Innate immunity and WBCs Flashcards
What is the innate immune system?
The innate immune system consists of non-specific mechanisms that are inherent to the host organism, providing immediate defense against a wide range of pathogens.
How does the innate immune system differ from the adaptive immune system?
The innate immune system is non-specific and responds immediately to pathogens, while the adaptive immune system is specific and develops a targeted response over time.
What are the key characteristics of the innate immune system?
Key characteristics of the innate immune system include being non-specific, rapid response, and the presence of physical barriers (like skin), phagocytic cells, and various chemical mediators.
How do phagocytes recognize pathogens in the innate immune system?
Phagocytes recognize pathogens through common microbial motifs, known as pathogen-associated molecular patterns (PAMPs), which are shared by many types of microorganisms.
Does the innate immune system require prior exposure to pathogens?
No, the innate immune system does not require prior exposure to pathogens; it is activated immediately upon encountering a pathogen.
What types of defenses are included in the innate immune system?
Defenses in the innate immune system include physical barriers (e.g., skin), chemical barriers (e.g., antimicrobial proteins), cellular defenses (e.g., phagocytes), and inflammatory responses.
What does it mean that the innate immune system is inherited?
The innate immune system is inherited, meaning it is present at birth and does not require previous exposure to pathogens to function.
Is the innate immune system specific or non-specific?
The innate immune system is non-specific; it provides immediate defense against a wide range of pathogens without targeting specific ones.
What role do phagocytes play in the innate immune system?
Phagocytes play a crucial role by engulfing and destroying pathogens through processes like phagocytosis, contributing to the immediate immune response.
What are some examples of phagocytes in the innate immune system?
Examples of phagocytes include neutrophils, macrophages, monocytes, dendritic cells, and mast cells.
What type of protection does the innate immune system provide?
The innate immune system provides nonspecific protection against foreign cells or substances without needing to recognize their specific identity.
How does the innate immune system identify foreign invaders?
It recognizes general, conserved properties that mark invaders as foreign, rather than specific characteristics.
Is the innate immune response present at birth?
Yes, the innate immune system is inherited and present at birth, allowing immediate defense against pathogens.
What distinguishes the innate immune system from the adaptive immune system?
The innate immune system is nonspecific and reacts quickly, while the adaptive immune system is specific and develops memory over time.
Why is it important for the innate immune system to recognise conserved properties?
Recognising conserved properties allows the innate immune system to respond effectively to a wide range of pathogens, providing immediate protection.
What are PAMPs and their role in pathogen recognition?
Back:
PAMPs (Pathogen-Associated Molecular Patterns) are molecular signatures on pathogens that are recognized by the innate immune system to initiate a response.
What is one of the primary functions triggered by the recognition of PAMPs?
The recognition of PAMPs triggers inflammation, which helps recruit immune cells to the site of infection.
How do PAMPs influence complement activation?
PAMPs activate the complement system, which enhances the ability to identify bacteria, activate immune cells, and promote clearance of pathogens
What is the significance of identifying bacteria through PAMPs?
Identifying bacteria through PAMPs helps activate immune cells and promotes clearance of the pathogens from the hos
How do PAMPs affect the adaptive immune system?
PAMP recognition activates the adaptive immune system, leading to a more specific and long-lasting immune response against pathogens.
What are the four steps of leukocyte extravasation?
Chemoattraction
Rolling adhesion
Tight adhesion
Endothelial transmigration via pseudopodia
What occurs during the chemoattraction step of leukocyte extravasation?
TLR activation leads to the release of cytokines and chemokines, which attract leukocytes to the site of infection.
What is the role of carbohydrate ligands in the rolling adhesion step?
Carbohydrate ligands on leukocytes bind with slight affinity to selectin molecules on endothelial cells, facilitating rolling along the vessel wall.
What activates integrin molecules during the tight adhesion step?
Chemokines produced by macrophages activate integrin molecules on leukocytes, leading to a stronger adhesion to the endothelial cells.
How do leukocytes undergo endothelial transmigration?
Leukocytes use pseudopodia to squeeze through the gaps in endothelial cells, allowing them to exit the bloodstream and enter the tissue at the site of infection.
What is the first step of leukocyte extravasation?
Chemoattraction: TLR activation leads to cytokine and chemokine release. Chemokines attract leukocytes to the site of infection or injury.
Describe the second step of leukocyte extravasation.
Rolling Adhesion: Carbohydrate ligands on leukocytes bind with slight affinity to selectin molecules on endothelial cells, causing the leukocytes to roll along the vessel wall.
What occurs during the third step of leukocyte extravasation?
Tight Adhesion: Chemokines from macrophages activate integrin molecules on leukocytes, increasing their affinity for adhesion molecules on endothelial cells, allowing firm attachment.
Explain the final step of leukocyte extravasation.
Endothelial Transmigration: Leukocytes use pseudopodia to migrate through the endothelial cell layer, exiting the bloodstream to enter tissues where they are needed.
What are selectins, and what role do they play in extravasation
Selectins: Adhesion molecules on endothelial cells (e.g., P-selectin, E-selectin) that bind to carbohydrates on leukocytes, facilitating their initial rolling adhesion.
Name two types of endothelial selectins involved in leukocyte recruitment.
P-selectin and E-selectin: Both are types of selectins that bind carbohydrates on leukocytes, helping them adhere to the endothelium during extravasation.
Give an example of an integrin and its function.
LFA-1 is an integrin that binds to Cell-Adhesion Molecules (CAMs) like ICAM on endothelial cells to promote tight adhesion.
What are integrins, and how do they function in extravasation?
Integrins are Adhesion molecules found on leukocytes that facilitate firm adhesion to endothelial cells. They interact with cell-adhesion molecules (CAMs) on the endothelium.
How do selectins and integrins work together during extravasation?
Selectins mediate the initial rolling adhesion of leukocytes, while integrins enable tighter adhesion to the endothelial cells, allowing for transmigration.
What role do chemokines play in cell recruitment?
Chemokines influence the migration of immune cells by attracting them to specific tissues.
How do different chemokines affect cell recruitment?
Different chemokines recruit different types of immune cells to various tissues based on the specific signals they provide.
What is the significance of different combinations of selectins in cell recruitment?
Different combinations of selectins on endothelial cells facilitate the selective recruitment of specific immune cells to sites of inflammation or infection.
Why is selective recruitment important in the immune response?
Selective recruitment ensures that the appropriate immune cells are directed to the right tissues at the right time, enhancing the effectiveness of the immune response.
What additional role do PAMPs play beyond activating phagocytes?
PAMPs also activate the complement system.
What are the three main roles of the complement system
Inflammation
Cell lysis
Opsonization
How do PAMPs contribute to inflammation?
PAMPs activate the complement system, which triggers inflammatory responses to recruit immune cells to the site of infection.
What is cell lysis in the context of the complement system?
Cell lysis refers to the destruction of pathogen cell membranes, leading to the death of the invader.
How does opsonisation enhance the immune response?
Opsonisation marks pathogens for destruction by phagocytes, making it easier for them to recognize and engulf the invaders.
What initiates the immune response?
It all begins with recognition of pathogens via PAMPs.
What do PAMPs do in the immune system?
PAMPs serve as flags on pathogens, enabling their recognition by the immune system
How do PAMPs trigger an immune response?
PAMPs trigger inflammation and cause cell recruitment to the site of infection.
What is the role of PAMPs in the complement activation?
PAMPs activate the complement system, which helps identify bacteria, activate immune cells, and promote clearance.
How do PAMPs affect the adaptive immune system?
PAMPs activate the adaptive immune system, enabling a specific response to pathogens.
What is complement?
Complement is a system of more than 30 proteins found in plasma and on cell surfaces.
What type of biochemical processes does the complement system involve?
The complement system involves a series of proteolytic cascades.
How many main pathways activate the complement system?
There are three main pathways of activation for the complement system.
What are the three main pathways of complement activation?
Classical
2. Alternative
3. Lectin
How do pathogens interact with the immune system?
The breakdown of pathogens generates numerous antigens.
What do the antigens generated from pathogens represent?
Antigens represent fragments of various proteins expressed by the pathogen.
Where can antigens be presented?
Antigens can be presented on phagocytic cells or released into the body.
How are antigens related to the adaptive immune system?
Antigens can be recognized by cells in the adaptive immune system.
