Additional Evidence as of September 29, 1999 that The Jackson Laboratory DOES NOT have MHV
JAX® Bulletin #3, Addendum 1
September 29, 1999
Evidence from Our Recent Intensive Testing Efforts
A COMMUNICATION FROM THE JACKSON LABORATORY ANIMAL HEALTH STAFF: Peggy J. Danneman, VMD, MS, dip ACLAM (Acting Director of Laboratory Animal Health), James R. Fahey, PhD, DVM, dip ACVM (Head of Diagnostic Laboratory), Terrie Cunliffe-Beamer, DVM, MS, dip ACLAM (Head of Clinical Laboratory Animal Medicine), John P. Sundberg, DVM, PhD, dip ACVP (Head of Pathology, Senior Staff Scientist)
Additional negative test results have been obtained confirming that The Jackson Laboratory does NOT have MHV. The information below describes the negative results obtained after publication of JAX Bulletin, No. 3, August 25, 1999.
As a follow up to the investigation in Jackson Laboratory Room AX-1, serum and fecal samples from DBA/2J sentinels placed in cages with B6.MRL-Faslpr (lpr/lpr) and B6Smn.C3H-Faslgld (gld/gld) weanlings were tested by ELISA and RT-PCR, respectively. Serum samples from all sentinels removed after 6 weeks (20 total) were negative for MHV. All fecal samples taken from the sentinels after 3 weeks (29 mice sampled) were negative; results are pending on samples taken from the samples at 6 weeks (20 mice sampled). Fecal samples from lpr/lpr (11 mice sampled), and gld/gld (7 mice sampled) weanlings from cages holding sentinels were also negative for MHV RNA by RT-PCR.
As follow up to the single RT-PCR positive sample from Jackson Laboratory Room AX-8 [a pooled fecal sample from a cage of MRL/MpJ-Faslpr (MRL-lpr/lpr) weanlings], blood samples from 768 mice in Room AX-8 were tested by ELISA for antibody to MHV. 746 samples were serologically negative for MHV and 22 samples gave nonspecific reactions. Fecal samples from the 22 animals whose sera gave nonspecific reactions were tested for MHV RNA using RT-PCR; all were negative.
A sentinel program was initiated to test for the presence of MHV among MRL mice in Room AX-8. Each week for 6 weeks, weanling (3 wk old) MRL-lpr/lpr mice will be placed in a "sentinel" cage with one immunocompetent (various strains, including BALB/cJ, CBA/J, and FVB/NJ) and one immunodeficient (C57BL/6J-Prkdcscid/SzJ or C3HSmn.C- Prkdcscid/J) weanling mouse. Each "sentinel" cage will contain 5-8 MRL-lpr/lpr weanlings from different litters in addition to the 2 sentinels. This approach will allow us to test progeny from all currently productive breeding cages in the MRL-lpr/lpr colony. Fecal samples from all sentinels will be tested by RT-PCR 2, 4, 6, and 8 weeks after placement in the "sentinel" cages, and samples from the MRL-lpr/lpr weanlings in these cages will be tested at 2 wk. Serum samples from all sentinels in the "sentinel" cages will be tested by ELISA after 4 and 8 weeks. To date, 13 fecal samples have been tested; all were negative for MHV RNA.
