rearrangement; mediated by cytokines and CD40 ligand) into plasma cells that secrete IgA, IgE, or IgG.

Question 12

Immunoglobulin Isotypes

IgG

• main antibody in what
• amount in serum (most or least abundant)
• what does it do to complement
• does it cross the placenta
• action to bacteria
• action to bacterial toxins and viruses

Answer 12

IgG

• main antibody in what: 2o delayed response to an antigen
• amount in serum (most or least abundant)
• what does it do to complement: fixes complement
• does it cross the placenta: yes
• action to bacteria: opsonization of bacteria
• action to bacterial toxins and viruses: neutralizes toxins

Question 13

Immunoglobulin Isotypes

IgA

• prevents attachment of bacteria and viruses to what
• action to complement
• what is it in circulation & secretion
• method of which it crosses the epithelial cells
• relative to antibody production (how much is produced, is it the most or least produced)
• location
• where does it pick up its secretory component from

Answer 13

• prevents attachment of bacteria and viruses to what: mucous membranes
• action to complement: does not fix complement
• what is it in circulation (monomer) & secretion (dimer):
• method of which it crosses the epithelial cells: transcytosis
• relative to antibody production (how much is produced, is it the most or least produced)
• location: released in secretions (tears, saliva, mucus) and early breast milk (colostrum)
• where does it pick up its secretory component from: picks up secretory component from epithelium cells before secretion

Question 14

Immunoglobulin Isotypes

IgM

• Produced in the (blank) repsone to an antigen
• does it fix complement and cross placenta
• Antigen receptor is found where
• What is the shape of antibody on B cell vs when secreted
• the shape of secreted antibody allows it to what

Answer 14

• Produced in the (1o immediate) repsone to an antigen
• does it fix complement and cross placenta: fixes complement but it does not cross the placenta
• Antigen receptor is found where: surface of Bcells
• What is the shape of antibody on B cell (monomer) vs when secreted (pentamer):
• The shape of secreted antibody allows it to: efficently trap free antigens out of tissue while humoral response evolves

Question 15

Immunoglobulin Isotypes

IgD

• Function
• Location

Answer 15

• Function: Unclear function
• Location: found on the surface of many B cells and in serum

Question 16

Immunoglobulin isotypes

IgE

• What cells does it bind to
• cross-links when exposed to what
• mediates immunity to what
• highest or lowest concentration in serum

Answer 16

• What cells does it bind to: mast cells and basophils
• cross-links when exposed to what: allergen, mediating immediate (type 1) hypersensitivity through release of inflammatory mediators such as histamine
• mediates immunity to what: worms activating eosinophils
• highest or lowest concentration in serum

Question 17

Thymus independent antigens

Answer 17

• Antigens lacking a peptide component
  
  • (lipopolysaccharides from gram negative bacteria)
  • cannot be presented by MHC to T cells
• Weakly or nonimmunogenic
  
  • vaccines often require boosters (e.g. pneumococcal polysaccharide vaccine)

Question 18

Thymus dependent antigens

Answer 18

• Antigens contaiing a protein component
  
  • diphtheria vaccine (dtap Tdap)
• **Class switching and immunologic memory occur as a result of direct contact of B cells with Th cells **
  
  • CD40-CD40 L (ligand interaction)