The disease of the NZB mouse. Examination of exchange ovum transplantation derived NZB and CFW mice.

Exchange ovum transplantation has been employed between the autoimmune NZB and normal CFW mice. The features of the disease in these mice have been examined together with a small group of milk fostered animals. Ovum transplanted NZB uterine nurtured to term from the CFW develop a positive Direct Coombs' Test (DCT) and, like normally derived NZB, this reaction, once positive, is usually maintained. Positive DCT reactions were also, on occasions, seen in the CFW uterine nurtured or milk fostered from the NZB, but these were always transient. Although anaemia and reticulocytosis characterize normal, ovum transplantation derived and milk fostered NZB, these changes could not be demonstrated in either the uterine nurtured or milk fostered CFW mice. Histological examination of the thymus, kidney and spleen of these CFW mice also failed to reveal any morphological feature present in either ovum transplantation or normally derived NZB. The fact that the disease in the NZB was not altered in spite of being uterine nurtured from a normal strain, suggests that the stimulus to develop the disease must be present prior to the stage of implantation. The transient nature of the positive DCT reactions in the CFW, and anaemia and morphological changes not being demonstrated, suggests that stimulation to develop autoantibodies might be common in mice but this process is normally suppressed and it is the age related failure of this recognition and suppression process that accounts for the progressive disease of the aged NZB.