Immunology Flashcards
What is the immune system
Body’s ability to resist or eliminate harmful foreign materials
What is a pathogen
Any micro-organism that causes harm
What are the two sections of the immune system
Innate Immunity
Adaptive immunity
What are the characteristics of innate response
- Non - specific
- Distinguishes between human cells & pathogens
- First to play
- No memory
What are the characteristics of the adaptive response
- Highly specific
- Distinguishes between pathogens via antigens
- Slower
- Immunological memory
What cells are involved in the innate and adaptive systems
Innate - Phagocytes, Complement, Natural Killer,
Adaptive - B lymphocytes, T lymphocytes
What are the two types of phagocytes
Neutrophils
Monocytes
What do Neutrophils do
Engulf, destroy pathogens
Contain granules with destructive enzymes
What happens to monocytes
Convert to macrophages
Break down and process pathogens
Present antigens -> adaptive immunity
Produces specific immune response via antibodies and cytotoxic cells
What are the steps of phagocytosis
- Phagocyte moves to microbe
- Microbes attach to phagocyte
- Microbe endocytosis= phagosome
- Fusion of phagosome+lysosome
- Microbe killing via enzymes
- Discharge of waste
What is the role of Eosinophils
Combat parasitic infections
Involved in allergy and asthma
Granules contain enzymes
Function of mast cells
IgE Antibody binds to mast cell receptor
Allergen binds to antibody
Mast cell degranulates releasing histamine w
Affects various bodily functions
What are the role of cytokines
Secreted by cells
Communicate with cells
Bind to specific receptors on cells
Produces signalling molecules ->biological effects
ACED (Activation, Chemotaxis, Enhancing cytotoxicity, Differentiation)
What is the difference between humoral and cellular immunity
Humoral immunity - antibody-mediated, B cells
Cellular immunity - cell-mediated, T cells
What are the stages of development of lymphocytes
Production- Synthesis of T/B lymphocytes
Maturation- aquirement of receptors
Activation - Reactions of lymphocytes with pathogens
What are the primary lymphoid organs
Places where blood cells produced
Bone marrow (Hematopoiesis)
Thymus (Training of T cells)
Medulla - immature T lymp.
Cortex - mature T lymp.
What is the role of the secondary lymphoid organs
Development of adaptive immune response to antigens by T/B cells
What are the secondary lymphoid organs
- Lymph node - induce adaptive immune responses to antigens
- Spleen - Red pulp: blood filter White pulp: initiates imm. response
- Tonsils
What are the phases of immune defense
Recognition of danger
Production of specific weapons
Transport of weapons to site
SEE SLIDE
Role of T lymphocytes
What are the two types of T lymphocytes
Cytotoxic T cells (CD8+) - used for killing
Helper T cells (CD4+) - stimulate B cells to produce immunity
What are the characteristics of T helper cells
Can’t kill infected cells/pathogens
Only activate and direct immune cells
What is the purpose of MHC Class 1
Found on all nucleated cells
Presents virally induced peptide to CD8+ T cells
Triggers cytotoxic response
What is the purpose of MHC Class II
Found on APC’s (Antigen presenting cells)
Presents exogenously induced peptide to CD4+ T cells only
Overview of Ag presentation and pathways
What is the function of B cells
Production of Antibodies
Express B cell receptor
On activation, differentiate into plasma cells via T helper cells
Where are B cells produced and matured
In the bone marrow
What are antibodies structure
Immune response against antigens
Contains two regions:
Upper region - antigen binding region
Lower region - Fc region
What are the different types of Antibodies
(Immunoglobulins)
MEGAD
What are the functions of antibodies
Neutralisation - Prevention of attatchment using IgA
Opsonization - Using macrophages
Activate complement system on surface of target cells
What is the role of the complement system
Important role in defense mechanism of innate imm,
Direct lysis of target cells via membrane attack complex
Enhance immune response
What are the different complement system pathways
Classic pathway
Alternative pathway
Lectin pathway
