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Archives -
Mice
of Black / 6 Lineage and MPV
Prepared by Dr. Huerkamp
A rumor that was initiated on a transgenic listserver and that
has been swirling around here since early August has been that C57BL/6
(aka B6) mice had an idiosyncratic tendency to not produce antibodies
to MPV after infection. I have spoken to investigators at the University
of Missouri and Yale University who have done extensive research
with MPV and neither could corroborate that this rumor has much
basis in fact. The rumor seems to be related to a single set of
unpublished pathogenesis experiments involving a number of mouse
strains, including B6, and terminated by design at day 10 post-infection.
The B6 mice used in these studies (n=5) did not seroconvert by 10
days post-infection. C3H mice seroconverted quickly, but DBA and
A strain mice were also poor responders over 10 days. It should
be noted, however, that it typically takes 7-21 days for an immunocompetent
mouse to seroconvert following infection and this is dependent upon
the genotype of the mouse and strain and quantity of virus, among
other factors. It should also be noted that the aforementioned study
was directed at studying viral pathogenesis and not assessing diagnostic
antibody response. Up to 6 weeks may be necessary to obtain an MPV
seroconversion in mice. Little other research has been done specifically
with MPV infection in B6 mice; BALB/c and SENCAR mice have been
used most commonly.
Intuitively, one would expect that an immunocompetent strain, such
as B6, given an infectious inoculum and sufficient time would develop
a detectable antibody titer. In fact, the B6 strain is noted to
be a very robust antibody responder to many infectious agents. They
are, for example, more sensitive in converting to MHV seropositivity
than C3H, BALB/c or DBA/2 mice (Lab Animals 17: 90-4, 1983; Lab
Animals 25: 106-9, 1991) and are noted to show a profound antibody
response to ectromelia virus (Bacteriol Rev 23: 61-95, 1959). It
seems incongruous that B6 mice would produce antibodies to so many
pathogens, but not MPV. Consequently, we believe that B6 mice infected
with MPV should develop serum antibody that will be detectable diagnostically.
We thus believe that serologic assessments of B6 mice from our colonies
were valid and useful.
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