Specific inhibition of anti-self reactivity following exposure of neonatal rats to lymphocytes with anti-neural activity

Regulation of experimental allergic thyroiditis

The susceptibility to experimental allergic thyroiditis (EAT) of rats that had previously been immunized against thyroglobulin was examined. Challenge with thyroglobulin 5 weeks previously conferred strong resistance to the induction of EAT after exposure to a sensitization protocol that was otherwise highly effective. Resistance to induction of EAT could also be conferred by the inoculation of spleen cells from thyroglobulin-sensitized donors on the day of birth. Heavily irradiated spleen cells from sensitized donors were able to confer resistance on neonatal recipients, indicating that prolonged survival of the transferred cells was not required.

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.

Migration of lymphocytes sensitized against syngeneic and allogeneic spinal cord after infusion into susceptible and resistant syngeneic and semi-allogeneic hosts

Lymphocytes from rats that had been sensitized against spinal cord were infused into unsensitized hosts, and the ability of cells subsequently recovered from the thoracic duct lymph of these recipients to mount anti-neural responses was tested. Lymph from normal recipients frequently contained reactive lymphocytes during the 4 days following infusion of sensitized cells, whereas cells that had been recovered from transfused rats, resistant to encephalomyelitis as a result of neonatal treatment, were almost invariably benefit of activity. If lymphocytes reactive against allogeneic neural cells were passaged through F1 hybrids of the lymphocyte and sensitizing allogeneic tissue strains, loss or retention of their ability to attack allogeneic neural cells was determined by the method of sensitization of the original lymphocyte donor.