Studies on the induction of immunological tolerance. The inhibition of toleranceinduction by antiserum: split tolerance and the time‐course of tolerance induction

Abstract

AbstractThe induction of immunological unresponsiveness to rabbit IgG has been studied in BALB/c mice. Single injections of 100 μg or more of centrifuged IgG produced unresponsiveness to the whole molecule. However, with 10 μg rabbit IgG, animals were rendered unresponsive to the Fab antigens, but remained responsive to the Fc antigens on challenge. Such a state is termed “split tolerance”.Tolerance induction could be prevented by anti ‐IgG serum administered either one day before or up to 4 days after injection of tolerogen. Therefore the induction of tolerance requires the presence of antigen for approximately 4 days.Using an antiserum directed against part of the IgG molecule only (anti‐Fab), a determinant‐specific inhibition of tolerance induction could be obtained when the antiserum was given 1 – 4 days after the tolerogen. Thus split tolerance was again obtained, this time with the animals tolerant only to Fc and responsive to Fab.A possible interpretation of split tolerance is that it involves tolerance of bone marrow‐derived cells.