intro to immunology Flashcards
what component is innate immunity composed of?
: fixed and mobile elements
Fixed components of immunity?
lymphoid organs
- Primary
- secondary
what is innate immunity?
: activates first
-provides instructional signals for adaptive immunity
what are myeloid cells?
the first line of defense
Myeloid progenitor to myeloblasts to basophils, eosinophils, neutrophils, using G-CSF
Lymphoid cells?
specific and long lasting immunity: in bone marrow
Mediators of adaptive immune responses
T,B, NK cells
T cell precursor, matures how?
, IL7, goes to thymus, become t cells
B cell precursor, matures how?
il7, B cells
Describe properties of innate immune cells
In the blood, leukocytes
Immediate protection against microbial invasion
Blocks entrance of microbes and pathogens
What is CBC?
most commonly performed hematological lab
- CBC with diff provides complete hematological picture
- Giemsa stain used
what are Phagocytes and what do they do?
Include 1.neutrophils and 2.macrophages
Ingest and destroy microbes, get rid of damaged tissues
Steps in functional responses of Phagocytes?
- recruit cells to infection sites
- recognize and be activated by microbes
- injest microbes
- destroy ingested microbes
Secrete cytokines to promote immune responses
what is leukocytosis?
elevated white blood count
-can be due to increased eosinophils, basophils,lymphocytes, monocytes
-neutrophilia most common
-nonmalignant causes:
Infection
Necrosis
Drugs
Stresses
-get worried if theres left shift or if the person is very unwell
what is Leukopenia?
WBC less than 4000
- usually neuropenia: reduced neutrophils
- often caused by cancer therapy
- severe neutropenia leads to life theatening infection risk
what are neutrophils, what do they do?
leukocytes with 3 to 5 lobule nucleuses
- most common wbc
- mediate earliest phases of inflammatory reactions
how do neutrophils eliminate their target?
- have peroxidase,lysozyme, defensins degradative enzymes
- produce inflammatory mediators such as cytokines, prostaglandins, leukotrienes
how long do neutrophils live, where do they come from?
- live for a few hours in blood
- function for 1-2 days in inflammatory tissues
-come from myeloid progenitor cells , generation controlled by G CSF
How do neutrophils kill bacteria?
by intra and extracellular means
I. can use phagocytosis to engulf bacteria and kill them with ROS
Ii. can release proteins to kill bacteria extracellularly
Iii. release traps to immobilize pathogens and prevent them from spreading and facilitate phagocytosis
Live after net formation
Monocytes vs. macrophages
Monocytes are predominant in blood, macrophages are in tissues
what are dendritic cells?
-dendritic cells are like macrophage and are the most efficient APC
where do monocytes come from, how long do they live?
come from myeloid cells, driven by M-CSF
-live a few days before undergoing apoptosis
monocytosis vs/monocytopenia
too many monocytes vs too few
-tissue resident macrophages?
are long lived cells that fulfill tissue specific functions, specialized phenotypes
what do monocytes do?
migrate into tissues and differentiate into inflammatory macrophages
- involved in inflammatory reactions - tissue remodeling to repair collateral damage produced by hypersensitivity
Mast Cells, Basophils, and Eosinophils, what do they do?
- innate immune responses, protect against helminthes
- granules filled with inflammatory and antimicrobial mediators
Mast Cells , what are they? role?
are tissue fixed
- parasites, allergic and anaphylactic reactions
- basophilic granules
- mature mast cells dont circulate in blood
- mast cell precursors differentiate locally
- sentinel cells, respond to pathogens, allergens, antigens quickly
Mastocytosis?
- increase in mast cells within tissues
- itching, hives, anaphylactic shock, due to release of histamine by mast cells
- cutaneous mastocytosis when in skin
Basophils, what do they do?
are circulating in blood
- parasites, allergic and anaphylactic reactions
- basophilic granules
Eosinophils, what do they do?
defend against parasites and are in allergic reactions
- large granules have 4 proteins
- small granules have peroxidase and lipase
- toxins against helminths!!
- implicated in cell damage, exfoliation, bronchospasm
-Eosinophila?
low eosinophil count, allergic or atopic disorders cause this, infections too
Antigen-Presenting Cells? what do they do? best example?
part of innate immunity, present antigens to T Cells
Dentritic Cells part of innate immunity professional APCs
-divided into myeloid (MDCs) and plasmacytoid (pDCs)
myeloid cells, what do they do?
MDCs come from monocytes
-capture, process, present antigens on their surface to Tcells
plasmacytoid cells, what do they do?
PDCs produce IFN, circulate through blood and peripheral tissues
what are langerhans cells?
DC cells in epidermis of skin, Ag dependent activation
unique thing about adaptive immune cells?
- need cluster of differentiation to tell these cells apart
- CD molecules are cell surface molecules used to differentiate leukocytes
- interactions between B cells and T cells is critical
where do t cells develop?
in thymus, cell mediated immunity when Ag stimulated
-Cell mediated immunity, what is it?
T cells with AGPs
host defense against microbes not accessible to Abs
-CMI kills host cells that are infected
B lymphocytes, where do they come from, what do they do?
- develop in bone marrow
- leads to development in humoral immunity, leads to development of antibodies
T helper lymphocytes, what do they do?
- help b cells make high affinity Abs
- activate macrophages to kill microbes
- attract CTLs to directly destroy infected cells
Cytotoxic T lymphocytes, what do they do?
cytotoxic T cell to attack and destroy virtually any cell that is infected with a cytosolic pathogen.
A membrane-bound molecule, the Fas ligand, expressed by CD8 and some CD4 T cells, is also capable of inducing apoptosis by binding to Fas expressed by some target cells
Natural Killer cells, what are they, what do they do?
- innate immune cells, broad specificity
- come from lymphoid progenitor cells
- granular lymphocytes that survey, purge body of infectd and precancerous cells
- recognize Ags normally expressed on host cells
- from bone marrow precursors, distinct from T or B cells, differentiation in bone marrow
what is unique about nk cell specificity?
-no antigenic specificity or immunological memory
destroy target cell without prior stimulation
generation of diversity and clonal selection in T and B lymphocytes?
-exposure to antigen causes proliferation of appropriate ag specific cell, diversity among immune cells exists before this
- all individuals have distinct lympocytes
- lymphocytes bind Ag, triggered to give rise to clones specific for Ag, which react to destroy Ag
-mature lymphocytes in tissues are activated by antigens, which activate immune specific response
