Suppression of experimental allergic encephalomyelitis with thoracic duct lymphocytes

Studies on the refractoriness to reinduction of experimental allergic encephalomyelitis in Lewis rats that have recovered from one episode of the disease

Lewis rats immunized with myelin basic protein (MBP) in Freund's complete adjuvant (FCA) suffer from a single episode of paralysis from which they recover spontaneously and become refractory to induction of further episodes of paralysis by reimmunization with MBP in FCA. We show that there is a transient period immediately after recovery when a second episode of paralysis can be induced in some animals by reimmunization with MBP in FCA, or soluble MBP prior to the development of complete refractoriness. We also show that rats that are refractory to the induction of experimental allergic encephalomyelitis (EAE) by active immunization with MBP in FCA are also refractory to the adoptive transfer of EAE by in vitro-activated MBP-primed lymphocytes.

Indomethacin augments in vitro proliferative responses of Lewis rat lymphocytes to myelin basic protein. Implications for experimental autoimmune encephalomyelitis

Indomethacin (IM), a specific inhibitor of prostaglandin (PG) synthesis, and PGE2 were studied in terms of their ability to modulate in vitro immune responses associated with experimental autoimmune encephalomyelitis (EAE) in Lewis rats. Lymphoid cells from either the spleens or the draining lymph nodes of myelin basic protein (MBP)-sensitized rats exhibited in vitro immune responses which were enhanced in the presence of IM. Specifically, IM enhanced (i) guinea pig MBP (GPMBP)- and rat MBP (RMBP)-stimulated lymphocyte proliferation, (ii) background proliferation, and (iii) interleukin 2 (IL-2)-stimulated proliferation. Conversely, PGE2 inhibited both GPMBP- and IL-2-stimulated proliferation of MBP-sensitized lymphocytes. Together, these results indicate that PGs secreted by cultured lymphoid cells can directly mitigate MBP- or IL-2-stimulated lymphocyte proliferation. Furthermore, the observation that IM and PGE2 modulate in vitro responses of MBP-specific lymphocytes may provide insight into how the in vivo administration of IM potentiates the severity of EAE (H. Ovadia and P.Y. Paterson, Clin. Exp. Immunol. 49, 386, 1982) and how PGs may be involved in the spontaneous remission of EAE in rats.

The fate of neonatally injected effector cells of allergic encephalomyelitis

Lymphocytes from rats sensitized with basic protein (BP) plus complete Freund's adjuvant (CFA), which produce allergic encephalomyelitis when transferred to adult recipients, fail to induce disease when transferred to 3- to 5-day-old neonatal rats. The transferred cells do, however persist in the recipients and can be revealed by actively challenging with BP-CFA later in adult life. Challenge leads to a significantly earlier onset of disease than is seen in control animals. We report here that the cells are long lived and persist in the recipients for at least 9 months. The cells can be demonstrated in the spleen and lymph nodes of recipient animals and can be activated by homologous and cross-reacting encephalitogenic antigenic preparations but not by antigen in nonencephalitogenic forms. These neonatal recipients, which carry autoimmune effector cells asymptomatically for prolonged periods, may provide a useful model for advancing our understanding of immunoregulatory events in this experimental demyelinating disease as well as the human demyelinating disease multiple sclerosis.

Regulation of experimental allergic encephalomyelitis. Part 5. Role of the recipient in suppressor cell induction

Suppressor cells that regulate experimental allergic encephalomyelitis (EAE) are present in spleens of Lewis rats that have recovered from the disease, as demonstrated by adoptive transfer of suppression to normal recipients. However, lethally irradiated recipients (850 rad) of spleen cells from recovered donors are not protected against EAE. Indeed, onset of EAE is accelerated in these irradiated recipients. These findings suggest that the host participates in the suppression of EAE.