Isolated primary RA-SFB versus conventional fourth-passage RA-SFB
The percentages of RA-SFB positive for MHC-II, as well as the MFI for VCAM-1 and c-Jun, were significantly decreased in conventional fourth passage in comparison with isolated primary RA-SFB (Fig. 7C,D,K,L and Table 5). The percentages of cells positive for MHC-I, CD13, prolyl-4-hydroxylase, vimentin, procollagen I and III, c-Fos and Jun-D were, in contrast, significantly increased in conventional fourth passage (Fig. 7E,F,G,H,I,J and Table 5).
The upregulation of the proto-oncogenes c-Fos and Jun-D was limited to RA, since the percentages of cells positive for these molecules were significantly decreased upon passaging in OA-SFB (c-Fos: isolated primary-culture OA-SFB, 53.9 ± 10.4%; conventional fourth-passage OA-SFB, 15.0 ± 6.6%; Jun-D: isolated primary-culture OA-SFB, 37.6 ± 17.7%; conventional fourth-passage OA-SFB, 25.1 ± 4.2%; n =3 for both SFB preparations) and numerically decreased upon passaging in normal skin-FB (c-Fos: primary-culture/first-passage skin-FB, 87.2 ± 2.1%; conventional fourth-passage skin-FB, 59.4 ± 26.0%; Jun-D: primary-culture/first-passage skin-FB, 87.4 ± 1.5%; conventional fourth-passage skin-FB, 66.2 ± 18.6%; n = 3 for both). These decreases were also noted for the MFI (data not shown). The percentage of positive cells and/or MFI for c-Fos and Jun-D in conventional fourth-passage RA-SFB were significantly higher than in OA-SFB as a consequence of these reciprocal changes, under these circumstances confirming previously published data [25].