MICR161

Lecture 1

The Essence of Immunity is the ability to distinguish between self and non-self. This means "Recognition"

 Recognition:

Discern	Specific	Discriminate	Latch on to
See	Hear	Smell	Respond to

Levels of Recognition: a rheostat, amplification

How is this accomplished?

Receptors:

Cell surface receptors

Soluble receptors in the fluids of the body

These receptors are Proteins capable of binding other molecules specifically. Specific binding is another way of saying "recognition"

See page 96, Fig 7.5 for a diagram of the receptors on the surface of B-cells

See page 105, Fig 8.5 for a diagram of the receptors on the surface of T-cells.

See page 131, Fig 10.2 for a diagram of how T-cells and Antigen Presenting Cells (APC's) interact.

See page 138, Fig 10.7 for a diagram of how T-cells and B-cells interact. Note also how the receptor molecules are believed to interact with each other.

Can you find the surface antibody? The T-cell receptor? The Major Histocompatibility Complex molecule?

Receptors are proteins. What other types of molecules are proteins?

Enzymes? What do enzymes do? How do enzymes interact with substrate?

Molecules involved in motility? Actin and myosin? What is the role of Ca⁺⁺?

A Brief History of Immunology

Edward Jenner - Developed vaccination. What is the connection between cowpox and smallpox? What is Variolation?

Louis Pasteur - Invented a variety of vaccines -- developed the science of immunization. Chicken cholera, anthrax and rabies vaccines were developed.

Emil von Behring and Shibasaburo Kitasato -- protected rabbits against tetanus toxin and diptheria toxin by immunizing them with very small amounts of toxin. Showed that passive transfer of immunity to these toxins was possible --> immune rabbit serum protected mice. This was later tried with humans, curing diptheria with immune serum made in other animals. What is a toxoid? What is serum sickness?

Paul Ehrlich -- Developed quantitative approaches to detecting and measuring antiserum in the test tube. Demonstrated the "specificity" of antiserum --> antiserum to ricin (castor bean toxin) could protect animals from this toxin but not from other toxins like abrin (a toxin from the rosary pea). Thought up the "side-chain theory" of antibody formation. In this theory, a vast variety of antibodies were present as side chains on immune cells. A foreign substance (antigen) would react with antibody on the surface of immune cells with a "lock and key" type of fit, inducing the cell to produce more of that particular side chain and secrete it into the blood.

Karl Landsteiner -- Developed highly quantitative methods for measuring antibody and antigen. Discovered "haptens" -- small molecules which themselves are not immunogenic, but when complexed to a larger molecule they can induce the production of antibody. Such anti-hapten antibody is then able to react with the free hapten as well as the hapten complexed to the larger molecule. Landsteiner also discovered the A, B, O blood group antigens.

Jules Bordet - Discovered "complement" -- a group of proteins in the blood which when activated can destroy bacterial cells by lysis. Complement can also destroy bystander cells and so can cause a lot of damage to the host's body.

Arne Tiselius -- applied electrophoresis to serum proteins. Antibodies were shown to migrate as g - globulin, a term now synonymous with the term antibody.

Ilya Metchnikov -- discovered "Phagocytosis" and phagocytic cells in starfish larva. These studies led him to theorize about the "meaning of pus" -- that white blood cells move into an area of inflammation in order to devour and destroy parasites.

Georges Kohler and Cesar Milstein – Discovered how to make monoclonal antibodies. Proving the clonal nature of antibody specificities. One cell = one specificity. Helped to create a biotech industry.

Kinds of Immunity?

Cellular vs. Humoral

Innate vs. Acquired