Organisation Of The Immune System Flashcards
What are some other names for the innate and adaptive immune systems?
Innate: Natural or Non specific
Adaptive: acquired or specific
Name the six non-cellular innate defences
Skin
Saliva (Antibacterial enzymes)
Tears (Antibacterial enzymes)
Mucus lining
Stomach acid
Good gut bacteria
Name the 3 granular cell types (granulocytes) of the innate immune system and their function?
Neutrophil (90% of Granulocytes) - phagocytosis
Eosinophils (2-5%) - destroys parasites
Basophils (0-2%) - inflammation
what is an antigen?
A foreign substance that causes a reaction from the immune system. E.g influenza
What is a Pathogen?
A microscopic organism that causes sickness
E.G bacteria and viruses
What is Bacteria and it structure?
what is bacteria with an outer membrane called?
Single cell, no nucleus
Can cause infections, but many species are non-infectious
come in variety of shapes (e.g rod like, spheres or spirals) and sizes.
gram negative bacteria has outer membrane
What are virus? and how do they function?
Cannot express its genes without taking over a host cell
uses host to make copies of itself
Can mutate during cell division, making it harder to detect them
What are the functions of the immune system
Protect
recognise
attack
destroy
What characterises neutrophils? and what is the difference between mature and immature neurtrophils?
Many shaped nuclei
60% of leukocytes
life-span 2-3 days
3 day reserve in the bone marrow
mature neutrophil have more lobes. Immature have a ‘band shaped nucleus’
Name the 4 processes of neutrophil function?
1) Attracted to site of infection by chemotaxins released by infected cell
2) Ingest infected tissue via phagocytosis, helped by opsonins
3) Destroy by release of free radicals and cytoxic enzymes
4) Exhibit refractory period post-stimulation
What is the difference between monocytes and macrophages?
Monocytes are found in blood
macrophage in the tissues
What do Monocytes and Macrophages do?
Phagocytosis
release cytokines
present antigens
What are ‘classical’ monocytes and their main function?
CD14++/CD16- anti microbial (killing cells)
What are ‘non-classical’ monocytes and their main function?
CD14+/CD16++
highly pro-inflammatory
What Cells do dendritic cells derive from? and what is their main function?
Derived from monocytes
their main role is to present antigens to initiate the acquired immune response
What two things does ‘Complement’ do?
1) Help to amplify phagocytic response
2) Also do things directly, by forming a shape ring, binding to cell surface; piercing the cell surface causing a lesion. The cell insides leak out causing cell death.
What are natural Killer cells? and how do they kill infected cells?
Large Granular Lymphocyte
Extracellular killing cell (bind to the outside of cell)
kill cells via perforin (release pins pierce the outside of target cell) activates apoptosis (cell suicide)
Why are NK cells labelled CD3-? and what is the difference between CD56 bright and CD56 dim?
CD3- is used to distinguish them from Tcells that contain CD3+.
CD56 dim NK cells are better at cytotoxic activity because they release more perforin. CD56 bright are better at proliferation
How is the correct acquired immunity response triggered?
Antigen presentation called the major histocompatibility complex
Name the overall Tcell CD badge?
CD3+
Name the Helper Tcell CD badge?
CD4+
Name the cytotoxic Tcell CD badge?
CD8+
What do Thelper cells do?
Bind to MHC class II, then control and modulate the immune response. Activate cytotoxic tcells. They also form memory of antigens.
How are cytotoxic Tcells activated? and what do they do?
Activated by Thelper cells or bind to MHC class I.
Function= destroy infected cells via perforin
they also form memory
What cytokines do th1 cells release? and what do these do?
They release IFN-gamma, IL-2, IL-12
Their function is defence against intracellular pathogens
What cytokines do th2 cells release? and what do these do?
IL-4, IL-5 and IL-13
Their function is defence against extracellular pathogens
Tcell activation requires 2 signals. The antigen presenting cell generates the first signal via MCH. But what must be present for the second signal?
The APC must express CD80-86 and the Tcell must bind with CD28 for the second signal
Why do you become more susceptible to viral infection with age?
Loss of CD28 on T helper cells, not allowing T cell activation
What are the CD badge for Treg cells? and what is their function
CD25
Mediate immune homeostasis. Tregs suppress activation, proliferation and cytokine production of CD4+ Tcells and CD8+ Tcells
What is the CD badge for BCells?
CD19 or 20
What is the main repsonsibility of Bcells?
Production of antigen-specific immunogloblins or antibodies
