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Humoral immunity and protection of mice challenged with homotypic or heterotypic parvovirus
G M Hansen1, F X Paturzo, A L Smith
1Section of Comparative Medicine, Yale University School of Medicine, New Haven, Connecticut, USA.
Background And Objectives:
Two serotypes of autonomously replicating parvoviruses infect laboratory mice. Genome regions coding for the nonstructural proteins of minute virus of mice [MVM] and mouse parvovirus [MPV] are almost identical, whereas capsid-coding sequences are divergent. We addressed these questions: Does humoral immunity confer protection from acute infection after challenge with homotypic or heterotypic parvovirus, and if it confers protection against acute MPV infection, does it also protect against persistent MPV infection?
Methods:
Infant mice without maternal antibody or antibody to MVM or MPV and young adult mice given normal mouse serum or antibody to MVM or MPV were challenged with homotypic or heterotypic virus. In situ hybridization with target tissues was the indicator of infection.
Results:
Humoral immunity failed to confer protection against acute heterotypic parvovirus infection. In passive transfer studies, MPV DNA was observed occasionally in lymph nodes, intestine, or the spleen of MPV-challenged mice given homotypic antibody and kept for 6 or 28 days. Variable proportions of mice given MPV antibody and homotypic challenge had viral DNA in lymphoid tissues 56 days after virus inoculation.
Conclusion:
A mouse or colony that has sustained infection with MVM or MPV is probably fully susceptible to infection with the heterotypic virus.
Insights
Humoral immunity does not protect mice from acute parvovirus infection, whether the challenge is with the same virus type or a different one. Mice infected with minute virus of mice or mouse parvovirus remain susceptible to the other virus.
Area of Science:
- Virology
- Immunology
Background:
- Two parvovirus serotypes, minute virus of mice (MVM) and mouse parvovirus (MPV), infect laboratory mice.
- While nonstructural protein genes are conserved, capsid genes differ between MVM and MPV.
Purpose of the Study:
- To determine if humoral immunity protects against acute homotypic and heterotypic parvovirus infection.
- To assess if protection against acute mouse parvovirus (MPV) infection extends to persistent MPV infection.
Main Methods:
- Mice lacking maternal antibodies or receiving specific antibodies (anti-MVM or anti-MPV) were challenged with homotypic or heterotypic viruses.
- In situ hybridization was used to detect viral DNA in target tissues.
Main Results:
- Humoral immunity did not prevent acute heterotypic parvovirus infection.
- MPV DNA was detected in lymphoid tissues and the spleen of MPV-challenged mice receiving homotypic antibodies, indicating incomplete protection against persistent infection.
Conclusions:
- Mice with prior MVM or MPV infection are likely susceptible to heterotypic parvovirus challenge.
- Existing humoral immunity is insufficient to protect against heterotypic parvovirus infections.