Comparison of an enzyme-linked immunosorbent assay, an immunofluorescence assay and a hemagglutination inhibition assay for detection of antibodies to K-papovavirus in mice

The sensitivity of a newly developed enzyme-linked immunosorbent assay (ELISA) for detection of antibody to K virus was compared with the sensitivities of an immunofluorescence assay (IFA) and a hemagglutination inhibition assay (HIA). Specific pathogen-free BALB/c RIVM mice, 5 weeks old, were inoculated intraperitoneally with a mouse organ suspension containing 10(4.5) TCID50 of K virus per dose. Control animals were inoculated with a control mouse organ suspension. No clinical signs were observed during the 7 weeks they were followed for the development of serum antibody. The ELISA proved to be the most sensitive of the three assays and demonstrated K virus-specific antibodies as early as 3 days after infection.     

Induction of protective immune response in cats by vaccination with feline leukemia virus iscom

An effective candidate subunit vaccine consisting of the gp 70/85 of feline leukemia virus (FeLV) was prepared by using the immunostimulating complex (iscom) method for the presentation of membrane proteins of enveloped viruses. Two 32-wk-old specific pathogen-free (SPF) cats were immunized with a FeLV iscom vaccine prepared from the supernatant fluid of the FL74 tumor cell line without adjuvant. Both cats developed FeLV serum antibodies, as measured in an enzyme-linked immunosorbent assay (ELISA) and in a virus neutralization test. A proportion of the antibodies were directed to an epitope located on gp70/85, which was shown in competition ELISA with a peroxidase-labeled virus-neutralizing monoclonal antibody to be shared by all three subtypes of FeLV. The protective effect of FeLV iscom was studied by vaccinating six 8-wk-old SPF cats with iscom prepared from cell culture supernatant of another tumor cell line F422, followed by oronasal challenge with 10(6) ffu FeLV-A (strain Glasgow-1). Six unvaccinated cats were also challenged with the same dose of FeLV. The vaccinated cats developed FeLV serum antibodies, some of which were directed to the shared epitope on gp70/85. At 10 wk after challenge, none was viremic, whereas three of the control cats had developed FeLV viremia. The potential of FeLV iscom as a vaccine against FeLV-associated disease in cats, and of iscom vaccines for protection against mammalian retrovirus infections, is discussed.     

Trichoderma spp. and Bacillus spp. as growth promoters in maize (Zea mays L.)

Microbes that are beneficial to plants are used to enhance the crop growth, yield and are alternatives to chemical fertilizers. Trichoderma and Bacillus are the predominant plant growth-promoting fungi and bacteria. The objective of this study was select, characterize, and evaluate isolates of Trichoderma spp. and Bacillus spp. native from the northern region of Sinaloa, Mexico, and assess their effect on growth promotion in maize (Zea mays L.). In greenhouse conditions, four Trichoderma isolates and twenty Bacillus isolates, as well as two controls, were tested in a completely randomized design with three replicates. We selected the two best strains of Trichoderma and Bacillus: TB = Trichoderma asperellum, TF = Trichoderma virens, B14 = Bacillus cereus sensu lato and B17 = Bacillus cereus, which were evaluated in the field in a completely randomized blocks in factorial arrangement design with three replicates applying different rates of nitrogen fertilizer (0, 150 kg N/ha, and 300 kg N/ha). Treatments 5 (B17 = B. cereus) and 11 (TF = T. virens) both fertilized with 150 kg N/ha showed similar yields and they did not reveal significant differences from the treatments fertilized with 300 kg N/ha. This indicated that treatment 5 (B17= B. cereus with 150 kg N/ha) and treatment 11 (TF= T. virens with 150 kg N/ha) were efficient as growth promoters, by not showing significant differences in root volume and dry weight of foliage. The results indicated a reduction of 50% in the rate of nitrogen to fertilizer required for maize (Zea mays L.) crops. These microorganisms Trichoderma and Bacillus could be an alternative to reduce the use of chemical fertilizers in maize.     

Influenza virus-specific cytotoxic T lymphocytes: a correlate of protection and a basis for vaccine development

Since influenza A viruses of the H5N1 subtype continue to circulate in wild and domestic birds and cause an ever increasing number of human cases, it is feared that H5N1 viruses may cause the next influenza pandemic. Therefore, there is considerable interest in the development of vaccines that confer protection against infections with these viruses or ideally, protection against influenza viruses of different subtypes. For the development of broad-protective vaccines the induction of virus-specific cytotoxic T lymphocytes (CTL) may be an important target, since it has been demonstrated that CTL contribute to protective immunity and are largely directed to epitopes shared by influenza viruses of various subtypes. In the present paper, the possibility to develop (cross-reactive) CTL-inducing vaccines is discussed.     

Metagenomic analysis of the viral flora of pine marten and European badger feces

A thorough understanding of the diversity of viruses in wildlife provides epidemiological baseline information about potential pathogens. Metagenomic analysis of the enteric viral flora revealed a new anellovirus and bocavirus species in pine martens and a new circovirus-like virus and geminivirus-related DNA virus in European badgers. In addition, sequences with homology to viruses from the families Paramyxo- and Picornaviridae were detected.     

Structural and immunological characterization of a linear virus-neutralizing epitope of the rabies virus glycoprotein and its possible use in a synthetic vaccine.

We have mapped a linear epitope recognized by the virus-neutralizing monoclonal antibody 6-15C4 within the primary sequence of the G protein from the Evelyn-Rokitnicki-Abelseth strain of rabies virus. This was accomplished by using fragments of the rabies virus G protein and deduced amino acid sequences of neutralization-resistant variant rabies viruses. The monoclonal antibody 6-15C4 specifically recognized a synthetic peptide (peptide G5-24) which resembles the 6-15C4 epitope in structure. In addition, a tandem peptide constructed from the G5-24 peptide and a dominant TH cell epitope of the rabies virus N protein induced protective immunity against lethal rabies virus challenge infection in mice.     

Vaccine-induced virus-neutralizing antibodies and cytotoxic T cells do not protect macaques from experimental infection with simian immunodeficiency virus SIVmac32H (J5).

To gain further insight into the ability of subunit vaccines to protect monkeys from experimental infection with simian immunodeficiency virus (SIV), two groups of cynomolgus macaques were immunized with either recombinant SIVmac32H-derived envelope glycoproteins (Env) incorporated into immune-stimulating complexes (iscoms) (group A) or with these SIV Env iscoms in combination with p27gag iscoms and three Nef lipopeptides (group B). Four monkeys immunized with recombinant feline immunodeficiency virus Env iscoms served as controls (group C). Animals were immunized intramuscularly at weeks 0, 4, 10, and 16. Two weeks after the last immunization, monkeys were challenged intravenously with 50 monkey 50% infectious doses of virus derived from the J5 molecular clone of SIVmac32H propagated in monkey peripheral blood mononuclear cells. High titers of SIV-neutralizing antibodies were induced in the monkeys of groups A and B. In addition, p27gag-specific antibodies were detected in the monkeys of group B. Vaccine-induced cytotoxic-T-lymphocyte precursors against Env, Gag, and Nef were detected on the day of challenge in the monkeys of group B. Env-specific cytotoxic-T-lymphocyte precursors were detected in one monkey from group A. In spite of the observed antibody and T-cell responses, none of the monkeys was protected from experimental infection. In addition, longitudinal determination of cell-associated virus loads at weeks 2, 4, 6, 9, and 12 postchallenge revealed no significant differences between vaccinated and control monkeys. These findings illustrate the need to clarify the roles of the different arms of the immune system in conferring protection against primate lentivirus infections.