Figure 3.

No significant effect of prior immune stimulation or CCI on transgene expression in CSF. (a) Rats were injected intrathecal with either vehicle (n = 12) or 100 µg of pCpG+ containing 0.2 ng of LPS (n = 18), 2 ng of LPS (n = 8) or 20 ng of LPS (n = 8) and, 2 days later, 25 µg of pCpG+ [SEAP] was injected. Fourteen days after pCpG+ [SEAP] injection, lumbosacral CSF was collected. SEAP was also measured in lumbosacral CSF 92 days post-injection in some of the rats (Vehicle, 1.8 ± 0.5 pM SEAP, n = 4 and pCpG+, 6 ± 2 pMSEAP, n = 6). All of these experiments used rats with CCI surgery. (b) Rats with (n = 16) or without (n = 14) CCI surgery were injected with 25 µg of pCpG+ [SEAP] 10 days after surgery. Fourteen days after pCpG+ [SEAP] injection, lumbosacral CSF was collected and assayed for SEAP activity. These rats also received a first injection of vehicle or pCpG+, which did not significantly affect transgene expression. The data presented in both panels originate from three independent experiments for each panel, using pCpG+ [SEAP] containing either 0.004 or 0.34 ng of LPS per injection; these varying LPS levels in the second injection did not significantly affect transgene expression so that the data were combined for analysis. Data are the mean ± SEM