Therapeutics and Immunology: Lecture 1: Principles of immunology Flashcards
What are the four disease categories
Transplantation
Autoimmunity
Activating the immune system
Controlling hypersensitivity reactions
What are two main immunology core concepts
Innate immune system
Adaptive immune system
What is the innate immune system and give examples of it
Body’s first line defence against pathogens
Specific innate microbial detection
Tissue and cellular injury- inflammation
Examples: Barrier: skin and acid Sequestration of nutrients Lysozyme- anti microbial Dendritic cells, macrophages and neutrophils
What is acute inflammation
Innate response to cellular and tissue injury
Involves: PAIN, HEAT, REDNESS ANDS SWELLING
What does PAMP stand for
Pathogen associated molecular patterns
Describe what is the innate microbial recognition
Body can recognise pathogens such as bacterial cell wall component (gram negative, e.coli)
Familiar with any lethal contaminant in parenteral formulation
What is the adaptive immune system and give examples of it
The immune systems memory capabilities of changing frequently and responding to antigens
Examples:
Lymphocyte responses
Expansion of specific T and B cells
Production of antibodies
What is the Innate system recognition, specificity, when is it learnt and how
Recognition: Microbes, injury
Specificity: any time, always the same
When: evolutionary and time
How: many mechanisms
What is the adaptive system recognition, specificity, when is it learnt and how
Recognition: Anything antigen with priming
Specificity: Memory of encounter
When: LIFE time
How: Antigen recognition
What can the adaptive immune system learn to recognise
Any molecule but mainly:
Antibody and proteins (peptides) using T cell receptors
How are structural regions recognised by antibodies, describe how
- Variable regions bind to antigen via mixture of hydrophobic/hydrophillic, electrostatic, hydrogen bonding and van der waal interactions
- Binding has high affinity and is stable
- Examples: infectious agents to small organic molecules
How are peptide antigens recognised by T cell receptor
An epitope (part of antigen) is recognised by T cell receptors but are often buried
Antigen must be first broken down into peptide fragments
Episode peptide binds to a self molecule known as a MHC (major histamine complex) molecule
T cell receptor binds to a complex of MHC molecule with the epitope peptide and proliferates to target this antigen
What do T and B cells do
T- respond to peptides
B- produce antibodies
How do lymphocytes recognise and bind to antigens
Using antibody molecule on surface of cell
What are the three life stages of lymphocytes
- Generation and selection
- Priming, replication and clonal expansion
- Effector Function
Describe the generation of lymphocyte life stage process
Lymphocytes and other blood cells are derived from bone marrow cells but are totally unique
Genome is randomly rearranged to give them each a single antigen receptor
The lymphocytes are then selected for safe and effective function “tolerance”
Describe how the lymphocyte learns what to respond to in the life stage process
Recognises one particular peptide in new viruses through the innate signals that activate dendritic cells
These dendritic cells present viral peptides on major histamine complex
Single T cell can replicate 20 or more rounds over 2-3 weeks
Describe how the effector cells function in the life stage process
Large number of T effector cells produced after dendritic cells
These are helper and killer T cells
B cells are selected and a large number of them secrete antibodies
What are the two mechanism of action of effector cells (antibody and T lymphocytes)
Antibody:
Binding and blocking
Histamine
Phagocytosis
T cell types:
Killers: direct killing of virally infected cells
Helpers: Cytokine release and inflammation, control B cell antibody responses
What are the types of antibodies and their roles
IgG and IgA: can bind to toxins and inactivate them or directly block the viral infection
IgG and IgM: activates complement which can punch holes in bacterial cell walls
IgE: release of histamine
What are the types of lymphocytes and their roles
CD8- direct killing of virally infected cells
CD4 helpers: trigger inflammation
Explain the steps for the central role of a T helper cell
- Antigen is bond by B cell antibody
- B cell presents peptide derived from antigen
- Peptide recognition by CD4 helper on B lymphocytes triggers activation signal to B cells
- High levels of antibody against same antigen that peptide was derived from is produced
What is the main response a dendritic cell can do
Show antigen peptides at specific concentration that can release and set off the immune system
