Immune System

1. Antigen

2. 2nd Encounter Antigen

3. T Cells

3.1. Cytotoxic T Cells

3.2. Helper T Cells

4. B Cells

4.1. Antibodies

4.1.1. IgM

4.1.2. IgG

4.1.3. Memory Cells

5. Secondary Response

6. Primary Response