Poliomyelitis in Intraspinally Inoculated Poliovirus Receptor Transgenic Mice

AbstractMice transgenic with the human poliovirus receptor gene develop clinical signs and neuropathology similar to those of human poliomyelitis when neurovirulent polioviruses are inoculated into the central nervous system (CNS). Factors contributing to disease severity and the frequencies of paralysis and mortality include the poliovirus strain, dose, and gender of the mouse inoculated. The more neurovirulent the virus, as defined by monkey challenge results, the higher the rate of paralysis, mortality, and severity of disease. Also, the time to disease onset is shorter for more neurovirulent viruses. Male mice are more susceptible to polioviruses than females. TGM-PRG-3 mice have a 10-fold higher transgene copy number and produce 3-fold more receptor RNA and protein levels in the CNS than TGM-PRG-1 mice. CNS inoculations with type III polioviruses differing in relative neurovirulence show that these mouse lines are similar in disease frequency and severity, demonstrating that differences in receptor gene dosage and concomitant receptor abundance do not affect susceptibility to infection. However, there is a difference in the rate of accumulation of clinical signs. The time to onset of disease is shorter for TGM-PRG-3 than TGM-PRG-1 mice. Thus, receptor dosage affects the rate of appearance of poliomyelitis in these mice

Graft-versus-host splenomegaly reactions among normal and recombinant haplotypes of the B complex of the chicken

Includes bibliographical references.During extensive immunogenetic analysis of the B complex (MHC) of the chicken conducted by W. E. Briles at Northern Illinois University, a series of eight recombinant haplotypes have been recovered (Briles and Briles, 1977; Briles, et al., 1979; Briles and Briles, 1980). Results are reported here which identify the major histocompatibility antigens acquired in each of these recombinant haplotypes. Identification of genes controlling histocompatibility antigens was performed by graft- versus-host (GVH) splenomegaly reactions. Considerable testing of both normal and recombinant haplotypes by this method has allowed determination of the histocompatibility shifts arising from recombination of genes within the B chromosome region. In addition, results of limited testing are presented which bear upon the role of antigens coded by B-F and B-G gene segments in allograft recognition. For these experiments, alloantisera raised against particular B-F or B-G alloantigens were used to treat peripheral blood lymphocytes administered as GVH splenomegaly grafts. In the course of these investigations other experiments have yielded information regarding the possible influence on GVH splenomegaly of minor histocompatibility antigens of the C blood group system. The results of these GVH splenomegaly tests indicate that B-F region genes control antigens which are involved in cellular recognition of allografts, while B-G region genes code for non-histocompatibility antigens as reported by Hala, et al. (1976). However, there are also indications that for at least some of these recombinants the site of recombination within the B chromosome region may not lie between the B-F and B-G segments, but may lie within the B-G region. Alloantigens of the C system do not appear to contribute to GVH splenomegaly reactions in this system.M.S. (Master of Science

Mapping of Genomic Segments of Influenza B Virus Strains by an Oligonucleotide Microarray Method

Similar to other segmented RNA viruses, influenza viruses can exchange genome segments and form a wide variety of reassortant strains upon coreplication within a host cell. Therefore, the mapping of genome segments of influenza viruses is essential for understanding their phenotypes. In this work, we have developed an oligonucleotide microarray hybridization method for simultaneous genotyping of all genomic segments of two highly homologous strains of influenza B virus. A few strain-specific oligonucleotide probes matching each of the eight segments of the viral genomes of the B/Beijing/184/93 and B/Shangdong/7/97 strains were hybridized with PCR-amplified fluorescently labeled single-stranded DNA. Even though there were a few mismatches among the genomes of the studied virus strains, microarray hybridization showed highly significant and reproducible discrimination ability and allowed us to determine the origins of individual genomic segments in a series of reassortant strains prepared as vaccine candidates. Additionally, we were able to detect the presence of at least 5% of mixed genotypes in virus stocks even when conventional sequencing methods failed, for example, for the NS segment. Thus, the proposed microarray method can be used for (i) rapid and reliable genome mapping of highly homologous influenza B viruses and (ii) extensive monitoring of influenza B virus reassortants and the mixed genotypes. The array can be expanded by adding new oligoprobes and using more quantitative assays to determine the origin of individual genomic segments in series of reassortant strains prepared as vaccine candidates or in mixed virus populations

Transgenic mice as an alternative to monkeys for neurovirulence testing of live oral poliovirus vaccine: validation by a WHO collaborative study

OBJECTIVE: Extensive WHO collaborative studies were performed to evaluate the suitability of transgenic mice susceptible to poliovirus (TgPVR mice, strain 21, bred and provided by the Central Institute for Experimental Animals, Japan) as an alternative to monkeys in the neurovirulence test (NVT) of oral poliovirus vaccine (OPV). METHODS: Nine laboratories participated in the collaborative study on testing neurovirulence of 94 preparations of OPV and vaccine derivatives of all three serotypes in TgPVR21 mice. FINDINGS: Statistical analysis of the data demonstrated that the TgPVR21 mouse NVT was of comparable sensitivity and reproducibility to the conventional WHO NVT in simians. A statistical model for acceptance/rejection of OPV lots in the mouse test was developed, validated, and shown to be suitable for all three vaccine types. The assessment of the transgenic mouse NVT is based on clinical evaluation of paralysed mice. Unlike the monkey NVT, histological examination of central nervous system tissue of each mouse offered no advantage over careful and detailed clinical observation. CONCLUSIONS: Based on data from the collaborative studies the WHO Expert Committee for Biological Standardization approved the mouse NVT as an alternative to the monkey test for all three OPV types and defined a standard implementation process for laboratories that wish to use the test. This represents the first successful introduction of transgenic animals into control of biologicals