faculty of biotechnology and life science ADAPTIVE IMMUNE RESPONSE TO EXTRACELLULAR BACTERIA
Nov 18, 2014
faculty of biotechnology and life science
ADAPTIVE IMMUNE
RESPONSE TO
EXTRACELLULAR BACTERIA
Group Members
DAYANA ‘AMIRAH BT.DARUS 4081017391
MANIZHEH KHALIPOUR FARSHBAFI 4081022241
MOHAMED ALI MOHAMUD 4072012671
NORMAZATULIZMA MOHAMAD 4081023341
NOR FARIDAH MOHD SAID 4081028481
RASYIDAH MISWANDI 4081025401
ROSLINA JAMALUDIN 4081021941
Immune system
Adaptive immune response
B cell
Effector functions of antibodies
Neutralization of microbes and their toxins by binding to their surface and neutralize it by blocking their active sites.
Opsonization of microbes (binding to Fc receptors on phagocytes; at the same time, stimulation of microbicidal activities of phagocytes) and also tagging the pathogen.
Activation of the complement system both IgG and IgM trigger the complement system which results in cell lysis and inflammation.
White Blood CellsLeukocytes
(White Blood Cells)
lymphocytesOther Types of
WBC
Eosinophils MacrophagesT cells NK CellsB Cells
Helper T cells- secrete lymphokines that direct B cells into producing antibodies and also direct the Killer T cells as to which cell they get to eliminate.
Killer T cells- They find specifically coded infected cells, and then destroy them with cytotoxins. They may be directed by Helper T cells
Suppressor T cells- in charge of slowing and stopping the immune response after the foreign substance is destroyed.
Memory T cells- derived from Helper T cells, have the same properties as their parent cell, and circulates until the body encounters the pathogen its parent cells were designer for.
T T CELLS !!CELLS !!
T Cells Activation
II. Second Line of Defense1. Phagocytosis: Derived from the Greek words “Eat and
cell”. Phagocytosis is carried out by white blood
cells: macrophages, neutrophils, and occasionally eosinophils.
Neutrophils predominate early in infection. Wandering macrophages: Originate from
monocytes that leave blood and enter infected tissue, and develop into phagocytic cells.
Fixed Macrophages (Histiocytes): Located in liver, nervous system, lungs, lymph nodes, bone marrow, and several other tissues.
Phagocytic Cells: Macrophages (Monocytes), Neutrophils, and
Eosinophils
(Macrophages)
Stages of Phagocytosis1. Chemotaxis: Phagocytes are
chemically attracted to site of infection.2. Adherence: Phagocyte plasma
membrane attaches to surface of pathogen or foreign material. Adherence can be inhibited by capsules
(S. pneumoniae) or M protein (S. pyogenes).
Opsonization: Coating process with opsonins that facilitates attachment. Opsonins include antibodies and
complement proteins.
Phagocytes are Attracted to Site of Infection by
Chemotaxis
Stages of Phagocytosis (Continued)
3. Ingestion: Plasma membrane of phagocytes extends projections (pseudopods) which engulf the microbe. Microbe is enclosed in a sac called phagosome.
4. Digestion: Inside the cell, phagosome fuses with lysosome to form a phagolysosome. Lysosomal enzymes kill most bacteria within 30 minutes and include: Lysozyme: Destroys cell wall peptidoglycan Lipases and Proteases RNAses and DNAses
After digestion, residual body with undigestable material is discharged.
Process of Phagocytosis
Conclusions
The most common disease-causing microbes are bacteria, viruses, and protozoa. Each uses a different tactic to infect a person, and, therefore, each is thwarted by different components of the immune system.
Virus Protozoa Bacteria
There are two mains sites where pathogens may reside: extracellular in tissue spaces or intracellular within a host cell, and the immune system has different ways of dealing with pathogens at these sites.
Most bacteria live in the spaces between cells and are readily attacked by antibodies.
Antibodies are the primary defense against extracellular pathogens. When antibodies attach to a bacterium; they send signals to complement proteins and phagocytic cells to destroy the bound microbes.
Some bacteria are eaten directly by phagocytes, which signal to certain T cells to join the attack.
Summary:
Macrophages are able to launch the first strike…
more help is needed to overcome rapidly reproducing invaders…
Help from the ADAPTIVE IMMUNE System results in a coordinated successful defense !
Major players the B lymphocytes
THANK YOU ……..