ENGRAFTMENT OF C6-2B CELLS INTO THE STRIATUM OF ACI NUDE RATS AS A TOOL FOR COMPARISON OF THE IN-VITRO AND IN-VIVO PHENOTYPE OF A GLIOMA CELL-LINE

The C6-2B is a well-characterized glioma cell line used extensively in the study of malignant glial biology, While the C6-2B cell line has t raditionally been thought of as a homogenous cell line, the in vitro p henotype of the C6-2B cell line can vary considerably depending on the culture technique used and the stratum on which the cells are grown, Thus, we asked whether the in vitro phenotype of the C6-2B cell line w as significantly different than the in vivo phenotype of the cell line once it was engrafted into the striatum of nude rats, Under culture c onditions used in our laboratory, 100% of the C6 cells were found to e xpress p75, the low-affinity nerve growth factor (NGF) receptor, and M ajor Histocompatability Class I(MHC Class I), while only 10-15% demons trated vimentin reactivity, Immunohistochemistry was consistently nega tive for GFAP, trkA (the high-affinity receptor for NGF), CD4, CD8, an d a macrophage specific marker (Ox-41), Once engrafted into the striat um of nude rats, the cells remained 100% p75 and MHC Class I positive, and again, only 15% of the cells demonstrated vimentin reactivity. Th e grafted cells retained this characteristic for 28 days in vivo, Alth ough an immunoincompetent host was selected to minimize the effects an inflammatory response would have on the graft, a transient inflammato ry response was detected, During the first week of engraftment, numero us MHC class II cells, some of which were macrophages, were seen infil trating the graft, However, by 4 weeks postengraftment, no inflammator y cells were appreciated in the graft and surprisingly little reactive gliosis was seen in the penumbra of the tumor mass, Thus, the limited number of in vitro phenotypic characteristics we examined in the C6-2 B cell line remained constant once the cells were engrafted into the s triatum of athymic nude rats. (C) 1997 Elsevier Science Inc.