Brief summaries

Pathogens are recognized via their antigens, which antibodies bind to and recognize as invaders. T cells and B cells also recognize antigens. T cells use MHC molecules complexes to recognize/detect antigens.

Things to remember

1. Pathogen enters the body
2. Macrophages and other phagocytes begin attacking the invaders
3. If deemed so, mast cells release histamine, leading to inflammation
4. Lymphocytes such as B cells attach to the antigen and secrete antibodies
5. Effector cells and memory cells begin production
6. Antigen fragments in macrophages activate T cells
7. The complement system, if activated, sends out signals for infected cells to undergo apoptosis
8. Humoral and cell mediated responses occur
9. Effector cells attack the pathogen
10. When the threat is dealt with, memory cells remember it to combat it better and faster next time