Intro to the Immune System Flashcards
How is active immunity conferred?
by host response to a microbe/ microbial ags
Where are mast cells found?
sites of body that are exposed to external environment - close to blood vessels
What are extracellular microbes?
microbes that are able to survive outside human cells; can just grow by being immersed in nutrients
Where do T cells congregate in a lymph node?
in the center
What type of immunity do T cells give rise to?
cellular immunity
T helper cells also help b cells in humeral immunity
What do activated macrophages secrete to promote or regulate immune responses?
cytokines
What is the clonal selection hypothesis?
Ag-specific close of lymphocytes dev before and independent of exposure to Ag –> a lot of clones are generated during maturation = maximizes potential for recognizing diverse microbes –> Ags select certain clones –> response
What are tissue-resident macrophages and what do they do?
heterogeneous pop'n of immune cells that fulfill tissue-specific functions: homeostasis immune surveillance response to infection resolution of inflammation
What do M cells do?
take antigens from lumen of mucosal tissue into peyer’s patch
What are the 2 types of dendritic cells?
myeloid DCs
plasmacytoid DCs
What do T cells turn into in tissue?
T lymphocytes
How are monocytes recruited?
inflammation –> monocytes move to tissue –> turn into macrophages
How is passive immunity conferred?
actually transfer antibodies or T lymphocytes for a disease to a person
What type of immunoglobulin is abundantly produced in mucosal tissues?
IgA
What are the phagocytic innate immune cells? (6)
basophils/mast cells eosinophils neutrophils monocytes/ macrophages dendritic cells NK cells
What do T helper cells express to help B cell growth and differentiation?
CD4
Who is the father of humoral immunity?
Paul Ehrlich
What part of the immune system (adaptive or innate) does memory of Ag arise from?
adaptive immunity
What are the parts of innate immunity?
epithelial barriers mast cells phagocytes dendritic cells complement NK and ILCs
What are dendritic cells?
innate immune cells
antigen-presenting
stimulate T cells –> induce adaptive immunity
Where do B cells congregate in a lymph node?
on the periphery
What do T helper cells do?
recognize Ags on Ag-presenting cells –> secrete cytokines –> other immune responses and inflammation
What is the most effective method of protection against infections?
vaccination
Where does the development and maturation of T cells occur?
thymus
How many neutrophils are produced a day?
How long do they circulate in the blood and tissue?
1x10^11 neutrophils per day
in blood for hours or a few days
in tissue for 1-2 days
What type of phagocyte activates the earliest phases of inflammatory reactions?
neutrophil
What does a developing B cell come in contact with that is essential for its differentiation
stromal cells
cytokines: IL-1, Il-6, and IL-7
Production of neutrophils is stimulated by what cytokine?
granulocyte colony stimulating factor (G-CSF)
Which part of the immune system (adaptive or innate) has more diversity in its cells and molecules?
adaptive immunity
What is the function of mast cells?
can regulate vascular permeability through heparin
can recruit effector cells through release of mediators
Where do mature T cells migrate?
secondary lymphoid tissues (spleen and lymph nodes?)
What is an antigen defined as?
any substance that is specifically recognized by lymphocytes or antibodies
What are the parts of adaptive immunity?
B lymphoctes –> antibodies an plasma cells
T lymphocytes –> effector T cells
Where do B cells mature?
bone marrow
Where do langerhans cells go after picking up an antigen?
travel to skin draining lymph nodes to present antigen –> activates naive T lymphoctes to go and kill pathogens
What are the components of the induced adaptive/ highly specific response?
When does it occur after an infection?
B cells, helper T cells, cytolytic T cells
occurs 96 hours after infection
What are the mobile elements of the immune system?
immune cells
soluble/ humoral components (antibodies, complement, acute phase proteins, etc)
What are the primary fixed elements of the immune system?
bone marrow
thymus
Where do CD4 T cells reside predominantly?
in the dermis
What do mast cells, basophils, and eosinophils function to do?
play roles in innate and adaptive immunity protect against helminthes function in allergic rxns
What is herd immunity?
when a high % of a population is vaccinated, it is difficult for infectious diseases that are also contagious to spread bc most ppl can’t be infected
What are the components of the induced innate/ broadly specific response?
When is this activated on the timeline of infection?
phagocytosis, complement activation, cytokine secretion, other inflammatory mechanisms
4 hours after infection
What does a basophil turn into in the tissue?
mast cell
What are the main things about the surface of skin that protect us from infection?
keratinocytes being sloughed off
keratinocytes produce antimicrobial peptides
microflora on skin
What are the secondary fixed elements of the immune system?
spleen and lymph nodes
mucosal immune tissues
What do B cells turn into in tissue?
plasma cells
What does a monocyte turn into in tissue?
macrophage
How do B lymphocytes work in humoral immunity?
B cells produce Abs –> recognize Ags, neutralize them, and target them for elimination
What do cytotoxic T lymphocytes express to recognize and kill viruses?
CD8
What is the goal of cellular immunity?
defense against intracellular microbes: kill infected host cells
How was the cellular theory of immunity proven?
in 1950s showed that resistance to an intracellular bacteria could be transferred with cells, but not with serum
What type of immunity do B cells do?
humoral immunity through immunoglobulins
What do regulatory T cells do/
suppress and prevent immune responses
What is clonal expansion?
property of adaptive immunity: can increase the number of Ag-specific lymphocytes to keep pace w/ microbes
What types of T cells are present in skin?
both CD4 T helper and CD8 cytotoxic
What are intracellular microbes?
germs that have to live and replicate within animal cells
What are the fixed elements of the immune system?
lymphoid organs (primary and secondary)
What do cytotoxic T lymphocytes do?
recognize Ags on infected cells and kill them
What are peyer’s patches and where are they located?
discrete structure of immune cells in the lamina propria of the intestine/ mucosal immune sys
What happens to B cells that react w/ self-Ags?
eliminated by apoptosis
What type of immune cell is a langerhan’s cell?
dendritic cell
