Analysis of Antibody Changes in Laboratory Mice Infected with Murine Norovirus

Abstract

ObjectiveTo study the changes of total IgG antibodies and neutralizing antibodies in KM, BALB/c, NIH, C57BL/6J and BALB/c-nu mice infected with murine norovirus (MNV).MethodsFive strains of KM, BALB/c, NIH, C57BL/6J and BALB/c-nu mice were collected. Each strain was divided into control group and infection group. The infection group was inoculated with MNV by gavage, and the control group was inoculated with the same volume of normal saline. Blood and serum were collected from 1 to 9 weeks after infection, total IgG antibody level (mean absorbance) was determined by ELISA, and neutralizing antibody titer (half protective dose, PD50) was determined by RAW264.7 cytopathic method. T-test was used to compare the mean absorbance difference between the infection group and the control group at each time point; One way ANOVA was used to compare the total antibody and neutralizing antibody titer of each strain of the infection group, and to analyze the antibody changes of each strain of mice.ResultsT-test showed that the mean absorbance of total IgG antibody in KM, BALB/c, NIH, C57BL/6J and BALB/c-nu mice infected on the day 21, 35, 14, 14 and 28 was significantly higher than that of the control group (P NIH>KM>BALB/c>BALB/c-nu, and the mean values of lgPD50 were 3.881, 3.819, 3.746, 3.146, and 2.338, respectively. Analysis of variance showed that neutralizing antibody titer of BALB/c and BALB/c-nu mice was significantly lower than that of C57BL/6J, NIH and KM mice (P < 0.01). Except for BALB/c-nu mice, the neutralizing antibody of the other four strains increased rapidly at the second week of infection, and the neutralizing antibody of BALB/c-nu mice was always at a low level.ConclusionThe humoral immune response of NIH, C57BL/6J and KM mice infected with MNV is stronger, and that of BALB/c and BALB/c-nu mice is weaker.

Keywords

• murine norovirus
• infection
• antibody changes
• mice