[Influence of sialic acid level in cultured pituitary cells on immunogenicity]

Many researches have demonstrated that cultured tissue or cells may reduce immunogenicity and can survive in a recipient if they are allografted or xenografted. The cause for this phenomenon remains uncertain. In this experiment, sialic acid (SA) content of BALB/C mice pituitary cells before and after culture was determined, and the influence of SA level on cell immunogenicity was studied by using the mixed lymphocyte reaction method and neuraminidase. The SA level was much higher in cultured cells than in uncultured cells. Cultured cells were found to have a reduced ability to stimulate splenocyte proliferation in allogeneic rats after the SA levels of the cells had been raised. Such ability could be restored by removing SA from the cell surface with sialidase. This suggests that the high SA levels in the cultured cells play an important role in reducing their immunogenicity.