The advent of Genetic engineering i.e. Recombinant DNA technology
to be more specific has made the vaccine technology a revolution.
The advent of new technology has helped in the production of different types of medicines for the common welfare of humans and animals. The role of vaccines in medical science is huge as it helps in immunizing against several life-threatening diseases. It plays an important role in human as well as veterinary medicines, though its role may be prophylactic or preventative in nature. The vaccines help the body to exploit the body’s innate immune system to fight against the infectious diseases.
From the moment a child is born, every day the body is exposed to a number of pathogens, which are mostly microorganisms, in the environment, food taken, inhaled air, drinking water, etc. Hence, the body needs to fight against these micro organic pathogens in order to protect itself from various infections and diseases.
The immune system within the body acts like soldiers to withstand the effect of the foreign, harmful substances, known as antigens and in doing so secretes various factors and proteins, known as antibodies that react with the antigens and protect the body. The vaccines are usually prepared from attenuated microorganisms or their secretions, which though harmless in nature initiate immunological response within the body producing antibodies, thereby immunizing the body from actual infections by the harmful organisms. The development of proper vaccines for various infectious diseases is possible only by the study of molecular mechanisms of the diseases within the body.
Traditional vaccines are antigen based, which are now being replaced by recombinant, genetically engineered vaccines. Being produced by genetic engineering method, these vaccines are completely safe on humans and animals and are produced in large- scale, thereby making their availability much easier and cheaper. There are a number of advantages of the production of recombinant technology aided vaccines:
(i) The polypeptides, derived from pathogens, are expressed in non-pathogenic recombinant host, thus eliminating the chance of an unknown pathogen to be present in the vaccines making it safe.
(ii) The Consistency in the production of vaccines eliminates the possibility of side effects in the administration of the vaccines.
(iii) The vaccines are produced in an unlimited manner, thus their availability is never a issue.
In some cases as in Hepatitis B, the antigenic polypeptide was directly extracted from the blood of infected individuals and purified to make the vaccines. However, it had many disadvantages like the non-availability of the plasma of Hepatitis infected individuals and the possible presence of intact, viral particles of Hepatitis in the blood or plasma collected, thus making the vaccines harmful. Hence, the latest method in the production of engineered vaccines includes the expression of the antigenic gene in a host followed by the extraction and purification of the polypeptides completely for use as vaccines. This eliminates the possibility of harmful properties in vaccines and even the production of the vaccines in large scale is possible. In some diseases, peptide vaccines are being used, whereby the peptides resembling the antigenic polypeptide are commercially synthesised and used as vaccines. Vaccine vectors are also a novel approach. In this method, the antigen is expressed on the surface of harmless vectors and the whole assembly including vectors is administered as vaccine.
The study of the different mechanisms within the body goes a long way in the development of vaccines for diseases like HIV, cancer, etc. AIDS does not infect some of the patients, who are carriers of HIV virus, even after many years. The study of the immunology and its factors in such patients may help in the development of vaccines for HIV. Large-scale clinical trials of the patients, who are carriers of the HIV virus, are very essential for the development of therapeutics for the disease. Many vaccines targeting cancer have been developed in the present times. The identification of the antigens associated with cancer has helped in the development of effective vaccines, for example, cervical cancer has developed specific vaccine. Many recombinant veterinary vaccines targeting pigs have been developed, which constitute the greater part of the veterinary biopharmaceuticals. Thus, it can be noted that vaccines play a very critical role in medical science and constant research is under progress to generate safe vaccines to protect against various infectious diseases.