Immunology Flashcards
Function of Neutrophils
- Rapidly respond to infections
- Engulf pathogens via phagocytosis
- Release antimicrobial substances
Function of Eosinophils
- Involved in allergic reactions
- Defense against parasitic infections
Function of Mast cells
- Release histamine and other mediators during allergic & inflammatory responses
Function of Basophils
- Involved in allergic responses and inflammation
- Release histamine and cytokines
Function of Natural killer cells
Destroy virus-infected cells and cancer cells without prior activation
Function of Dendritic cells
Capture and present antigens to T cells to initiate adaptive immunity
What makes up the Innate Immune System?
- Physical & chemical barriers (e.g. skin, stomach acid)
- Immune cells (e.g. neutrophils, macrophages)
- Soluble factors (e.g. complement proteins, cytokines)
Name the 3 activation pathways of the Complement System.
- Classical pathway
- Alternative pathway
- Lectin pathway
What is the Immune System?
A complex network of cells, tissues, and molecules that work together to defend the body against pathogens.
What is Immunity?
The ability of an organism to resist infection, typically through action of immune system.
What is Immune Response?
The body’s coordinated reaction to harmful agents - involving recognition, activation of immune cells, and elimination of the threat
Difference between Active and Passive Immunity
Active: Developed by the body through exposure to antigens (either infection or vaccination)
Passive: Acquired by transfer of antibodies (maternal antibody, or injection)
What is an Immunogen?
A substance capable of inducing an immune response
What is an Epitope?
The specific part of an antigen recognised by an antibody
What is an Antigen?
A substance that can be recognised by the immune system and may trigger an immune response
What are the Major organs and tissues of the immune system?
Primary lymphoid organs: Bone marrow, thymus (site of immune cell development)
Secondary lymphoid organs: Lymph nodes, spleen, tonsils (site of immune response activation)
Where do immune cells originate?
From haematopoietic stem cells in the bone marrow
Function of Monocytes and Macrophages
Monocytes: Circulate in the blood and differentiate into macrophages or dendritic cells
Macrophages: Engulf pathogens, present antigens, and release cytokines
Function of T Lymphocytes
Mediate adaptive immunity, either by killing infected cells or by regulating immune response
What are the main varieties of T Lymphocytes?
- T Helper cells - activate B cells and other immune cells
- Cytotoxic T cells - kill infected and cancerous cells
- Regulatory T cells - suppress excessive immune responses
Function of B Lymphocytes
Produce antibodies and present antigens to T helper cells
What are the varieties of B Lymphocytes?
Plasma cells - produce antibodies
Memory cells - provide long-term immunity by remembering past infections
Function of Cytokines
Small signalling molecules that regulate immune cell activity, inflammation, and communication
Important examples of cytokines
- Interleukins (IL-1, IL-6, IL-10): mediate immune responses
- Tumour Necrosis Factor - alpha (TNF-alpha): promote inflammation
- Interferons: antiviral responses
Function of Chemokines
Direct the movement of immune cells to site of infection/inflammation
Important examples of Chemokines
CXCL8 (IL-8): attract neutrophils to infection sites
CCL2: recruits monocytes and macrophages
Function of Interferons
Inhibit viral infections and activate immune cells
Function of Acute-phase proteins
Proteins that enhance immune responses during inflammation
e.g. C-reactive protein
