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.
The main types of immune cells are white blood cells. There are two types of white blood cells â lymphocytes and phagocytes. When weâre stressed, the immune systemâs ability to fight off antigens is reduced. That is why we are more susceptible to infections.