Effect of bone xenograft transplantation on total T lymphocyte and its subset counts in mouse blood and spleen

Fresh calf cancellous bone xenograft (FX), antigen free cancellous bone carrier (BC) and reconstituted bone xenograft (RBX) were inplanted in the thigh muscle pouches of Balb/c mice. Histological examinations were done at 7, 14 and 28 days postoperation, and indirect immunofluorescence was used to determine the positive counts of Thy1, L3T4, Lyt2, and Tac T lymphocyte of the blood and spleen at the same time, with the normal mouse lymphocytes as control. There was no significant difference between the BC implanted group and the normal (control) group, while the FX group had a significant increase rates of Thy1, L3T4 and Lyt2, especially of Tac lymphocytes. The RBX implanted group had no increase of Tac but increase of Thy1 and Lyt2. Th-Ts ratio decreased, and it was probably caused by bovine bone morphogenetic protein (bBMP) in the RBX. Histologically, intense immune rejection was noted in FX implanted group but not in the other two groups. Heterotopic ossification was noted in the RBX implanted group. FX increased intense immunologic rejection in the host, bat RBX did not, that might be due to the decrease of Th/Ts caused by bBMP. Tac lymphocyte count may indicate the immunologic rejection of bone xenograft transplantation.