The Japanese word for Japan is æ¥æ¬, which is pronounced Nippon or Nihon and literally means the origin of the sun. The earliest record of the name Nihon appears in the Chinese historical records of the Tang dynasty, the Old Book of Tang.
The secondary immune response occurs the second time (3rd, 4th, etc.) the person is exposed to the same antigen. At this point immunological memory has been established and the immune system can start making antibodies immediately.
Key Difference â Primary vs Secondary Cell Culture. Before discussing the difference between Primary and Secondary Cell Culture, let us first briefly define what cell culture is. Cell culture is the process of removing cells from an animal or plant and subsequent growth in an artificially controlled environment.