Download B Cells - Ms Nickel`s Biology 11H

pGLO Reflection
1.What were we trying to do in this lab?
Did we accomplish it? How do you know
that the lab was/wasn’t successful?
2.What were the controls used in this lab?
What did they show us?
3.What role did arabinose play in the GFP
gene expression?
Biology 11H
Microbiology
Fighting Infections – a nod to AP and Immunity
Objectives
By the end of the lesson you should be able to:
• Describe the levels of our immune system
• Describe the ways in which we fight back against
an infection
Immune System
The immune system
is mainly comprised
of lymphatic system
and a population of
White Blood Cells
(WBC) called
leukocytes that
patrol the circulatory
system
Immune System Overview
• We have 2 ways of fighting infections:
1.Innate Immune System: “non-specific” broken down
into 2 types External and Internal
2.Adaptive Immune System: “specific” broken down
into 2 types Humoral and Cell-Mediated
Innate Immune System
Animals are the only organisms with a major immune system
External: “barriers”
Internal: phagocytes & inflammation
1.
SKIN: water-proof, sweat glands,
“good” micro-organisms
2. MUCOUS MEMBRANES: lined with
mucus – sticks to pathogens,
contains lysozyme – disrupts
bacterial cell walls
3.
CILIATED MEMBRANES: contain
cilia, works with mucus to trap and
move pathogens
1.
PHAGOCYTES: WBCs that patrol circ
system and “eat” anything that is
foreign, present foreign pieces for
specific response
2. INFLAMMATORY RESPONSE: Mast cells
at area of infection release histamine
and call phagocytes to the infected area.
Histamine also increases blood flow to
the area ( = red/swelling/hot)
INFLAMMATORY RESPONSE
Adaptive Immune System
The responsibility of the WBCs called lymphocytes that live in the lymphatic
system. There are 2 types: B cells & T cells
• B Cells: born and raised in the
bone marrow. Responsible for
the HUMORAL response.
• T cells: born in the bone
marrow but raised in the
thymus gland. Responsible for
the CELL-MEDIATED response.
Adaptive Immunity: Humoral Response
• Responsibility of the B cells
• Results in the production of antibodies SPECIFIC to the antigen of
the invading pathogen
STEPS:
4. The cloned B cell creates 2 types
1.
Phagocytes present antigens
to Helper T cells
cells: Plasma cells and Memory B
cells
2.
3.
Helper T cells activate B cells
Plasma Cells: make and secrete
B cells produce different
antigen receptors until the
reactive one is made. This B
cell is cloned.
antibodies to the circ. system
Memory B Cells: circulate in the
lymphatic system in case of future
infection from same pathogen
So what?? Why antibodies???
Antibodies can cause 3 different responses when they’ve
attached to an antigen
1.Opsonization: tagged pathogens are “eaten” by
macrophage
2.Neutralization: tagged pathogens are unable to
infect other cells
3.Complement Activation: complement system
forms pores in the cell membrane of tagged
pathogen - LYSIS!! 
Adaptive Immunity: Cell-Mediated Response
• Responsibility of T cells
• Results in activation of T cells that recognize specific antigens
STEPS:
1. Phagocyte presents antigen to Helper T Cell
2.Activated Helper T Cell activates specific T Cells
3. Activated specific T Cells creates 2 populations of T Cells: Cytotoxic T
cell and Memory T Cells
Cytotoxic T Cells: find cells with specific antigen
Memory T Cells: circulate lymphatic system in case of future infection by
same pathogen
4.
Cytotoxic T Cells trigger death by secreting perforin (creates holes in
pathogen’s cell membrane)