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Flashcards in Immune cells Deck (17)
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1

Cells involved in the immune response

All types of leukocytes, endothelial cells, adipocytes and epithelial cells

2

Differentiation of immune cells

Leukocytes differentiate from self-renewing stem cells in the bone marrow

They then become pluripotent stem cells, at which point they are 'committed'

The process relies on hormones and growth factors such as cytokines and colony stimulating factors (CSF)

3

Myeloid progenitor lineage

Myeloid progenitor cells contain cytoplasmic granules

They give rise to mast cells, erythrocytes, platelets, basophils, eosinophils, neutrophils, monocytes and dendritic cells

These cells have have a polymorphic nucleus and are important for the innate immune response

4

Neutrophils

The most prominent granulocyte

10-20 microns
Lifespan 2-3 days

Granules contain a variety of enzymes to kill bacteria and stain neutral

Main function is as a phagocyte

5

Eosinophils

Granules contain eosin basic protein and stain red

Main function is against helminths and worms, although they have been known to phagocytose

Kill parasitic worms grouping around the parasite and simultaneously releasing their granules

Have receptors for antibody

6

Basophils

Only enter the tissues during inflammation

Granules contain basophilic proteins and stain blue

Main function is to promote inflammation by releasing chemicals such as histamine

Can be stimulated in the lab to phagocytose

Have receptors for antibody

7

Mast cells

Only fully differentiate after leaving th bone marrow

Found in connective and mucosal tissues

Cytoplasmic granules contain histamine and are important in the allergic response

Have receptors for antibody

8

Macrophages/monocytes

Exist as monocytes in the blood and macrophages in the tissue

Main function is as a phagocyte but they also carry out antigen presentation to T-cells

Macrophages survive much longer and are much larger

Can be identified by their expression of CD14 and CD15

9

Macrophages in different tissues

Liver = Kupffer cells
Connective tissue = Histiocytes
Lung = alveolar macrophages
Kidney = mesangial cells
Brain = microglial cells
Bone = osteoclasts

10

Dendritic cells

Irregularly shaped with many protruding branches

Are able to arise from both lymphoid and myeloid progenitor lineages

Main function is antigen presentation

11

Megakaryocytes

Give rise to platelets by cytoplasmic fragmentation

Are polyploidy

12

Lymphoid progenitor lineage

Lymphoid progenitor cells do not have cytoplasmic granules but have a large nucleus and small cytoplasm

Give rise to innate lymphoid cells, natural killer T-cells, natural killer cells, T-lymphocytes and B-lymphocytes

13

B-lymphocytes

Differentiate and remain in the bone marrow

Express CD19 and CD21

Bind whole antigens via the B-cell receptor

Can differentiate into plasma cells or memory cells

14

T-lymphocytes

Differentiate in the bone marrow and migrate to the thymus

Express CD3 and either CD4 or CD8

Bind antigen fragments via MHC molecules

15

Innate lymphoid cells

Have a large, granular cytoplasm and kill cancerous and virally infected cells

Are considered to be between the adaptive and innate immune responses

16

Natural killer T-cells

Have a T-cell receptor and kill cells in a similar way to CD8 cytotoxic T-cells

Synthesise many growth factors and signalling molecules

17

Natural killer cells

Do not have a T-cell receptor

Other cell surface receptors recognise self and non-self structures