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Characteristics of cell mediating spontaneous resistance to bone marrow allografts
1Department of Anatomy, McGill University, Montreal, Canada.
Mice of most strains show a genetically determined ability to reject foreign bone marrow grafts even after lethal irradiation. The effector cells mediating this resistance are spleen localised, lymphoid in morphology, and rapidly renewing. Two additional aspects of these cells were characterized in the present study, i.e., their sensitivity to: 1) anti-T cell and -B cell antibodies, and 2) the immunoregulator PGE2. T and B cell depleted splenocytes, or splenocytes from PGE2 pre-treated, highly resistant mice (C57Bl/6J) were transferred into irradiated, non-resistant secondary host mice (129/J) to establish whether or not they would retain their normally strong ability to spontaneously reject a third party (DBA/2) bone marrow allograft. In all cases, bone marrow seeding was assayed by enumerating the spleen colonies present in the secondary host 7 days after bone marrow grafting. Irradiated 129/J mice injected with low numbers (20 x 10(6) of untreated C57Bl/6J spleen cells prior to DBA/2 bone marrow contained 27.8 +/- 1.9 colonies/spleen, while mice injected with the same number of T and B depleted C57Bl/6J spleen cells contained significantly fewer (16.3 +/- 1.7) colonies/spleen. On the other hand, when C57Bl/6J spleen cells were incubated overnight with PGE2 prior to injection (20 x 10(6) into the 129/J hosts, they were unable to prevent the development of numerous colonies upon challenge with the DBA/2 bone marrow allograft (31.5 +/- 1.5 colonies/spleen: PGE2 pre-treated vs 16.9 +/- 2.1 colonies/spleen: non-pre-treated, control). The results demonstrate firstly, that spleen cells depleted of both Thy-1- and Ig-bearing cells appear to have concentrated for the effector cells responsible for bone marrow allograft rejection, and secondly, such effector cells could be suppressed by short-term exposure to PGE2, resulting in successful "take" of the bone marrow allograft.
Mice of most strains show a genetically determined ability to reject foreign bone marrow grafts even after lethal irradiation. The effector cells mediating this resistance are spleen localised, lymphoid in morphology, and rapidly renewing. Two additional aspects of these cells were characterized in the present study, i.e., their sensitivity to: 1) anti-T cell and -B cell antibodies, and 2) the immunoregulator PGE2. T and B cell depleted splenocytes, or splenocytes from PGE2 pre-treated, highly resistant mice (C57Bl/6J) were transferred into irradiated, non-resistant secondary host mice (129/J) to establish whether or not they would retain their normally strong ability to spontaneously reject a third party (DBA/2) bone marrow allograft. In all cases, bone marrow seeding was assayed by enumerating the spleen colonies present in the secondary host 7 days after bone marrow grafting. Irradiated 129/J mice injected with low numbers (20 x 10(6) of untreated C57Bl/6J spleen cells prior to DBA/2 bone marrow contained 27.8 +/- 1.9 colonies/spleen, while mice injected with the same number of T and B depleted C57Bl/6J spleen cells contained significantly fewer (16.3 +/- 1.7) colonies/spleen. On the other hand, when C57Bl/6J spleen cells were incubated overnight with PGE2 prior to injection (20 x 10(6) into the 129/J hosts, they were unable to prevent the development of numerous colonies upon challenge with the DBA/2 bone marrow allograft (31.5 +/- 1.5 colonies/spleen: PGE2 pre-treated vs 16.9 +/- 2.1 colonies/spleen: non-pre-treated, control). The results demonstrate firstly, that spleen cells depleted of both Thy-1- and Ig-bearing cells appear to have concentrated for the effector cells responsible for bone marrow allograft rejection, and secondly, such effector cells could be suppressed by short-term exposure to PGE2, resulting in successful "take" of the bone marrow allograft.