Permissiveness of athymic (“nude”) mice towards congenic memory cells

Abstract

Spleen cells from BALB/c or BALB-Ig^b mice immunized against the determinant oligo-D-alanine were transferred to the following recipients: normal BALB/c; lethally irradiated BALB/c; and congenitally athymic BALB/c-nu. Irradiated as well as nude recipients permitted the development of a strong adoptive antibody response, while the response in normal BALB/c recipients was very low (“isogeneic barrier”). Using allotypically marked spleen cells from BALB-Ig^b donors it was shown that the antibodies in irradiated as well as in nude recipients were produced by donor cells. The same conclusion was drawn by assessing isoelectric focusing spectra, which in each transfer displayed the individually characteristic pattern of the donor. In addition to specific antibodies, the donor cells produced considerable levels of IgG, as characterized by allotype, but again only in nude and in irradiated recipients. The ready permissiveness of nude recipients towards congenic memory cells could be abolished when prospective recipients were restored, some time prior to transfer, by BALB/c thymus or BABL/c spleen cells. The results are interpreted to suggest that the isogeneic barrier in normal recipients is due to a thymus-dependent suppression or rejection of memory cells by the recipients.