Immunology: Fundamentals, Cells Tissues and Organs Flashcards
Immune cells produced:
Primary Lymphoid Organs
Immune cells perform their effector functions:
Secondary Lymphoid Organs
Antigen:
A molecule that stimulates an immune response.
- Usually a protein.
Epitope:
The portion of the antigen molecule that interacts with the immune effector molecule or receptor.
Paratope
The portion of an immune effector molecule or receptor that interacts with the epitope.
Immunogenicity:
The capacity to stimulate the development of innate or acquired immunity.
Antigenicity:
The ability to bind to immune effector molecules or cells such as the receptors on T cells.
Innate Immunity:
The elimination of microbial agents through nonspecific protective mechanisms.
Acquired immunity:
Elimination of microbial agents through specific protective mechanisms.
- Once cell, one peptide recognized.
Cytokines:
Hormones made by immune effector cells.
- Autocrine or paracrine.
Autoimmunity:
Inappropriate reactions to self antigens.
Immunodeficiency:
Ineffective immune response.
Hypersensitivity:
Overactive immune system.
Humoral immunity:
B cells, antibody production.
Cellular immunity:
T cells, helper and killer cells.
Hematopoietic stem cells differentiates into (2):
- Common lymphoid progenitor.
2. Common myeloid progenitor.
Common myeloid progenitor differentiates into (2):
- Granulocytes.
2. Monocytes.
Common lymphoid progenitor differentiates into (3):
- B cell
- T cell
- NK cell
Granulocytes (3):
- Neutrophil
- Eosinophil
- Basophil
Monocytes (2):
- Dendritic cell
2. Macrophage
Neutrophils:
- Effectors in the initial response to bacterial infection.
- Infiltrate areas of infection –> phagocytosis.
- Short lifespan.
- Pus = dead neutrophils.
- 40-60%
Eosinophils:
- Granules contain Major Basic Protein, Eosinophil Cationic Protein, peroxidase and cytokines.
- Increase during parasitic infections allergies and hypersensitivity.
- Bi-lobed nucleus.
- 1-4%
Basophils:
- Granules contain heparin, serotonin and histamine.
- Inflammatory response.
- Lie close to vasculature.
- Bi-lobed nucleus.
- Contribute to allergic immune responses
- 0.5-1%
Mast Cells:
- Found only in tissues.
- Bi-lobed nucleus.
- Granules containing histamine and heparin.
- Reside close to blood vessels, skin, mucosa.
- Important for immune response to parasites and allergic immune response.
Monocyte:
- Predominantly found in blood.
- Kidney-shaped nucleus.
- Weakly phagocytic, weakly microbicidal.
- Differentiates to macrophage or dendritic cell upon leaving blood.
- 2-8%
Macrophage:
- Predominantly found in tissue sites.
- Strongly phagocytic and microbicidal.
- Promote tissue repair.
Dendritic cell:
- Predominantly found in tissue sites.
- Strongly phagocytic.
- Activates T helper cells.
- Take up antigen from environment, process it to peptides, present to T cells.
NK cells:
- Tissues and blood.
- Kills virus-infected cells and tumor cells.
- CD3-, CD16+, CD56+
- Release gamma interferon.
- 5%
B cells:
- Make antibody.
- Very specific for single antigen.
- Some remain as memory cells.
- CD19+, CD20+, CD22+
Helper T cell markers:
CD3+, CD4+, CD8-, AlphaBeta+
Cytotoxic T cell markers:
CD3+, CD4-, CD8+, AlphaBeta+
MALT:
- Mucosal Associated Lymphoid Tissue.
- Diffuse, non-encapsulated tissue associated with mucosal epithelial surfaces.
Primary lymphoid organs (2):
- Bone marrow.
2. Thymus.
Types of defenses along epithelial surfaces (3):
- Mechanical.
- Chemical.
- Microbiological.
T cell progression in thymus:
Pass from cortex to medulla.
Central Tolerance Induction:
T cells that possess reactivity against self are eliminated.
Spleen:
Site of adaptive immune responses to blood-borne antigens.
Red Pulp (spleen):
Rich in macrophages which filter blood of foreign material and aged RBCs
White pulp (spleen):
Multiple immune cell types necessary to initiate adaptive immune response.
PALS:
Periarteriolar Lymphoid Sheath: area surrounding central arterioles in the white pulp of the spleen that is rich in T cells.
Lymphoid follicle (spleen):
Out-pocketing of lymphocytes from PALS that is rich in B cells.
Primary lymphoid follicle:
Naive B cells.
Secondary lymphoid follicle:
Outer mantle of naive B cells with a germinal center containing activated B cells.
Naive lymphocytes enter lymph node via:
Specialized post-capillary venules called High Endothelial Venule or HEV.
