Basic concepts

Question 0

Timeline of immune response

Answer 0

Response changes drastically over time!!
- over course of infection
- over lifetime
Recognition -> decision making -> effector

Waves of response, amplification

Question 1

Overview of defense systems

Answer 1

Physical barriers
Innate immunity (broadly reactive, non-specific)
Adaptive immunity

Question 2

Antigen

Answer 2

Anything that reacts with antibody

Should be foreign or non-self protein, pathogenic vs normal microbiome

Question 3

Immunogen

Answer 3

Anything that produces immune response

not necessarily “antigen”

Question 4

Immunologic memory

Answer 4

Specific response to previously encountered antigen

Produces secondary response that is more rapid and effective

Question 5

Interleukin

Answer 5

Type of cytokine

Communication between leukocytes

Question 6

Interferon

Answer 6

Type of cytokine

Fights viruses

Question 7

Chemokine

Answer 7

Type of cytokine
For chemotaxis (ie neutrophil extravasion)

Question 8

Passive vs active immunity

Answer 8

Passive is via transfer of antibodies or cells (ie breastmilk)
Active is response from patient’s cells

Question 9

Types of immune receptors

Answer 9

Innate:
- PRR - pattern recognition - non-specific for bacteria, virus
- self - NK and cytokines
- FcR - bind to antibodies and direct innate cell function (NK, PMN, macrophage, eosinophil, mast)
Specific:
- Ig on B cells (specific for antigen)
- TCR (specific for MHC + peptide)

Question 10

General receptor function

Answer 10

External light chain yields specificity
Internal structure + function are constant

Most fx through aggregation and crosslinking

Can either be constant expression or induced

Question 11

Innate immune system

Answer 11

Nonspecific -> rapid (hours), same with reinfection
Detection and activation of specific responses

Includes:

• acute phase proteins
• complement
• macrophages
• neutrophils/PMNs
• NK cells

Question 12

Phases of immune response

Answer 12

Antigen recognition -> presentation ->
Lymphocyte activation (clonal expansion, differentiation)
Effector phase (humoral and cellular)
Contraction via homeostasis -> memory cells

Question 13

Antigen presentation

Answer 13

Presentation of proteins + MHC for recognition by TCR
Professional APCs:
 - macrophage/mononuclear system
  - ex dendritic cells
 - some B cells

Question 14

MHC

Answer 14

Major histocompatibility complex
MHC I - all nucleated cells, presents sample of internal proteins -> CD8 cell (recognizes if this cell is infected)
MHC II - only APCs, presents external proteins -> CD4 (recognizes presence of external invader)

Question 15

Adaptive immunity

Answer 15

Specificity of response via receptors
- Ig on B cells
- TCR
Memory from memory cells

Question 16

Immune activation signals

Answer 16

Two separate signals needed!
Signal 1 = antigen (B cell Ig) or MHC + peptide (TCR)
Signal 2 = costimulatory from cell in distress

(ex can get autoimmunity from too many costimulatory signals)

Question 17

Clonal expansion

Answer 17

Activated lymphocyte rapidly divides -> clones with same specificity of receptors
Most become effectors
10% become memory

Question 18

General antibody properties

Answer 18

Antibody = immunoglobulin = Ig
5 types: IgM, IgD, IgG, IgE, IgA
Fab - antigen binding domain - usu multiple sites for same antigen
Fc - effector portion -> differentiation (migrate, gain of fx), cytokines (recruitment), release of granules (PMN, eosinophil, mast, NK, cytotoxic), etc

Question 19

Types of T cells

Answer 19

Cytotoxic = CTL = CD8
Helper = Th - direct immune response
- ex CD4, Th1 (inflammatory), Th2 (antibodies), Th17 (autoimmune)
Regulatory = Treg - suppress immune response

Question 20

Lymphoid tissues

Answer 20

Drainage and organs designed for maximum interaction between APCs (dendritic) and circulating T-cells
Primary - marrow and thymus -> dev’t
Secondary - nodes, spleen -> interaction