MMI133 Lecture Notes - Lecture 14: Antigen, Lysozyme, Immunoglobulin E
21 Jun 2018
School
Department
Course
Professor
Milkmaids who contracted cowpox were immune to the more severe smallpox disease.
Vaccination - Jenner attempted to deliberately induce immunity
What is the Immune System?
● Body's defense system (pathogens, cancers and transplanted organs)
● Functions to keep microorganisms out, remove those that get in, combat those that remain
inside and fight mutated cells (cancer)
● A well balanced immune system should be able to identify between self and non-self
Innate/Natural Immunity and Nonspecific Responses
(immunity you are born with/hold the fort until adaptive
immunity kicks in)
Adaptive/Acquired Immunity
and Specific Responses
1st Line
2nd Line
3rd Line
1. Skin - a physical
barrier with keratin
waterproof layer. Skin
often dry inhospitable
environment
2. Mucus Membrane -
thin and permeable
membranes
-ciliated cells (moves
pathogens via cilia hair
cells)
- Goblet cells produce
mucus
- Mucus and other
secretions flush away
microorganisms
- Prevent pathogen
binding to host cell
3. Secretions
Tears/Saliva - uses enzyme
Lysozyme to break down
peptidoglycan
Crevicular Fluid - Fluid that
flows into gingival crevice
between teeth (gums), similar
in composition to blood
1. Innate Immune Cells -
white blood cells
(a.k.a. leukocytes)
2. Inflammation - when
white blood cell levels
rise through immune
response, swelling up
lymph nodes. It is a
localized response to
infection or injury.
Swelling
Heat
Altered Function
Redness
Pain
Puss - mixture of dead cells,
neutrophils and body fluid
Abscess - accumulation of pus
(pustules and boils
)
Pyogenic or pus producing
bacteria include Streptococcus
pyogenes and Staphylococcus
aureus.
3. Complement (C) -
immune cytolysis
using different
Specialized Lymphocytes
1. B Cells (produce
antibodies)
2. T Cells
- Helper T Cells (CD4)
- Killer T Cells (CD8)
3. Antibodies
(immune cells/molecules)
Gastric Juice - pH 1-2
Urine/Vaginal Secretions -
uses flushing action and low
pH as defence.
4. Normal Flora - competition
for space and nutrients in
mouth, skin and lower GI
protein serums from
the liver/catalase
(reaction occurs on the
surface of the cell
).
There are 3 pathways.
- Classical Pathway :
triggered by
antibody-antigen/im
mune complex
(AG-AB)
- Alternative Pathway:
triggered by
lipid-carbohydrates
(LPS)
- Lectin Pathway:
triggered by
mannose
4. Antimicrobial
Substances
- Interferons (IFN) -
defense molecule
produced by virally
inactivated cells
- Antimicrobial Agents
(AMPs) - triggered by
activation of TLRs,
broad spectrum
Examples:
Dermcidin - produced by
sweat glands
Defensins - produced by
neutrophils (pore formation and
cell destruction)
Thrombocid - produced by
platelets
- Acute Phase Proteins
Arrives first after infection
C-Reactive Protein (CRP)
marks bacteria for enhanced
phagocytosis (opsonization)
*produced in liver during
infection, with increased levels
indicating bacterial infection
Innate Immune Cells
Neutrophils
Eosinophils
Basophils Granulocytes or PMNL
Mast Cells
Document Summary
Milkmaids who contracted cowpox were immune to the more severe smallpox disease. Vaccination - jenner attempted to deliberately induce immunity. Body"s defense system (pathogens, cancers and transplanted organs) Functions to keep microorganisms out, remove those that get in, combat those that remain inside and fight mutated cells (cancer) A well balanced immune system should be able to identify between self and non-self. Innate/natural immunity and nonspecific responses (immunity you are born with/hold the fort until adaptive immunity kicks in) Specialized lymphocytes: b cells (produce antibodies, t cells. Killer t cells (cd8: antibodies, skin - a physical barrier with keratin waterproof layer. Skin often dry inhospitable environment: mucus membrane - thin and permeable membranes ciliated cells (moves pathogens via cilia hair cells) Mucus and other secretions flush away microorganisms. Prevent pathogen binding to host cell: secretions. Crevicular fluid - fluid that flows into gingival crevice between teeth (gums), similar in composition to blood.
