Basic Components of the Immune System Flashcards
What are mucosa-associated lymphoid tissue?
Lymphoid tissues found within the linings of multiple organ systems, including the gastointestinal and respiratory tracts
The bone marrow contains several cell types that coordinate HSC development like:
Osteoblasts- Generate bone and control the differentation of HSCs
Endothelial cells- Line the blood vessesls and regulate HSC differentation
Reticular cells- Send processes connecting cells to bone and blood vessels
Sympathetic neurons- Can control the release of hematopoietic cells from the bone marrow.
What is the role of NADPH oxidase?
Catalyzes the production of superoxide radicals
T lymphocytes only recognize processed pieces of antigen bound to the cell membrane proteins called______________
Major Histocompatibility Complex (MHC)
Hematopoietic stem cells are defined by what two capacities?
- The ability to “self-renew”
- The ability to differentiate into all diverse blood cell types
Granulocytes have granules that are released in response to ____________
Contact with pathogens
Lymphoid follicles are found within the _________ of the intestines and in the mucous membranes lining the _________, _____________, and ___________.
Lamina propria, upper airways, bronchi, and genitourinary tract
The white and red pulp of the spleen are separated by?
The marginal zone
The myeloid progenitor gives rise to which cells? What do each of the cells guve rise to?
The Granulocyte-monocyte progenitor (Neutrophil, Monocyte)
Eosinophil progenitor (Eosinophil)
Basophil progenitor (Basophil)
Megakaryocyte (Platelets)
Erythroid Progenitor (Erythrocyte)
Dendritic cell
Mast Cells
Secondary Lympoid Orhans all share what key features?
- All have anatomicall distinct reqions of T- cell and B-cel activity
- They all develop lymphoid follicles
- Both connected by two different circulatory systems: Blood and Lymphatics
Where is the spleen located?
High in the left side of the abdominal cavity
Which SLOs are highly organized?
Lymph nodes, spleen
Persistent infections to the mucous membranes, skin, and respiratory tract can lead to:
Adenopathy (Swollen lymph nodes)
Gingivitis (Gum inflammation)
Sinopulmonary infection
Pyoderma (skin infection with formation of pus
Innate cells
Myeloid cells and Natural killer cells
Two Types of Lymphoid Organs. What are the roles of each? Which organs fall under each type?
Primary Lymphoid Organs- Regulate the development of immune cells from immature precursors
- Bone Marrow
- Thymus
Secondary Lympoid Organs- Coordinate the encounter of antigen with antigen-specific lymphocytes and their development into effector and memory cells
- Spleen
- Lymph Nodes
- Specialized sites in the gut and other mucosal tissues
Chronic Granulomatous Disease (CGD)
Congenital immunodeficiency, X-linked recessive, involving phagocytic function
Caused by a mutation in one of the five genes that code for subunits of the enzyme NADPH oxidase
Lack of NADPH Oxidase results in the inability to create superoxide, other reactive oxygen species, and reactive chloride species
Can lead to repeated infections of the skin, mucous membranes, and lining of the respiratory and GI tract with catalase positive organisms.
Subset diseases: recurrent lymphadenitis, pneumonia, and dermatological infections
Chronic granulomas occur within the first two yeards of life, but diagnosis may be delayed as late as the second decade of life.
In children, splenectomy can lead to _____________ characterized by systemic bacterial infections caused primarily by ________________, ______________, and ______________.
Overwhelming post-splenectomy infection (OPSI); Streptococcus pneumoniae; Neisseria meningitidis; Hemophilus influenzae
Where is the hematopoietic stem cell found?
Bone Marrow
How many types of LAD are known?
3
What sets the spleen apart from other secondary lymphoid organs?
The spleen is connected only to blood vessels
Which SLOs are less organized?
Mucosa-associated lymphoid tissue
- Tonsils
- Peyer’s patches
- Appendix
- Lymphoid follicles
Adaptive Cells
Cells with T or B cell receptors
Blood vessels and lymphatic systems connect the lymphoid organs, uniting them into a ___________
Functional whole
Role of trabeculae in spleen
Structural support
What molecules are found in the granules of neutrophils? What examples of each? What are their functions?
Proteases- Tissue Remodeling
- Examples: Elastase, Collagenase
Antimicrobial proteins- Direct harm to pathogens
- Examples: Defensins, Lysozyme
Protease Inhibitors- Regulation of Proteases
- Examples: alpha1-anti-trysin
Histamine- Vasodilation, inflammation
In respiratory epithelium the MALT is referred to as ___________
In intestinal epithelium the MALT is referred to as _________
Bronchus-associated lymphoid tissue (BALT)
Gut-associated lymphoid tissue (GALT)
LAD 1 results from the deficiency of the ____________subunit, also called__________, encoded by _________gene found on chromosome __________
Beta2 Integrin
CD18
ITGB2
What is the role of lymphoid folloicles?
They are responsible for the development of B cells that produce high affinity antibodies
Neutrophil Diapedesis Steps
- Neutrophil enters vascular lumen
- Neutrophil is slowed down by PGSL-1
- Neutrophil is then able to binf P-Selectin
- CD11/18 expressed on the neutrophil binds to ICAM-1
- Neutrophil extravated
The process by which hematopoietic stem cells differentiate into mature blood cells is called ___________
Hematopoiesis
In this deficiency white blood cell count and absolute neutrophil count are high
LAD
Monocytes can differentiate into specific tissue macrophases such as:
Osteoclasts in the bone
Microglial cells in the central nervous system
Alveolar macrophages in the lung
What molecules are found in the granules of basophils/ mast cells? What examples of each? What are their functions?
Cytokines- Modulation of adaptive immunre response
- IL-4, IL-13
Lipid mediators- Regulation of inflammation
- Leukotriene
Histamine- Vasodilation, smooth muscle activation
Location of the thymus
Found just above the heart
Monocytes give rise to _______ and __________.
Macrophages; Dendritic cells
Components of the GALT
Loose, barely organized clusters of lymphoid cells in the lamina propria of intestinal villi
Well-organized structures such as the tonsils and adenoids, the appendix, and Peyer’s Patches
What are the three types of helper T cells and what are their roles?
T Helper Type 1: Regulate the immune response to intracellular pathogens
T Helper Type 2: Regulate the response to many extracellulr pathogens
T Helper Type 17: Secrete IL-14 and play an important role in cell-mediated immunity and may help the defense against fungi.
All immune cells taht traffic through tissues, blood, and lymp nodes are guided by small molecules known as ___________
Chemokines
What are M cells?
M cells are flattened epithelial cells that lack microvilli. they are filled with a cluster of B cells, T cells, and macrophages
Role of Gamma Interferon
Used to normalize the oxidative burst of neutrophils to most organisms but is not effective for treating fungal infections
What are the most active sites of hematopoiesis?
The long bones (femur, humerus), hip bones (ileum), and sternum
What is peripheral neuropathy? What are the symptoms?
Damage to the peripheral nervous system.
Numbness or tingling, pricking sensations (paresthesia), or muscle weakness
The splenic white pulp surrounds the branches of the ___________, and consists of the ______________populated by T lymphocytes as well as B-cell follicles.
Central artery; Periarteriolar Lymphoid Sheath (PALS)
3 major components of the thymus and their structures
Cortex- Densely populated with immature thymocytes
Medulla- Sparsely populated with mature thymocytes
Corticomedullary junction- Separated cortex and medulla and allow cells to enter from and exit to the blood stream
What molecules are found in the granules of eosinophil? What examples of each? What are their functions?
Cationic protein- Induces formation of reactive oxygen species
- Examples: Eosinophil peroxidase
Ribonucleases- Vasodilation, basophil degranulation
- Major basic protein
Cytokines- Antiviral activity
- ECP, EDN
Chemokines
- Examples
- IL-4, IL-10 IL-13, TNFa (Modulation of adaptive immune responses)
- RANTES, MIP1a (Attract leukocytes)
In B cells, the receptor is also known as _________
Immunoglobins
Which lymphoid organ is important in the response to systemic infections?
Spleen
Neutophil Test
The nitroblue tertazolium (NBT). Activated Neutrophils are tested for their ability to phagocytose and reduce NBT
Cells that generate a refined antigen specific immune response are considered _________. These cells also give rise to immune _________
Adaptive; Memory
What are the catalase positive organisms?
Candida
S. Aureus
P. Auruginosa
Listeria
Aspergillus
Serratia
Enterobacteriaceae
Roles of the spleen
Organizes the immune response against blood-borne pathogens
Filtering blood and trapping blood-borne antigens
Important in the response to systemic infections
The lymphatic system is a network of thin willed vessels that play a major role in immune cell trafficking, including:
The travel of antigen and antigen-presenting cells to the secondary lymphoid organs
Used for exit of lymphocytes from the lymph nodes
Lymph is derived from the plasma of blood
Components of lymph nodes and their functions/structure
Cortex- Contains lymphocytes (mostly B cells), macrophages, and follicular dendritic cells arranged in follicles
Paracortex- Populated largely by T lymphocytes and also contains dendritic cells that migrated from tissues to the node
Medulla- The innermost layer and the site where lymphocytes exit the lymph node through the outgoing (efferent) lymphatics
Germinal centers- substructures that facilitate the generation of B cells with increased receptor affinities
Thymocytes are positively selected in the the __________
Cortex
Autoreactive thymocytes are negatively selected in the _________
Medulla
Lymphocytes make up ________ to _______% of circulating white blood cell and ______% of cells in the lymph.
20; 40; 99
When do lymphocytes become active? What happens after they become active?
Upon contact with antigen. They proliferate and differentiate into both effector and memory cells.
The lymphoid progenitor gives rise to which cells? What do each of the cells guve rise to?
Natural Killer cell
T- cell progenitor (Helper T Cell, Cytotoxic T cell)
B- cell progenitor (B cell)
Dendritic cells
In this defiency, there is a mutation in lysosomal trafficking receptors that inhibits phagocytosis
Chediak-Higashi Syndrome
High C-reactive protein is indicative of __________
Inflammation
The hematopoietic stem cell gives rise to ________ and __________.
Myeloid progenitor; lymphoid progenitor
What cells secrete chemokines?
Stomal cells
Antigen presenting cells
lmyphocytes
granulocytes
Are hematopoietic stem cells static to the bone marrow?
No they can go to different organs
What role do the natural killer cells play?
They distinguish cells that should be killed from normal cells, by recognizing the absence of the MHC I, which is expressed in almost all normal cells.
They are also involved in the Antibody- Dependent Cell-Mediated Cytotoxicity Complex. The natural killer cells express receptors for immunoglobulins, which allows them to bind antibodies. The antibodies are then able to bind ligands that are attached to the target cell. The Natural killer cells then releases granules that induces apoptosis.
T cytotoxic expresses ___________ and T Helper cells express __________.
CD8, CD4
Flow of immune reaction
- Foreign antigen gains entrance
- Antigen pick up by the lympatic system
- Antigen carried to the lymph nodes
- Lymph nodes become enriched in specific leukocytes
The first cells to respond to infection are considered ____________
Innate
Activated B cells differentiate into effector cells known as ___________, which lose expression of ________ and become highly specialized for secretion of __________.
Plasma Cells; B-cell receptor; antibodies
Leukocyte adhesion defeciency
Rare, autosomal recessive disorder affecting the expression of integrins on the cell surface pf neutrophils. Integrins are needs for white blood cells to extravasate out of the circulation and respond to sites on infections. LAD is typically present early on in life with delayed umbilical cord detachment and omphalitis (infection of the umbilical cord stump). Left untreated patients will go on to develop gingivitis, stomatitis, skin infection, and gut infection. White blood cell count and absolute neutrophil count will be high through any infection
Do natural killer T cells express antigen specific receptors?
No. They are considered a part of the innate immune system
Chediak-Higashi Syndrome
Very rare, autosomal disorder involving lysosomal functioning. Involves the CHS1 and LYST genes (lysosomal trafficking regulators)
Poor traficking of lysosomes, especially affecting the leukocytes, melanocytes, and platelets
Imunodeficiency primarily involves S. aureus, beta- hemolytic strep, and fungus infections
Persistent infections especially involving the mucous membranes, skin, and respiratory tract
Platelet type bleeding
Neurological dysfunction (especially peripheral neuropathy)
Three types of lymphocytes
B lymphoctye
T lymphocyte
Natural Killer Cells
What are the two main microenvironmental compartments of the spleen?
Red pulp
White pulp
How many liters of lymph seep daily?
2.9
One HSC is present per ____________ cells in the bone marrow.
5x104
Where are B lymphocytes derived from in birds?
•Bursa of Fabricius
Plasma cell lose expression of ___________ and become highly specialized for secretion of ____________
BCR; antibody
Pathogen in LAD
Streptococcus milleri
