BRAINCAKECell-Mediated Immunity
Neutrophils engulf and then completely destroy pathogens then die. Dead neutrophils and pathogens form pus at the site of infection.
Macrophages engulf the pathogens and then combine the fragments of bacterial or viral protein with a protein complex called the major histocompatibility complex.
This then migrates to the cell surface where it displays the fragment on the cell surface.
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Key terms in this lesson
- mitosis
- Nuclear division that produces two daughter nuclei, each genetically identical to the parent nucleus.
- pathogen
- A microorganism, such as a virus, bacterium, fungus or protoctist, that causes disease.
- antigen
- A protein or glycoprotein, usually on a cell surface, that is recognised as foreign by the immune system and triggers an immune response.
- antibody
- A Y-shaped protein, made of four polypeptide chains with variable regions complementary to a specific antigen, produced by B plasma cells.
- phagocytosis
- The process by which a phagocyte engulfs and digests a pathogen or foreign particle.
More in Cell Recognition and the Immune System
- Recognising Self and Non-Self Cells
- Phagocytosis
- Antigens
- Lymphocytes
- Cytotoxic T-cells
- Humoral Immunity
- Primary and Secondary Immune Response
- Antibody Structure
All 30 lessons in Cell Recognition and the Immune System · All AQA AS-level Biology topics