Transcript No Slide Title

Introduction to immunology
Jan. 19
Reading: Chapter 1
Objectives
• Compare and contrast the general
functions of different types of immune
cells
• Summarize the roles of:
– innate versus adapative immunity
– cellular versus humoral immunity
History of immunology
• Early observers noticed that
survivors of certain diseases were
resistant to re-infection
Mary Wortley Montagu
Excerpt from a letter by M. W. Montagu, 1717:
“….The old woman comes with a nutshell full of the
matter of the best sort of smallpox and asks what veins
you please to have opened. She… puts into the vein as
much venom as can lie upon the head of her needle.
…You may believe I am very well satisfied of the safety
of the experiment since I intend to try it on my dear little
son. …I should not fail to write to some of our doctors
very particularly about it if I knew any one of 'em that I
thought had virtue enough to destroy such a
considerable branch of their revenue for the good of
mankind….”
http://www.foundersofscience.net/lady_mary_montagu.htm
History of immunology
•
•
Edward Jenner, 1796
–
1st vaccinations: cowpox (vaccinia)
Louis Pasteur, 1880s
–
Vaccines against cholera in chickens,
rabies
• Emil von Behring & Shibasaburo Kitasato,
1890
– Serum from animals immune to diptheria
or tetanus conferred immunity to
recipients
– “Antitoxic activity” = antibodies
History of immunology
•
Eli Metchnikoff (shared Nobel Prize,
1908)
–
•
Phagocytic cells
Paul Erlich (shared Nobel Prize, 1908)
–
Described different types of immune
cells, antibodies
Components of the immune
system
• Lymphoid cells
– Lymphocytes
• Myeloid cells
– Granulocytes
– Monocytes/macrophages
– Dendritic cells
http://www.mhhe.com/biosci/ap/his
tology_mh/wbc1.html
Hematopoiesis
General functions of immune cells
General functions of immune cells
General functions of immune cells
Lymphocytes are small and inactive
unless antigen recognition occurs
Components of the immune
system: Lymphoid tissues
Primary lymphoid tissues
Secondary (peripheral)
lymphoid tissues
Inflammation is triggered by
infection
Lymphocytes encounter antigens in
the peripheral lymphoid tissues
Two general types of immunity
• Innate (natural, native)
• Adaptive (specific, acquired)
Innate vs adaptive immunity
Innate
immunity
Response time
Number of
specificities
Specificity
improves during
response
Memory
responses
Adaptive
immunity
Innate immunity
• Phagocytes (macrophages, neutrophils,
dendritic cells)
– Engulf microbes or foreign particles
– Release proinflammatory cytokines,
chemokines
• Complement
• Inflammation (early)
• Antigen processing and presentation
Antigen presentation
• T cell receptors cannot
bind antigens in the
native state
• Must be processed and
presented on an MHC
protein
• Antigen presenting cells
(APCs)
– Crucial bridge
between innate and
adaptive immunity
Adaptive immunity
• APCs required
• Lymphocytes activated
• Effector mechanisms respond to different
types of pathogens
– Humoral (B cells, antibodies)
– Cell-mediated (T cells)
• Memory cells generated
Adaptive immunity
• Lymphocyte activation
– Clonal selection and
clonal expansion
Adaptive immunity: humoral responses
Adaptive immunity: cell-mediated
immunity
• Cytotoxic T cells
(CD8+, CTL)
– Recognize antigens
presented by MHC I
– Response to
cytosolic pathogens
– Directly lyse target
cells
Adaptive immunity: cell-mediated
immunity
• Helper T cells (CD4+)
– Recognize antigens presented
by MHC II
– Response to extracellular
pathogens
– 3 major classes:
• TH1
• TH2
• Regulatory T cells
– Boost proliferation and
function of other immune
cells
Immune-related diseases