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(NZB x NZW)F1 mice spontaneously develop an autoimmune syndrome characterized by a fatal immune complex glomerulonephritis. Administration of monoclonal antibodies specific for an I region gene product (I-Az) of the H-2 haplotype associated with susceptibility to glomerulonephritis in these animals produced a remission in female mice with established renal disease. The results demonstrated that anti-I-A therapy stabilized the level of proteinuria and increased the 1-yr survival rate from 10% to greater than 90% in treated animals relative to control mice. These findings may ultimately have therapeutic potential for the treatment of systemic lupus erythematosus.

A mouse model for encephalopathy induced by pertussis immunization has been described; it has features that closely resemble some of the severe reactions, including seizures and a shock-like state leading to death, occasionally seen after administration of Bordetella pertusssis (whooping cough) vaccine. Susceptibility to encephalopathy maps to genes of the major histocompatibility complex and correlates as well with the genetic regulation of the level of antibody response to bovine serum albumin. In this study we have investigated which bacterial determinant is responsible for the encephalopathy. Two lines of evidence implicate pertussis toxin as the active bacterial component. Single-site mutants of B. pertussis with single affected virulence factors were tested. A mutant that produces a defective pertussis toxin had greatly diminished capacity to induce encephalopathy, whereas a hemolysin-and adenylate-cyclase-deficient avirulent mutant had the same activity in the mouse model as a virulent strain. Purified pertussis toxin plus bovine serum albumin was tested and found to induce the lethal encephalopathy, demonstrating that the toxin was the critical constituent of B. pertussis responsible for encephalopathy.The pertussis vaccine component of diphtheria-pertussis-tetanus (DPT) vaccine is associated with convulsions in one of 1750 doses (1), while severe and permanent neurologic damage has been calculated to occur with one of every 310,000 doses (2). Although the benefits of the current pertussis vaccination program outweight the-risks by a considerable margin (3), development of a safer, efficacious vaccine is an important goal. In the past this effort has been hampered by lack of definitive information "about which bacterial antigens were essential for vaccine efficacy and which bacterial products were responsible for the reactogenicity.A lethal-shock-like syndrome preceded by mnyoclonic seizures is induced in mice with an appropriate major histocompatibility (H-2) gene after immunization with heat-killed Bordetella pertussis vaccine and bovine serum albumin (BSA) (4, 5). This model, which resembles post-pertussis immunization encephalopathy, involves daily injections alternating BSA with vaccine for 4 days, then a BSA challenge 5 days later. Death usually results within minutes of the final challenge. Previous studies have shown that the linkage of susceptibility to pertussis vaccine encephalopathy i i associated with high antibody responsiveness to BSA. The strain distribution of high immune responsiveness to BSA was identical to that reported by Riley et al. (6) and conforms to our results with susceptibility to B. pertussis encephalopathy. Thus, H-2d mice were high responders to BSA and highly susceptible to encephalopathy (57/65 died), while H-2b mice The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby mnarked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this' fact.were low responders to BSA and totall...

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