SERODIAGNOSIS OF HELICOBACTER-HEPATICUS INFECTION IN MICE BY AN ENZYME-LINKED-IMMUNOSORBENT-ASSAY

Helicobacter hepaticus is a newly recognized bacterium associated with chronic active hepatitis, hepatic carcinoma, and inflammatory bowel d isease in mice, Currently, fecal or tissue PCR, fecal culture, or hist ologic examination of silver-stained liver sections is used to diagnos e H, hepaticus infection, In this report, we describe an enzyme-linked immunosorbent assay (ELISA) for serodiagnosis of H, hepaticus infecti on in mice with a membrane digest preparation of H. hepaticus as the a ntigen, Sera from mice positive for H, hepaticus by PCR or histologic examination (n = 88), positive for Helicobacter bilis by PCR (n 13), p ositive for other helicobacters (not identifiable to species level) by PCR (n = 25), or negative for all Helicobacter species by PCR (n 162) were used to evaluate the ELISA, Results indicated that ELISA provide d 93.2% sensitivity, 94% specificity, 87.2% positive predictive value, and 96.9% negative predictive value, Cross-reactive antibodies were d etected in some mice infected with helicobacters not identifiable to s pecies level, To further define ELISA sensitivity and specificity, gro ups of 10 C57BL/6 mice were inoculated per os with H, hepaticus, Helic obacter muridarum, or H, bills, Sera were collected and examined by th e ELISA, H. hepaticus-infected mice seroconverted by 2 weeks and maint ained ELISA reactivity throughout the 18-week study, while mice infect ed with H, muridarum and H. bills were negative by ELISA. These result s indicate that this reported ELISA is highly sensitive and specific f or the serodiagnosis of H, hepaticus infection in mice.