Lect 2 - -Lymphatic organs Flashcards
What is the function of The Immune System
distinguishing between self or non-self, dangerous or non-dangerous and responding to those with tolerance or elimination.
What is Immunohomeostasis?
maintenance of the genomic permanency
What is Antigen?
every structure (cells, molecules, microbes) that the immune system recognizes and responds to it
Steps of Innate immune system?
Cells → cellular immune response
(Monocytes - macrophages
Granulocytes
Dendritic cells
Mast cells)
Soluble molecules → humoral immune response
Complement proteins (glycoproteins, enzymes, receptors)
Steps of adaptive immune system
Cells → cellular immune response
(B lymphocytes
T lymphocytes)
Soluble molecules → humoral immune response (Antibodies)
Activation of the Innate System
-> What are some recognized structures?
Pathogen Associated Molecular Pattern (PAMP), or Damage-Associated Molecular Patterns (DAMP)
What are Receptors in Activation of the Innate System?
Pattern Recognizing Receptors (PRR).
(They are not clonal. They are the same on different cell types. )
Function of Major Histocompatibility Complex:MHC-I
MHC I displays endogenous antigens, or antigens from within the cell
- a diverse set of cell surface receptors expressed on all nucleated cells in the body, as well as platelets.
Function of Major Histocompatibility Complex: MHC-II
MHC II displays exogenous antigens, or antigens from outside the cell
- MHC class II molecules thereby are critical for the initiation of the antigen-specific immune response.
Origin of Antigens
originated from lipids join to CD1, peptide antigens join to MHC-I or MHC-II.
Antigen presentation
-> Antigen processing of endogenous proteins (the host cell synthesizes foreign proteins with tumour cell like characteristics in viral or bacterial infected cells).
proteasome (enzymes)
→ ER (peptide fragments join to MHC-I
→ Golgi
→ vesicular transport
→ appearance on the cell surface
Antigen presentation
-> Antigen processing of Exogenous proteins (the host cell synthesizes foreign proteins with tumour cell like characteristics in viral or bacterial infected cells).
endo- and lysosome system
→ protected MHC II - formed in the ER join to vesicular system
→ protein binds to MHC-II
→ appearance on the cell surface
The role of NK cells
NK cells express „Killer Activating Receptor (KAR) „ and „Killer Inhibitory Receptor” (KIR).
Steps of activation of NK cells
- Binding „self” MHC-I molecules to the KIRs inhibits the KARs.
- NK cell does not destroy self. Virus infected and tumour cells decrease the MHC-I expression to hide themselves from cytotoxic T-cells.
=> Therefore there is no enough MHC-I to activate the KIR so the NK cells attack.
(NK cells express „Killer Activating Receptor (KAR) „ and „Killer Inhibitory Receptor” (KIR). )
Does NK cells destroy itself? Why?
NK cell does not destroy self.
=> Virus infected and tumour cells decrease the MHC-I expression to hide themselves from cytotoxic T-cells.
=> Therefore there is no enough MHC-I to activate the KIR so the NK cells attack.
(NK cells express „Killer Activating Receptor (KAR) „ and „Killer Inhibitory Receptor” (KIR). )
Virus infected and tumour cells decrease the MHC-I expression to hide themselves from ____ (which type of cells?)
cytotoxic T-cells
What is CD (Clusters of Differentiation)?
The cell surface molecules that determine the type of the cell, the stage of the differentiation or activation.
Example of Cell line markers
1/ Hemopoietic stem cell CD34+
2/ T-helper cell - CD4+
3/ T-citotoxic-CD8+
2 types of cell line markers
- Maturation markers
- Activation markers
Examples of maturation markers
Tymocytes in the thymus CD1+, mature T lymphocyte does not express this
What are Cytokines?
small peptides or glycoproteins that regulate the cell functions in the immune system through receptor mediated pathways.
What are Lymphokines?
cytokines produced by lymphoid cells.
5 types of Antibodies – Immunoglobulins (Ig)
1/ IgM
2/ IgD
3/ IgG
4/ IgA
5/ IgE
Identify the 5 types of antibodies
What is IgM?
naive B cell antigen binding receptor
What is IgD?
naive B cell antigen binding receptor
What is IgG?
„switched” B cell antigen binding receptor (opsonisation, complement activation, maternal immunity)
What is IgA?
„switched” B cell antigen binding receptor (mucosa immunity)
What is IgE?
„switched” B cell antigen binding receptor (immediate hypersensitivity)
What does it mean when it comes to Diversity of the Antigen Binding Receptors?
Genetic mechanism that results in diversity and specificity is the somatic recombination of genes that code the antigen binding site of the immunoglobulins and T-cell receptors.
What is B-cell Receptor (BCR)?
membrane bound immunoglobulin molecule with signal transduction chains
BCR: membrane bound immunoglobulin molecule with signal transduction chains.
-> BCR reacts with _____
soluble or corpuscular antigens
Antigen-activated B-cells may follow two pathways which are ____ and ____
1/ T-dependent activation
2/T-independent activation
How does T-dependent activation occur?
T-cell-independent antigen, B cells will proliferate and differentiate into short-living (SL) plasma cells and release low-affinity antibodies (first-line defence)
How does T-independent activation occur?
(2) T-cell-dependent antigen, B cells proliferate, undergo somatic hypermutations and isotype class switch, and differentiate into either long-living (LL) plasma cells releasing high-affinity antibodies and memory B cells.
T-cell Receptor (TCR) coded by ___
genes belonging to the Ig super-family
T-cell Receptor (TCR) recognize only ___
linear sequence of peptide fragments that join to MHC molecules!!!
Is TCR-MHC-antigen binding enough for T-cell activation? Why?
TCR-MHC-antigen binding is not enough for T-cell activation.
-> Co-stimulatory molecules are necessary!!!
What are included in cellular immune response?
- Production of cytokines (lymphokines) – activation of macrophages
- Regulation of inflammatory and cytotoxic processes
- Defense against intracellular pathogens
What are the 2 responses relating to T-cell classes?
- Cellular immune response
- Humoral immune response
What are included in humoral immune response?
- Production of lymphokines – activation of B cells
- Differentiation into plasma cells
- Defense against extracellular pathogens
What is included in regulation of immune response?
Production of lymphokines
The role of T-cell classes
Destroys virus or intracellular pathogen infected or tumour cells (perforin, granular enzymes.)
3 Organization Levels of the Immune System
- Cells: cells of the innate and adaptive immune system
- Tissues: blood and lymphatic tissues
- Organs: lymphatic organs
Organization of Lymphatic Organs
-> What are the 2 Primary (central) lymphatic organs?
- Bone marrow
- Thymus
Organization of Lymphatic Organs
-> Primary (central) lymphatic organs
-> The role of Bone marrow
formation of T and B lymphocyte and maturation of B-cells
Organization of Lymphatic Organs
-> Primary (central) lymphatic organs
-> The role of Thymus (thymus gland)
maturation of T-cells
Organization of Lymphatic Organs
-> What are the 5 Secondary (peripheral) lymphatic organs?
- Mucosa Associated Lymphatic Tissue (MALT: antigen in the mucosa)
- Skin Associated lymphatic Tissue (SALT), antigen in the skin)
- Lymph and lymph node (antigen in tissues)
- Spleen (antigen in the blood)
- Gastriontestinal tract (digestive tract) GALT
Organization of Lymphatic Organs
-> The role of Secondary (peripheral) lymphatic organs
„meeting with the antigens”
→ activation of B and T cells
Different Forms of Lymphatic Tissue
-> Identify this form of lymphatic tissue
Diffuse lymphoid elements (lymphocytes)
Different Forms of Lymphatic Tissue
-> Identify this form of lymphatic tissue
Aggregated lymph nodules (pl. Payer’s plaque)
Different Forms of Lymphatic Tissue
-> Identify this form of lymphatic tissue
Lymph node
Different Forms of Lymphatic Tissue
-> Identify this form of lymphatic tissue
Solitary lymph nodule or follicle
Different Forms of Lymphatic Tissue
-> Identify this form of lymphatic tissue
Epithelium related lymphatic tissue : tonsils
Different Forms of Lymphatic Tissue
-> Identify this form of lymphatic tissue
spleen
Different Forms of Lymphatic Tissue
-> Identify this form of lymphatic tissue
Thymus
Types of lymphatic organs
Capsulated lymphatic organs
Primary Lymphatic Organ: Thymus
-> What is the arterial supply?
a. thoracica interna, a. pericardiophrenica, a. thyroidea sup. et. inf.
Primary Lymphatic Organ: Thymus
-> What is the venous supply?
v. brachiocephalica
Primary Lymphatic Organ: Thymus
-> What are the included lymph vessels?
only efferents!!!
-> Anterior mediastinal lymph nodes
Primary Lymphatic Organ: Thymus
-> What is the Vegetative innervation?
n. vagus, sympathetic innervation