IMMUNOLOGY By ZOHA and SAMIHA. Our learning objectives pay attention – we will test you! Types of...
-
Upload
ira-shepherd -
Category
Documents
-
view
215 -
download
3
Transcript of IMMUNOLOGY By ZOHA and SAMIHA. Our learning objectives pay attention – we will test you! Types of...
IMMUNOLOGY
By ZOHA and SAMIHA
Our learning objectivespay attention – we will test you!
• Types of immune responses and cells involved• Definitions :Learn them all but make sure you
understand affinity vs avidity • CD markers, APCs… lots of letters but they will
make sense!• Innate immunity – COMPLEMENT • Antibodies
TYPES OF IMMUNITY
• INNATE immunity1) Broad specificity
(require Pattern Recognition Proteins)
2) Anatomical and Physiological barriers
3) Rapid response4) NO immunological
memory
• ACQUIRED immunity1) Antigen specific2) Slower response3) Involves
immunological memory
** Innate immune system directs the acquired immune system
INNATE IMMUNE SYSTEMTHIS IS THE EARLY PHASE RESPONSE TO PATHOGEN
INVASION
CELLULAR COMPONENTS HUMORAL COMPONENTS
NEUTROPHILS CYTOKINES
NATURAL KILLER cells COMPLEMENT
MONOCYTES/ MACROPHAGES ANTI MICROBIAL Peptides
MAST cells
DENDRITIC cells
NB- some cellular and humoral factors of the innate system are also involved in the adaptive system
The Key PlayersNEUTROPHILS
(PMN):• Blood Tissue via
DIAPEDESIS and CHEMOTAXIS
• PHAGOCYTOSIS
This is aided by the process of OPSONISATION
• KILLINGOxygen dependent/independent
MACROPHAGES:• Monocytes (blood)
Macrophages (tissue)
• Express pattern recognition molecules
• Become activated by molecular patterns on
bacterial surface
PHAGOCYTOSIS CYTOKINE RELEASE
WHAT HAPPENS IN SYSTEMIC INFECTION???
BACTERIAL SEPTIC SHOCK
COMPLEMENT SYSTEMCLASSICAL PATHWAY
ALTERNATIVE PATHWAY
ANTIBODY INDEPENDENT/ LECTIN PATHWAY
C3
MEMBRANE ATTACK COMPLEXES
OPSONISATIONLYSIS
DEGRANULATION OF MAST CELLS
LEUKOCYTE RECRUITMENT
1)
2)
3)
** BUT THIS IS LIKE AN ENZYME CASCADE SYSTEM – small input gives BIG outputSO WE NEED TO CONTROL THIS SYSTEM
A TYPICAL LOCAL ACUTE INFLAMMATORY RESPONSE
LOCAL ACUTE to SYSTEMIC ACUTE PHASE response
• CYTOKINE INDUCED
FEVER LEUKOCYTOSISACUTE PHASE
PROTEINS IN LIVER
1. CRP2. MBL3. SERUM AMYLOID 4. COMPLEMENT
*Complement activation by Lectin pathway
ADAPTIVE IMMUNE RESPONSE
CELLULAR COMPONENTS HUMORAL COMPONENTS
MONOCYTES/ MACROPHAGES COMPLEMENT
DENDRITIC CELLS CYTOKINES
MAST CELLS ANTIBODIES
LYMPHOCYTES
THIS IS THE SPECIFIC, ANTIGEN MEDIATED IMMUNITY
LYMPHOCYTES
• PRODUCED IN THE PRIMARY LYMPHOID ORGANS in HEMATOPOESIS
BONE MARROW THYMUS
* So how does the body ensure that these naive lymphocytes interact with complimentary antigens?
• INTERACTION WITH ANTIGEN OCCURS IN SECONDARY LYMPHOID ORGANS
SPLEEN LYMPH NODES MALT eg Peyer’s Patches
LYMPHOCYTES
B- Lymphocytes• Express CD19 and CD20• Express Surface Antigen
Receptor (Ig molecule).• Express MHC class II
molecules to “present” antigens to T cells.
• Produce antibodies to mount an immune response.
T- Lymphocytes• All express CD3. • 2/3 express CD4 (helper T cells)
which secrete cytokines.• 1/3 express CD8 (cytotoxic T cells)
which are responsible for lysing infected cells and also producing cytokines.
• Recognise processed antigen presented by APCs with MHC class II.
APCs• B cells (present to T cells)• Dendritic cells (present to T cells)• Follicular Dendritic cells (present to B cells)• Activated Macrophages (present to T cells)
Antibodies• Work by: Complement activation, opsonisation or cell
activation by antibody-binding receptors. • Define Affinity: strength of an individual bond between an
antigen and an antibody • Define Avidity: overall strength of all the bonds.• This means IgM – which has more binding sites – will have a
greater avidity that IgG, which may have greater affinity.• G – 4 subclasses. Most abundant. Placental transfer• A – 2 subclasses. Secretory. Dimer• M – agglutination in a primary response. Pentameric
molecule. • E – parasites/allergies. Bound to mast cells &
basophils=histamine release. • D – involved in B cell development.
MCQs
• ALL T cells express the CD3 marker • Lysozyme is present in tears• IgG antibodies are more efficient at
agglutination than IgM antibodies • IgE is useful for passive immunity• MALT is lymphoid tissue• antibody-antigen complexes activate the
classical pathway of complement
• T
• T
• F
• F• T
• T
Take home points• This was just an overview of some areas – there
are lots of other details to remember that you just need to get under your belt.
• Definitions – learn them basically but make sure you understand first.
• Innate immunity – Complement – but you should also look over acute phase response, learn the proteins involved and try to integrate everything.
• Antibodies – we just gave you a way to remember but you will need to learn the details.