Cells & Organs of Immune system Flashcards by Hugo Siu

Hematopoiesis

What is the definition of Hematopoiesis?

Formation & Development of red & white blood cells

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Hematopoiesis

What is the migration path of HSCs ( Hematopoietic stem cells )?

Embryonic Yolk sac -> Fetal liver -> Spleen -> Bone marrow

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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

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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

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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

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Hematopoiesis

What is the anti - apoptotic protein that regulates activated B - cell numbers by apoptosis?

Bcl - 2

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Cells of Immune System

What are the 3 types of lymphocytes?

B cells
T cells
NK cells

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Cells of Immune System

What is 4 attributes that only lymphocytes possess?

Diversity

Specificity

Memory

Self / Non-self recognition

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Cells of Immune System

What are the 2 fates of antigen - activated lymphocytes?

Effector cell
-> Apoptosis

Memory cell

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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

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Cells of Immune System

What are the 2 sites of maturation for B lymphocytes?

Bursa of Fabricius ( birbs )

Bone marrow

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Cells of Immune System

What is the site of maturation for T lymphocytes?

Thymus

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Cells of Immune System

What is the cell marker for B lymphocyte?

BCR ( B - cell receptor )
-> mIg ( membrane - bound immunoglobulin )

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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 )

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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

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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

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Cells of Immune System

Is NK cells ( Natural killer cell ) part of the innate or adaptive immune system?

Innate

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Cells of Immune System

Does NK cells have antigen receptors?

They don’t have antigen receptor

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Cells of Immune System

What are the 2 most important protein in NK cells’ cytoplasmic granules?

And what are their functions?

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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?

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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 )

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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 )

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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?

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Nope

Cell of immune system

Which of the following are differentiated tissue macrophages?

Alveolar macrophages
Histiocytes
Kupffer cells
Mesangial cells
Microglial cells
Osteoclasts

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ALL :D ( you know the drill )

Cell of immune system Choose the correct option to finish the description of morphological changes in monocytes -> macrophage 1. Cell size __ ( enlarges / shrinks ) 5 - 10 folds 2. Its intracellular organelles __ ( increase / decrease ) in both number and complexity 3. It acquires increased __ ( phagocytic / exocytic ) ability 4. Produces __ ( lower / higher ) levels of hydrolytic enzymes 5. Begins to secrete a variety of __ ( soluble / insoluble ) factors

1. Cell size enlarges 5 - 10 folds 2. Its intracellular organelles increase in both number and complexity 3. It acquires increased phagocytic ability 4. Produces higher levels of hydrolytic enzymes 5. 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

Cells & Organs of Immune system Flashcards

(47 cards)