Blood's Defence System

Ethical Issues & Phagocytes

Ethical Issues & Phagocytes

There are a number of ethical issues surrounding the use of vaccines and monoclonal antibodies:

  • The production of monoclonal antibodies involves the use of live mice.
  • The use of transgenic mice, which involves placing a human gene in a mouse, raises questions over the ethics of genetic engineering.
  • Testing new drugs and vaccines on humans always carries risks.
  • It’s important to know how effect a vaccine is throughout a population but testing it on vulnerable groups, like children, would raise concerns.
  • There are also issues over the idea of consent.



When a phagocyte finds a pathogen it engulfs it in a process called phagocytosis, trapping it in a membrane sac or phagosome. The phagosome then fuses with lysosomes. These contain lysozymes which are digestive enzymes including lipases, proteases and carbohydrases. They hydrolyse these components which make up the microbe thereby destroying it.

There are two types of phagocyte:

  • neutrophils mainly engulf whole bacteria and circulate the blood
  • macrophages engulf microbes before they enter the blood and are found in tissue fluid, lymph, and body cavities

Due to their size and shape they’re able to easily manoeuvre themselves through gaps in the walls of venules in order to reach infected tissue. Phagocytes are able to find the infected site through a process known as chemotaxis.