IL-12 induces growth of the IL-4-dependent CT4S line and has a synergistic effect on IL-4-induced CT4S proliferation.
In the course of studies designed to explore the effect of interleukin 12 (IL-12) on the development of experimental autoimmune uveoretinitis (EAU), we observed that supernatants from IL-12-treated cultures of ocular antigen-specific lymphocytes induced proliferation of the interleukin 4 (IL-4)-dependent CT4S line. This result was surprising, as these supernatants were not expected to contain high levels of IL-4. We therefore explored the possibility that IL-12 itself, that remained in the supernatants, could induce proliferation of CT4S cells. In this series of experiments we demonstrate that CT4S cells proliferate to recombinant as well as to naturally produced IL-12, and that IL-4 and IL-12 synergize in supporting proliferation of CT4S cells. The proliferation induced by IL-12, as well as the synergistic effect with IL-4, can be reversed by neutralizing anti-IL-12 antibodies. Proliferation of CT4S can be abrogated completely by a combination of antibodies against IL-4 and IL-12. Our data have important implications for the use of CT4S as a specific bioassay for IL-4, since both IL-4 and IL-12 may be found together in at least some culture supernatants. Furthermore, our results suggest that the CT4S line (or a derivative selected from it) could be used as a bioassay for detection of IL-12 in combination with the specific antibodies.
Xu
H
H
National Eye Institute, Bethesda, MD 20892, USA.
Rizzo
L V
LV
Caspi
R R
RR
D000818:Animals; D002455:Cell Division / Q000187:drug effects*; D002460:Cell Line; D018664:Interleukin-12 / Q000008:administration & dosage*; D015847:Interleukin-4 / Q000008:administration & dosage*; D015461:Leukemia, Prolymphocytic, T-Cell / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D011994:Recombinant Proteins
D011994:Recombinant Proteins; D018664:Interleukin-12; D015847:Interleukin-4