Classification of IBV S1 genotypes by direct reverse transcriptase-polymerase chain reaction (RT-PCR) and relationship between serotypes and genotypes of strains isolated between 1998 and 2008 in Japan.

In this study, we attempted to establish a simple detection method for classification of IBV S1 genotypes by direct reverse transcriptase-polymerase chain reaction (RT-PCR). Then, to evaluate the usefulness of the S1 genotype-specific RT-PCR, we examined the relationship between S1 genotypes and serotypes of IBV in Japan. Sequencing of the S1 genes of IBV and phylogenetic tree analysis were conducted. On the basis of the sequencing data of the S1 genotype samples, we determined primer sets specific for each genotype. Five vaccine strains in Japan as reference strains and 46 field isolates were classified into different genetic clusters by phylogenetic tree analysis (JP-1, JP-II, JP-III, Mass and 4/91) and were matched to the results of S1 genotype-specific RT-PCR. A cross virus-neutralizing test showed that the five vaccine strains in Japan exhibited different serotypes from each other. The concordance rate of the 46 field isolates between the S1 genotypes and serotypes was 65.2%. The present study indicates that genotype-specific RT-PCR could be a convenient and useful tool for determining IBV serotypes and could contribute to the control of IBV outbreaks in Japan.

Sequential immunization with V3 peptides from primary human immunodeficiency virus type 1 produces cross-neutralizing antibodies against primary isolates with a matching narrow-neutralization sequence motif.

An antibody response capable of neutralizing not only homologous but also heterologous forms of the CXCR4-tropic human immunodeficiency virus type 1 (HIV-1) MNp and CCR5-tropic primary isolate HIV-1 JR-CSF was achieved through sequential immunization with a combination of synthetic peptides representing HIV-1 Env V3 sequences from field and laboratory HIV-1 clade B isolates. In contrast, repeated immunization with a single V3 peptide generated antibodies that neutralized only type-specific laboratory-adapted homologous viruses. To determine whether the cross-neutralization response could be attributed to a cross-reactive antibody in the immunized animals, we isolated a monoclonal antibody, C25, which neutralized the heterologous primary viruses of HIV-1 clade B. Furthermore, we generated a humanized monoclonal antibody, KD-247, by transferring the genes of the complementary determining region of C25 into genes of the human V region of the antibody. KD-247 bound with high affinity to the "PGR" motif within the HIV-1 Env V3 tip region, and, among the established reference antibodies, it most effectively neutralized primary HIV-1 field isolates possessing the matching neutralization sequence motif, suggesting its promise for clinical applications involving passive immunizations. These results demonstrate that sequential immunization with B-cell epitope peptides may contribute to a humoral immune-based HIV vaccine strategy. Indeed, they help lay the groundwork for the development of HIV-1 vaccine strategies that use sequential immunization with biologically relevant peptides to overcome difficulties associated with otherwise poorly immunogenic epitopes.

Pre-exposure treatment of cats with anti-FHV-1 and anti-FCV mouse-cat chimeric antibodies.

Prior to pre-exposure treatment of cats with two mouse-cat chimeric antibodies, FJH2 and F1D7, having neutralizing activity to feline herpesvirus-1 (FHV-1) and cat calicivirus (FCV), respectively, these chimeric antibodies were labeled with (125)I and administered to cats to examine their blood kinetics. Concentrations of the both administered chimeric antibodies in the blood reached maximum at the 48th hour post-administration, and the level was 34% for FJH2 and 54% for F1D7. Then the concentration levels declined gently, and decreased afterwards to 8.2% for FJH2 and 25% for F1D7 on the 20th day post-administration. The blood half-lives of FJH2 and F1D7 were 8.3 days and 10.7 days, respectively. In order to examine effectiveness in pre-exposure treatment of cats with these chimeric antibodies, cats were administered on the 15th day prior to the challenge infections with FHV-1 and FCV by subcutaneous route with 0.5 ml/kg of an FJH-F1D7 mixture being adjusted to contain each chimeric antibody of 10 mg/ml. The cats that received the pre-exposure treatment with the cocktail, showed obvious reductions in manifestations of symptoms caused by those viral infections. The protective effectiveness of the pre-exposure treatment against these viral challenge infections was almost equal to that of the treatment given at right after these challenge infections.

Post-exposure treatment of cats with mouse-cat chimeric antibodies against feline herpesvirus type 1 and feline calicivirus.

In order to confirm the in vivo effectiveness of anti- feline herpesvirus type 1 (FHV-1) mouse-cat chimeric antibody (FJH2), and anti-feline calicivirus (FCV) mouse-cat chimeric antibody (F1D7), cats that had been experimentally infected with FHV-1 or FCV were administered intravenously with the chimeric antibodies, and observed for clinical manifestations. The symptoms due to FHV-1 or FCV infection in the cats administered FJH2 or F1D7 were obviously decreased when compared with those of the non-administered control cats. From these results, it was confirmed that both FJH2 and F1D7 were effective at reducing the appearance of symptoms due to FHV-1 and FCV infection, respectively.