Immunology Flashcards
Where is the site of B-cell localization and maturation?
Follicle of lymph node
Which part of the lymph node contains contain Reticular cells and Macrophages
Medulla
The region of the cortex between follicles and medulla is called
Paracortex
Where is T cells housed in the lymph node
Paracortex
Lymphatic drainage for the head and neck
Cervical Lymph node
Lymphatic drainage for the LUNGS
Hilar Lymph node
Lymphatic drainage for the Trachea and esophagus
Mediastinal Lymph Node
Lymphatic drainage for the Upper limb, breast, skin above umbilicus
Axillary Lymph node
Lymphatic drainage for the Liver, stomach, spleen, pancreas, upper duodenum
Celiac Lymph node
Lymphatic drainage for Lower duodenum, jejunum, ileum, colon to splenic flexure
Superior Mesenteric Lymph node
Lymphatic drainage for Colon from splenic flexure to upper rectum
Inferior Mesenteric Lymph Node
Lymphatic drainage for Lower rectum to anal canal (above pectinate line), bladder, vagina (middle third) cervix, prostate
Internal Iliac Lymph Node
Lymphatic drainage for Testes, Ovaries, Kidneys, Uterus
Para-aortic Lymph Node
Lymphatic drainage for Anal canal (below pectinate line), skin below umbilicus (except popliteal area), scrotum, vulva
Superficial Inguinal Lymph Node
T and B-cell activation is through
APC (antigen presenting cells)
What are the antigen presenting cells
B-cells, Dendritic cells, Langerhans cells, Macrophages
Which cells require Two signals before they can be activated
T-cells, B-cells and Class switching
Which SPECIALIZED APC cells sample antigens, processes antigens and migrates them to the draining lymph node
Dendritic Cells
What is the 1st signal in T-cell activation?
- Antigen is presented on MHC II and recognized by
TCR on Th (CD4+) cells— ( exogenous synthesized) - Endogenous or cross-presented antigen is presented
on MHC I to Tc (CD8+) cell
What is the 2nd signal in T-cell activation?
- Co-stimulatory signal via interaction of B7 protein on
dendritic cells (CD80/86) and CD28 on naive T cell.
** The cells activate and produce cytokines.
** Tc cells activate and is able to recognize and kill
virus-infected cells
What is B-cell receptor-mediated endocytosis
Foreign antigen is presented on MHC II and recognized by TCR on Th cell
Which receptor binds the CD40L on Th cell during B-cell receptor mediated endocytosis
CD40 receptor
What happens in B-cell receptor endocytosis after the binding of CD40 and CD40L
Th cell secretes cytokines that determine Ig class switching of B-cell
What determines the unique antigen-binding pocket
Fab region
What determines the Isotype (eg. IgM, IgD etc)
Fc region
Which cytokine when secreted causes 1. Fever, 2. acute inflammation, 3. activates endothelium to express adhesion molecules and 4. Induce chemokine secretion to recruit WBC’s
Interleukin -1
Interleukin-6 causes
Fever and stimulate production of acute phase proteins
Cytokine for Major Chemotactic factor for neutrophils
Interleukin-8
Interleukin-12
- Induces differentiation of T cells into Th1 cells and
2. Activates NK cells
What does Tumor necrosis factor-alpha do
- Activates endothelium 2. Causes WBC recruitment
3. Vascular leak
Which cytokines are secreted by T-cell
- Interleukin-2 and 2. Interleukin-3
Cytokine for Stimulating GROWTH of 1. Helper,
2. Cytotoxic and 3. Regulatory T cells and 4. NK cells
Interleukin-2
Interleukin-3 secretion is for
Supporting growth and differentiation of bone marrow stem cells. Function like GM-CSF
What are the components of innate immunity?
- Neutrophils
- Macrophages
- Dendritic Cells
- Natural Killer Cells (NK) - lymphoid origin
- Complement
How does innate immunity respond to pathogens?
- Nonspecific
- Rapid response (Minutes –> Hours)
- No memory response
What are the secreted proteins associated with innate immunity?
- Lysozyme
- Complement
- C-reactive protein (CRP)
- Defensins
What are the components of adaptive immunity?
- T cells
- B cells
- Circulating antibodies
How does adaptive immunity respond to pathogens?
- Highly specific
- Refined over time
- Develops over long periods
- Memory response that is faster and more robust
What are the secreted proteins associated with the adaptive immune response?
Immunoglobulins (Ig)
What cytokine is secreted by NK cells and T cells in response to antigen or IL-2 from macrohages
Interferon-gamma
Which cytokine stimulates macrophages to kill phagocytosed pathogens and inhibit differentiation of Th2 cells
Interferon-gamma
Cytokine that 1. Activates NK cells to kill virus-infected cells and 2. Increases MHC expression and antigen presentation by all cells
Interferon-gamma
Which cytokines is produced from Th2 cells
Interleukin-4, Interleukin-5 and Interleukin-10
Function of interleukin-4
- Induces differentiation of T cells into Th2 cells
- Promote growth of B cells
- Enhances class switching to IgE and IgG
Function of Interleukin-5
- Promote growth and differentiation of B cells
- Enhance class switching to IgA
- Stimulate growth and differentiation of Eosinophils
Function of Interleukin-10
- Attenuates inflammatory response
- Decreases expression of MHC class II and Th1
cytokines - Inhibits activated macrophages and dendritic cells
Which cytokines ATTENUATE immune response
TGF-beta and Interleukin-10
Which enzyme place a role in the creation and neutralization of reactive oxygen species
NADPH oxidase
NADPH oxidase deficiency
Chronic granulomatous disease
Which enzyme has the blue green heme containing pigment that gives sputum its color
Myeloperoxidase
Which enzyme converts O2- to H2O2
Superoxide dismutase
What condition are patients with Chronic granulomatous disease at risk of
Increased risk of infection with
(catalase +) species. { staph aureus, Aspergillus)
Why are patients with chronic granulomatous disease at an increased risk with catalase + species
They are capable of neutralizing their own H2O2
What does Pseudomonas aeruginosa use to generate reactive oxygen species (ROS) to kill competing microbes
Pyocyanin
What are the major functions of T cells?
- Cell mediated immunity
- CD8+ T cells directly kills virus infected cells
- CD4+ T cells help B cells help B cells make Ab and produce cytokines
- Assoc with delayed cell mediated hypersensitivity (IV)
- Assoc with chronic cellular organ rejection
Which interferons are synthesized by virus-infected cells that act locally on UNinfected cells to prime them for viral defens by helping degrade viral nucleic acid and protein
Interferon alpha and interferon-beta
Where are T cells located in the spleen?
Periarteriolar lymphatic sheath (PALS) in the white pulp
Where B cells found in the spleen?
Follicles within the white pulp
What is positive selection?
Ability for TCR of T cells to survive the binding to self MHC on cortical epithelial cells
What is negative selection?
T cells expressing TCR with high affinity for self Ag undergo apoptosis
What should pts undergoing splenectomy or are asplenic or SS pts be vaccinated against?
encapsulated organisms:
1. HiB
2 Pneumococcus
3. Menningococcus
Where do antigen presenting cells (APC) capture blood-borne antigens for recognition by lymphocytes
Marginal zone
Where are B cells found
Follicles within white pulp
Where are T cells found
Periarteriolar lymphatic sheath (PALS)
What happens in splenic dysfunction (eg. sickle cell disease, post-splenectomy)
decrease IgM—> decrease complement activation—> decrease C3b opsonization—> increase susceptibility to encapsulated organisms
What infection should a patient be vaccinated against before undergoing splenectomy
pneumococcal, Hib, meningococcal)
Which pharyngeal pouch is the thymus derived from
Third pouch
The thymus is hypoplastic in which condition
DiGeorge and SCID
The thymus is derived from which pharygeal pouch?
3rd pharyngeal pouch
What does the cortex of the thymus contain?
Immature T cells
What does the medulla of the thymus contain?
Mature T cells Hassal corpuscles (contain epithelial reticular cells)
What is a thymoma?
Benign neoplasm of the thymus
What dz is associated with thymoma?
- Myasthenia Gravis
2. Superior Vena Cava syndrome
What is superior vena cava syndrome?
Obstruction of the superior vena cava —> impaired blood drainage from the head, inc. ICP
What dz are associated with hypoplastic thymus?
- SCID
2. DiGeorge syndrome
What cytokines enhances the activity of Natural Killer cells?
IL-2, IL-12, IFN-alpha, IFN-beta
What is the MOA of Natural Killer cells?
Use perforin and granzyme to induce apoptosis of virally infected cells and tumor cells
What are the major functions of B cells?
- Humoral immunity
- Recognize Ag
- Produce Ab
- Maintain immunological memory
What are the major functions of T cells?
- Cell mediated immunity
2.
What is the general function of cytokines?
Recruit phagocytes and produce cytokines
Where does positive selection of T cell occur?
Cortex of thymus
Where does negative selection of T cell occur?
Medulla of thymus
Why is tissue specific Ag expressed in the thymus?
d/t action of (AIRE) autoimmune regulator
What is the cause of autoimmune polyendocrine syndrome-1
Deficiency in AIRE
What does T helper cell differentiate into?
Th1, Th2, Th17 and T-reg
What Ig are expressed on the surface of mature, naive B cells prior to their activation?
IgM and IgD
Where do B cells differentiate?
In germinal center of the lymph node
What do B cells class switch to?
Plasma cells that secrete IgA, IgE or IgG
What the functions of IgE?
- Bind mast cells and basophils
- Mediate type I hypersensitivity
- Release inflammatory mediators eg: histamine
- Activate eosinophils (immune response to worms)
Where is IgD found?
In serum and on the surface of B cells
What is the function of MHC
Present antigen fragments to T cells and bind T cell receptor and are coded by HLA genes
What is the Loci of MHC I
HLA-A, HLA-B, HLA-C
MHC I binds to which components
TCR and CD8
MHC II binds to which components
TCR and CD4
Where are MHC I expressed
All Nucleated cells, APCs, Platelets but Not RBC
Where are MHC II expressed
APCs
What is the structure of MHC I
1 long chain and 1 short chain
The structure of MHC II
2 equal length chain
What are the loci of MHC II
HLA-DP, HLA-DQ, HLA-DR
Which MHC class present ENDOGENOUSLY synthesized ANTIGENS (eg. viral or cytosolic proteins) to CD8+ cytotoxic T cells
MHC I
EXOGENOUSLY synthesized ANTIGENS (eg. bacterial proteins) are presented to CD4+ helper T cell by
MHC II
Which protein is associated to MHC I
Beta2-microglobulin
Invariant Chain is associated to which class of MHC
MHC II
Hemochromatosis is associated to which subtype of HLA
HLA-A3
HLA - B8 is associated to which conditions
Add Mye Graves Bi8/ B8 is GAMe
- Addison disease—— Add
- Myasthenia Gravis— Mye
- Graves disease——- Graves
HLA - B27 is associated to which conditions
PAIR of B27 bombers/ Seronegative PAIR
- Psoriatic arthritis
- Ankylosing spondylitis
- IBD-associated arthritis
- Reactive arthritis
Which HLA subtype is associated with Celiac disease
I ate (8) too (2) much gluten at DQ HLA-DQ2/ HLA-DQ8
HLA-DR2 is associated to which disease
2 GLAM to give a damn!/ Hey MSG
- Multiple sclerosis
- Hay fever (Allergic Rhinitis)
- SLE (Lupus)
- Goodpasture syndrome
Which two HLA subtypes are associated to SLE
HLA-DR2 and HLA-DR3
Diabetes mellitus type -1, Graves disease, Hashimoto thyroiditis, Addison disease and SLE are associated to which HLA subtype
HLA-DR3
HLA-DR4 is associated with which diseases
There are 4 walls in a Rheum (room)
- Rheumatoid arthritis
- Diabetes mellitus type 1
- Addison disease
Hashimoto thyroiditis, Pernicious anemia—–> vitamin B12 deficiency is associated to which HLA subtype
HLA-DR5
Hush Puppies
