Objectives
B Lymphocytes Marker
T cell dependent Ag
T cell independent Ag
Natural Killer cell Markers
Functions of NK cell
NK cells & innate immunity
LAK cell
B lymphocyte 15-35% of total lymphocytes
pre B cell
Intra cytoplasmic chain
Immature B
surface IgM
Mature B
surface IgM +
IgD
Activation
plasma cell secrete Ig
memory cell
B
Surface marker
Receptor& Mol
Receptor
FCR
C3b R(CD35)
Mol =B7
Class I & II MHC
Sp. Marker CD 19, 20,21
B cell secrete IL1 ,IL6
B lymphocytes : (activation)
T cell dependent Ag (majority)
B cell can not be activated effectively in the
absence of assistance from Th2 cell
(help by secreting of cytokine)(Th2 IL4.IL5,IL6)
B cell need 2 signals:
1-Recognition of Ag & present it to T cell in ass. with
class 2 to activate T cell
2-Interaction of CD40 with CD40L then B cells begin
to Express receptors for various cytokines
Humoral Response to T Dependent Antigens
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IL 4,5,6
T cell independent Ag (TI)
TI-1: like bacterial lipopolysaccharid, E.B. virus
Inherited mitogenic activity have a
Receptor on B cells .
activation many B lym.= poly colonel B cell activation
TI-2:like pneumococcal polysacch.
These Ag have multiple repeats of their epitope &
cross link numerous Ag receptors on B cell
surface
Receptors
Natural Killer cell
Specific Marker
CD 56+ve
CD3-ve
Non T non B large granular lymphocyte
Not present at early & old ages so increase risk of
cancer at those ages
Kills in a non specific (innate immunity)
non MHC restriction
not needs sensitization
not needs APC
no memory
so belong to non specific immunity.
NK cells cytotoxic for
tumor cells
, viral
infected cell ,also for some bacteria ,fungal, ¶sitic
infection
Mode of killing is by ADCC (Ab dependent cell
cytoxicity)
(R eceptor no. CD 16)for FC of IgG
Activated by
gamma IFN
( مIFN) , IL2,IL12
LAK cells (NK +
gamma IFN
, IL2) Lymphocyte
activated killer
*Perforating cell memb. by inserting perforin=
Into cell memb.
Polymerize
Polyperforin channel
*Protease =degrade prot. in cell memb.
*Nuclease=degrade N.A.
*TNF=prevent protein synthesis . Produce toxic free
radical
