Genetic studies in NZB mice. I. Spontaneous autoantibody production

The appearance of naturally occurring thymocytotoxic autoantibodies (NTA) and spontaneously produced antibodies to single-stranded DNA (ssDNA) was studied in NZB, and DBA/2 mice and their F1 and backcross progeny. NTA production was markedly decreased in males; however, castrated males produced quantities of NTA similar to those of females. Because the amount of NTA was influenced by sex hormones, it was necessary to gonadectomize all progeny to determine the mode of inheritance. Such studies suggested that NTA production was determined by a single locus with a gene dosage (codominant) mode of expression. The spontaneous production of antibodies to ssDNA appeared to be inherited as a single dominant genetic trait. The quantity of anti- ssDNA was also found to be under additional regulation; either a gene dosage effect or more likely a regulatory gene. The genes controlling the presence and quantity of ssDNA antibodies were not linked to the gene controlling the appearance of NTA.