Related Experiment Videos
Immune response to polyglycolic acid implants
S Santavirta1, Y T Konttinen, T Saito
1Helsinki University, Central Hospital, Finland.
Insights
Polyglycolic acid (PGA) implants appear immunologically inert, despite causing some lymphocyte activation. PGA induces inflammatory cell adhesion and slight, non-specific immune responses, but not significant DNA synthesis.
Area of Science:
- Biomaterials Science
- Immunology
- Cell Biology
Background:
- Polyglycolic acid (PGA) is used in osteosynthesis implants.
- Effusions around PGA implants show inflammatory cells, suggesting potential immune responses.
Purpose of the Study:
- To investigate the immunological inertness of PGA implants.
- To determine if PGA induces lymphocyte activation and immune cell interaction.
Main Methods:
- Cultured peripheral blood mononuclear cells with PGA.
- Assessed lymphocyte activation markers (MHC locus II, IL-2R) and DNA synthesis.
- Used phytohaemagglutinin (PHA) and PPD antigen as controls.
Main Results:
- Lymphocytes and monocytes adhered to PGA particles.
- PGA induced MHC locus II and IL-2R expression, but no significant DNA synthesis.
- Observed slight, non-specific lymphocyte activation, less than antigen-driven responses.
Conclusions:
- PGA appears to be an immunologically inert implant material.
- PGA induces inflammatory cell migration and adhesion.
- Slight, non-specific lymphocyte activation occurs, but it's not a robust immune response.
Abstract:
Cytological analysis of material aspirated from the effusion which occasionally develops around a polyglycolic acid (PGA) osteosynthesis implant showed a predominance of inflammatory monocytes and in particular lymphocytes. In order to discover whether PGA implants are immunologically inert, density gradient-isolated peripheral blood mononuclear cells were cultured in 0.2 ml of 10% delta FCS-RPMI 1640 culture medium supplemented with 10 mg PGA. Phytohaemagglutinin (PHA) lectin, a purified protein derivate of tuberculin (PPD) antigen and culture medium alone were used as positive and negative controls. We studied lymphocyte activation kinetics on days 0, 1, 3 and 5. Major histocompatibility complex locus II antigen (MHC locus II antigen) and interleukin-2 receptor (IL-2R) expression were analysed using the avidin-biotin-peroxidase complex (ABC) method and lymphocyte DNA synthesis by using 3H-thymidine incorporation and beta-scintillation counting. Especially on culture days 0 and 1, lymphocytes and monocytes were seen by light microscopy to be attached to PGA particles. However, our results show no PGA-induced lymphocyte DNA synthesis, but PGA-induced MHC locus II antigen and IL-2R activation marker expression was seen, greater than in negative controls, but less than that seen in PPD antigen driven lymphocyte response. This suggests that PGA is an immunologically inert implant material, but it does seem to induce inflammatory mononuclear cell migration and adhesion, leading to a slight non-specific lymphocyte activation. This activation is lower than that seen in mitogen and antigen-driven lymphocyte responses.