Three monoclonal antibodies (mAbs), 49. Evidence increasingly implicates virus and microbial infections as triggers of autoimmune diseases (1-3). Antigenic mimicry has been demonstrated between a wide range of infectious agents and normal tissue antigens (4-11), and antibodies to these crossreactive epitopes can often be obtained (7). These autoreactive antibodies frequently have variable effects on disease pathogenicity (7,8,11,12). Some monoclonal antibodies (mAbs) to crossreactive epitopes directly cause tissue injury in vivo (7,11). Other antibodies are poorly pathogenic when given to normal animals but significantly augment tissue injury in the presence of virus (8). Various picornaviruses, including coxsackieviruses, contain mimicking epitopes in their structural proteins to selfmolecules in the heart and other organs (8,10,11,(13)(14)(15) (22). In the present work, we used three anti-streptococcal mAbs to select new CVB3 variants which were evaluated for changes in their ability to induce myocarditis in inbred strains of mice. This study demonstrates that viruses altered by antibodies to crossreactive epitopes shared between an infectious agent and host tissue can substantially shift the genetic susceptibility associations of virus-induced diseases. These epitopes may disturb the interaction between infections and the immune system, resulting in autoimmune destruction in genetically susceptible individuals.MATERIALS AND METHODS Mice. Male DBA/2, A/J, CBA/J, C57BL/Snl0J (B10), B1O.D2/nJ, B10.A, B10.A(2R), and B10.BR mice 5-7 weeks of age were purchased from Jackson Laboratories, Bar Harbor, ME.Viruses. A plaque-purified CVB3 variant (H3) was isolated as described (23). Antibody-selected variant viruses were obtained by culturing 106 plaque-forming units (pfu) of H3 virus with 100 ,g of mAb on HeLa cells. After culture for 20 hr, the HeLa cells were homogenized, mixed with 100 pg of the mAb, and added to fresh HeLa cell cultures. This process (blind passage) was repeated up to two more times until the supernatants produced >50%o lysis of HeLa cell monolayers. The new CVB3 variants designated H3-36, H3-49, and H3-54 were derived by using mAbs 36.2.2, 49.8.9 and 54.2.8, respectively, and were plaque purified (23) and purified by ultracentrifugation on sucrose gradients (24).Antibodies. Production, maintenance, and antigen specificities of murine IgM mAbs to M-type-5 Streptococcus pyogenes have been described (25,26 (25)(26)(27). A hyperimmune horse anti-CVB3 was purchased from the American Type Culture Collection. Hybridoma clones GK 1.5 (anti-L3T4), 2.43 (anti-Lyt-2.2), and 30-H12 (anti-Thy-1.2) were purchased from the American Type Culture Collection. mAbs from these clones were isolated as described (29).Organ Virus Titers and Virus Neutralization Assays. These procedures were performed as described (30).Abbreviations: CVB3, coxsackievirus B3; mAb, monoclonal antibody; MHC, major histocompatibility complex; pfu, plaque-forming unit(s). tTo whom reprint requests should be addressed.
5543The publicat...