Factors in the Selection of Surface Disinfectants for Use in a Laboratory Animal Setting.

Because surface disinfectants are an important means of pathogen control within laboratory animal facilities, these products must have an appropriate spectrum of antimicrobial activity. However, many other factors must also be considered, including effects on human health, environmental safety, and animal behavior. Aqueous solutions of sodium hypochlorite often are considered to be the 'gold standard' for surface disinfection, but these products can be corrosive, caustic, and aversive in odor. This study was designed to identify disinfectants that are as effective as hypochlorite solutions but more acceptable for use in a laboratory animal setting. An antiviral disinfectant-efficacy assay was developed by using viral vectors that expressed green fluorescence protein as surrogates for wild-type viruses of concern in laboratory animals. Efficacy testing revealed that most of the products were highly effective when used against viral vectors in suspension. However, when the disinfectants were challenged by buffering virus in protein or drying virus on nonporous surfaces, the hypochlorite and peroxymonosulfate products performed the best. Review of safety data sheets for the agents indicated that a peroxide-based product was considerably safer than the other products tested and that the pH of most products was not conducive to disposal down a drain. Behavioral testing of Swiss Webster, C57Bl/6, and BALB/c mice showed that the hypochlorite- and peroxide-based products were clearly aversive, given that the mice consistently avoided these products. All of these factors must be considered when choosing the appropriate disinfectant.

Reduction of HLA class I expression by ribonucleic acid interference mitigates allogenicity of human primary and Immortalized cells.

Unmatched human leukocyte antigens (HLA) expressed by allogeneic donor cells are the major target for immunological rejection. In order to reduce the immunogenicity of allograft cells, we have developed lentiviral vectors for delivery of short hairpin ribonucleic acid (shRNA) against Class I HLA. This approach was evaluated in both an established human embryonic kidney cell line and primary human CD34+ hematopoietic stem/progenitor cells. Target cells transduced with lentiviral vectors expressing either HLA-A*0201 allele-specific or HLA-A, -B, -C consensus sequence-specific shRNA showed effective knockdown of cell surface HLA expression. Mixed lymphocyte-target cell reactions showed significantly reduced interferon-gamma production from alloreactive cytotoxic T lymphocytes and significantly reduced levels of target cell apoptosis after shRNA-mediated knockdown of HLA expression and target cell survival correlated with vector transduction efficiency. Furthermore, increasing resistance to complement-dependent cytotoxicity mediated by anti-HLA antibodies was observed to correlate with increasing levels of shRNA vector transduction in primary human CD34+ cells. Notably, non-HLA restricted killing by lymphokine-activated killer cells was not incurred after HLA knockdown. These data demonstrate the potential for genetic engineering strategies targeting incompatible HLA alleles to reduce both cellular and humoral responses and enable graft survival after transplantation of allogeneic cells and tissues.