Cells and Tissues Flashcards
antiG that INDUCES an immure response
Immunogen
molecule that BINDS to and is RECOGNIZED by an antibody or T cell
AntiG
Type of antiBs Passive immune system receives
Receiving PREFORMED antiB
RAPID protection: passive or active
Passive
Duration of passive antiB’s
SHORT duration—half life about 3 wks
Where can we get passive immunity?
IgA in breast milk or humanized antB
EXPOSED to foreign antiG
Active immunity
Slow or fast protection for active immunity
SLOW protection
Duration of active immunity
Long duration→ d/t memory lymphocytes
What causes active immunity?
Natural infection, vaccine
Toll like receptors or Nod-like receptors are what type?
Innate receptors
= Pattern Recognition Receptors
Innate
Innate receptor diversity:
-Limited diversity, non-clonal expression—meaning very little genetic diversity with simular recognition patterns
Adaptive receptors are:
Antigen Receptors
Type of Adaptive receptors
- T Cell ReCeptors (TCR)
- B Cell Receptors (BCR)
- Somatic recombination → DIVERSITY and clonal
Does the innate system have memory cells?
no
Type of immune cells adaptive immunity express?
clones of lymphocytes remain in body and will recognise and respond to antG more rapidly then first exposure
Type of vaccine:
PROS: strong/life long
CONS: may revert to virulent form
LIve Attenuated
Micro-org is modified—decreases pathogeniticy and see limited growth post injection
Induces: Cellular response= T Cells
Live Attenuated Vaccine
Path is Inactivated (heat/chemically) but retains IMMUNOLOGIC EPITOPE on surface
Inactivated Vaccine
What type of response does inactivated vaccine induce?
Induces: Humoral Response = B Cells
Pros/Cons of inactivated vaccine
Pros: Stable and safer then live
CONS: weaker immunity—need a booster
Cells of Innate Immune System
a. Phagocytes-
= Macros and Neutros (MnoP)
Phagocytes
b. Granulocytes
= Eosinos, Baso, Masts (Be a GEM)
Cells Linking the INNATE and Adaptive immune sytesms
a. Dendritic Cells
- folicular DC, Conventional DCs and plasmacytoid DCs
- NK cells
Lymphocytes are part of what immune system
Adaptive immune system
Circulate and enter tissue and differentiate into tissue macrophage, present in all tissues of body
Monocyte/Macrophage
LOTS of cytoplasm→ moves into tissues→ becomes Macrophage
Monocyte
When does a monocyte get activated?
-monocyte is inactivated till become macrophage in tissue and has little pseudopods to reach out and engulf stuff
motile phagocyte (acid staining, red) KEY for PARASITE and ALLERGY
Eosinophils
Type of granules eosinophils contain
Granules contain Heparin + Hydrolytic enZ
Non-phagocytic (basic dye staining, blue)
Basophils
Type of IL basophils release
release IL4 (Th2 cytokine)
Circulate in blood
Release pharmagologically acitve immune mediators (histamine)
basophils
From bone marrow & emigrate/differentiate in tissue
Mast Cells
Type of granules released by mast cells?
granules have heparin and histamine
key for ALLERGY
Mast cells
Derived from same Bone marrow progeitor as Monos→ then migrate + reside in tissues near site of microbe entry
Dendridic Cells
Function of DC cells
b. Primary funx = APC
i. TRANSPORT and PRESENT microbial antigens to T lymphos in peripheral lymphoid tissues as matures DCs
- Large, granular lymphos that recognize foreign cells of many diff antigenic types
a. Lack T cell receptors and lack surface IgM or IgD
NK cells
Active w/out exposure to antiG
Active Independent of antiG presentation
NK cells
What kind of cytokines do NK cells release?
a. secreate cytotoxins such as Perforin and granzyme into cells
Specialize in killing of virus-infected cells and tumor cells
NK cells
How do NK cells induce apoptosis?
b. Induce apoptosis via Fas-FasL interactions
How do NK cells get activated?
- Activated by IFN-α, IFN β, IFN γand IL-12
When NK cells stimulate adaptive immune response what do they make?
Make IFN-γ and IL-12 → which then go on to activate Th1 type Tcells
CD3 is common to
all T lymphs
CD19 and CD 20 typical of most
B cells
help distinguish btwn subclasses of T cells
CD4 an CD8
What is recpetor portion of immunoglobulin (anitibody) molecule
Fc (FcR)
Naïve B Lymphos express what Igs?
a. express IgM and D with low affinity
Naive B’s express?
and don’t express?
Express CXCR5 (high) Don’t express CD27
Effector B cells: contains
RER, Mitochondrion and Golgi Complex
Activated/Effector B lymphs Increase expression on
IG:G/A/E during response
Activated or effector B lymphs high expression of?
Low expression of?
LOW exp of CXCR5
HIGH exp of CD27
these dudes secreate antiB
they are large plasma cells
Activated B lymphs
Memory B Cells have high expression of
IG:G/A/E
no effector funx and are very small
not sure if they have CXCR5
HIGH expression of CD27
Activated B Lymphs
Location of hematopoetic progenitors and lymphocyte devo;
Bone Marrow
- Naïve lymphocytes are small
- Mature lymphocs are larger and more cytoplasm
Location of devo annd maturation of T lymphocytes
Thymus
Secondary (Perpheral) Lymphoid tissues
Lymph Nodes
Spleen
Mucosal or skina associated lypmhatic tissue (MALT/SALT)
a. Peyers patches
Maturation of Lymphocytes of B cell
Bone marrow stem cell→ (B cell lineage)→ Bone marrow (generative lyphoid organ)→Mature B lympho→ Blood→ Peripheral Lymphoid organs and recirculate back to blood
Maturation of Lymphocytes of T cell
Bone Marrow Stem Cell→ (T Cell lineage) → Thymus→ Mature T lymphos→ Blood/lymph→ Peripheral lymphoid organs→ back to blood/thymus
Generative Lymphoid tissue
1. Cortex:
on periphery: dark purple staining
a. densely packed with immature T cells called thymocytes
Part of Lymphoid tissue with fewer T cells and endothelial cells, macrophages and CD
- Medulla: inner part, lighter pink
Where devoing thymocytes mature to immunocompetent T cells via gentic changes that modify the cell surface antiG receptors (TCR) that the naïve T cell uses to recognise antiG
Medulla
Multi-functional, secreate factors to attract precursor thymocytes to thymus
TMEC: key for T cell devo
Makes support for T cells during maturation and surround blood vessels to make blood-thymus barrier
TMEC
Present self antiG to maturing thymocytes during neg and positive selection
TMEC
Central Tolerance =
process of negative and positive selection
abilty to recognize peptide antiG complexed w/ self-MHC molecules
Positive selection
next step… when cells above recognize self-antiG are removed via apoptosis
–>Survivors will migrate to medulla→ on to lymph vessels to secondary organs
Negative selection:
Specialized vessels to drain fliud from regional tissues into and out of lypmh nodes and into Blood
Lymphatic system
Lymph vessels
made of overlapping endothelial cells that LACK proteins needed form tight bonds for a basement membrane
Lymph vessels have tight/leaky epithelia?
a. result = leaky epithelia
provides direct cnx btwn peripheral and secondary immune tissues
Lymphatic system
collects microbial antiG as both free in the lymph of if they’re associated with APC’s
Lymphatic system
Position on immune cells and lymphocytes
in peripheral tissue along interfaces btwn environment and organism
ust deep or in close proximity to surface of skin, digestive and respiratory, urinary or reprotract
Drainage of lymph: drain inferior and SVC and have collection of nodes;
AntiG are captured at peripheral site of infection then the draining lymph nodes will be sites of adaptive immune activation
Pathogen gains entry via
DC through the epithelium
Pathway of associated antiG
Pathway
- Pathogen gains entry via a DC through the epithelium–>You get Free antigens in blood + DC associated antiG and both go down dif paths.
- -> DC assoicated antiG will enter a lymphatic vessel–>DC associated antiG will then travel to lymph node–> Lymph node captures antiG from epithelium and CT along with DC cell.
Pathway of free antiG
- Pathogen gains entry via a DC through the epithelium–>You get Free antigens in blood + DC associated antiG and both go down dif paths–> Free antiG in blood will enter a venule→ enter the blood stream–> Free antiG in blood will then enter circulation and be carried to the spleen–>Blood borne antiG are captured by antiG presenting cells in the spleen
Encapsulatd secondary lymphoid tissue that initiate immune responses to cell-associated antiG
Lymph Nodes
Where do follicle of lymph node lay?
w/in outer cortex
- when central area of follicle stains less intesnse w/ te hematoxylin stain
- here in an increased level of B cell activation and proliferation
Germinal center:
Area where there is no germinal center
Parafollicular cortex
= rich in T cells, DCs and macrophage
-most T cells here are naïve
Parafollicular Cortex
Vascular organ that removes damaged cells and immune complexes or opsonized microbes from circulation
Spleen
when microbes are coated with host proteins to enhance phagocytosis by myeloid cells
Opsonization
blood filled vascular space
has large sinusoid where blood from vessels drain into that are lined with macrophages
Red Pulp
Drainage for Red pulp of spleen
c. sinusoids drain→ splenic vein→ portal circulation
- location of leukocytes and lymphocytes
- initiates adaptive immune response to blood borne antiG
White pulp
Package scheme in white pulp
c. lypmhos here dense packed around central arteriole en passage to marginal sinus
sep red/white pulp
marginal zone
pulp has follicle w/ naïve B cells and are surrounded by periarteriolar lymphoid sheath paked with T cells, DCs and macrosphages
white pulp
CC: pt w/out spleen very suseptible to
infections w/ encapsulated bacteria: pneumococci and meningococci (stuff cleared by complement and phagocytosis)
only cells that make receptors specific for diverse antiG and are key mediators of adaptive immunity
Lymphocytes
This APC will initiate T cll response
DC
This APC will cause the effector phase of cell-mediated immunity
Macrophage
This APC will display antiG to B lymphocytes in humoral immune response
Follicular DCs
what turns on NK cells?
IFN, gamma/alpha or beta and IL-12
how does NK induce cellular apoptosis?
Fas-FasL interaction
Which immune response does NK stimulate?
Adaptive immune response
differentiated progeny of naive cells that can make molecles w/ function to eliminate antiG
Effector cells
effector cells of B lineage that secreate antibodies
plasma cells
These effector B’s devo in response to antigenic stimulation in pheripheral lymphoid organs where they may stay and produce antiB’s
Plasma cells
Effector CD4+ cells also known as helper T’s make
cytokines
These guys activate B cells, macrophages and mediate the helper function of CD4 T cells
cyotkines
Theses T cells have machinery to kill infected host cells
CD8+ or CTLs
cells are functionally inactive, make up less than 5% peripheral T cells in infant and up to 50% in adult
memory T cells
