أحتاج مساعدة في الترجمة

السلام عليكم

الله يخليكم أحتاج ترجمة هذا النص





Vaccines are harmless agents, perceived as enemies. They are molecules, usually but not necessarily proteins, that elicit an immune response, thereby providing protective immunity against a potential pathogen. While the pathogen can be a bacterium or even a eukaryotic protozoan, most successful vaccines have been raised against viruses and here we shall deal with anti-viral vaccines.

Immunity to a virus normally depends on the development of an immune response to antigens on the surface of a virally infected cell or on the surface of the virus particle itself. Immune responses to internal antigens often play little role in immunity. Thus, in influenza pandemics, a novel surface glycoprotein acquired as a result of antigenic shift characterizes the new virus strain against which the population has little or no immunity. This new strain of influenza virus may, nevertheless, contain internal proteins that have been in previous influenza strains. Surface glycoproteins are often referred to as protective antigens. To make a successful vaccine against a virus, the nature of these surface antigens must be known unless the empirical approach