Overview of adaptive system Flashcards
What are the 4 ways to spot pathogens?
- generic recognisable features eg.TLR – PAMPs
-presence is associated with damage eg. co-stimulation – CD28
Damage-associated molecular pattern molecules (DAMP
- memory
- self versus non-self
What are effectors primarily?
- lymphocytes
What are two B cell deficiencies?
- Congenital agammaglobulinaemia- not enough antibodies
- Common variable immunodeficiency (CVID)
What is CVID?
- common variable immunodeficiency
- primary immune deficiency disease characterized by low levels of protective antibodies and an increased risk of infections
How is CVID treated?
- Rituximab, novel biologics
What is congenital agammaglobulinaemia?
- not enough antibodies produced
- X-linked
What are three T-cell deficiency diseases?
- Severe Combined Immunodeficiency (SCID)
- DiGeorge syndrome -thymic failure
- Acquired – HIV / Chemotherapy / Novel biologics
Name some cells involved in innate response
- neutrophils
- monocytes
- dendritic cells
- basophils
- eosinophils
- macrophages
- tissue cells
- platelets
- fibroblasts
Name some adaptive cells
- B cells
- T cells
- NK Cells
Why are NK cells both innate and adaptive?
- NK cells are lymphocytes but have no memory
Which cells arrive within 12 hours of affection?
- mast cells
- phagocytes
- dendritic cells
- NK cells
- complement
What are bridging cells?
Congenital agammaglobulinaemia-
What are MAIT cells?
- have memory properties
- Mucosal associated invariant T cells
How do virally infected cells present atigens?
-MHC I molecules
What cells do virally infected cells activate?
- cytotoxic Tcells
- release cytokines for killing
Examples of bridging cells
- memory NK cells
- iNKT cells
- Vdelta2 gamma delta T cells
- MAIT
Which cells are MAIT cells similar to?
-like alpha beta T cells but is preprogramed because of common targets
How can lymphocytes be defined?
- morphology
- lineage
- location
- differentiation
- function
- type of receptor
- by what they produce
What are the two locations lymphocytes can be found?
- Tissue-resident memory cells (TRM)
- Marginal zone B cells
What are some functions used to define lymohcytes?
- helper
- cytotoxic
- regulatory
- antibody-producing
Describe Bcells
- Defined by their antibody
- May class switch / undergo affinity maturation but always the same basic Ig
Describe Tcells
-Selection and expansion of that clone ± differentiation
-Retention in “memory” of clonal progeny
Has the same specificity
Where do Bcells mature after bone marrow?
-spleen
Where can Bcells migrate to after maturation?
- spleen
- lymph nodes
Where can Tcells migrate to after maturation and selection?
- spleen
- mucosal and cutaneous lymphoid tissue
What are the two types of receptors found on Bcells?
- surface immunoglobulin
- Bcell receptor
What do Tcell receptors detect?
- peptide sequence on MHC
What do all cells present?
- intracellular content
- Recognised by CD8 T cells through their TCR
What is MHC-peptide recognition important for?
- viruses
Which cells present to CD T cells?
- APCs
When are cells killed by NK cells?
- when viruses downregulate MHC
What are marginal zone B cells?
- located at the interface between the circulation and the white pulp of the spleen
What are the two key features of the adaptive immune system?
- specificity
- memory
How are B cells defined compared to T cells?
- by their antibody
- one cell, one Ig
How are T cells defined?
- one cell, one TCR
- has the same specificity
Summarise positive selection of Tcells
- must bind to MHC
Summarise negative selection of Tcells
-must not bind to self antigens
How are lymphocytes labelled?
-in vivo with deuterium-labelled glucose
What does slow turnover of Naive CD4+ cells indicate?
-very slow turnover in peripheral blood
Compare effector memory CD4 Tcells with central memory Tcells
Effector Memory CD4 T cells have faster turnover than Central Memory T cells
Describe Tcell effector memory cells
- short-lived population
- continually replenished
- doubling time about 15 days
- Need to be able to expand and contract population pathogens are met
Describe Tcell central memory cells
- turnover at a significant rate
- Doubling time about 48 days
Describe Treg cells
- very dynamic
- Control the responses of other T cells
What happens when Treg cells are knocked out?
-autoimmunity
Summarise the life process of Bcells
- Positive selection
- Receptor editing
- Negative selection
- Transition to IgM+ IgD+ mature B cell
- Antigen recognition leads to proliferation/differentiation
- Activated B cells transform into Plasma cells
What type of disease does splenectomy increase?
-pneumococcal infection
What do lymph nodes and veins have in common?
-valves
What is a key marker of tissue resident Tcells?
-CD69+
