Innate
What is the innate immune response cascade?
Pattern recognition receptors activated
Release inflammatory mediators
Increased vasodilation & capillary permeability
Influx of phagocytic cells and soluble mediators
Increased release of mucus and antimicrobial peptides on mucosal surfaces
Fever, pain, appetite suppression
What are the 2 basic steps of adaptive immunity
Clear infection
Memory
What are the three classes of b lymphocytes
Naive
Ab secreting effector cell
Memory cells
What are antigen presenting cells (APC's)
Macrophages, dendritic cells
B-cells (special types)
MHC class ii bearing cells capable of phagocytosis or endocytosis and antigen presentation
What is the primary lymphoid tissue? And where is it made and matured?
Bone marrow (made), thymus (matured)
Areas of leukocyte production and maturation
Where are pattern recognition receptors
Present on epithelial cells of skin and mucosa as well as resident macrophages/dendritic cells
What are the lymphocytes of adaptive immunity
T and B cells
what are the antibody isotypes of B lymphocytes
IgM - transmembrane, complement activation, opsinization
IgG - Serum ig, complement activation, opsinization
IgA - mucosal secreted Ab
IgE - allergy, parasite protection
B cells
T cells
Antigen presenting cells
What is the secondary lymphoid tissue? And where is it made and matured?
Lymph nodes, spleen, peyers patches
sites of immune cell localization and activation - drainage of extracellular fluid (ECF) to lymph nodes delivers antigens and tissue-resident immune cells, activated cells leave lymph nodes enter blood and are delivered to site of infection
Naive T and B cells tend to circulate between lymph nodes via blood
Memory T and B cells tend to circulate from blood to tissues and then drain via ECF to nodes
What are the inflammatory mediators released during the innate immune response cascade
Eicosanoids (Prostaglandins, leukotrienes) - plasma membrane fatty acid metabolites
Interleukins (cytokines and chemokines), histamine - protein hormones of the immune system
Control of local and systemic inflammation cascade
What does MHC class i do?
Transmembrane protein complex on all cells
All proteins produced in a cell are partially degraded and presented on the cell surface in association with MHC class i
Viral, tumor surveillance
Where a T lymphocytes produced and what do they do?
Produced in marrow, mature in thymus
Recognize antigen presented on MHC via a T cell receptor (TCR)
Generation of TCR binding diversity - Random gene rearrangement of TCR, 1 T cell = 1 Specificity
What are the steps of activation of Antibody or humoral immunity (B cells)
APC processing of antigen on MHC class ii
Activation of Th
Th activation of B cells
Clonal expansion of B cells
Production plasma cells, memory cells
What are the specific immunity at mucosal sites?
Intestine, lung, reproductive tract, mammary
Intestinal peyer's patches - Area of dense immune cell localization similar to lymph node, overlaid by M cells which sample antigens from gut lumen, induction of IgA type responses, tolerance versus immunity
Common mucosal immune system - implications for vaccines
What are the phagocytic cells and soluble mediators in the innate immunity cascade response
macrophages, neutrophils
acute phase proteins, complement, anti-microbial peptides
Complement and some bacterial proteins are chemotactic
What does MHC class ii do?
Transmembrane protein complex found only on specialized antigen presenting cells
Proteins entering the cell via phagocytosis or endocytosis are degraded and presented on MHC class II
Viral particles, bacteria
What are the three classes of T lymphocytes
Naive
Effector (activated) T cells
Memory
What are the signals for naive lymphocyte (T or B cell) activation
Signal 1 - antigen presentation
Signal 2 - costimulatory molecules
Signal 3 - "Danger" microbial molecule
What is the T cell function in differentiation of Self/non-self
In the thymus new T cells reacting with MHC class i or ii in association with a self antigen are induced to die
Requires all self antigens are expressed in thymus and processed for class i and ii presentation
Failure of process results in autoimmune disease - SLE, Graves, MS
What are the basic aspects of Adaptive or acquired immunity
Acts days/weeks following infection
Specific to a pathogen - antibodies, cytotoxic T cells
Provide memory
Where a B lymphocytes produced and what do they do?
Produced and mature in bone marrow
Recognize extracellular antigens via transmembrane antibodies
Generation of Ab binding diversity - Random gene rearrangement Ab variable region, Estimated 1010 possible specificities, 1 B cell = 1 Specificity
What are the two subpopulations of T lymphocytes? What do they do?
T helper cells (Th) - recognize MHC class ii
- Secrete cytokines, activate B cells, Tc cells and macrophages, neutrophils
- Essential for activation for specific immunity
Cytotoxic T cells (Tc) - Recognize MHC class i
- Direct killing of virally infected cells or tumour cells
How does the activation of cellular immunity happen
Three cell cluster
APC plus TH and Tc via MHC class ii and MHC class i respectively
Clonal expansion of Th and Tc cells
Production of effector Tc cells
What is the B cell function in differentiation of Self/non-self
Naive B cells reacting with self antigens are therefore present in the circulation but die due to lack of appropriate T helper cells