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.
A secondary immune response (second exposure to an antigen) is not only faster but produces antibody with up to a 10,000 fold increase in binding affinity. This higher affinity comes from a mechanism that alters the variable regions of light and heavy chains of the memory cells by specific somatic mutation.