Introduction to Immunology Flashcards
Which branches of immunity do not require previous exposure to a pathogen?
physical barriers and innate immunity
Innate immunity is mainly moderated by what process?
phagocytosis
The major players of the innate immunity system are derived from what progenitor?
myeloid precursor (dendritic cells, macrophages, neutrophils and mast cells)
What do the innate immunity cells need to recognize in order to work?
they have to recognize a pathogen associated molecular pattern (PAMP) which are found on foreign invaders but not host cells
What are the two ways complement can be activated
- alternative pathway: microorganisms can spontaneously activate the complement system
- classical pathway: antibodies or mannose-binding-lectin bound on the pathogen surface
What does the complement system do?
- opsonizes microbes for phagocytosis
- chemotaxis of phagocytes
- increase blood flow nad permeability so phagocytes can get there
- damage the plasma membranes on gram negative and enveloped bacteria, enveloped viruses, etc
- signals release of inflammatory mediators from mast cells
What are the general functions of interferons?
they are cytokines that limit the spread of certain viral infections
What releases type 1 interferons? What releases type 2 interferons?
type 1 - the alphas and betas - are produced by the actual infected cells
type 2 - the gammas - are produced by activated T-helper cells
What is TLR3 an example of?
A pattern recognition receptor
What PAMP is recognized by TLR3?
dsRNA - present in long strands only in pathogens
Describe the signalling pathway of TLR3 after it binds dsRNA.
- Activated TLR3 activates TRIF and TAC
- TAC activates TBK1 and IKK, which are kinases
- TBK1 will phosphorylate IRF3
- IRF3 will homodimerize and translocate to the nucleus
- TRIF will phosphorylate IKB (keppa beta) which will release NFKB
- the released NFKB will translocate to the nucleus
- the combination of IRF3 and NFKB will act as a transciprtion factor that increases expression of interferon beta
What is the link between the innate and adaptive immune responses?
Phagocytes that are antigen presenting cells in the innate response process antigens and present them to the T cells for the adaptive response
Which is stronger/faster - the first adaptive immunity response or a second adaptive immunity response?
the second (and other subsequent)
What does “tolerance” mean in terms of adaptive immunity?
it means it’s unable to make an immune response towards self-antigens
Each antibody binds to a restricted part of an antigen called what?
an epitope
How do antibodies link back to phagocytosis?
Antibodies can also bound via their Fc portion to phagocytes, which makes it easier for phagocytes to find and destroy invaders
What’s the difference between active and passive immunity?
active - you develop a natural immunity in response to exposure to a pathogen
pasttive - you acquire preformed immune cells or antibodies via transfer or cells or antibodies from an immune person - like newborns
What cytokine will trigger a pluripotent stem cell to start differentiating in the immune ssystem?
IL3
If a pluripotent stem cell receives signalling from IL3 ONLY, what lineage will it go down?
IL3 only will send it down the lymphoid progenitor pathway
What signalling molecule in addition to IL3 is necessary for a pluripotent stem cell to do down the myeloid progenitor pathway?
GM-CSF
What cells will be derived from the lymphoid progenitor cell?
B cells (memory and plasma) T cells (T helper cells, T killer cells, memory T cells) Dendritic cells (odd because it's in the innate immunity system)
What cells will be derived from the myeloid progenitor cells?
red blood cells
Granulocyte macrophage progenitor - will continue on to form eosinophils, basophils, neutrophils, and monocytes
monocyte will go on to form macrophages and dendritic cells
What is the most common type of SCID? What happens?
ADA deficiency - ADA is required to remove toxic metabolites in cells that are in the process of differentiating into T and B cells. If you don’t have it, the toxic metabolites will build up and the precursor cells will die. This means you don’t have any lymphocytes and you’re super prone to infections.
What do immune cells use to communicate?
cytokines
What are the cytokines that attract cells into inflamed tissues?
chemokines
What system do we used to identify/differentiate immune cells?
the Classification Determinant - CD system
What CD marker do ALL leukocytes have?
CD45
In addition to CD45, what do ALL T cells have?
CD3
What CD do Helper T cells have? Killer T cells?
helper - CD4
killer - CD8
Which leukocyte is most prevalent in the blood?
neutrophil (60-70% in adults)
Describe some characteristics of the human blood monocyte?
- it’s veyr large
- nucleus is horseshoe shaped
- contains primary axurophilic granules
- possess ruffled membranes, a well-developed golgi complex and many intracytoplasmic lysosomes
