Fine-tuning the EBV+ hu-PBL-SCID xenogeneic chimera model using in vivo superinfection

K Kvell, MD, P Balogh, MD, PhD, P Németh, MD, PhD

Department of Immunology and Biotechnology, Faculty of Medicine, University of Pécs, Hungary

AIM: Our purpose was to establish a predictable chimera model of the human posttransplant lymphoproliferative disease (LPD). Our modified protocol standardizes an acute disease course. METHODS: We injected Epstein-Barr virus positive or negative human peripheral blood lymphocytes (PBL) intraperitoneally into immuno-deficient (SCID) mice, with or without superinfection by B95-8 EBV 11 days later. We measured survival and performed immuno-histochemical and flow-cytometric analysis at different intervals in vivo and later on in vitro cultures. We also performed RT-PCR to detect active EBV strains at the mRNA level. RESULTS: Our preliminary data show that a standard dose of EBV positive PBL (3x107 to 6x107 per mouse) led to death by LPD in 3 of 3 mice within 46 to 67 days. Mice who received EBV negative cells survived over 122 days. A lower dose of EBV positive PBL (1x107 to 2x107 per mouse) did not kill 3 of 3 mice within 74 days. EBV infection alone did not kill mice either. However, a low dose of EBV positive PBL and superinfection together led to the death of 3 of 3 mice within 41 to 43 days. All mice showed the histology of typical LPD and massive EBV infection of B cells according to LMP-1 expression. The B95-8 EBV strain was dominant in infected B-cells. CONCLUSIONS: Following our modified protocol LPD was lethal in a shorter and more predictable time compared to the originally described model as a result of in vivo superinfection. This model should be useful for studying the effects of experimental anti-viral and anti-lymphoproliferative therapies.

KEY WORDS: SCID mouse, B cell proliferation, posttransplant lymphoproliferative disease, EBV superinfection.

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Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Paris, France; February 9 - 12, 2002; in the section on Viral Oncogenesis.