Cells & Organs of Immune system Flashcards
Hematopoiesis
What is the definition of Hematopoiesis?
Formation & Development of red & white blood cells
Hematopoiesis
What is the migration path of HSCs ( Hematopoietic stem cells )?
Embryonic Yolk sac -> Fetal liver -> Spleen -> Bone marrow
Hematopoiesis
What are the two characteristic of HSC that allows it to consistently produce new and different blood cells?
Self renewal ( Though decrease in level at old age )
Multi - potent : Able to differentiate and generate various cells
Hematopoiesis
What happens with stem cell mitosis when
a) Normal
b) Injury
c) Infection
Normal : No increase in stem cells
Injury : Increase in stem cells
Infection : Increase in differentiating cells
Hematopoiesis
What are the 4 factors involve in hematopoietic homeostasis?
Control of levels & types of cytokines produced by Bone - marrow stromal cell
Production of cytokines w/ hematopoietic activity by other cell types
(e.g. Activated T cells & macrophage (during infection))
Regulation of expression of receptors
Removal of certain cells by apoptosis
Hematopoiesis
What is the anti - apoptotic protein that regulates activated B - cell numbers by apoptosis?
Bcl - 2
Cells of Immune System
What are the 3 types of lymphocytes?
B cells
T cells
NK cells
Cells of Immune System
What is 4 attributes that only lymphocytes possess?
Diversity
Specificity
Memory
Self / Non-self recognition
Cells of Immune System
What are the 2 fates of antigen - activated lymphocytes?
Effector cell
-> Apoptosis
Memory cell
Cells of Immune System
What are the 4 molecules expressed on the membrane of Mature B cells?
mIg ( membrane - bound immunoglobulin )
Class ll MHC
B7-1 & B7-2
CD40
Cells of Immune System
What are the 2 sites of maturation for B lymphocytes?
Bursa of Fabricius ( birbs )
Bone marrow
Cells of Immune System
What is the site of maturation for T lymphocytes?
Thymus
Cells of Immune System
What is the cell marker for B lymphocyte?
BCR ( B - cell receptor )
-> mIg ( membrane - bound immunoglobulin )
Cells of Immune System
What are the cell markers for T lymphocytes?
TCR
-> recognizes only antigen on self - cells
- -> MHC restriction
CD4 ( T helper : Th1 & Th2 )
CD8 ( T cytotoxic )
Cells of Immune System
What is the cytokines released in Th1 ( MHC ll restricted )?
What are their functions?
IL - 2 & IFN - y ( gamma )
Functions :
-> Activation of macrophages
-> Inflammation
Cells of Immune System
What is the cytokines released in Th2 ( MHC ll restricted )?
What are their functions?
IL - 4 & IL - 5
Functions :
-> Stimulation of B lymphocytes
Cells of Immune System
Is NK cells ( Natural killer cell ) part of the innate or adaptive immune system?
Innate
Cells of Immune System
Does NK cells have antigen receptors?
They don’t have antigen receptor
Cells of Immune System
What are the 2 most important protein in NK cells’ cytoplasmic granules?
And what are their functions?
Perforin : Poke pores on targets’ cell membrane
Granzyme : Initiate apoptosis in target cell
Cells of Immune System
What are the two pathway of NK cells sensing?
Interaction between NK receptors MHC - 1
ADCC ( antibody-dependent cell-mediated cytotoxicity )
Cells of immune system
Explain the interaction between NK receptor & MHC - 1 ( Pathway of NK cell sensing )
Cells with proper expression of MHC - 1 sends inhibition signals to NK cells
-> NK cells considered these cells normal & healthy
Cells with missing / reduced / altered MHC - 1 is recognized as abnormal cells by NK cells
-> Activation of NK cells
Cell of immune system
Explain ADCC ( Pathway of NK cells sensing )
Antibodies produced by plasma cell binds to target cell
Recognition and binding of antibodies with NK cells’ Fc receptor activates NK cells
Cell of immune system
Are NKT cells present in all mammals?
Nope
Cell of immune system
Which of the following are differentiated tissue macrophages?
Alveolar macrophages
Histiocytes
Kupffer cells
Mesangial cells
Microglial cells
Osteoclasts
ALL :D ( you know the drill )
Cell of immune system
Choose the correct option to finish the description of morphological changes in monocytes -> macrophage
- Cell size __ ( enlarges / shrinks ) 5 - 10 folds
- Its intracellular organelles __ ( increase / decrease ) in both number and complexity
- It acquires increased __ ( phagocytic / exocytic ) ability
- Produces __ ( lower / higher ) levels of hydrolytic enzymes
- Begins to secrete a variety of __ ( soluble / insoluble ) factors
- Cell size enlarges 5 - 10 folds
- Its intracellular organelles increase in both number and complexity
- It acquires increased phagocytic ability
- Produces higher levels of hydrolytic enzymes
- Begins to secrete a variety of soluble factors
Cell of immune system
What is the cytokines in Th1 that activates macrophage?
IFN - gamma
Cell of immune system
What is the rate of phagocytosis 4000 - fold higher in the presence of specific antibody to the antigen?
Exterior of cell membrane carries negative charge
-> Difficult for phagocytic cells to get close ( e.g. bacteria )
What are 2 categories of antimicrobial and cytotoxic substances produced by activated macrophages?
Oxygen - dependent killing
Oxygen - independent killing
Cell of immune system
What is oxygen dependent killing?
NOS ( Nitric oxide synthase ) produces NO
-> NO is a potent antimicrobial substance
Cell of immune system
What is oxygen - independent killing?
Defensin
Hydrolytic enzyme
TNF ( tumor necrosis factor )
Cell of immune system
What are 3 types of granulocytes?
Neutrophil
Eosinophil
Basophil
Cell of immune system
What are the 4 steps of neutrophil killing?
Attraction by chemotaxis
Adherence
Ingestion
Destruction
-> Primary granules ( Larger , denser )
-> Secondary granules ( Smaller )
Cell of immune system
What are the difference between eosinophil & basophil?
Eosinophil
-> Phagocytic cells ( Blood -> tissue spaces )
-> Against parasite
Basophil
-> Non - phagocytic
-> Certain allergic responses
Cell of immune system
What does mast cells release?
Histamine
Cell of immune system
What are dendritic cells and what molecules do they express?
Antigen - presenting cells
They express high levels of MHC - 2 & B7
Organs of immune system
What are the difference between primary organs & secondary organs in immune system?
Primary organs : Production & maturation of immune cells
Secondary organs : Activation of immune cells
Organs of immune system
What are some primary organs & secondary organs?
Primary : Thymus & bone marrow
Secondary : Lymphatic tissues & spleen
Organs of immune system
What are the difference in cortex & medulla of thymus?
Cortex : Immature T cells ( thymocytes )
Medulla : Less populated, more mature thymocytes
Organs of immune system
Which 2 types of T cells will be eliminated by thymus?
Can’t recognize antigen - MHC complexes
Reacts with self - antigen - MHC
-> Possible autoimmune disease
Organs of immune system
Match the correct tissue to the corresponding animal species?
( Human, Rodents, Birbs, Ruminants, Rabbits, Dogs, Pigs )
( Bursa of Fabricius, Bone marrow, Peyer’s patches, Appendix )
Human, Rodents : Bone marrow
Birbs : Bursa of Fabricius
Ruminants, Pigs, Dogs : Peyer’s patches
Rabbits : Appendix
Organs of immune system
Does bone marrow undergo a selection process that eliminates B cells with self - reactive antibody receptors, just like T cells in thymus?
Yes
Organs of immune system
What is the difference of lymph nodes’ cortex, paracortex & medulla?
Cortex : Germinal centers & Follicles
-> B lymphocytes
-> T helper cells
-> Follicular DCs
Paracortex :
-> T lymphocytes
-> Interdigitating DCs ( High MHC ll & B7 expression )
Medulla :
-> Plasma cells
Organs of immune system
Which one has more lymphocytes,
afferent lymph or efferent lymph?
Efferent lymph has 50 - fold more lymphocytes
What is the functional importance of MALT ( Mucosal - associated lymphoid tissues )?
Large population of antibody - producing plasma cells
> > spleen + lymph nodes + bone marrow
Which of the following is part of MALT?
Tonsils
Appendix
Peyer’s patches
ALL
Organs of immune system
What is M cells?
Where can they be found?
M cells are specialized epithelial cells that transport pathogens from mucosal surfaces to MALT
They are found in places with MALT
Organs of immune system
What antibody does plasma cell MAINLY produce in MALT?
IgA