Introduction to immunology Flashcards
Name some physical barriers
lysozyme in tears and saliva mucous membranes mucociliary escalator normal flora of gut gastric acid physical flushing - urinary tract
Does innate or acquired immunity have memory?
acquired
What does innate immunity detect?
alteration from haemostasis
damage to host or a pathogen
innate immune cells
basophils neutrophils eosinophils NK cells macrophage mast cell monocyte
What do cytokines regulate?
nature, duration and intensity of immune response
What cells predominantly produce cytokines?
macrophages
T helper cells
pro-inflammatory cytokines
TNF alpha
IL-1,6
Chemokines
anti-inflammatory cytokines
IL-10
TGF-B
What can cytokines activate?
macrophages, eosinophils, mast cells, B and T cells
What do cytokines do to bone marrow?
act on it to increase leukocyte production
Inflammation
vasodilation increased vascular permeability increased cell adhesion chemotaxis increased sensitivity to pain
Chemicals involved in inflammation
NO Bradykinin prostaglandins TNF alpha and IL-1 Histamine
3 pathways to activate complement
classical
lectin
alternative
MAC
C5B, c6, 7, 8, 9
opsonisation complement
c3b,c4b
What does opsonisation do?
reduces repellent negative cell charge
increases number of binding sites for phagocytes
Main opsonin
complement C3B,4B
antibodies
plasma proteins - mannose binding lectin
humoral immunity
antibody mediated - B cells
cell mediated immunity
T cells
Where do B and T cells mature and then where do they go?
B = bone marrow
T = bone marrow then thymus
secondary lymphoid organs eg LN and spleen to encounter antigens
Antigen
molecule capable of inducing an immune response
Antibody
glycoprotein produced by B lymphocytes that binds antigen with high specificity and affinity
How to B and T cells have specificity for an antigen?
BCR
TCR
genetic changes
What do T cells require to recognise antigen?
presentation by MHC
CD4 and CD8 MHC
4 = MHC2 8 = MHC1
How do B cells recognise antigens?
directly via BCR
MHC 1+2 - extracellular or intracellular?
1= intracellular eg virus 2 = extracellular
Central tolerance - T cells
\+ve = T cell recognise MHC? -ve = too strongly with self antigens via MHC?
Central tolerance B cells
self reacting BCR?
Peripheral tolerance
monitor lymphocytes in secondary lymphoid organs and circulation
regulatory T cells
Tc cells - 3 actions
IFN gamma and TNF alpha
cytotoxic granules - perforin and granzyme
FasL-fas interactions
What cells promote B cell antibody class switching?
T helper cells
3 types of T helper cells
Th1, 2, 17
Which T helper cells are intracellular and extracellular?
1-intracellular
2+17, extracellular
What do regulatory T cells secrete?
IL-10 and TGF-B
2 regions of antibodies
Fab region - bind antigen
Fc region - communicate with immune cells
Different antibodies and main function
IgM - activate complement
IgG - cross placenta
IgE -allergy
IgA and IgD
Functions of antibody
opsonisation
immune complex formation
activate cascade complement
Elderly immune function variation
thymic involution
fewer naïve T cells
reduced B cell diversity
secondary immune deficiencies
malnutrition
infection, diabetes, malignancy
drugs, splenectomy
HIV - which immune cells does it bind?
CD4+
Malnutrition and immune function
protein-calorie - energy
zinc, iron
