A comparison of the amounts of mouse interferon obtained from different sources

Pathogenesis of genital herpes simplex virus infection in mice. IV. Quantitative aspects of viral latency

Experiments in the mouse model of herpes simplex virus (HSV) infection involving the intact genital mucous membranes as inoculation site yielded the following results. In untreated mice the extent of latency was correlated with the degree of peripheral virus replication. This correlation could not be observed when the course of infection was interrupted by chemotherapy, interferon, or passive immunization. Acyclovir had little effect on peripheral virus multiplication, but markedly reduced latent ganglionic infection. As acute ganglionic infection and virus concentration in the spinal nerves were already reduced, acyclovir is assumed to inhibit either virus penetration into the nerve endings or virus replication in the ganglia. Interferon apparently has an active role in the elimination of virus infected cells from the ganglia, as its effect was restricted to a reduced rate of latency and of lethality. Passive immunization with antiserum led to similar results as ACV-treatment. While lacking a pronounced effect on virus replication in the mucous membranes, specific antibody was found to influence both virus elimination from the ganglia, and conversion from productive to latent ganglionic infection. Immune lymphocytes proved to be the only agent capable of suppressing peripheral infection, thereby inhibiting the neural spread of the virus. These results suggest that the decrease in latency may result from modulations occurring at different stages in the course of infection.

Interferon in nasal secretions and sera of calves after intranasal administration of avirulent infectious bovine rhinotracheitis virus: association of interferon in nasal secretions with early resistance to challenge with virulent virus

Calves which had received avirulent infectious bovine rhinotracheitis virus (AV-IBR) by intranasal (IN) administration developed detectable levels of interferon (IF) in nasal secretions as early as 40 hr later. Peak titers (1:640) of IF appeared in secretions 72 to 96 hr after administration of virus, and titers of 1:80 to 1:320 were maintained through the 8th day. Lower titers (1:5 to 1:10) of IF were detected in sera obtained on the 4th to 8th days after administration of virus. Peak titers of IF in respiratory tract secretions were accompanied by a 100- to > 1,000-fold reduction in the levels of AV-IBR present in the secretions. Serum antibody was not detected prior to the 8th day after administration of AV-IBR. Calves which received AV-IBR by the IN route 72 or 96 hr earlier were refractory to challenge with virulent infectious bovine rhinotracheitis virus (IBR), whereas calves receiving AV-IBR 18 or 40 hr earlier became clinically ill following challenge. The temporal association between appearance of IF in respiratory tract secretions and onset of protection against challenge suggests a cause and effect relationship. No IF was detected in either nasal secretions or sera of calves receiving modified IBR virus by intramuscular injection. Following subsequent IN challenge of these calves, IF was detected in nasal secretions as early as 24 hr postchallenge and was maintained at titers of 1:40 to 1:80 for approximately 4 days, even in the absence of virus recovery. Greater ease of local IF induction with IBR virus in calves previously sensitized with that virus is suggested.