Relationships between cell-mediated immunity and the IgE antibody response. II. Delayed hypersensitivity and antibody production to DNP-ascaris conjugates

The role of myelin lipids in experimental allergic encephalomyelitis. III. Transfer of suppression from guinea pigs recovering from EAE, induced by myelin basic protein--galactocerebroside complexes

Juvenile strain 13 guinea pigs were immunized with myelin basic protein (MBP) combined with galactocerebrosides (MBP + GC) or with total myelin lipids without GC [MBP + (TL-GC)] in CFA. Control animals received dinitrophenylated-ovalbumin (DNP-OA) in CFA, CFA or IFA alone. The animals injected with MBP + GC showed a higher rate of recovery from the first EAE episode (83%) than those treated with MBP + (TL-GC) (50%). With the exception of the group treated with IFA alone, all animals were refractory to EAE following rechallenge with MBP in CFA 90 days after the first exposure. The in vitro proliferative response to MBP, of peripheral blood lymphocytes (PBLs) derived from guinea pigs freshly sensitized to MBP in CFA, was drastically suppressed in the presence of PBLs from animals injected with MBP + GC. Upon transfer to normal syngeneic recipients, spleen cells from MBP + GC-treated animals completely suppressed the clinical and histological manifestations of EAE following recipient challenge with MBP in CFA. Cell-free supernatants from PBLs and spleen cells of strain 13 guinea pigs treated with MBP + GC inhibited lymphocyte proliferation to MBP, of allogeneic responder cells, and spleen cell supernatants completely suppressed the induction of EAE upon transfer to allogeneic recipients. Suppression could not be transferred with cells from other treated groups. These results suggest that animals immunized with MBP + galactocerebrosides in CFA develop suppressor cells that may be in part responsible for the recovery from the first EAE episode and for protection against rechallenge with MBP in CFA. Their cell-free supernatants act in an MHC-nonrestricted fashion. These results do not rule out an additional protective mechanism since all animals exposed to CFA were refractory to rechallenge despite lack of demonstrable suppressor cell activity.

Suppression of experimental allergic encephalomyelitis in Lewis rats treated with myelin basic protein-liposome complexes: clinical, histopathological, and cell-mediated immunity correlates

Guinea pig myelin basic protein (MBP) was inserted into phosphatidylserine liposomes and Lewis rats were injected by the intracardiac (ic) route with 75 microgram doses of MBP-liposomes according to various schedules. After challenge with 75 microgram guinea pig MBP in complete Freund's adjuvant, the rats were followed for clinical signs, were tested for delayed hypersensitivity (DTH) and lymphocyte transformation (LT) to MBP. The animals were sacrificed 30 days after challenge and the central nervous system tissue was examined for histological modifications. Rats treated with two injections of MBP-liposomes, 7 days before and 7 days after challenge, showed the highest degree of protection from clinical manifestations. Histological lesions were not significantly reduced. DTH reactions to MBP were all positive, regardless of treatment. LT assays were positive overall in only 50% of the animals tested. The response to rat MBP was significantly lower than to guinea pig MBP, especially in the groups treated with MBP-liposomes. Adoptive transfer of spleen cells from MBP-liposome-treated donors reduced the clinical scores of actively induced EAE in syngeneic recipients by 40-50%. These results suggest that at least one mechanism responsible for antigen-specific protection in EAE by MBP-liposomes operates through active suppression transferable by spleen cells.