Introduction to Infection & Immunity Flashcards
What are the physical and chemical barriers to infection?
Skin, Mucus, Epithelial barrier
These barriers serve as the first line of defense against pathogens.
What characterizes innate immunity?
Early response, Rapid, No memory, Pattern recognition receptors
Innate immunity provides immediate defense against infection.
What are the components of adaptive immunity?
Humoral and cellular, Later response, Slower, Antigen-specific receptors, Memory
Adaptive immunity develops over time and targets specific pathogens.
What are the exterior defenses to infection?
Lysozyme, Cilia, Mucus, Sebaceous glands, Acid in stomach, Skin
These components help prevent pathogens from entering the body.
What are collectins in innate humoral immunity?
Mannose binding lectin, Pentraxins, C-reactive protein
Collectins are proteins that play a role in recognizing pathogens.
What antibodies are involved in humoral immunity?
IGM, D, G, A, E
Different antibodies have various roles in the immune response.
What is the main function of antibodies?
Opsonisation, Phagocytosis
Antibodies enhance the ability of immune cells to clear pathogens.
What types of cells are involved in innate cellular immunity?
Neutrophils, Monocytes, Dendritic cells, Macrophages, Mast cells
These cells are crucial for the immediate response to infections.
What role do T-cells play in adaptive immunity?
Activated T-helper cells, B-cells, Plasma cells, Memory cells
T-cells are essential for coordinating the immune response.
What do PRRs recognize?
Pathogen-associated molecular patterns (PAMPs), Danger associated molecular patterns (DAMPs)
PRRs help identify harmful pathogens and tissue damage.
Which cells carry out phagocytosis?
Macrophages, Neutrophils, Dendritic cells
These cells engulf and destroy pathogens through phagocytosis.
What are the signs of acute inflammation?
Erythema, Oedema
These signs indicate the body’s response to injury or infection.
How do dendritic cells contribute to the adaptive immune response?
Present antigens on MHC to T cells, Activate T cells
Dendritic cells act as antigen-presenting cells.
What are the components of T-cell receptors?
Variable antigen receptors, Constant and variable regions
T-cell receptors are specific to the antigens they recognize.
What is the function of CD4 T cells?
Recognize MHC 2
CD4 T cells help activate other immune cells.
What is required for T-cell activation?
Antigen, MHC
T-cells need to recognize both the antigen and the MHC molecule to become activated.
What is the process of B-cell activation?
Secrete antibodies, Differentiate into memory B cells and plasma cells
B-cells play a crucial role in humoral immunity.
What are the three signals required for T-cell activation?
TCR –> Activation,
Co-stimulation –> Survival,
Cytokines –> Differentiation –> Function
These signals ensure proper activation and function of T-cells.
What are the two categories of barriers to infection?
Physical and chemical barriers.
What role does skin play in the immune system?
Acts as a mechanical barrier with tightly packed epithelial cells and keratin.
What are mucous membranes and where are they found?
Traps microbes in mucus; found in the respiratory, gastrointestinal, and urogenital tracts.
What function do cilia serve in the respiratory tract?
Move mucus and trapped pathogens out of the airways.
What is lysozyme and where is it found?
An enzyme that breaks down bacterial cell walls; found in tears, saliva, and mucus.
What is the function of gastric acid in the immune system?
Kills many ingested pathogens.
What are defensins?
Antimicrobial peptides that disrupt microbial membranes.
What is the role of sebum and sweat in immunity?
Contains antimicrobial properties and creates an acidic environment on the skin.
What is the innate immune system?
The body’s first active defense mechanism against infections; it is non-specific.
What are the humoral components of the innate immune response?
Complement system, cytokines, acute phase proteins.
What is the complement system?
A group of proteins that tag pathogens for destruction and recruit immune cells.
What do cytokines do in the immune response?
Coordinate immune responses.
What are phagocytes?
Cells that engulf and digest pathogens; includes macrophages and neutrophils.
What is the function of natural killer (NK) cells?
Kill virus-infected and cancerous cells.
How do dendritic cells contribute to the immune response?
Bridge between innate and adaptive immunity by presenting antigens to T cells.
What do mast cells and basophils release?
Histamine, which causes inflammation and recruits immune cells.
What is the adaptive immune system known for?
Specificity and memory in response to previously encountered pathogens.
What are B cells responsible for?
Produce antibodies that neutralize pathogens or mark them for destruction.
What are memory B cells?
Cells that remain in circulation to rapidly respond to previously encountered pathogens.
What do helper T cells (CD4⁺) do?
Release cytokines to activate other immune cells.
What is the role of cytotoxic T cells (CD8⁺)?
Kill virus-infected and cancerous cells directly.
What is the function of regulatory T cells (Tregs)?
Suppress the immune response to prevent autoimmunity.
How does the innate immune response activate the adaptive immune response?
Through antigen presentation, cytokine signaling, and inflammation.
What do dendritic cells and macrophages do with pathogens?
Engulf pathogens and display antigens on MHC molecules.
What are Major Histocompatibility Complex (MHC) molecules?
Molecules that present antigens to T cells.
What is the difference between MHC I and MHC II?
MHC I presents antigens to cytotoxic T cells; MHC II presents antigens to helper T cells.
What triggers immune responses through Pattern Recognition Receptors (PRRs)?
Detection of Pathogen-Associated Molecular Patterns (PAMPs).
What is the coordination between the innate and adaptive immune systems?
Both systems work together to eliminate infections efficiently.
What is one example of coordination between the immune systems?
Macrophages activate T cells.
Fill in the blank: The innate immune system is ______ and responds rapidly.
non-specific
True or False: The adaptive immune system provides immediate protection.
False
What are the key points summarizing the immune systems?
Barriers prevent infection; innate immunity is rapid and non-specific; adaptive immunity is specific and long-lasting.
