Body's Response to Infection Flashcards
(33 cards)
Lymphocytes
WBCs that cause adaptive immunity
Primary lymphoid organs
Organs where lymphocytes develop from stem cell precursors
Bone Marrow
Thymus
Thymus
Site of T lymphocyte development after their precursor is formed
It is a primary lymphoid organ
Secondary Lymphoid Tissues and 3 Examples
Where mature lymphocyte cells accumulate
Lymph Nodes
Spleen
Mucosal Tissues
Peripheral Tissue
Non lymphatic tissues of the body where lymphocytes can pass into, which then leave in tissue fluid through afferent lymphatics
What happens after lymphocytes spend a couple days in lymph nodes
They go to the thoracic duct through the efferent lymphatic where they recirculate around the body to search for pathogens
(this is not 100% accurate)
Two Types of T Cells
CD8+ Tc (Cytotoxic) Lymphocytes
[Killing other cells of the body - infected]
CD4+ Th (Helper) Lymphocytes
[Helping to activate other immune cells]
Which cells are granulocytes/polymorphonuclear (have nuclei with arm like thingies)
Neutrophils
Eosinophils
Basophils
Mast Cells
Mononuclear Cells
Cells with simple nuclear shapes
Monocytes/Macrophages
Dendritic Cells
Natural Killer Cells
Lymphocytes
Monocytes
Circulating cells that can migrate into tissues and differentiate into macrophages
Dendritic Cells
Carry out arm like or dendritic processes
Natural Killer Cells
Responsible for killing early tumour cells as well as infected cells
Neutrophils
Type of phagocyte that rush to the site of infection and digest the pathogen - most common type of WBC
Lymphoid vs Myeloid Cells
(RBCs also myeloid)
Think of the progenitors in haematopoeisis
3 Secreted mediators of immunity that are not proteins
Prostaglandins, Leukotriens and Histamines
Two Main Conceptual Parts of Immunity
Recognition and Defence
Which cells are innate and which are part of adaptive immunity
Innate Immunity
In-born Immunity
Unspecialised
The same at each exposure to the same microbe
Good with weaker infections; not as good with stronger
How do innate immune cells recognise pathogens as not foreign
Ability to detect Pathogen-Associated Molecular Patterns (PAMPs); e.g. Bacterial lipopolysaccharide or viral double stranded RNA
PAMPs bind to molecules on the surface (sometimes cytoplasm) of innate cells called Pattern Recognition Receptors (PRRs); e.g. toll-like receptors
Adaptive/Acquired Immunity
Slowly Activated
Developed along with age
Improves on repeated exposure to same microbe
Can be highly efficient against even virulent pathogens
Specific response
How do lymphocytes detect pathogens
Antigens detected by antigen specific receptors expressed on lymphocytes
Stages of primary immune response - example of skin infection
- Epithelial Barrier cut
- Bacteria enter dermis and begin to replicate
- Come into contact with innate immune system and complement proteins; damage to bacteria but also produces inflammatory mediators
- Inflamatory Mediators produced by mast cells which activate walls of nearby blood vessels making them leaky to allow leukocytes and fluid with complement proteins to leave blood stream and enter infected tissue
- Simultaneously, adaptive immune response is being kicked off; antigens are carried from infected site to draining lymph node through afferent lymphatics either freely or by dendrites (Takes a few days)
- Specialised AND activated lymphocytes can leave lymph nodes and go to site of infection through bloodstream
- Some lymphocytes don’t involve themselves with treating infection, instead become memory T and B cells associated with memory of those same antigens which can be reactivated much more quickly and intensely to manage future infection
Different categories of infections and what immune components deal with them
How does intra-cellular vesicular infection occur
Phagocytosed pathogens that are too resistant to being digested - e.g. TB Bacteria
