Protective effect of serum antibody on respiratory infection of influenza C virus in rats

Abstract

The effects of serum antibody on the replication of influenza C virus in the nose and lung were evaluated in rats challenged with the virus by the intranasal and endotracheal routes, respectively. Convalescent rat serum administered intraperitoneally prior to infection suppressed virus replication significantly in both the nasal and pulmonary tissues. Resistance achieved was however much greater in the lung than in the nose. Rats with a serum neutralizing antibody titer of 1:800 showed almost complete resistance to pulmonary virus infection, and virus yield from the lung was reduced 10- to 100-fold in animals with the antibody titer of 1:80-160 or less. In contrast, significant decrease in virus shedding from the nose was observed only in animals with a serum antibody titer of 1:800 or greater. The effect of adoptive transfer of monoclonal antibodies (MAbs) to haemagglutinin-esterase (HE) glycoprotein and matrix (M) protein on pulmonary virus replication was also examined. Anti-HE MAbs with neutralization activity prevented virus shedding from the lung almost completely whereas non-neutralizing anti-HE MAb and anti-M Mab showed no inhibitory effect.

The Ferret Model for Influenza

“…Such ex vivo neutralization can account for a reduction in detectable virus (Subbarao et al, ). The use of nasal and bronchiolar wash samples, instead of tissue homogenates, for viral quantitation are also employed as a solution to this issue (Takiguchi et al, ).…”

Host Range, Biology, and Species Specificity of Seven-Segmented Influenza Viruses—A Comparative Review on Influenza C and D

“…The viral shedding peaked at 24 hpi, and stayed until 5 dpi [109]. Administration of convalescent sera before ICV infection rendered complete resistance to lung infection in rats [110]. Interestingly, the ICV genome was detected in the chicken lung by RT-PCR until 53 dpi, indicating the long-term stability of the ICV genome [33].…”

Respiratory Virus Vaccines

“…During a natural influenza infection of the URT, mucosal immune responses, including secretory IgA antibodies, play an important role in controlling disease (Section Immune Responses to Respiratory Virus Infection). Several studies have documented that higher levels of serum antibodies are required to provide protection against respiratory viruses in the URT compared to the LRT (Prince et al, 1985;Ramphal et al, 1979;Takiguchi et al, 1992). Additionally, influenza in ferrets is primarily a URT infection and vaccination with killed or inactivated influenza viruses does not protect against influenza infection unless administered with an adjuvant (Potter et al, 1972a,b).…”