Novel nonmajor histocompatibility complex-linked loci from mouse chromosome 17 confer susceptibility to viral-mediated chronic autoimmune myocarditis.

BACKGROUND: Development of viral-induced chronic myocarditis is thought to involve both environmental and genetic factors. However, to date, no susceptibility genes have been identified. METHODS AND RESULTS: We sought to identify loci that confer susceptibility to viral-induced chronic myocarditis with the use of chromosome substitution strain mice that are composed of 1 chromosome from the disease susceptible A/J strain on an otherwise resistant C57BL/6 background. By this method, we identified chromosome 17 to confer susceptibility. To further isolate the region of susceptibility, 8 strains of mice congenic for different portions of chromosome 17 were generated. Characterization of these strains identified at least 4 susceptibility loci on the chromosome. Three of these loci are located in the proximal 22.8 cM, whereas the fourth locus is located in the portion of the chromosome distal to 34.3 cM. CONCLUSIONS: We have identified 4 loci that confer susceptibility of viral-induced chronic myocarditis. Of these loci, 3 were distinct from the major histocompatibility complex locus and thus represent novel susceptibility loci. The close proximately of the 2 novel loci with susceptibility loci for other autoimmune diseases such as type 1 diabetes and chronic experimental autoimmune thyroiditis suggests the presence of global autoimmune susceptibility genes.

A novel approach to development of monoclonal antibodies using native antigen for immunization and recombinant antigen for screening.

The production of monoclonal antibodies (MAb) specific to microbes is rapidly growing. Finding an appropriate antigen to screen hybridoma clones has become increasingly important. However, the conventional method, in which the purified antigen from the microbe is routinely used for screening, cannot avoid selection of false positive hybridoma clones, since even highly purified antigen is found to be contaminated with some other proteins from the microbe. In this study, MAbs against anthrax protective antigen (PA), the central component of the three-part toxin secreted by Bacillus anthracis were developed using a pair of the roughly purified native PA as an immunogen and the recombinant PA as a screening antigen without any possibility of false selection, since the recombinant PA was produced by a gene engineering approach and impossible to be contaminated with any other proteins from B. anthracis. In total, nine stable hybridoma clones secreting anti-PA MAbs were developed. All of them had the same type of heavy and light chains, IgG1/kappa. The binding profiles for these anti-PA MAbs were investigated by ELISA. This novel approach to the development of MAbs should be applicable to the production of MAbs to other microbes, especially to those from which antigens can hardly be purified to a high degree.