Flashcards
CD4 T cells: The Master Controllers of the Immune System
Cards in this deck (30)
- 1Where do T cells develop?thymus
- 2What are the two types of T cells?Conventional and Unconventional
- 3What are the subcategories of conventional T cells?T helper cells CD4+
Cytotoxic T cells CD8+ - 4What are the subcategories on unconventional T cells?yd cells
-good at fighting carcinomas
intraepithelial lymphocytes (IELS)
-go to epithelial layers of body e.g. gut/lung
-good at fighting carcinomas (tumours with epi origin)
NKT cell
-T cells with NK properties - 5What is the importance of CD4+ T cells in HIV?they are progressively lost in HIV infection
infected, strong flu few weeks later
virus level peaks and dip in CD4
as CD4 target
virus levels drop a bit - clinical latency
virus resurfaces
CD8 killing infected CD4
CD4 reaches v. low
immunodeficiency
AIDS - opportunistic infections problem - 6How do T cells recognise antigens?using a T cell receptor
^this is the definition of a T cell - 7What distinguishes CD4 T cells from other cells?has 60-70 thousand CD4 molecules on surface
- 8Describe the autocrine growth pathwayT cell recognises correct peptide plus MHC
activates CD4 T cell
starts expressing receptor for cytokine IL-2 (CD25)
starts producing IL-2 - growth factor that acts upon itself in an autocrine fashion
produces alpha subunit of IL-2 receptor so has a receptor that can bind with IL-2 - 9What do activated CD4+ Th cells do?didifferentiate into eitherTh0 or Th1 or Th2
(Th0 secretes IL-2, IL-4 and INF-y then differentiate into Th1 or Th2) - 10What do Th1 cells produce and which immune response do they control?IFN-y
TNFa
TNFb
IL-2
IL-3
cell-mediated immunity - 11What do Th2 cells produce and which immune response do they (control?IL-4
IL-5
IL-13
humoral immunity
(immunity of fluids) - 12Out of cell-mediated and humoral immunity which one deals with intracellular and which deals with extracellular pathogens?intracellular pathogens (cell mediated)
extracellular pathogens (humoral) - 13What do Th1 cells do?they help macrophages
when viruses and bacteria have evolved mechanisms to live inside them
Th1 cells come along and secrete IFN-y
activates macrophage
becomes activated macrophage
kills viruses and bacteria - 14Why don't you make activated macrophages from the start?they cause scarring
making substances that damage tissue
if not controlled get more tissue damage than the pathogen would have done
resulting in immunopathology - 15Some bacteria are hard to kill such as TB. What happens then?TB-infected activated macrophage
Th1 walls off the infected macrophages
called caseating granuloma
full of macrophages, Th1 and TB but is physically walled off
so tissue around it is healthy
person won't know they're infected
patient is asymptomatic
if get rid of Th1, wall breaks down, TB spreads - 16What does IL-4 induce in B cells?induces b-cells to make IgE
- 17Explain the concept of 'T-cell help'DC sees pathogen, internalizes it and displays protein on MHC-Class II
goes to lymph nodes, Th2 made
antigen from infected tissue washed down in lymphatic fluid to lymph node
B cells in lymph nodes
B cells sees antigen, internalizes it and displays protein on MHC-Class II
Th2:TCR:protein:MHC-Class II-B cell
Th2 release cytokine (IL-4,5,13)
stimulates B cell produce plasma cells IgM, IgG, IgE, IgA - 18How do T cells know to become Th1 or Th2 cells?start off as Th0 cells
cytokines turn Th0 into either Th1 or Th2 - 19In what situation will Th0 turn to Th2?Th0 cells differentiate into T2 cells in presence of IL-4
made from mast cells - 20In what situation does Th0 turn into Th1?Th0 differentiate into Th1 in presence of
IL-12 or IL-23 - 21Explain the two manifestations of leprosy?Tuberculoid
Th1 is dominate response
limited disease
cytokines: IFN-y
activated macrophages
low numbers of organisms
Lepromatous
Th2 is dominate response
disseminated disease
Cytokines: IL-4, IL-5, IL-13
hyperglobulinemia
high numbers of organisms - 22Explain the two manifestations of LeishmaniasisCutaneous/orient boils
Th1 is dominant response
limited disease
Visceral/black fever
Th2 is dominant response
disseminated response - 23What are the two manifestations of Tuberculosis?Lepromatous TB
Th1 dominant
limited disease
Miliary TB
Th2 dominant
disseminated disease - 24Problem with Th2 response in the westTh2 responses lead to IL-4 which leads to IgE which causes allergies
- 25Give an example of a classical IgE-mediated allergy (Type-I hypersensitivity)Eczema
- 26Th0 differentiates into many different transcription factors, state what they are and which cytokines stimulate the differentiate of Th0 to themT-bet Th1 IL-12, IL-23
GATA-3 Th2 IL-4
RORyt Th17 TGFb,IL-6,IL-21
Foxp3 iT-Reg TGFb - 27What do Th17 and iT-Reg cells make?former: IL-17, IL-22
latter: TGFb, other suppressive molecules (dampens down immune response) - 28Th17 and iT-Reg cells defend against?...Th17 - extracellular bacteria (autoimmunity), induce production of neutrophils
iT-Reg- immunosuppression (autoimmunity, cancer) - 29What do a fraction of the activated T and B cells become?memory cells
providing long-lasting immunity to that infection
-stored for rapid deployment if infection re-occurs - 30Define the term immunological memorythe ability of the immune system to respond quicker and better to pathogens that have been encountered previously
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- University Fundamentals of Medicine (Immunology) Flashcards on CD4 T cells: The Master Controllers of the Immune System, created by Ifeoma Ezepue on 10/11/2015.
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