Plotkin S R, Banks W A, Maness L M, Kastin A J
Partners Neurology Program, Harvard Medical School,Boston, MA 02115, USA.
Brain Res. 2000 Oct 20;881(1):57-61. doi: 10.1016/s0006-8993(00)02772-4.
Human interleukin-1alpha is transported across the murine blood-brain barrier (BBB) and blood-testis barrier (BTB) by a saturable transport system. Differences in the biological activity and binding of human IL-1 in mouse and rat brain raise the possibility of species differences in the transport of IL-1 across the BBB and BTB. We measured the transport of recombinant human 125I-IL-1alpha (I-huIL-1alpha) and rat 125I-IL-1alpha (I-ratIL-1alpha) across the rat BBB and BTB after intravenous injection using a sensitive in vivo technique and film autoradiography. I-ratIL-1alpha was found to cross the rat BBB and rat BTB at rates comparable to those reported previously for murine IL-1alpha in mice. Passage across the BBB was inhibited by the addition of unlabeled rat IL-1alpha, demonstrating saturable transport. In contrast, I-huIL-1alpha entered the brain of the rat much more slowly, and its entry was not inhibited by the addition of unlabeled human IL-1alpha. These results show that the rat interleukin-1 transporter, unlike the murine transporter, does not transport human IL-1alpha. This difference highlights the importance of species specificity in IL-1alpha transport and may partly explain the different physiological responses to exogenous human IL-1alpha among rodent species.
