Specific immune regulation of chronic-relapsing experimental allergic encephalomyelitis in mice.

These studies were designed to examine immunologic means of regulating the clinical course of murine chronic-relapsing experimental allergic encephalomyelitis (R-EAE). We asked whether induction of specific immune tolerance to the major CNS myelin proteins, myelin basic protein (MBP) and proteolipid protein (PLP), could inhibit the development of R-EAE. Neuroantigen-specific tolerance was induced in SJL/J mice in a dose-dependent manner by the i.v. injection of mouse spinal cord homogenate-coupled syngeneic splenocytes (MSCH-SP) on day -7 relative to immunization on days 0 and +7. Sham-tolerized controls developed significant MBP- and PLP-specific DTH responses before the onset of clinical R-EAE. In contrast, MSCH-SP tolerized mice exhibited a dramatically reduced incidence of clinical and histologic signs of disease which correlated with the failure to develop MBP- and PLP-specific DTH responses. In 10 separate experiments, 118/149 (79%) of control mice, but only 22/137 (16%) of tolerized mice developed clinical R-EAE. Tolerance took time to develop and lasted at least 4 wk as mice injected with Ag-coupled splenocytes on day -1 relative to immunization remained susceptible to R-EAE, whereas mice injected on days -7, -14, or -28 were resistant. Tolerance induction required neuroantigens as injection of splenocytes coupled with a syngeneic mouse kidney homogenate failed to significantly alter the incidence of R-EAE or the development of neuroantigen-specific DTH responses. Thus, induction of R-EAE can be specifically and significantly regulated after the i.v. injection of splenocytes coupled with a crude, heterogeneous mixture of neuroantigens (i.e. MSCH).