1. Immunology: diagnosing infections

2. What is diagnostic immunology? Term for a variety of diagnostic techniques that rely on the specificity of the bond between antibodies and antigensantibodies antigens Using antibodies to identify pathogens

3. Uses serological tests Direct tests detect antigens (from patient sample). Indirect tests detect antibodies (in patient′s serum).

4. What are some serological tests? Monoclonal antibodies Many techniques –Precipitation reactions –Agglutination reactions –Complement-fixation reactions –ELISA –fluorescent-antibody –Western blot

5. What are monoclonal antibodies? Produced by specialized B cells. –Single type of Ab. From any substance –Possible to create monoclonal antibodies that specifically bind to that substance Can serve to –detect or purify that substance Useful –Uniform –Highly specific –Produced in large quantities

6. What are monoclonal antibodies? Immunotoxins: Mabs conjugated –with a toxin to target cancer cells. Chimeric mabs: Genetically modified mice that produce Ab –with a human constant region. Humanized mabs: Mabs that are mostly human – except for mouse antigen-binding. Fully human antibodies: Mabs produced from a human gene – on a mouse.

7. What are precipitation reactions? Involve soluble antigens with antibodies. Figure 18.4

8. What are agglutination reactions? Involve particulate antigens and antibodies. Antigens may be –On a cell (direct agglutination). –Attached to latex spheres (indirect or passive agglutination). Figure 18.5

9. What is direct agglutination? Antibody titer Is the concentration of antibodies against a particular antigen. Figure 18.6

10. Reactions in indirect agglutination

11. What are complement fixation reactions?

12. What is ELISA? Enzyme-linked immunosorbent assay A positive direct ELISA to detect antigens A positive direct ELSIA to detect antibodies

13. What is fluorescent-antibody testing? Tagged antibodies Direct method Indirect method

14. What is the Western Blot? Similar to Southern Blot Proteins, not DNA