Intro to Immunology Flashcards
What are some immune physical barriers present in the body?
Saliva Mucocilliary escalator Gastric acid Normal flora Physical flushing e.g. urination
What is the innate immune system?
Rapidly responding immune reaction with some specificity and no immunological memory
What cells are involved in the innate immune system?
Mast cells Natural killer cells Basophils Neutrophils Eosinophils Monocytes Macrophages Dendritic cells
What are the mechanisms of the innate immune system?
Inflammation Recruitment of immune cells Activation of complement Oponisation Phagocytosis NK toxicity
What responses cause inflammation?
Vasodilation Increased vascular permeability Increased cell adhesion molecules Chemotaxis Increased sensitivity to pain
What causes vasodilation in inflammation?
Nitric oxide Bradykinin Prostaglandins TNF-alpha IL-1
Wha causes increased vascular permeability in inflammation?
Nitric oxide
Histamine
Leukotrines
What caused increased cell adhesion in inflammation?
TNF-alpha
IL-1
What causes chemotaxis in inflammation?
CXCL-8
What causes increases sensitivity to pain in inflammation?
Bradykinin
What recruits immune cells in the innate immune system?
IL-8
What are the 3 pathways by which complement can be activated?
Classical
ALternative
Lectin
What signals cause chemotaxis of phagocytes to site of inflammation?
C3a
C5a
What signals cause ozonisation?
C3b
C4b
What signal causes lysis of organisms?
C5b-9 complex
What signals maintain solubility of Ag/Ab complexes?
C3b, C4b, C2
What are the main cells in the innate immune system involved in phagocytosis?
Macrophages, neutrophils, dendritic cells
What do NK cells cause?
Perforin induced apoptosis
What is the adaptive immune system?
Specific immune system with delayed response but immunological memory
What are the 2 types of pathway in the adaptive immune system?
Humoral
Cell mediated
What cells are involved in the humeral immune system?
Antibodies, B lymphocytes
What are the actions of cytotoxic T cells CD8+?
Release IFN-gamma and TNF-alpha- direct anti-viral and anti tumour effects
Release cytotoxic granules–> perforin induced apoptosis
Apoptosis via FasL-Fas interactions
What is the method of perforin induced apoptosis?
Perforin creates a pore in the cell membrane for granzyme to enter and trigger apoptosis
What are the actions of T helper cells CD4+?
Release cytokines Promote B cell antibody class switching
What are the 3 types of T helper cell?
Th1
Th2
Th17
What are Th1 cells esp involved in?
Intracellular pathogen response
What are the actions of Th1 T cells?
Maximise macrophage and cytotoxic T cell activity
Release IFN-gamma
Inhibit Th2 response
What are Th2 and 17 cells esp involved in?
Extracellular pathogen response
What are the actions of Th2?
Release IL 4, 5, 13
Activate mast cells, basophils and eosinophils
Class switching to IgE
Inhibit Th1 response
What are the actions of Th17?
Pro-inflammatory
Recruit neutrophils and macrophages
What are the actions of regulatory T cells?
Suppress CD4+ and CD8+
Control response to self antigens
Secrete TL-10 and TGF-beta- anti inflammatory, suppress immune system
What are the 2 regions of antibodies?
FAB region
FC region
What is the function of the FAB region of antibodies?
Binds to antigen
What is the function of the FC region of antibodies?
Communicates with immune cells
What are the types of immunoglobulin isotopes?
IgM IgG IgA IgE IgD
What is IgM?
Pantamer antibody formation
Best at activating complement
What is IgG?
Predominant antibody
Can cross placenta
What does IgE mainly attack?
Parasitic infections and in allergies
How are antigens recognised?
T lymphocytes- require presentation of antigens via MHC
B- recognise directly from B cell receptor
What are the functions of antibodies?
Immune complex formation
Oponisation
Activate complement cascade
Antibody dependent cellular cytotoxicity
What is antibody dependent cellular cytotoxicity?
Antibodies bind to target cells and initiate non phagocytic cell mediated destruction
What are the 2 types of immune tolerance?
Central
Peripheral
What is central tolerance?
Destroys auto reactive or ineffective lymphocyte cells before maturity e.g. in thymus or bone marrow
What is peripheral tolerance?
Monitoring of lymphocytes in lymphoid organs and circulation
What cells are in charge of peripheral tolerance?
Regulatory T cells
Wh is a normal variation of immune function seen in?
Neonates
Pregnant
Elderly
What are the immune irregularities in the elderly?
Fewer naive T cells
Reduced probability for T expansion
Reduced B cell development and diversity
More dependent on innate immunity
What environmental factors can cause a secondary immune deficiency?
Malnutrition
Trauma
Burns
Inadequate levels of what can cause immune deficiency?
Protein/calories
Zinc
Iron
Why can a zinc deficiency cause immune deficiency?
Essential for proliferating cells
Imapirs PMN, NK, monocyte and lymphocyte function
Why can an iron deficiency cause an immune deficiency?
Impairs innate immune system
What diseases can cause a secondary immune deficiency?
Infection e.g. HIV DM Renal failure Asplenia Malignancy- CLL, myeloma, lymohoma
How does HIV cause an immune deficiency?
Virus binds t CD4+ cells
Decreased activity of C cells, CK, CD8+ and macrophages
What drugs can cause a secondary immune deficiency?
Immunosuppression
Anti-rheumatic
Anti-epileptic
