1. Lecture 6Humoral Immune Response

2. The Antibody Response

3. Antibody Protection of the Host

4. Immunologic Memory Virgin lymphocyte pool PRIMARY RESPONSE effector cells memory cell pool SECONDARY RESPONSE effector cells memory cell pool

5. Immunologically Naive No previous experience No memory Must be educated

6. The Primary Immune Response antibody titer lag log phase plateau decline time antigen challenge

7. Class Switching antibody titer IgM IgG time

8. Four phases of the primary response • a lag phase where no antibody is detected • a log phase in which the antibody titer rises logarithmically • a plateau phase during which the antibody titer stabilizes • a phase (decline) during which the antibody is cleared or catabilized

9. The Anamnestic Immune Response Secondary Response antibody titer 1000 100 Primary Response 10 1 Time

10. Comparison of Primary and Secondary Responses • Time course • Antibody titer • Antibody class • Antibody affinity

11. Terms to remember • Opsonization • Neutralization • Complement activation • Primary response • Secondary/ anamnestic/ booster response • Lag phase • Log phase • Plateau period • Memory cells • Class switching • Affinity maturation/ change in affinity with time