Cells, Organs, and Cytokines Flashcards
What is the unique capability of Hematopoietic stem cells (HSCs)?
They can renew or differentiate into many types of blood cells
-> Differentiate into Erythrocytes
-> Differentiate into Leukocytes
What are the two paths a leukocyte can differentiate into?
-Myeloid: Granulocytes, Megakaryocytes, Erythrocytes, Monocytes (Macrophages, dendritic cells)
-Lymphoid: T cell (develop in Thymus), B-cells (bone narrow)
Innate lymphoid cell (ILC)
What are the functions of the red blood cells and Megakaryotes?
-Red blood cells: transfer oxygen and also immune compounds
-Megakaryocytes: bud off platelets, which are used primarily as clotting factor
What is the function of the Granulocytes?
-Neutrophils: they move around and wait for signals -> First circulating cell to the infection site, harm pathogens, can also phagocytose
-Basophils/mast cells: inflammation/allergies
-Eosinophils: antiviral, antiparasite activity
Why is the nucleus of Granulocytes broken up?
Because it can easier squeeze into slids to get to the site of infection
What do Granulocytes contain?
Proteases, antimicrobial proteins, protease inhibitors, Histamines, Ribonuclease (antiviral), Cytokines, Chemokines
What is the function of adhesins?
-They are on the surface of immune and tissue cells, mediating the migration of cells
-Their activation and degradation is regulated by cytokines
In which cells will Monocytes differentiate?
Macrophages (tissue-specific) -> function to repair/remodel, destroy pathogens (phagocytosis), present antigens
Dendritic cells -> “ingesters” of antigens, followed by presentation to naïve T lymphocytes
Which receptors are encoded by T Helper and T cytotoxic cells?
T-Helper cells encode CD4 receptors –> interact MHC-II
T-cytotoxic cells encode CD8 receptors –> interact MHC-I
What is the Function of T-helper and cytotoxic cells?
CD4-Helper cells: direct the adaptive immune system through cytokines
CD8 T-cells: convert to cytotoxic T-cells upon activation
How are B-cells different from plasma cells?
B-cells turn into plasma cells upon activation, they lose membrane-bound B-cell receptor and produce the soluble variant of the BCR (antibodies)
NO MHC involved
What are the characteristics of Innate lymphoid cells (ILC) and NK-cells?
NK-cells: They are the cytotoxic T cells of the innate immune system but lack T-cell receptors
their function is to kill infected or sick cells, mediated through signals
ILC: they absorb cytokines and amplify them, to direct the immune response in the right direction
What are the antigen-presenting cells?
Usually MHC-II: Macrophages, B-cells, Neutrophiles, dendritic cells
Which cells express unique recombinant receptors
T-cells (Th and Tc), B-cells,
What cells originate from lymphatic lineage?
T-cells, B-cells, dendritic cells
Which cells contain toxic granules?
Granulocytes, Neutrophiles, cytotoxic T-cells, Mastcells
Which cells secrete cytokines?
Which expresses MHC-I?
ALL
ALL express MHC-I besides red blood cells
What are the primary and secondary lymph organs?
Primary: Bone marrow, Thymus
Secondary: Lymph nodes, Spleen, MALT/GALT
How can stromal cells contribute to the development of immune cells?
-facilitate HSC proliferation, direct migration, and stimulate differentiation
-B-lymphocytes develop in contact with stromal cells of the bone marrow
Where does the development of the T-cells occur?
-initially in the bone marrow but then in the thymus (cortex and medulla)
-Cortex - positive selection: Can you interact with MHC-I or MHC-II?
95% fail
-negative selection: Kill off the auto-immune T-cells
-Medulla: after development, they will wait in the secondary lymph organs upon activation
What is the role of the spleen?
-The first line of defense against bloodborne pathogens
-> Redblood cells in the red pulp, and white blood cells in the white pulp
specialized macrophages and B-cells in the marginal zone
What is the MALT/GALT?
a layer of defense against infection at mucosal and epithelial layers
MALT: Mucosa-associated lymphoid tissue
Which immune cells are located in the GALT?
-Naive T and B-cells
-Macrophages and dendritic cells provide innate cell defense
-Microfold (M) cells pass Ag across GI epithelium to antigen-presenting cells
-CD8 intraepithelial lymphocytes (IELs)
-Tuft cells detect helminth infections
-Goblet cells (mucus) and Paneth cells secret barrier immunity
What are the functions of the Interleuikin-1 cytokines and which molecules stimulate them? Secreted by which cells?
-They promote inflammation
-It is stimulated by viral, parasitic, or bacterial antigens
-Secreted by macrophages and dendritic cells
