Clone of cells can be a lot of culture, supernatants were collected and a large number of single clone of antibody in vitro. But the law is limited monoclonal antibody in vitro culture, can not exceed a specific concentration of cells, and every day want to change the culture medium. Hybridoma propagation in vivo can overcome these limitations. Hybridoma cell has the genetic characteristics of lymphocytes from the parental generation to the tumor cells. Such as histocompatibility inoculated into syngeneic mice, or mice (athymic nude mice) can not exclude the hybridoma, hybridoma cells began to unlimited reproduction until host death. Produce mouse ascites tumor cells and serum contain a large number of hybridoma monoclonal antibodies secreted by this antibody titers are often higher than the culture supernatant was 100 to 1000 times. The use of immunosuppressive agents, such as pristane, liquid paraffin, anti-lymphocyte serum, can accelerate and promote tumor growth.