| These mice are transgenic for the SV40 large T antigen under the control of a rat insulin promoter, and spontaneously develop beta adenomas.
At passage 18, most cells stained positively for insulin, less than 5% were positive for glucagon and none were positive for somatostatin or pancreatic polypeptide.
Insulin secretion is responsive to glucose concentration in the medium.
There is low constitutive expression of MHC class I, class II and ICAM-1 mRNA, but expression of both is markedly increased by treatment with interferon gamma.
Stimulation of class I mRNA is accompanied by increased class I antigen expression and induction of an occult class I product expressing the H-2.39 specificity.
MHC class II antigen is not induced despite the induction of the mRNA.
NIT-1 cells show ultrastructural features of differentiated mouse beta cells (well developed rough endoplasmic reticulum, extensive golgi apparatus and beta granules).
The cells shed a mature ecotropic type C retrovirus. The retrovirus is capable of infecting other Fv-1 n mouse cell lines, so care should be taken to avoid cross infection.
NOTE: NIT-1 cells will not form a confluent monolayer; however, they will form nice colonies of monolayered cells in a fairly dense array.
When the NIT-1 colonies begin to ball up slightly and show many round cells on top of the monolayers as well as floating in the media, it is time to passage them. |
