Unresponsiveness to Experimental Allergic Encephalomyelitis in Lewis Rats Pretreated with Complete Freund’s Adjuvant

Abstract

A single injection of complete Freund’s adjuvant blended with aluminum hydroxide gel (ALU-CFA) was successfully used to prevent clinical as well as histologic experimental allergic encephalomyelitis (EAE) in Lewis rats for more than 330 days. Adjuvant preparations with Mycobacterium tuberculosis were more potent than those with Mycobacterium butyricum. Neither the removal of the ALU-CFA inoculum nor a splenectomy 1 month after immunization arrested the adjuvant induced unresponsiveness. However cyclophosphamide restored responsiveness in more than half of the treated animals when applied 2 days before the encephalitogenic challenge at a dose of 20 mg/kg. Passive EAE was not prevented by the ALU-CFA pretreatment. The disease was induced by the transfer of 4 × 10⁶ T lymphocytes of a cell line reactive against myelin basic protein. This indicates that the adjuvant prevents EAE at the inductive rather than at the effector phase of the autoimmune response.

A T-cell dormant state in the autoimmune process of nonobese diabetic mice treated with complete Freund's adjuvant.

“…To induce experimental allergic encephalomyelitis susceptible animals must be immunized with autoantigen emulsified in CFA. However, reports indicate that CFA administered to rats before challenge with encephalitogenic antigen protects the animals from experimental allergic encephalomyelitis (14)(15)(16), and that muramyl dipeptide (17), a component of the mycobacteria of CFA, prevents the adoptive transfer of experimental allergic encephalomyelitis in guinea pigs. Thus, the phenomenon described in NOD probably operates in other T cellmediated autoimmune diseases.. Other experiments described in the literature also indicate the immunosuppressive capability of CFA (18)(19)(20).…”

Protection against Experimental Allergic Encephalomyelitis with Complete Freund’s Adjuvant Is Unaffected by Ionizing Irradiation

“…That the effect of an ionizing irradi ation on immunoregulatory cells increases with the dose rate was demonstrated by Gengozian et al [11] and Gottlieb and Gengozian [12], The dose rate differ ences are most profound after 500 rad. Furthermore the polyclonal activation by Freund's adjuvant should be higher in our experiments because we used M. tuberculosis together with a mineral adjuvant whereas he only used M. butyricum, which is not as protective as M. tuberculosis [ 14], Therefore in Willen-borg's experiments radiosensitive Tsag cells might be of more importance than in ours.…”

“…In the present experiment 1 animal displayed a mild clinical EAE and in another case histological alterations of EAE could be detected. Because in more than 100 experi ments of this type complete unresponsiveness was found [10,14], we suggest that in these 2 cases protec tion might have been incomplete for unknown techni cal reasons.…”

“…In all animals histological examinations were done in spi nal cords, which were removed on day 18 or 19 after the second challenge. Details of the histopathological grading were given else where [14].…”

“…A protection against EAE can be achieved by recovering from acute disease [15], by pretreatment with complete Freund's adjuvant [14], by pretreatment with myelin basic protein [5] or pep tides derived from it [9], and finally by a total body irradiation prior to challenge [1,20,23].…”