Presence Of HEV Research Articles

The latex allergen Hev b 5 transcript is widely distributed after subcutaneous injection in BALB/c mice of its DNA vaccine

Background: DNA vaccines reduce IgE responses to selected allergens, but severe reactions to the expressed antigen may limit the usefulness of the technique in allergen immunotherapy. Objective: We sought to determine the extent of spread of an injected DNA vaccine in mice. Methods: We placed the gene encoding the potent Hevea latex allergen Hev b 5 in a mammalian expression vector and injected this DNA vaccine subcutaneously into BALB/c mice. At several times after injection, the presence of Hev b 5 transcript was determined in multiple tissues by RT-PCR. The identity of the amplification product was confirmed by Southern hybridization and restriction analyses. Results: Hev b 5 RNA appeared at the injection site and in the lymph nodes, spleen, and lungs within 1 day after injection and persisted for at least 14 days. Hev b 5 RNA was also identified in the blood and tongue 14 days after injection. Antibody and cell-mediated responses to Hev b 5 were also noted in the immunized animals at later time points. As expected, animals injected with the identical plasmid containing the Hev b 5 DNA in the antisense orientation mounted no immune response to Hev b 5. Conclusions: The rapid and widespread appearance of the Hev b 5 transcript in the injected mice confirms that DNA is translocated from the injection site, transcribed, and expressed in immune and nonimmune tissues after injection. Controlling the extent and degree of expression in specific target tissues may allow therapeutic DNA vaccination with plasmids that encode potentially toxic allergens. (J Allergy Clin Immunol 1998;102:469-75.)

On the allergenicity of Hev b 1 among health care workers and patients with spina bifida allergic to natural rubber latex

Background: Recent studies have caused much controversy about the prevalence of IgE antibodies to Hev b 1 among health care workers (HCWs) and patients with spina bifida (SB) who are allergic to latex. This investigation was carried out to verify the results reported. Method: Serum samples from 140 patients with SB as well as from 105 HCWs allergic to latex were tested by enzyme allergosorbest test (EAST) and EAST-inhibition assay to evaluate the rate and degree of sensitization to highly purified Hev b 1. Results: Eighty-one percent of patients with SB who were allergic to latex had IgE antibodies against Hev b 1. The prevalence of anti–Hev b 1 antibodies among HCWs allergic to latex was 52.3%. In 15 of 33 serum samples from patients with SB that were randomly tested, the IgE binding to commercial latex allergens could be completely inhibited by Hev b 1; in only six cases was the maximum inhibition of IgE binding to latex by Hev b 1 less than 50%. Testing two monoclonal anti-Hev b 1 antibodies with extracts of five brands of latex gloves revealed a predominant presence of Hev b 1 protein as a monomer or its aggregates. Molecular analysis of human leukocyte antigen–D region genes DRB and DQB1 suggested no statistically significant correlation between the human leukocyte antigen alleles tested and IgE responsiveness to Hev b 1. Conclusions: Our results indicate that Hev b 1 not only makes significant contributions to the IgE binding to latex, but it is also the unique sensitizer in about 45% of patients with SB who are allergic to latex. (J Allergy Clin Immunol 1997;100:684-93.)

Propagation of Group II Avian Adenoviruses in Turkey and Chicken Leukocytes

An avirulent hemorrhagic enteritis virus isolate (HEV-A) as well as a virulent one (HEV-V), both belonging to the group II avian adenoviruses, were successfully propagated in turkey leukocyte cell cultures. HEV antigens were detected as early as 12 hr after infection of the cells, using HEV-specific monoclonal antibodies in a fluorescent antibody test, and virus particles were observed by electron microscopy in the nuclei of infected cells at 18 to 24 hr after infection. Electron microscopy revealed the presence of HEV in the nuclei of nonadherent cells, as well as in adherent cells. The nonadherent infected cells had the characteristics of immature mononuclear leukocytes, whereas the adherent cells had monocyte-macrophage characteristics. HEV produced in turkey leukocytes was mostly cell-associated, particularly with the nonadherent cells. HEV-A could be serially passed in turkey blood leukocyte cultures at least seven times. Various methods employed to culture virus indicated that cells grown in spinner cultures were superior to cells grown in stationary cultures. In contrast to the successful infection of HEV in turkey leukocytes, the infection of chicken leukocytes with either HEV or splenomegaly virus of chickens, or turkey leukocytes with splenomegaly virus, was poor.