Virulent Rinderpest Virus Research Articles

Morbillivirus v proteins exhibit multiple mechanisms to block type 1 and type 2 interferon signalling pathways.

Morbilliviruses form a closely related group of pathogenic viruses which encode three non-structural proteins V, W and C in their P gene. Previous studies with rinderpest virus (RPV) and measles virus (MeV) have demonstrated that these non-structural proteins play a crucial role in blocking type I (IFNα/β) and type II (IFNγ) interferon action, and various mechanisms have been proposed for these effects. We have directly compared four important morbilliviruses, rinderpest (RPV), measles virus (MeV), peste des petits ruminants virus (PPRV) and canine distemper virus (CDV). These viruses and their V proteins could all block type I IFN action. However, the viruses and their V proteins had varying abilities to block type II IFN action. The ability to block type II IFN-induced gene transcription correlated with co-precipitation of STAT1 with the respective V protein, but there was no correlation between co-precipitation of either STAT1 or STAT2 and the abilities of the V proteins to block type I IFN-induced gene transcription or the creation of the antiviral state. Further study revealed that the V proteins of RPV, MeV, PPRV and CDV could all interfere with phosphorylation of the interferon-receptor-associated kinase Tyk2, and the V protein of highly virulent RPV could also block the phosphorylation of another such kinase, Jak1. Co-precipitation studies showed that morbillivirus V proteins all form a complex containing Tyk2 and Jak1. This study highlights the ability of morbillivirus V proteins to target multiple components of the IFN signalling pathways to control both type I and type II IFN action.

Rinderpest virus (RPV) ISCOM vaccine induces protection in cattle against virulent RPV challenge

Rinderpest virus (RPV), a member of genus Morbillivirus in the family Paramyxoviridae, causes an acute and often fatal disease in cattle and other large ruminants. A subunit rinderpest vaccine consisting of an immune-stimulating complex (ISCOM) incorporating the RPV haemaggulutinin (H) protein, was examined for its ability to induce protective immunity in cattle, the natural host of RPV. All of four cattle vaccinated with the ISCOM vaccine survived challenge with virulent virus. Three were solidly protected, showing no clinical signs of infection, while the fourth animal developed only mild and transient symptoms. Virus neutralizing antibodies were produced at a significant level in all vaccinated cattle. These results indicate that this ISCOM vaccine is effective in producing protective immunity in cattle and should be a suitable means of delivering glycoprotein antigens from other morbilliviruses.

Mapping of T-helper epitopes of Rinderpest virus hemagglutinin protein.

Rinderpest virus (RPV) is a highly contagious and often fatal disease of domestic and wild ruminants, caused by rinderpest virus of the genus Morbillivirus under the family Paramyxoviridae. Hemagglutinin (H) and fusion (F) proteins of this enveloped virus confer protective immunity against experimental challenge with virulent rinderpest virus. We have earlier demonstrated that immunization with a single dose of recombinant extracellular baculovirus expressing H protein elicits H-specific humoral and lymphoproliferative responses in cattle. The lymphoproliferative responses are predominantly BoLA class II restricted. In this work, we have analyzed lymphoproliferative responses of peripheral lymphocytes from immunized cattle to truncated H protein fragments expressed in E. coli for locating domains harboring Th epitopes. One region (aa 113-182) recognized by immune T cells is conserved in the H protein of measles virus, which was earlier shown to contain a dominant Th epitope in mouse. Synthetic peptides within this region of measles virus H protein were used to identify a Th epitope conserved in the H protein of RPV virus (aa 123-137) in cattle. A second Th epitope located at the C-terminus of RPV-H was mapped to the region corresponding to aa 512-609 using truncated protein fragments expressed in E. coli. The C-terminal epitope (aa 575-583) was mapped using synthetic peptides corresponding to measles virus H as well as RPV-H protein.

Cell-mediated immune responses in cattle vaccinated with a vaccinia virus recombinant expressing the nucleocapsid protein of rinderpest virus.

Rinderpest virus (RPV) is a member of the genus Morbillivirus in the family Paramyxoviridae which causes an acute and often fatal disease in large ruminants. To examine the immune response to the virus nucleocapsid (N) protein, a recombinant vaccinia virus expressing RPV nucleocapsid protein (rVV-RPV-N) was used to vaccinate cattle. The recombinant vaccine induced low levels of non-neutralizing anti-N antibodies. RPV-specific cell-mediated immunity induced by the recombinant was assessed by measuring both the lymphocyte proliferation and cytotoxic T-lymphocyte responses. The protective immune response was examined by challenging the vaccinated cattle with either a highly virulent (Saudi 1/81) or a mild (Kenya/eland/96) strain of the virus. The vaccinated cattle were not protected against challenge with the virulent RPV strain, except they showed a slight delay in the onset of disease when compared with the unvaccinated controls. In cattle challenged with the mild strain, apart from a transient fever, no clinical signs of rinderpest infection were seen in the vaccinated cattle. One out of two control cattle showed a similar response but the other died from classic rinderpest disease. Virus-neutralizing antibodies were induced more quickly following challenge with the mild strain in vaccinated cattle compared to the control animals. These data suggested that the cell-mediated immunity induced by rVV-RPV-N could stimulate the rapid production of neutralizing antibodies following RPV challenge but this response was not sufficient to protect against challenge with a virulent strain of the virus. Protection was seen in one of three animals challenged with a mild strain of the virus; however, a greater number of animals would need to be tested to estimate the significance of the protection afforded by the N protein.

Potency testing of tissue culture rinderpest vaccine in rabbits

Rinderpest (RP) vaccine potency testing requires virulent bovine rinderpest virus (RPV). Use of virulent RPV is a biosafety hazard. In this study we had vaccinated rabbits with tissue culture RP vaccine at different doses and thereafter challenged with lapinized virus. No thermal reaction in vaccinated rabbits was observed. Serum neutralizing antibody response to vaccine was dose dependent until the second week post-vaccination but by the fourth week post-vaccination all the rabbits had similar neutralizing antibody titres. Vaccinated rabbits exhibited mild clinical signs as compared to unvaccinated controls after challenge. All the vaccinated rabbits survived challenge while only 40% unvaccinated rabbits survived challenge with virulent lapinized RPV. A strong anamnestic response in all the vaccinated rabbits was observed after challenge with lapinized virus. This study shows that rabbits could be used for potency testing of RP vaccine virus.

Protection of goats against rinderpest by vaccination with attenuated peste des petits ruminants virus

The ability of the attenuated peste des petits ruminants vaccine virus to protect small ruminants against virulent rinderpest virus was investigated. Out of four susceptible goats that were infected with the highly virulent Saudi strain of rinderpest virus by intranasal ioculation, three developed mild clinical signs of disease and infected susceptible in-contact goats and cattle with rinderpest virus. However, four goats which had been vaccinated with the attenuated peste des petits ruminants virus resisted challenge with virulent rinderpest virus and did not infect susceptible in-contact animals.

Rapid Recovery of Rinderpest Virus in Vero Cells from Fresh Infected Tissues by Fusion and Co-culture Methods

Abstract Singh, R.K, Bhat, P.N. and Bhat, P.P. 1995. Rapid recovery of rinderpest virus in vero cells from fresh infected tissues by fusion and co-culture methods. J. AppL Anim. Res., 7: 145–151. Two virulent rinderpest virus isolates (Hisar and Bangalore) and one caprinised strain known as goat tissue virus (GTV) were adapted to in vitro growth in vero cells by fusion and co- culture methods. Both these methods were found to be efficient for rapid recovery of rinderpest virus but the co-culture technique was simpler in comparison to the fusion method where more stringent fusion conditions were required. The co-culture technique can easily be adopted for use in any virology laboratory engaged in routine virological work.

Humoral antibody response in animals infected with virulent rinderpest virus

Humoral antibody responses in cattle or rabbits infected with virulent rinderpest virus or lapinised rinderpest virus respectively were assessed. Rinderpest specific antibodies could be first detected 6 days post-infection. No correlation could be established between antibody response and the course of the disease in infected animals during the early stages of infection. The animals with fatal infection either did not respond or had a transient antibody response. A gradual increase in antibody titre from 7 days post-infection was observed in animals which ultimately recovered.

Confirmation of rinderpest in experimentally and naturally infected cattle using microtitre techniques

Virulent rinderpest virus was detected by immunoperoxidase staining of microtitre bovine kidney cell cultures within 24 to 48 hours of inoculation with prescapular lymph node and spleen homogenates from experimentally infected steers. Rinderpest virus specific cytopathic effects were evident from 48 hours in microtitre plates and from 72 hours in rolled tube cultures. Nasal and ocular secretions collected from cattle naturally infected with rinderpest and inoculated into bovine kidney cell cultures did not readily yield cytopathic virus in both tubes and microtitre plates, but immunoperoxidase staining of microtitre cultures on the fourth day of inoculation detected replication of virus in cultures inoculated with ocular and nasal secretions from seven of 17 cattle tested.

Immunohistological localisation of rinderpest virus in formalin-fixed, paraffin-embedded tissues from experimentally infected cattle.

Six Freesian steers were subcutaneously inoculated with the virulent rinderpest virus strain Kabete "0" and sacrificed at the height of fever. Sections of formalin-fixed, paraffin-embedded tissues were stained according to the peroxidase anti-peroxidase (PAP) technique. Labelling of viral antigen, both in the cytoplasm and in the nuclei of infected cells, was observed in the epithelial cells of the upper and lower alimentary tract and in lymphoid organs, i.e. spleen, lymph nodes, pharyngeal tonsils, Peyer's patches and thymus. Electron microscopy studies confirmed the results.

RESPONSE OF WHITE-TAILED DEER TO INFECTION WITH PESTE DES PETITS RUMINANTS VIRUS

White-tailed deer (Odocoileus virginianus) were infected experimentally with two strains of peste des petits ruminants virus. The response varied from fatal consequence to subclinical infection. The clinical signs and gross lesions were similar to those in goats. Virus was recovered from all the infected deer, and survivors developed specific antibodies demonstrated by complement fixation and virus neutralization tests. Survivors also resisted challenge with virulent rinderpest virus that was lethal to a control deer.

Transmission of Rinderpest by Contact from Cattle to Sheep and Goats

SUMMARY Contact transmission of rinderpest from cattle to sheep and goats, and from these to other sheep and goats is described. Virulent rinderpest virus was recovered from the nose and faeces of the small ruminants. In 2 experiments, 70% and 85% of the small ruminants became infected. In a third experiment, only 6% became infected. It was postulated that the degree of contact was responsible for these differences. The clinical symptoms in the sheep and goats in 2 experiments were mild and transient; in a third experiment very severe. It was considered that a high level of nutrition and secondary agents play a role in the severity of rinderpest symptoms in the small ruminants. It was thought unlikely, although not conclusively proved, that bovine rinderpest virus could maintain itself for some time in the small ruminant population. Carriers among the sheep and goats were not found.

Long-term Studies of the Immunity in East African Cattle Following Inoculation with Rinderpest Culture Vaccine

Virus-neutralising antibody was investigated over periods of 24 to 50 months in East African cattle which had been inoculated with culture-attenuated rinderpest virus of 91 or more passages in calf kidney monolayers. The cattle were of 3 types, viz: Friesian or fersey grades, Boran (shorthorn zebu) and Ankole (longhorn). Grade cattle showed a peak mean antibody titre of 102.17 at 4 weeks, but a considerable decline occurred between 12 and 18 months after inoculation; in the following 3 years little additional change took place. A few animals had very low titre antibody after 6 to 12 months, but this was probably associated with the presence of minimal quantities of passively-acquired antibody at the time of vaccination. When 3 such cattle were challenged after 27 and 37 months, 2 developed inapparent reinfection, with a delayed serological response, beginning on the fifth day. Two other animals showed a rapid anamnestic response reaching a peak within 48 hr.; one of the latter probably injected arinderpest-susceptible ox which was housed with it during the post-challenge period. Four grade cattle which were challenged after 50 months showed no clinical or serological reaction. Boran cattle produced a high mean antibody level 0f about 102.0 which persisted until the end of the second year, while any fall thereafter was very slow. Of the individual animals, only 26% showed a decline > 1 log10 unit in the first 3 to 4 years, compared with 46% among the grades. Not one of 56 vaccinated animals was serologically negative at the end of 3 1/2 years. In the Ankoles, no significant decline in mean antibody titre occurred during the first 2 years of the experiment but, as in other groups, there was great variation in the peak titres attained in different individuals (100·6 to 102·8). The rate of decline of antibody and the resistance to challenge of animals with very low titres makes it probable that rinderpest culture vaccine confers a lifelong immunity. Nevertheless, "immune" cattle with very low levels of circulating antibody may contract inapparent reinfection, thus becoming transitory "carriers" of virulent rinderpest virus.

Studies with Rinderpest Virus in Tissue Culture: A Technique for the Detection and Titration of Virulent Virus in Cattle Tissues

SUMMARY Virulent strains of rinderpest virus were isolated and titrated directly in rolled tube cultures of primary calf-kidney cells. The time to appearance of cytopathic changes varied from 3 to 12 days, depending on the amount of virus in the inocula, which were blood or tissue suspensions derived from infected cattle. No period of adaptation to cultural growth was necessary. Immune serum incorporated in the medium as late as the 2nd day p.i. completely suppressed viral cytopathogenicity, thus allowing the rapid, specific identification of isolates. Culture titres were probably somewhat lower than those which have been recorded in cattle titrations of comparable materials, but cultural methods may be reliably applied to the laboratory diagnosis and quantitative study of virulent rinderpest infections. Two attenuated vaccine strains of virus were not cytopathogenic to calf-kidney monolayers. These findings are discussed in the light of previously reported observations, which suggested some difficulty in the adaptation of virulent rinderpest virus to growth in monolayer cultures.

A Procedure for Detecting Complement-fixing Antibody to Rinderpest Virus in Heat-inactivated Bovine Serum

SUMMARY Complement-fixing antibody to rinderpest virus was demonstrated in heat-inactivated cattle sera. The method used an extract of rinderpest-infected bovine lymph nodes as antigen, increasing concentrations of guinea-pig complement, and overnight fixation. By this procedure, specific complement-fixing antibody was demonstrated from 5 days after fever peak or 10 days after inoculation through at least 50 days. Sera were obtained from the cattle inoculated with lapinized Nakamura III, Kabete attenuated goat, and tissue culture attenuated Kabete O and Pendik strains of the virus. Cattle showing complement-fixing antibody resisted challenge with virulent rinderpest virus

Cytopathogenicity of rinderpest virus in tissue culture.

Takematsu and Morimoto1 have reported cultivation of lapinized rinderpest virus in roller-tube cultures of rabbit lymph node, spleen and bone marrow; but details are not available to us, and it is not known if cytopathological effects were observed. In this laboratory, we have found that the Kabete ‘O’ strain of virulent rinderpest virus multiplies in mono-layers of bovine embryonic kidney cells and produces characteristic cytological changes. In addition, kidney-passaged virus destroys bovine fibroblasts grown from embryonic skin-muscle tissue and prepubertal testis.

Lapinised rinderpest virus and a vaccine: Some observations in East Africa: I. Laboratory experiments

Summary The findings of Cheng and Fischman (1948) have been confirmed at Kabete. The Nakamura strain III of lapinised rinderpest virus was also “fixed” for the local breeds of rabbits and during 21 passages at Kabete there was no increase in virulence for rabbits, or attenuation of the antigenic properties for cattle. Freeze-drying of the major virus-containing tissues of rabbits ensured the maintenance of the virus and dried material or “seed-virus” remained viable for long periods when kept under optimum conditions. The symptoms and post-mortem findings of infected rabbits at Kabete have closely simulated those reported by other workers. It was noted that the temperatures of normal rabbits kept under laboratory conditions were slightly lower than those generally accepted. Rabbits below the age of 4 1/2 months did not react thermally when injected with the virus, but showed lesions typical of rinderpest; pregnant does were also unsuitable subjects for the propagation of the virus. Alternate passage of the virus in cattle and rabbits appeared to alter the character of the virus, which showed a decreased virulence for rabbits with an irregular and somewhat increased virulence for cattle. Co-habitation of infected rabbits with non-infected rabbits and infected cattle with susceptible cattle, did not result in passage of the virus by contact to the susceptible animals. In contra-distinction to goat-adapted virus, lapinised virus provoked a very mild reaction in high and medium grade cattle at Kabete which could not be readily recognised. The development of an immunity in cattle so inoculated could not be determined until challenged with virulent rinderpest virus. The immunity induced by the injection of lapinised virus in susceptible cattle was sufficient to prevent clinical symptoms of rinderpest after challenge with Kabete bovine virus. Lapinised virus induced a serviceable protection in cattle challenged 84 hours and at 108 hours respectively, after inoculation.