MIC 419

Learning Objectives: Antibody Structure and Functions

Reading Assignment: Janeway Chapter 3 pp 103-115 and Appendix A-12 and Chapter 4 pp 156-157 or Parham Chapter 2 pp 37-47 and 57-61

Supplementary Materials: Antigen, Antibody, ToolBox

Antibody (Ig, BCR) is the specific proteins that B cells use to recognize antigen. Antigen molecules binding to BCR molecules on naive or memory B cells deliver signals that initiate activation of the cells to effector B cells (plasma cells). Plasma cells secrete antibodies into the blood, where they can travel to the site of infection. Antibody functions include neutralizing viruses and toxins (blocking binding to host cells), opsonizing (coating) pathogens to promote phagocytosis, and activating complement. This unit describes the structure of antibody, discusses how antibody molecules specifically bind antigen, and explains the functions of the five antibody isotypes.

When you finish Antibody Structure and Functions, you should be able to

Draw and label an IgG molecule, including the specific names for the H and L chains, the V and C regions, the Fab and Fc regions, the antigen-binding sites, and the locations of the interchain disulfide bonds. Describe the characteristics of immunoglobulin that define the immunoglobulin superfamily of molecules and name some other members.
Explain the relationship of the hypervariable regions (CDR) to the antigen-combining region and discuss the possible consequences of amino acid changes in either the framework or CDR to the antigen-binding affinity of the antibody.
Understand the naming of antibodies, and from their names deduce their source and antigen-binding specificity.
Name the five antibody isotypes and the body locations and functions of each.
Define and identify antigens, epitopes, and haptens.
Explain the similarities and differences between monoclonal and polyclonal antibodies.
Apply this information to a clinical case - be able to compare pathogen antigen recognition by T cells and B cells.