Over the past decade, Type 1 immediate hypersensitivity to natural rubber latex (NRL) has become a significant health problem in the United States. The IgE-mediated cascade is initiated by cytoplasmic proteins produced by the rubber tree Hevea brasiliensis. The major protein allergens found in NRL products range in size from 5-100+ kDa. Health care worker (HCW) exposure and sensitization to latex proteins are thought to occur mainly via inhalation and dermal exposure. Major efforts to reduce inhalation exposures are being implemented worldwide which would lessen the role of respiratory sensitization. The other route of latex sensitization is via percutaneous absorption, but it has been postulated that molecules greater than 1 kDa in size are unable to penetrate an intact skin barrier. Therefore, the purpose of these studies was to evaluate the skin's role in NRL sensitization. Initial studies investigated the sensitization potential of NRL in the murine LLNA and a draining lymph node phenotyping assay. Groups of female B6C3FI mice were topically exposed to NRL for 3 consecutive days (days 1-3) and radioassayed on day 5 and phenotyped on day 10. In these intact skin models, no sensitization occurred following exposure to NRL as evidenced by a lack of increase in lymph node proliferation (as compared to controls) or alterations in CD3+,CD4+,CD8+,lgE+,or B220+ cells, However, most conditions for NRL exposure for HCW involve abraded skin under occluded conditions. Therefore, subsequent studies will evaluate the potential for latex proteins to penetrate through different skin conditions. Using in vitro diffusion models for intact, abraded, irritated, and occluded skin, human and animal skin. preparations will put in flow-through cells to determine the penetration of non-ammoniated protein mixtures, ammoniated protein mixtures, and purified latex proteins. Penetrating proteins will be characterized by Western immunoblouing techniques.
The Toxicologist. Society of Toxicology 37th Annual Meeting, March 1-5,1998, Seattle, Washington