RESULTS

Rabbits preimmunized with peptides corresponding to sequences of the AChR, prior to injection with AChR, were protected against EAMG. Namely, six out of eight rabbits survived three inoculations of AChR and lived at least five months after the third injection with AChR, whereas all four control rabbits got sick and died shortly following one or two injections of AChR. Most of the protected rabbits exhibited transient EAMG that did not develop into the fully expressed, lethal form of the disease (FIG. 1).

The ability of specific synthetic peptides to protect against EAMG did not correlate with their ability to elicit a high anti-AChR antibody titer or to induce the production of antibodies reacting with the native receptor. On the other hand, there seemed to be a correlation between the protection against the lethal effect of AChR inoculation and a delayed reactivity with all four subunits of the receptor, as tested by Western blot analysis. Control rabbits that died shortly after the second injection of AChR developed antibodies to all AChR subunits as early as 13-17 days following AChR inoculation, whereas peptide-preimmunized protected rabbits exhibited the reactivity towards all subunits at day 24 or later