Cap _2 Inmunologia (2012).Ppt

8/12/2019 Cap _2 Inmunologia (2012).Ppt

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Hematopoiesis

Is the formation and development of both

erythrocytes and white blood cells

A precursor cell known as stem cell can

differentiate in a myeloid or lymphoid cell

Only this precursor is capable of cell

division

Way to control mutation rate


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Hematopoiesis activity


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Important regulators of apoptosis

p53 is responsible for cell cycle controlling

When inhibited cell with damage will continue their

cell cycle

FAS/FASL

Can promote activation of caspases to induce

apoptosis

BCl-2

Inhibits apoptosis in large amounts

Can translocate to the Ig heavy chain and be

transcriptionally activated


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CD proteins or cluster of differentiation

proteins found on the surface of white blood

cells (leukocytes) at various stages of their

development

Help the white blood cells interact with the

body's tissues and attack invaders

Some CD genes play a role in cell signaling and

the development of the nervous system.


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Ab for stem cells enrichment

Sca-1

stem cell antigen-1. Murine cell surface antigen is

called also Ly6A/E or Ly6D (Lai et al, 1998).

CD34

Protein encoded by this gene may play a role in

the attachment of stem cells to the bone marrow

extracellular matrix or to stromal cells. This single-pass membrane protein is highly glycosylated and

phosphorylated by protein kinase C.


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B cell

Specialized for the production ofimmunoglobulins after differentiation intoplasma cells

B-cells process and present antigen via surfaceMHC class II

Usually require T-cell help to respond to

antigen (interleukins) but can also recognizeantigen directly through surface Ig

B cells mature in the bone marrow


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NK

classed as part of the lymphoid system

particularly effective against virus-infected

and tumor cells

They are larger than T and B lymphocytes,

have distinctive cytoplasmic granules

NK cells are activated in response to

interferons or macrophage-derived cytokines

Kill cells with low MHC-1


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Eosinophils

Granulocytes

Phagocytic cells

Associated with parasitic infections Secrete granule content to destroy

invaders


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Basophils

Granulocytes

Do not perform phagocytosis

They primary function inhypersensitivity reactions mediatedby IgE

Can be activated in parasiticinfections (Lantz et al 1998, Nature)


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Mast cells

They are restricted to tissue

Highly specialized to act during

hypersensitivity reactions Contains histamine granules that are

release upon allergen triggering


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Lymphoid tissue

Small B and T lymphocytes that have matured

in the bone marrow and thymusbut have not

yet encountered antigen are referred to as

naive lymphocytes.

Both are considered primary lymphoid tissue

These cells circulate continually from the

blood into the peripheral lymphoid tissues


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Lymphoid tissue

In the event of an infection, lymphocytes thatrecognize the infectious agent are arrested inthe secondary lymphoid tissue

There cells proliferate and differentiate intoeffector cells capable of combating theinfection.

Mature lymphocytes recirculate continuallyfrom the bloodstream through the peripheralor secondary lymphoid organs


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Peripheral lymphoid tissue

Spleen, which collects antigens from the

blood

Lymph nodes, which collect antigen fromsites of infection in the tissues

Adaptive immune responses are initiated

in these peripheral lymphoid tissues


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Thymus: T cells' school


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Thymus

Select and maturate T cells

90-95% of the entering thymocytes are

eliminated

Cells in this stage develop TCR to recognize a

broad amount of Ag

done by genetic recombination

T cells high specificity is acquire after Ag

encounter


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Lymphatic system

extensive system of vessels that collects

extracellular fluid from the tissues and returns

it to the blood.

This extracellular fluid is produced by filtration

from the blood, is called lymph.

The vessels are lymphatic vessels or

lymphatics


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Lymphatic system and lymph node

In the lymph nodes, B cells are localized

in follicles and T cells in the paracortical

areas

Antigen-bearing cells and antigens from

infected tissues travel to these nodes


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Spleen

Collects antigen from the blood

It also collects and disposes of senescent

red blood cells Two major areas are the red pulp and

white pulp


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All the ALTs

gut-associated lymphoid tissues (GALT), whichinclude the tonsils, adenoids, and appendix, andspecialized structures called Peyer's patches inthe small intestine

collect antigen from the epithelial surfaces of thegastrointestinal tract

bronchial-associated lymphoid tissue (BALT)

mucosal-associated lymphoid tissue (MALT)

nose-associated lymphoid tissue (NALT) vulvovaginal-associated lymphoid tissue (VALT)


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Cap _2 Inmunologia (2012).Ppt