The Adjuvancy of Silicones: Dependency on Compartmentalization
Studies have been conducted in mice (B6C3F1) and rats (Sprague Dawley, Fischer 344) to investigate the adjuvancy potential of silicone mammary gel and the low molecular weight silicone fluid, octamethylcyclotetrasiloxane (D4). Dependent on the experimental conditions employed, a divergent data profile emerges. If the antigen (bovine serum albumin, BSA) is emulsified with either the gel or the D4 prior to intramuscular immunization, an amplified anti-BSA IgG antibody response, as measured by multipoint ELISA methodology, is noted over the 8 week measurement period. In parallel studies, a variety of non-silicone personal care ingredients (lanolin, white mineral oil, isopropyl palmitate) were also capable of amplifying this humoral response relative to the non-adjuvant phosphate buffered saline control. These observations are consistent with the empirical knowledge that hydrophobic substances tend to augment immune responses. However, under conditions in which the antigen is not blended with the silicone prior to immunization, normal immune responses are noted. In short (10 day) and long (180 day) term gel implant studies, the optimal IgM and IgG antibody responses, as determined in the antibody forming cell assay, were equivalent between the gel implanted and control animals. Moreover, under similar exposure conditions, no adjuvancy was noted in the three Host Resistance models (B16F10 Melanoma, Listeria monocytogenes, and Streptococcus pneumoniae) tested. Antibody forming cell studies conducted after 28 days of oral or inhalation exposure to D4 have also yielded responses similar to the non-silicone exposed vehicle controls. Collectively, these data suggest that in the absence of premixing the antigen with the silicone test material, there does not appear to be any silicone induced adjuvant response.
KeywordsListeria Monocytogenes Sheep Erythrocyte Antibody Form Cell Cobra Venom Factor Intramuscular Immunization
Unable to display preview. Download preview PDF.
- Bradley SG, Munson AE, McCay JA, Brown RD, Musgrove DL, Wilson S, Stern M, Luster MI, White KL, Jr. (1994a) Subchronic 10 day imunotoxicity of polydimethylsiloxane (silicone) fluid, gel and elastomer and polyurethane disks in female B6C3F1 mice. Drug Chem Toxicol 17:175–220PubMedCrossRefGoogle Scholar
- Bradley SG, White, KL, Jr., McCay JA, Brown RD, Musgrove DL, Wilson S, Stern M, Luster MI, Munson AE (1994b) Immunotoxicity of 180 day exposure to polydimethylsiloxane (siloxane) fluid, gel and elastomer and polyurethane disks in female B6C3F1 mice. Drug Chem Toxicol 17:221–269PubMedCrossRefGoogle Scholar
- Gott DM, Tinkler JJB (1994) Evaluation of evidence for an association between the implantation of silicones and connective tissue disease. Medical Devices Directorate Report, UK Department of Health, 14 Russell Square, London.Google Scholar
- Page WF, Norman JE, Benenson AS (1993) Long-term follow-up of Army recruits immunized with Freund’s incomplete adjuvanted vaccine. Vaccine Res 2:141–149Google Scholar
- Warren HS (1992) Adjuvants. In: Roitt IM (ed) Encyclopedia of Immunology. Academic Press, London, pp 28–30Google Scholar