What are recombinant vaccines ? Explain the types .

Explanation

(i) Recombinant DNA technology has been used to produce new generation vaccines.
(ii) The recombinant vaccines are generally of uniform quality and produce less side effects as compared to the vaccines produced by conventional methods.
(iii) Different types of recombiant vaccines include subunit recombinant vaccines, attenuated recombinant vaccines and DNA vaccines.
(a) Subunit recombiant vaccines : Vaccines that use componets of a pathogenic organism rather than the whole organisms are coalle subunit vacciens . It includes components like proteins, peptides and DNAs of pathogenic organisms. The advantages of these vaccines include theirf purity in preparation, stability and safe use.
Attenuated recombinant vaccines : This includes genetically modified pathogenic organisms (bacteria or viruses) that are made nonpathogenic and are used as vaccines. It is now possbile to genticall engineer the organisms (bacteria or viruses) and use them as live vaccines and such vaccines are reffered to as attenuated recombinant vaccines.
(c) DNA Vaccines : Genetic immunisation by using DNA vaccines is a novel approach . The immune response of the body is stimulated by a DNA moelcule.
(iv) A DNA vaccine consists of a gene encoding an antigenic protein, inserted onto a plassmid, and then incorporated into the cells in a target animal . DNA instructs the cells to make antigenic molecules which are displayed on its surfaces. This would evoke an antibody response to the free floating antigen secreted by the cells.
(v) DNA vaccines are relatively easy and inexpensive to design and produce .
(vi) Such Vaccines have definite advantages like producing target proteins, long lasting immunity and trigger immune response only against specific pathogens with less toxic effects. Eg : Recombinant hepatitis B vaccine.