Human coronaviruses (HCV) in two serogroups represented by HCV-229E and HCV-OC43 are an important cause of upper respiratory tract infections. Here we report that human aminopeptidase N, a cell-surface metalloprotease on intestinal, lung and kidney epithelial cells, is a receptor for human coronavirus strain HCV-229E, but not for HCV-OC43. A monoclonal antibody, RBS, blocked HCV-229E virus infection of human lung fibroblasts, immunoprecipitated aminopeptidase N and inhibited its enzymatic activity. HCV-229E-resistant murine fibroblasts became susceptible after transfection with complementary DNA encoding human aminopeptidase N. By contrast, infection of human cells with HCV-OC43 was not inhibited by antibody RBS and expression of aminopeptidase N did not enhance HCV-OC43 replication in mouse cells. A mutant aminopeptidase lacking the catalytic site of the enzyme did not bind HCV-229E or RBS and did not render murine cells susceptible to HCV-229E infection, suggesting that the virus-binding site may lie at or near the active site of the human aminopeptidase molecule.
To develop a less reactogenic but equally immunogenic vaccine, this study of 91 human volunteers compared the safety and immunogenic potency of a new, cell culture-derived vaccinia virus vaccine administered intradermally and intramuscularly with the licensed vaccinia vaccine administered by scarification. Cutaneous pox lesions developed in a higher proportion of scarification vaccinees. Scarification and intradermal vaccine recipients who developed cutaneous pox lesions had more local reactions but also achieved significantly higher cell-mediated and neutralizing antibody responses than those who did not develop pox lesions. Although less reactogenic, intradermal or intramuscular administration of vaccinia vaccine without the concomitant development of a cutaneous pox lesion induced lower immune responses.
Wound infections remain a significant source of morbidity in patients undergoing major head and neck operations that invade the aerodigestive tract. Infection rates have been significantly reduced by the administration of perioperative intravenous antibiotics; however, the incidence of infection remains unacceptably high. This study was undertaken to help identify an oral antiseptic that could significantly reduce the bacterial colony count of human saliva. A randomized, prospective clinical trial was conducted to analyze and compare the effects of Listerine antiseptic and Peridex oral rinse on the aerobic and anaerobic bacterial counts in healthy human subjects. Thirty healthy adult volunteers between the ages of 18 and 61 participated in the study. The patients were randomized to receive normal saline solution, Listerine antiseptic, or Peridex oral rinse. Aerobic and anaerobic bacterial colony counts of saliva were measured before treatment and at 1 and 4 hours after treatment. Both Listerine antiseptic and Peridex oral rinse significantly reduced bacterial counts at 1 hour after treatment in our volunteers. At 4 hours after treatment, Peridex oral rinse showed a further reduction in the bacterial colony count whereas Listerine antiseptic showed no difference compared with normal saline solution. At 4 hours after treatment, Peridex oral rinse reduced the total bacterial colony count by 85%.
Human coronaviruses (HeV) are the cause of 25 percent of common colds. Difficulty in isolation of clinical pathogens has limited the characterization of these viruses and their interaction with host cells. The purpose of this research project was to characterize and identity the cellular receptor(s) for HCV-229E. Assays to detect virus binding demonstrated that HCV-229E would bind to membranes from hUman respiratory and intestinal epithelium and from several susceptible human cell lines. HCV-229E binding and infection of hUman cells could be blocked by antiserum from mice immunized with human cell membranes. Using splenocytes from these mice, we developed an anti-receptor monoclonal antibody, MAb-RBS, which would block HCV-229E binding and infection. Concurrently with MAb-RBS development, others reported that a porcine coronavirus, TGEV, could utilize iii aminopeptidase N (APN), a cell surface metalloprotease, as a receptor on swine testicular cells. Because of the relatedness of TGEV and HCV-229E and the similar chromosomal assignments of the genes for human aminopeptidase N (hAPN) and HCV-229E sensitivity, hAPN was tested as a receptor for HCV-229E. HCV-229E and MAb-RBS bound competitively to membranes from mouse cells transfected with hAPN, but not to the untransfected parental mouse cells. MAb-RBS also immunoprecipitated the hAPN from these transfected mouse cells. Immunofluorescence assays for intracytoplasmic HCV-229E antigens demonstrated that both mouse and hamster cells would permit HCV-229E entry and replication only after the cells were transfected with an hAPN expression vector. When the same parental mouse cell line was engineered to express a deletion mutant of hAPN, MAb-RBS failed to recognize this form of hAPN and these cells were not susceptible to HCV-229E infection. MAb-RBS and other anti-hAPN antibodies inhibited both HCV-229E infection and hAPN protease activity. Zn ++-chelating enzyme inhibitors, but not competitive inhibitors of hAPN enzyme activity, also protected human cells from HCV-229E infection. These results demonstrate that HCV-229E can utilize human aminopeptidase N as a cellular receptor and that the site of HCV-229E binding may be near the region of hAPN enzyme activity. The identification of this well-characterized
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