Mod 3: The Immune Response Flashcards
Phase:
Identify and activate the cells from adaptive immunity that are able to recognize and bind to the antigens from the specific pathogen that’s invading
Antigen Recognition
Phase:
Produce a large quantity of immune cells specific to the pathogen in order to stop the invasion
Lymphocyte activation
Phase:
To completely destroy the pathogen that has invaded the body
Elimination of Pathogens
Phase:
Majority of immune cells die as they are not needed anymore (could cause more damage if they stay)
Contraction (Apoptosis of Immune Cells)
Phase:
When re-exposed to the same antigen, these memory cells proliferate quickly to generate an immune response that is much faster and more robust than the first response to the pathogen
Memory (establishment of immunological memory)
2 Antigen Presenting Cells
Helper T-cells
APCs
Essential in the process to induce an effective adaptive immune response
Are not able to recognize extracellular pathogens by themselves so they require an intermediate to present them the antigens found inside the body
Helper T-cells
Internalize pathogens
by phagocytosis or receptor-mediated endocytosis
Processes pathogens into peptides
Antigen Presenting Cells (APCs)
Most efficient cells that both present antigens thru MHC class II and express costimulatory signals to activate helper t-cells
macrophage
b-cell
dendritic cells
Professional APCs
Can be induced to express MHC class II complexes or stimulatory molecules, but normally they don’t (rarely needed, for short periods)
- fibroblasts
- glial cells
Non-Professional APCs
Pathway:
- MHC Class I (CD8)
- Processed intracellular particles and presents them on cell surface to be recognized
Endogenous pathway (Antigen Processing)
Pathway:
- MHC Class II (CD4)
- 5 steps
Exogenous Pathways (Antigen Processing)
Name the 5 Steps of Exogenous Pathways
- Antigen Engulfment
- Proteolytic Processing
- Formulation of MHC Complex
- Cell Surface Expression
- Recognition by Helper T-cell
Receptor:
•composed of a membrane-bound antibody & signal transduction
molecules (ITAMs)
•they recognize and bind to extracellular pathogens or toxins directly
B-cell Receptor
Receptor:
•formed of membrane-bound antigen-specific molecule and signal
transduction molecules (CD3 and ITAMs)
•in association w/ co-receptor (CD4 & CD8) recognize and
bind to peptide: MHC complex
T-cell Receptor (TCR)
2 Parts of Immune System Communication
Lymphocyte Activation
Cytokine Networks
- involves many interactions with other immune cells, which will mediate the efficiency of the specific immune response
- macrophage, dendritic cell, B-cell, helper T-cell, cytotoxic T-cells
Lymphocyte Activation
- coordinate appropriate immune responses and modulate the balance between humoral and cell-mediated immunity
- are divided into various classes depending on their functions the structure of the receptor
Cytokine Networks
5 Kinds of Cytokine Networks
- Chemokines
- Interleukins
- Interferons
- Tumour Necrosis Factor
- Growth Factors
B- T-cell Signalling Pathways (6 Steps)
- Peptide-MHC class II complex
- Signal 1: TCR-Peptide: MHC Complex
- Expression of Co-Stimulatroy Molecules
- Signal 2: Co-stimulation
- Signal 3: Cytokines
- Outcome of 3 Signals
3 Components of Immune Synapse
- Signalling Molecules (cSMAC)
- Adhesion Molecules (pSMAC)
- Signal Regualtion Molecules (dSMAC)
•induce chemotaxis
•call in cells to the region of infection or injury
•key role in
- inflammation’ wound healing
- cell-mediated and humoral immune responses
-hematopoiesis
Chemokines
- contain over 10 subfamilies
- regulate immune & inflammatory responses
- primarily affect the proliferation and differentiation of various hematopoietic and immune cells
Interleukins (IL)
- most common and well-known molecules are IFN-a, IFN-b, IFN-y
- induce an antiviral state – inhibit the replication process of viruses
- help regulate immune responses
Interferons (IFN)
- the most common and well-known are TNF-a & TNF-b
- involved in systemic inflammation (septic shock)
- involved in tumor regression
- can cause apoptosis (cell death)
Tumour Necrosis Factor (TNF)
•stimulate - growth - proliferation - healing - cellular differentiation •regulate a variety of cellular processes such as immune responses
Growth Factors
- acquired by the fetus or newborn from the mother
- placental transfer of antibodies during pregnancy or breastfeeding
- short-lived immunity (~6months)
- no immunological memory for the recipient
Natural Passive Immunity
- acquired by an injection of serum containing antibodies
- immunity is temporary
- no immunological memory for the recipient
Artificial Passive Immunity
•acquired through infection by a pathogen
- possibly leading to symptoms/a disease state
•development of innate and adaptive immune responses
•immunological memory has a significant change of being developed
Natural Active Immunity
- acquired through vaccination
- development of innate and adaptive immune responses
- no symptoms/disease states present
- immunological memory has a significant chance of being developed
Artificial Active Immunity
