W3: Lymphocytes Flashcards
largest + smallest wbc
largest = monocyte
smallest = lymphocyte
3 types of wbcs that are part of the innate immune sys
basophils
neutrophils
eosinophils
what other granulocytes are part of innate IS
mast cells
what do granules of each of the innate IS stain with
B - methylene blue
N - neutral
E - eosin
3 other cells that are part of innate IS
macrophages
dendritic cells
NK cells (BUT are a type of lymphocyte)
which cells trigger adaptive IS + how
dendritic cells (are antigen presenting cells) present antigens to lymphocytes
cells in adaptive IS
lymphocytes
(T cells + B cells)
3 features of innate IS
fast
non-specific (trigger)
generic (response)
what are part of both innate + adaptive immunity
interferons
complement
which 3 cells part of IIS can phagocytose
macrophages
neutrophils (APCs)
eosinophils
role of NK cells
immunological surveillance
detects foreign cells but doesn’t raise specific resp
body surface defences - part of IIS
physical barriers - skin, hairs, epithelial mems
antimicrobial substances - HCl (in stomach), lysozymes (in saliva), natural Abs
inflammation caused by IIR or AIR
IIR
4 physiological resps of inflammation
rubor = redness
calor = heat
dolor = pain
tumour = swelling
which types of lymphocytes cause which type of immunity + roles
B = humoral immunity (prod Abs)
T = cell mediated immunity (involved in killing infected cell/ bacteria/ viruses)
type of infection causing high no. of neutrophils
bacterial
type of infection causing high no. of lymphocytes
viral
MHC + role
major histocompatibility complex
antigen presentation - displays fragments of cell for t-cell recog
what is HLA
human leukocyte antigen
gene encoding MHCs (MHC-I) in humans so presents intracellular material to surface
does highest or lowest polymorphism give better survival chances/ less susceptible to infection
highest
3 types of HLA
A
B
DR
*lots of alleles for each
how many HLAs of each type
A - 59
B - 118
DR - 124
how many sets of HLAs does each person inherit from each parent
3
what does individual HLA expression determine
compatibility of tissues for organ/ bone marrow transplants
diff btwn MHC-I vs MHC-II
MHC I
found on surface of ALL nucleated cells (not rbcs + platelets)
presents to T cytotoxic cells
MHC II
found on surface of APCs
presents to T helper cells
why are lymphocytes heterogenous
bc diff lineages/ stages of maturation can be distinguished by expression of diff CD (cluster of differentiation) molecules
which type of lymphocytes match w which CD (co-receptor) markers
CD4+ = t helper - MHCII
CD8+ = t cytotoxic - MHCI
CD19 = B cell
synonym for NK cells
LGL = large granular lymphocytes
which type of immunity is mediated by t cells
cell-mediated
which type of immunity is mediated by b cells
humoral
where are t cells made and then matured
made in BM
mature in thymus
name for immature t cells
thymocytes
first thing t cells are screened for in thymus (as they mature)
positive selection at cortex
to see if they have functioning t cell receptor
second thing t cells are screened for in thymus (as they mature)
negative selection at cortex-medulla border
apoptosis of thymocytes that recog self
which CD is a dimeric mem glycoprotein
CD8+
which CD is a mem glycoprotein (monomer)
CD4+
role of CD4+ t cells
release cytokines to help recruit + activate other immune cells
2 mechanisms CD8+ Tc cells used to kill infected cells
apoptosis -> perforin -> cell lysis
secrete interferon gamma - limits viral rep + spread of infection
final trigger of which CDs is req for full activation of MHCII Th cells
CD80/CD86 with CD28
4 molecules expressed on B cells
B cell receptor
CD19 (coreceptor)
MHCII
CD40
B cell receptor = synonym for
surface antibody
IgD, IgM, IgG
what is central tolerance process
testing + elimination of B cells (before they leave the BM) that react strongly to self by apoptosis
plasma cells known as
Ab prod “factories”
important components inside B cells
lots of rough ER
extensive golgi apparatus to secrete Abs
which Ab prod during initial infection
IgM
IgM class switched w which Ab later on in infection
IgG
blood w high IgM + IgG indicates
recent infection
blood w ONLY high IgG indicates
longer period since infection
*timings differ w each type of infection
3 Ab actions
- opsonisation - coats Ags in receptors - more easily recog
-> enhances phagocytosis - complement activation - forms complement complex, makes hole in mem -> lysis
- neutralisation - Abs mop up pathogens/ toxins - prevents their action
role of memory B cells
confer immunological memory, ensuring that re-exposure (secondary response) to pathogen is rapid
where are memory B cells mostly found
spleen
lymph nodes
MALT tissue
circulating blood
B cells must undergo ____ before they can become memory B cells
(Ab) class switch
memory B cells prod high levels of which Abs
IgA
IgG
IgE - linked to inflamm + asthma
