Serologic Response to Canine Distemper Viral Antigens in Gnotobiotic Dogs Infected with Canine Distemper Virus

Abstract

The humoral immune response to canine distemper viral antigens in gnotobiotic dogs experimentally infected with canine distemper virus was studied by the complement fixation and serum neutralization tests. Antibody titers measured by both serologic methods varied inversely with the severity of disease produced. Recovered dogs demonstrated the highest titers of antibody, whereas fatally infected dogs had little or no antibody activity in their sera. A third group of dogs, characterized by chronic persistent infection, had intermediate levels of anitbody to canine distemper virus. Preliminary characterization of the viral antigens involved in the complement fixation test indicated that at least two antigenic components were involved. One antigen was soluble in ether and was heat-labile, whereas the other was relatively heat-stable and was unaffected by treatment with ether. No evidence for serologic cross-reaction between viral and central nervous system components was found. A vigorous antibody response to envelope antigen determinants in addition to core determinants distinguished immune dogs from persistently infected dogs. The results of this study suggest that the inability to produce antibodies to envelope antigens may be a crucial factor in the establishment of a persistent infection with canine distemper virus in these dogs.

Níveis de anticorpos contra o vírus da cinomose canina e o parvovírus canino em cães não vacinados e vacinados

“…Há alta correlação entre os títulos de anticorpos e o nível de proteção e, devido a isso, a determinação dos níveis de anticorpos é uma medida amplamente utilizada como indicador de imunidade ao CDV e CPV, ao (Krakowka et al, 1975).…”

In vitro and in vivo Properties of the Virus Causing Natural Canine Distemper Encephalitis

“…It has been suggested in previous studies by other investigators that the demonstration of IFN in the CSF obtained from dogs more than 20 days after experimental infection with CDV is a valid marker for viral persistence and severity of pathological lesions in the CNS (Tsai et al, 1982), and that an intermediate antibody response modifies the clinical course of the infection, tending to permit chronic infection rather than causing recovery from infection (Krakowka et al, 1975). As almost all of the confirmed cases in the present study retained a low level of IFNlike activity in their CSF more than 20 days post-infection and exhibited a moderate to vigorous antibody response (Table 1), it appears that they had already become persistently infected and were at transitional stages between the acute primary infection and the chronic infection with the serious neurological symptoms approximately 2 months or more post-infection.…”

“…Sera taken from the cases at the time of autopsy were tested for neutralizing antibody to CDV (Table 1) Interferon-like activity was assayed in CSF collected at the time of autopsy when the infection had already passed the critical phase (20 days post-infection; Krakowka et al, 1975) (Table l). A low level of IFN-like activity was detected in the CSF of only those dogs from whose brains infectious CDV was recovered, with the exception of Case 5, but it was not demonstrated in the CSF of dogs negative for virus isolation or in that of healthy dogs.…”

Retrospective Serological Analysis of Spontaneous CDV Infection in 192 Dogs

“…However, it is difficult to make a definitive diagnosis from the clinical signs and a serological diagnosis alone, since CDV induces severe immune suppression and lymphocyte depletion. Moreover, only a few studies have been done on the inability to produce antibodies against canine distemper virus [7,9].…”

“…It has been experimentally demonstrated that severe or fatal cases of CDV infection had low or undetectable levels of CDV antibody, which would suggest that they were at the early stage or even the fatal [7,9]. However, there have been no serological reports on natural CDV infection.…”