Lymphoid System I Flashcards
Innate (non-specific) immunity
Neutrophils and Macrophage can phagosotzie bacteria and remove them from that location
PIC
Natural Killer Cells (NK Cells)
- Surgical Stress reduces NK cell numbers and function
- Post operative los of NK cell numbers/function is greatest after 3 days and recovers by 1 month
- Loss of NK cells may allow enhanced seeding of metastatic foci
Acquired (specific) immunity
-bacteriafragment is presented by lymphocyte with surfaced (IGD) that acts as receptors. If IGD variable portion is complementary to fragments of bacteria, itll activate the LYMPHOSYTE.
PIC
Acquired (specific) immunity Evolution
Sharks are the oldest vertebrate class
- Have an adaptive immune system based on immunoglobulins (IG)
- Rearrange mechanisms and T cell receptors and major histocompatiblity complex
Functions of the Lymphoid System
Protection and immunity
Functions of the Lymphoid System: Antigen recognition
must distinguish self VS non-self
Functions of the Lymphoid System: Antigen Inactivation/Elimination
“The immune response”
- foreign material
- microorganisms
- cancer cells
- organ transplants (unless from twin, organ translplants will be recognized as foreign so they have to take immunity depressors)
Types of acquired immunity
Humoral
-B cell lymphocytes
Cell-mediated
-T cell lymphocytes
PIC
Physical barriers that help the body protect itself in a limited way
Bronchi
- gut- acid, pH change
- Skin barrier
- lysozyme in tears
Body Defense Mechanism
Physical/Biochemical Barriers
(1st line of defense)
Innane (non-specific) immunity
(2nd line of defense
Acquired (specific) immuninty
(3rd line of defense)
Types of Adaptive Immunity
PIC
Sources of Lymphocytes: Bone Marrow and Thymus
Central Lymphoid Tissues
all other organs are peripheral lymphoids
Sources of Lymphocytes: B/T cells are derived from…
B cells are derived from Bone marrow
T Cells are sent to Thymus to mature
If Stem cells are converting to B Lymphocytes, itll occur in the bone marrow (PIC)
Humoral Immunnity (production of antibodies)
- B cell origin & development
- Bone Marrow - Plasma Cells
- Antibody (immunoglobulin)
- Humoral Response
Central Lymphoid Tissues (PIC): Memory Cell functions
Help the body have a rapid response if you ever get attacked by the antigen again
Central Lymphoid Tissues (PIC): Fetal Liver Function
In the 2nd trimester- the
Fetus produces B lymphocytes in liver.
Production can be reactivated later on in life if bone marrow is damaged due to disease. Liver has a memory from its fetal life
Distinguishing characteristics of Plasma Cells
Off center nucleus
Abundance of RER - to make immunoglobulins
-sometimes can see cartwheel chromatin
Plasma Cells “Antibody factories”
- Produce and Secrete ABS
- Terminally differentiated
- Survive weeks to months
Basic Structure of Immunoglobulins:
2 heavy chains
2 light chains
Both help together by disulfide bonds
Significant, variable portions
(amino acids vary from b cell to b cell)
Basic Structure of Immunoglobulins: Variability portion occurs by…
Variablility in variaboel portion occurs by somatic recombination
- Exon Shuffle
- If final product is complementary to a pathogen then that’s the GO signal to attack them
Classes of Immunoglobulin (IG)
PIC STUDY GRAPH
IgG
Most frequent in bodu (80%) in serum
What happens when you get imunized?
LOOK AT GRAPH
5 Different Mechanisms in which antibodies promote humoral response to destroy foreign pathogens:
- Agglutination
- Opsonization
- Neutralization
- Cytoxicity
- Complement Activation
5 Different Mechanisms in which antibodies promote humoral response to destroy foreign pathogens: Agglutination
Antibodies bind to antigens, forming aggregates and reducing the amount of free antigens
5 Different Mechanisms in which antibodies promote humoral response to destroy foreign pathogens: Opsonization
Binding of antibodies ot the microorganism stimulates phagocytosis
5 Different Mechanisms in which antibodies promote humoral response to destroy foreign pathogens: Neutralization
The binding of antibody to microorganism blocls their adhesion to the cells and inactivates toxins
5 Different Mechanisms in which antibodies promote humoral response to destroy foreign pathogens: Cytotoxicity
Mediated by cells which onvolve antibodies adhering to the surface of worms activating cells of the immune system (eosinophils and macrophages) and inducing them to liberate chemical agents that attack the surface of the animal
5 Different Mechanisms in which antibodies promote humoral response to destroy foreign pathogens: Complement Activation
Binding of antibodies to the initial protein of the complement system triggers the complement cascade which in turn eventually produces the membrane attack complex (forms transmembrane channels) and causes cell lysis
Cell Mediated Immunity:
- T Cell Origin & Development
- Thymus: Naive T Cell->Mature T cell - T Cell Receptors (TCR)
- T Cell Types (memory, helper, cytotoxic) & Functions
- Cytokines (Lymphokines)
What is PD-1?
A cell surface receptor expressed on T Cells. PD-1 and it’s ligands (PD-L1 & PD-L2) down regulate the immune system by reventing the activation of T-cell. PD-1 inhibitors activate the immune Ststem to attack tumors and treat cancer
Milestones in Therapy
Surgery, radiation, Endocrine, Chemotherapy, Gene Therapy (stem cell), Immunotherapy
Peripheral Lymphoid Tissues
PIC
Antigen Recognition
LOOK AT PIC
Do All cells contain MHC-1?
YES and can interact with CD8+ cells, Cytotoxic T Cells
MHC-I
Present on all cell types
-interact with CD8+ (cytotoxic) T Cells
-Do NOT pass through Endosome-lysosome vesicles (viruses)
(PIC)
MHC-II
-Present on APCs
-Interact with CD4+ (helper) T Cells pass through endosome-lysosome vesicles (phagocytosis)
(PIC)
Helper T Cell (CD4+)
PIC
- Interact with antigen presenting cells
- Recognize fragment as foreign and produces interlucens (cytokines)
- Calls B Cells to produce antibodies
Cytotoxic T Celsl (CD8+): Mechanisms of Killing
Target cell infected with a virus
-virus is presented to the T cell and if the receptor component of the T cell is complimentary to the Virus then the CTL destorys Target cells via…
- Perofrin (proteins makes perferations on target cell)
- FAS Ligand (member of death receptor fam that when activated cause cell to undergo Apoptosis
Necrosis: Necrotic cell death
Apoptosis: Causes cell to destory itself from within (suicide from within)
