The effect of thymopoietin32-36 and ubiquitin on spontaneous immunopathology of New Zealand mice.

The effects of synthetic thymopoeitin32-36 and purified ubiquitin, in daily doses of 1 or 10 microgram, were studied in New Zealand mice. The most striking result was a 4-month delay in the appearance of Coombs' positive tests or Coombs' antibodies in New Zealand black (NZB) mice treated from 4 wk of age with ubiquitin. Ubiquitin also reduced the spleen weight in the animals and stimulated suppressor T cell activity in shorter term studies of older NZB and black and white (B/W) mice. Thymopoietin was also active in this assay and improved the mitogen responsiveness of lymph node cells in older treated NZB and B/W mice. Thymopoietin injections, from 4 wk of age, reduced the titer of Coombs' antibodies and thymocytotoxic antibodies in NZB mice and caused an increase in Thy 1+ spleen cells in these animals. In correspondingly treated B/W mice, thymopoietin reduced the anti-DNA antibody titer. While our present injection protocol did not result in clinical cure of the genetically determined autoimmune diseases of NZB and B/W mice, they do point to the feasibility of selective immunoregulation by these peptides in diseases associated with altered states of immune reactivity.