Auto-MHC class II-reactive T cell line obtained from MRL/+ mice suffering from lpr-GVHD. II. Analyses of functional characteristics of T cell line by in vivo administration

Attenuation of lpr-graft-versus-host disease (GVHD) in MRL/lpr spleen cell-injected SCID mice by in vivo treatment with anti-V beta 8.1,2 monoclonal antibody

When MRL/lpr (H-2k) spleen cells were intraperitoneally injected into C.B-17-scid/scid (severe combined immunodeficient (SCID)) (H-2d) mice, the SCID (SCID-MRL/lpr) mice manifested a severe wasting syndrome with weight loss, splenic atrophy, and lymphoid cell infiltration in the liver and lung, as seen in lpr-GVHD. In contrast, MRL/+ spleen cell-injected SCID (SCID-MRL/+) mice did not show lpr-GVHD. The spleens of SCID-MRL/lpr mice showed progressive increases in donor CD4+ and CD8+ T cells from 4 to 12 weeks after injection and a decrease in B cells at 12 weeks. SCID-MRL/+ mice showed a stable engraftment of CD4+ and CD8+ T cells and a progressive increase in B cells. Analyses of T cell receptor (TCR) repertoires (V beta 6, V beta 8.1,2 and V beta 11) revealed that the V beta 8.1,2+ T cells were found more frequently in SCID-MRL/lpr mice than in SCID-MRL/+ mice. When SCID-MRL/lpr mice were treated with intraperitoneal injection of an anti-V beta 8.1,2 (KJ16) MoAb, V beta 8.1,2+ T cells were markedly depleted, and the severity of lpr-GVHD was attenuated at 4 and 8 weeks after treatment, in contrast to normal rat IgG-injected SCID-MRL/lpr mice. However, the KJ16 MoAb-treated SCID-MRL/lpr mice suffered from severe lpr-GVHD 12 weeks after treatment, although V beta 8.1,2+ T cells were still maintained at a low level. These findings suggest that V beta 8.1,2+ T cells are a major T cell population that mediates lpr-GVHD in the early stage of lpr-GVHD, but that in the later stage, the other T cell populations may proliferate naturally or in accordance with the depletion of V beta 8.1,2+ T cells, and contribute to the development of lpr-GVHD.

Analyses of lpr-GVHD by adoptive transfer experiments using MRL/lpr-Thy-1.1 congenic mice

When MRL/Mp- +/+ (MRL/+) mice are lethally irradiated and then reconstituted with MRL/Mp-lpr/lpr (MRL/lpr) spleen and/or bone marrow cells (BMCs), the mice develop a graft-versus-host disease (GVHD)-like syndrome which is known as lpr-GVHD. We analyzed lpr-GVHD by adoptive transfer experiments using congenic MRL/lpr-Thy-1.1 mice to distinguish the donor and recipient cells. MRL/+ mice were lethally (9.5 Gy) irradiated and then reconstituted with BMCs of MRL/lpr-Thy-1.1 mice treated with anti-Thy-1.1 monoclonal antibody (mAb) plus complement (C). The mice were sacrificed 5 to 6 weeks after bone marrow transplantation (BMT), and the spleen cells were transferred to second recipients. The second recipients (MRL/+ or MRL/lpr mice) were non-irradiated, sublethally (6 Gy) irradiated or lethally (9.5 Gy) irradiated. The lethally irradiated mice were also injected with syngeneic BMCs treated with anti-Thy-1.2 mAb plus C. When whole spleen cells (1 x 10(8) were injected into lethally irradiated MRL/+ mice, the mice showed short survival (1.2-1.5 months) and severe histological changes in the spleen (atrophy and fibrosis), liver (lymphoid infiltration in the Glisson's sheath) and lung (lymphoid infiltration around the bronchus and vessel). The sublethally irradiated MRL/+ mice at 2 months after transfer showed histological changes similar to the lethally irradiated MRL/+ recipients, although the former survived more than 3 months, suggesting that histological changes do not reflect on mortality. These GVH-like diseases were not transferable to MRL/lpr mice; they developed autoimmune diseases.(ABSTRACT TRUNCATED AT 250 WORDS)