Induction of microthrombotic thrombocytopenia in normal mice by transferring a platelet-reactive, monoclonal anti-gp70 autoantibody established from MRL/lprmice: an autoimmune model of thrombotic thrombocytopenic purpura

Abstract

SUMMARYMRL/MpJ-lpr/lpr (MRL/lpr) mice spontaneously develop immune complex-mediated glomerulonephritis and thrombocytopenia. Although the presence of cross-reactive anti-phospholipid antibodies in sera of MRL/lpr mice has been demonstrated, possible relationships between detected autoantibodies and the development of thrombocytopenia have not been elucidated. Recent genetic analyses in a few different strains of lupus-prone mice have pointed out a close correlation between autoantibodies reactive with endogenous retroviral env gene product, gp70, and the development and severity of glomerulonephritis. In the process of establishing possibly nephritogenic anti-gp70 autoantibodyproducing hybridoma cells from MRL/lpr mice, we identified an IgG2a-producing anti-gp70 hybridoma clone that induced microvascular intraluminal platelet aggregation, thrombocytopenia, and amenia upon transplantation into syngeneic non-autoimmune mice. This and two other anti-gp70 antibodies bound onto the surface of mouse platelets, and purified IgG2a of the anti-gp70 autoantibody induced glomerular lesions with characteristics of thrombotic thrombocytopenic purpura when injected into non-autoimmune mice. The pathogenic anti-gp70 autoantibody specifically precipitated a platelet protein with an approximate relative molecular mass of 40 000.

Pathogenesis of Thrombotic Microangiopathy: Insights from Animal Models

“…EC injury was prevented by complement depletion and worsened by blockade of Crry. Hashimoto et al [[9]] generated a hybridoma clone in lupus-prone mice (MRL/ lpr ) which, when transplanted into syngeneic non-autoimmune mice, caused microvascular intraluminal platelet aggregation, thrombocytopenia and anaemia. This pathogenic autoantibody (anti-gp70) specifically precipitated a platelet protein with an approximate relative molecular mass of 40 kDa.…”

Role of Natural Killer Cells in Resistance against Friend Retrovirus-Induced Leukemia

“…Flow cytometric analyses of cell surface markers were performed as described elsewhere (12,19,34,40). Spleen tissue was dissociated in PBBS containing 2% FBS, and single-cell suspension was prepared by passing the dissociated tissue through a nylon mesh.…”

“…TER-119 reacts with a molecule associated with glycophorin A and marks the late erythroblasts and mature erythrocytes (19). To detect cells infected with F-MuLV, MAb 720 (29) reactive with F-MuLV gp70 but not with any other mouse retrovirus was purified and conjugated with biotin as described previously (12,22,29). R-PE-conjugated streptavidin (PharMingen) was used for staining with the biotin-conjugated antibodies.…”

“…R-PE-conjugated streptavidin (PharMingen) was used for staining with the biotin-conjugated antibodies. All staining reactions were performed in the presence of 0.25 g of anti-mouse CD16/CD32 (PharMingen)/10 6 cells as described previously (12), to prevent the binding of MAb to Fc receptor-expressing cells. Cells were also incubated with isotype-matched control antibodies purchased from the same suppliers, and staining patterns obtained with these negative control antibodies were used to draw demarcation lines that separate positively stained cells from those not stained.…”

Thrombotic microangiopathic haemolytic anaemia and antiphospholipid antibodies

“…72 73 In addition, Hashimoto et al were able to find from lupus prone mice a hybridoma clone producing an antibody able to induce thrombotic microangiopathy with some characteristics of TTP when injected into syngeneic mice. 74 The clinical picture of TMHA, SLE, and APS may overlap and, if any two of the three conditions coexist in the same patient, the diagnosis may be difficult at the time of initial presentation. In one patient the diagnosis of TTP was based on thrombocytopenia, microangiopathic haemolytic anaemia, motor epileptic fits, and fever without any evidence of infection or disseminated intravascular coagulation.…”