Lec 1 - intro Flashcards
List the major cells involved in the innate and adaptive immune response
Describe the main functions of the innate immune system
Describe the process of phagocytosis and intracellular killing
Describe the basic role of Eosinophils and Mast cells
Describe the role of cytokines as chemical messengers within the immune system
Briefly describe the complement system and its main functions
Describe the fundamental properties of an adaptive immune response
Define the primary and secondary lymphoid organs and their functions
Outline the structure and function of antibodies
Describe the role of B-Lymphocytes in immunity
Describe how antigen processing cells and T-lymphocytes interact
Describe the origin of T-Lymphocytes
Describe the role of Helper T-Lymphocytes and Cytotoxic T Lymphocytes in the immune response
Cells of innate immune system
Macrophages (in tissue) NK cells Dendritic cells (in tissue) Mast cells (in tissue) Neutrophils, eosinophils, basophils, monocytes (in blood)
How do innate immune cells in tissues (i.e. macrophages, mast cells, dendritic cells) recognise foreign pathogens?
What do they release once foreign pathogen is recognised
Pattern recognition receptors
Cytokines
Function of cytokines
Vasodilation
Inflammatory response,
Increased vascular permeability (more leaky
Recruit other immune cells to site of injury
Functions of innate immune system
Antigen presentation Complement activation Phagocytosis Inflammation Recruit immune cells Opsonisation NK cytotoxicity
Describe the process of phagocytosis and intracellular killing
When the phagocyte encounters the bacterium, it engulfs it and takes it into a small vesicle called a phagosome
This phagosome is then taken inside the cell where it fuses with another vesicle called a lysosome. The lysosome is full of digestive enzymes that kill the bacterium
Other function of macrophages and dendritic cells apart from phagocytosis
Antigen presenting cells to T cells via MHC class I & II
General difference between MHC class I & II
MHC class I - present on all nucleated cells and present INTRACELLULAR foreign antigens
MHC class II - found only on professional APCs (dendritic cells, macrophages, B cells) and present EXTRACELLULAR foreign antigens
MHC class I presents to which subtype of T cell
MHC class II presents to which subtype of T cell
CD8
CD4
Functions of the complement system (enzyme cascade that’s activated to help immune response)
Chemotaxis of phagocytes to sites of inflammation
Opsonisation - tagging of a microbe so it can be phagocytosed quicker
Lysis of micro-organisms
Maintenance of solubility of Ag/Ab
Dendritic cells present antigens via which MCH class (think about definition of dendritic cell)
MCH class II - since dendritic cell is a PROFESSIONAL APC
Examples of phagocytes (4)
Macrophages
Dendritic cells
Monocytes - LARGEST PHAGOCYTE
Neutrophils
Cells of the adaptive immune system
T lymphocytes
B lymphocytes
Plasma cells (differentiated B lymphocyte)
Where are both lymphocytes produced and where do they then mature
Bone marrow
T cells - mature in thymus
B cells - mature in bone marrow
After B and T cells have matured, where do they go?
Move to secondary lymphoid organs (e.g. lymph nodes) where they encounter antigens and differentiate into more specific subtypes
T helper cells produce cytokines which help to do what
Activate + recruit other immune cells
CD8 (cytotoxic) T cells kill cells by what process
Inducing apoptosis of the target cell by releasing cytokines which apoptosis
What type of T cells suppress excessive immune response
Regulatory T cells
Actions of T helper cells
Activate macrophages
Induce inflammation
Activate (proliferate + differentiate) other T and B cells
How do natural killer cells kill pathogens
NK cell releases perforin and granzyme - perforin creates a pore in the cell membrane of the pathogen and granzyme enters the cell to trigger apoptosis (PERFORIN INDUCED APOPTOSIS)
Antibodies are produced by the activation of B lymphocytes by antigens and other signals
Antibodies of different heavy chain classes (isotypes) [i.e. IgG, IgM etc) perform different effector functions
List some functions of antibodies
Neutralise microbes and toxins by binding to antigens via its Fab region
Opsonise + phagocytose microbes
Antibody dependent cytotoxicity via NK cells
Activate complement
In initial infection, which Ig is produced first
When the same antigen is encountered again, memory B cells accelerate response by doing what
IgM
Proliferating and differentiating into plasma cells –> fast high release of IgG specific to the antigen
Physical + chemical barriers of immune system
- Skin
- Mucociliary escalator
- Acidic pH in stomach
- Rapid pH change in duodenum + alkaline pH in jejunum & ileum
- Lysozymes in tears, saliva, sweat
- Normal flora in bowel, vagina and on skin
- Flushing of urinary tract
