Intro to immune response Flashcards
- List some features of skin that makes it an effective barrier to infection.
Consists of tightly-packed keratinised cells
Low pH
Low oxygen tension
Sebaceous glands
- What do sebaceous glands produce that has antibacterial effects?
Hydrophobic oils – repels water and microorganisms
Lysozyme – destroys the structural integrity of the bacterial cell wall
Ammonia and defensins – anti-bacterial properties
- Describe the defensive features of mucosal surfaces.
Traps invading pathogens
Cilia promote the removal of mucus
Contains secretory IgA which binds to pathogens and prevents them from attaching to and penetrating epithelial cells
Contains lysozyme and other antimicrobial peptides
Lactoferrin starves invading bacteria of oxygen
- List the cells of the innate immune system.
Polymorphonuclear cells
Monocytes/macrophages
NK cells
Dendritic cells
- List the soluble components of the innate immune system.
Complement
Acute phase proteins
Cytokines and chemokines
- List some key features of cells of the innate immune system.
Identical responses in all individuals
Cells express genetically-encoded receptors (PRRs) that allow them to detect pathogens at the site of infection
Cells have phagocytic capacity
Cells secrete mediators (e.g. cytokines/chemokines) that regulate the immune response
- Name the resident macrophage in the following tissues/organs:
a. Liver
b. Kidney
c. Bone
d. Spleen
e. Neural tissue
f. Connective tissue
g. Skin
a. Liver Kupffer cells b. Kidney Mesangial cells c. Bone Osteoclasts d. Spleen Sinusoidal lining cells e. Neural tissue Microglia f. Connective tissue Histiocytes g. Skin Langerhans cells
- How do macrophages differ from polymorphonuclear cells?
They can process antigens and present them to T cells
- Describe how cells of the innate immune system recognise pathogens.
Pattern-recognition receptors (e.g. TLR) recognise generic motifs called PAMPs (e.g. bacterial sugars, DNA and RNA)
Fc receptors on these cells allows binding to the Fc portion of immunoglobulins thereby allowing phagocytosis of immune complexes
- Which other factors can bind to phagocytes to facilitate phagocytosis?
Complement components (e.g. by binding to CR1)
Acute phase proteins (e.g. CRP)
Antibodies
- Describe the reactions involved in oxidative killing of pathogens within phagolysosomes.
NADPH oxidase converts oxygen into reactive oxygen species (e.g. superoxide and hydrogen peroxide)
Myeloperoxidase catalyses the production of hydrochlorous acid (from hydrogen peroxide and chloride)
- Why do neutrophils die after phagocytosis? What does this form?
Phagocytosis depletes the glycogen stores of the neutrophil resulting in neutrophil death
The accumulation of dying neutrophils forms pus
- Describe the main features of dendritic cells.
Reside in peripheral tissues
Express receptors for cytokines/chemokines
Express pathogen recognition receptors
Express Fc receptors for immunoglobulin
Capable of phagocytosis
Present processed antigens to T cells in lymph nodes to prime the adaptive immune response
- What does a dendritic cell do after phagocytosis?
Upregulate expression of HLA molecules
Express co-stimulatory molecules
Migrate via lymphatics to lymph nodes
- Which receptor is involved in the migration of dendritic cells to lymph nodes?
CCR7