An immunological study of infection of hamsters with large and small plaque canine distemper viruses

Abstract

The small plaque virus (SPV), derived from the Onderstepoort strain of canine distemper virus (CDV) does not cause a lethal encephalitis in weanling hamsters. When we immunosuppressed hamsters infected with this virus they developed an acute disease, similar to that produced by the large plaque virus (LPV). Passive transfer of maternal antibody from SPV infected mothers to their offspring was effective in preventing acute disease following LPV infection. Co-infection of animals with both LPV and SPV resulted in increased hamster survival, associated with high titres of serum antibody. Similarly, heat inactivated SPV, present during infection with LPV, increased the survival rate. Heat inactivated LPV did not inhibit acute disease, although hamsters had high titres of neutralizing antibody. A small number of animals developed a delayed or recurring paralysis after immunosuppression, exposure to maternal antibody or co-infection. It would appear that the neurovirulence of CDV for hamsters can be modified by altering the levels of circulating antibody early in infection.

The Generation of Small-Plaque Mutants during Undiluted Passage of Canine Distemper Virus

“…However, SPV8-FU and SPV9-FU did not establish persistently infected cultures at all MOIs tested and, when hamsters were infected with these vi ruses, a number developed acute encephali tis or a prolonged paralysis. These results are similar to those obtained in a previous study [Cosby et al, 1983], where animals were co-infected with LPV and SPV. In this case there appeared to be a correlation between the concentration of SPV in the inoculum and the percentage of animals protected against acute disease.…”

“…A detailed classification of virus-induced disease in hamsters, on the basis of clinical signs, has been described [Cosby et al, 1983]. …”

“…and develop high titers of serum neutralizing antibody. In a more recent study [Cosby et al, 1983] we have shown that the difference in immuno genicity between LPV and SPV is a major factor in the determination of neuroviru lence, as alteration of the levels of circulating antibody early in infection can modify the course of both LPV-and SPV-induced dis ease. Therefore, to advance our understand ing of the basis of CDV neurovirulence, it was of interest to examine whether mutations from LPV to SPV are always associated with a corresponding change in immunogenicity and, hence, neurovirulence.…”

Correlation between humoral immune responses and presence of virus in the CNS in dogs experimentally infected with canine distemper virus

“…These correlations suggest that the immune response plays an important if not dominant role in determining the outcome of infection by this virus. Similarly, in hamsters we have shown earlier [5] that the immune status of the animals is important to determine the outcome of infection since the neurovirulence of the infection in hamsters could be modified by altering the levels of circulating antibody early in infection.…”

“…The importance of the humoral immune response in determining the outcome of infection by CDV has been reported for dogs [1,8] and more recently for hamsters [5]. In this paper, we describe the major antigens to which antibodies could be found in infected dogs by the technique of immunoprecipitation.…”