Why does your immune system begin to get weaker in old age?
• Thymus atrophies and shrinks to 1/3 original size
• Bone density drops and marrow also atrophies
List the broad categories of disease the immune system participates in
• Allergy
• Autoimmunity
• Immunopathology
• Graft rejection
• Graft vs. host disease
Allergy
Allergies are a number of conditions caused by hypersensitivity of the immune system to something in the environment that usually causes little or no problem in most people. Food intolerances and food poisoning are separate conditions.
Autoimmunity
Autoimmunity is the system of immune responses of an organism against its own healthy cells and tissues. Any disease that results from such an aberrant immune response is termed an autoimmune disease.
Immunopathology
Damage caused to an organism by its own immune response, as a result of an infection.
Graft rejection
Transplant rejection occurs when transplanted tissue is rejected by the recipient's immune system, which destroys the transplanted tissue.
Graft vs. host disease
Graft versus host disease (GVHD) is a condition where following transplantation the donor's immune cells in the transplant (graft) make antibodies against the patient's tissues (host) and attack vital organs. Organs most often affected include the skin, gastrointestinal (GI) tract and the liver.
Broadly, what is Immunology?
The study of the body's defenses against infection
How was the field of Immunology founded?
Edward Jenner (late 18th century)
Saw that people exposed to cowpox did not get smallpox. Demonstrated that deliberate innoculation with cowpox prevented smallpox (first natural vaccination).
vaccination
The deliberate inoculation of individuals with weakened or attenuated strains of disease-causing agents to provide protection from disease.
Edward Jenner, first (natural) vaccine; prevented smallpox by injecting cowpox
What disease has vaccination eliminated? What disease is (likely) next? How do we know these diseases are eliminated?
Smallpox, next likely Polio.
Smallpox and Polio have no aminal reservoirs.
How was Polio wiped out?
Ring vaccination: vaccinating the areas around known infection sites to that the infection cannot spread outside the area.
What are the four categories of pathogens?
vuruses, bacteria, fungi, parasites
Who discovered that individual microbes were responsible for a particular disease?
Robert Koch (19th century), believed you need to be able to find the cause of disease, and identify it.
What categories are modern disease-causing organisms (pathogens) placed into?
Pathogens are placed into four categories:
• viruses
• bacteria
• fungi
• parasites
Who created the first intentional, "man-made" vaccine?
Louis Pasteur (1880)
• Developed vaccine for chicken cholera.
• Developed rabies vaccine by passing the virus through rabbits and using their dried spinal chord.
How did Pasteur weaken viruses for his vaccines?
He passed them through mammal hosts, which attenuated the pathogenicity of the virus.
Who first demonstrated how immunity worked?
Emil von Behring (who won the first Nobel prize in Medicine, 1901) and Shibasaburo Kitasato.
Discovered the blood serum of animals immune to diptheria bacteria contained "anti-toxic activity" (antibodies) that protected others from infection.
Where are immune responses directed?
Against pathogens.
What are the two divisions of the immune system?
Innate and adaptive immune system
antigen
• Any substance that can induce any part of adaptive immunity, not just antibodies.
• Can be almost anything, peptide, pathogen, allergen, food protein, commensal microbe
• Doesn't have to be truly foriegn
What is the rough order of the immune response?
• Many pathogens handled sucessfully by innate immunity and cause no disease.
• When innate immunity is not enough, adaptive system is triggered by innate system.
• If the pathogen is overcome, adaptive immune system is often followed by long-lasting immunological memory, decreasing severity or preventing re-infection.
leukocyte
• White blood cell (WBC)
• Only blood cells with a nucleus.
• Two types, myeloid cells or lymphoid cells.
monocyte cellular "ancestry"
Multipotent hematopoietic stem cell (Hemocytoblast) > myeloid progenitor > Myeloblast > Monocyte
monocyte
precursors of tissue macrophages (which are phagocytes)
PMN
Polymorphonuclear leukocytes (PMN) (also called granulocytes:
• Have multi-lobed nuclei and cytoplasmic granules
All are Myeloblast daughter cell types:
• Basiophils
• Neutrophils
• Eosinophils
What are the possible daughter cell types of lymphoid progenetor cells?
Natural killer (NK) cells (also called large granular lymphocytes)
Small lymphocytes, which can become either B or T lymphocytes
Plasma cells, which arise from B lymphocytes
General features of the innate immune system
• Built-in, does not learn before acting and doesn't need to
• First line of defense, then alerts adaptive immune system
• Anti-microbial peptides are produced in a steady state
• Specific receptors found on many cell types that recognise microbial products
What part of the immune system produces responses to specific microbes?
adaptive
What are white blood cells called?
leukocyte
