Influence of three currently used bone replacing materials on the in vitro proliferation of human peripheral blood mononuclear cells

Objectives: A cell culture system for biocompatibility testing of bone grafting materials is described. We investigated the in vitro viability and proliferative response of peripheral blood mononuclear cells (PBMC) from 10 healthy donors in the presence of three materials currently used for bone grafting: Algipore, Bio-Oss and Bone Source, for immunologic biocompatibility testing. Material and methods: PBMC isolated from venous blood from 10 healthy donors were incubated for 4 days with each bone replacing material, in the presence and absence of interleukin-2 (IL-2). After 4 days, H3-thymidine was added for 18 h and the incorporated radioactivity was measured with a beta-plate counter. Results: Basal PBMC counts were 152.9 +/- 66.2 counts per minute (c.p.m.) (mean +/- SD), in the presence of 0.4 U IL-2/well 206.5 +/- 83 c.p.m. were measured. With Algipore and Bio-Oss, which are deproteinized bone replacing materials, the proliferation rate of PBMC with IL-2 was not significantly modified: for Algipore 151 +/- 51 c.p.m./+IL-2 188.8 +/- 62 c.p.m., for Bio-Oss 144.5 +/- 64.9 c.p.m./+IL-2 176.3 +/- 71.23 c.p.m. For Bone Source 164.2 +/- 80.4/+IL-2 188.3 +/- 81 c.p.m. were measured. Conclusion: This in vitro experiment indicates, that the investigated bone replacing materials are not acting as specific antigens/haptens and are not generating increased proliferative responses of human PBMC from healthy donors. Even with IL-2, that induces proliferation of T lymphocytes, which encountered their specific antigen, the proliferation rate of PBMC from healthy donors was not increased after incubation with this bone grafting materials.