Vaccines from chicken embryos

Vaccines are drugs that train the immune system when the body is attacked by pathogens such as viruses or bacteria. Antigens, expressed from the pathogens, are responsible to trigger an immune response in our body. Once in contact with these antigens, the body immediately produces antibodies against the pathogen containing the corresponding antigen. The pathogens will then be attacked before spreading of the viruses and bacteria is possible. Figure 1 (next page) shows the classical procedure of an immune response, where the concentration of the antibody is lower after initial exposure with a primary immune response. A second exposure allows the body to show a faster and more intense immune response with a higher antibody affinity. Vaccinations provokes a “second exposure response”. There are different types of vaccines: (1) the live attenuated vaccines, where a weak version of the virus or bacteria is introduced into the body (Mumps), (2) inactivated vaccines, where the pathogens are killed, and the dead cells are introduced into the body (Polio, Hepatitis A), (3) toxoid, dead toxins are injected into the body, as some pathogens can produce toxins harming the body (Tetanus), and other vaccines like subunit, conjugated, DNA and recombinant vector vaccines. The integration of a living pathogen cannot be handled by everyone. People with a weak immune system (cancer or HIV patients) can get sick as the pathogen is too strong. On the other hand, inactivated vaccines often require multiple vaccination shots because the dead cells do not behave in the same intensity as the living pathogens. Therefore, another possibility is the direct injection of antibodies into the body, extracted from animals. An efficient and fast extraction is required to reduce costs and material.