Bid rent theory in the central business district (CBD) [edit]. Land users, whether they be retail, office, or residential, all compete for the most accessible land within the CBD. The amount they are willing to pay is called bid rent.
Recombinant or purified protein vaccines consist of protein antigens that have either been produced in a heterologous expression system (e.g., bacteria or yeast) or purified from large amounts of the pathogenic organism.
A vaccineâalso called a âshotâ or âimmunizationââis a substance that teaches your body's immune system to recognize and defend against harmful viruses or bacteria before you get infected.These are called âpreventive vaccinesâ or âprophylactic vaccines,â and you get them while you are healthy.reventive vaccines are widely used to prevent diseases like polio, chicken pox, measles, mumps, rubella, influenza (flu), and hepatitis A and B.