Innate Immunity Flashcards
What tissues are involved in innate immunity?
skin and mucous membranes
What cells are involved in innate immunity?
macrophages, neutrophils, NK cells
In innate immunity, what is the barrier and what does it do?
- skin
- barrier to infection
- kills microbes
Besides the barrier, how else are microbes killed?
intraepithelial lymphocytes
What are the characteristics of neutrophils?
- MOST ABUNDANT
- short lived
- phagocytic
What are the characteristics of macrophages?
- activated from monocytes
- found in tissues NOT blood
- phagocytic
- present Ags to adaptive system
What are the characteristics of dendritic cells?
- found in tissues open to external environment
- phagocytic
- present Ags to adaptive system
What are the characteristics of NK cells?
- found in blood and spleen
- not phagocytic
- cytotoxic lymphocyte, but still apart of innate system
How do immune cells recognize pathogens?
Pattern Recognition Receptor (PRR) that recognize pathogenic molecule patterns
What are Pattern Recognition Receptors (PRR)?
- inherited through germline
- located on cell surface & cytoplasm
- ex: toll-like receptor (TLR)
What are the microbe signals?
danger signals called PAMPs that are associated with microbial function
What are the symptoms of inflammation?
- redness (rubor)
- swelling (calor)
- pain (dolor)
- loss of function
What happens during inflammation?
macrophages and neutrophils release inflammatory cytokines -> IL-1, IL-6, TNF-alpha, chemokines
What is the result of inflammation?
- more cells coming to area
- fever -> inflammatory cytokines act on hypothalamus
What is the process of PAMPs and inflammation?
- bacteria enters and activates innate system
- chemo and cytokines create open space in membrane (inflammation process)
- endothelial receptors bring in IL-6 and IL-1
What are natural killer cells?
- cytotoxic lymphocyte
- common in blood & spleen
- self-defense: targets infected, stressed, or tumurous cells
- decrease in number as we change
What is the direct killing pathway for NK cells?
- release perforins & granzymes
- synthesize & secrete cytokines
- does NOT need Abs
- no formal presentation of Ags
What is the indirect pathway of NK cells?
- phagocytic cells detect Ags
- produce cytokines
- cytokine stimulate NK cells to release other cytokines
What do cytokines act on?
- cells that produce them -> autocrine
- closely located cell -> paracrine
- cells at a distance -> endocrine
What is the alternative system?
- compliment proteins interact with pathogenic proteins to be activated
- does NOT require Abs
- part of innate immune system
What is the classical system?
- compliment proteins react to Ab that is bound to Ag -> activation
- part of adaptive immune system
What is the primary cell of the adaptive immune system?
lymohocytes (T & B cells)
What are B cells?
- educated in the bursa of chickens (bone marrow in humans)
- function to make Abs
What are T cells?
- educated in the thymus
- function in cell mediated immunity
What is positive and negative selection?
- positive: occurs if cell reacts to selg Ags -> cell survives
- negative: occurs if cell reacts to self Ag too much -> cell destroyed
When T and B cells are stimulated what do they produce?
- T cell -> cytokines
- B cells -> become plasma cells and produce Abs
What are secondary lymphoid tissues?
- lymph nodes
- spleen
- gut associated lymphoid tissue
What is the structure of lymph nodes and gut associated lymphoid tissues?
- outer cortex composed of follicles with B cells
- inner cortex composed of T cells
- medulla with large numbers of plasma cells
What is the spleen composed of?
- white pulp: surrounds central artery
- red pulp: 80% of spleen & surrounds white pulp
What is clonal selection?
when Ag stimulates cell recpetors on lymphocytes to result in production of memory & effector cells
What is humoral immune response?
- Abs
- produced by activated B cells
- have heavy and light chains
- classes: IgG, IgA, IgA, IgE, IgD
What is the immunoglobulin structure?
- 2 heavy & 2 light chains
- variable domain -> binds to Ags
- constant region -> does NOT bind to Ags
How are loops made in the immunoglobulin structure?
with disulfide bonds
Where on the immunoglobulin structure do antibodies differ from one another?
Ag binding site
What immunoglobulin family do B cells express?
IgM monomers
What is the difference between IgM pentamers & monomers?
secreted IgM = pentamer
IgM on B cell surface = monomer
What are T cell independent antigens?
- does NOT require T cell presentation
- have multiple repeating subunits
- produce IgM only
In antibodies, what is a pentamer? Dimer? Monomer?
- pentamer -> IgM
- dimer -> IgA
- monomer -> IgG, IgD, IgE
What are T cell dependent antigens?
- require T cell presentation
- protein Ags
- allows for class switching -> can produce different Abs
