Public versus personal serotypes of a viral quasispecies

AUTOR(ES)
FONTE

The National Academy of Sciences

RESUMO

Noncytopathic RNA viruses persist in their natural hosts at various levels as highly mutating quasispecies. They exhibit only one known serotype. In most inbred DBA/2 mice infected with 2 × 104 or 2 × 106 plaque-forming units (pfu) of lymphocytic choriomeningitis virus (LCMV), the virus is transiently controlled below detectable levels measured with conventional assays (<1.7 pfu), but reemerges despite a common neutralizing Ab (nAb) response. Wild-type virus and cloned mutant viruses that had escaped polyclonal nAb responses in vivo induced nAb titers in new hosts that were usually cross-reactive; some sera were highly specific for certain mutants. The few mice that controlled LCMV infection for >170 days produced not only nAb against wild-type but also variably against many other mutants isolated from other mice with reemerging viremia. When DBA/2 mice were immunized and boosted with 200 pfu of a LCMV mutant, the neutralizing Ab response was limited to the immunizing “personal” clone. Thus, in contrast to classical serotype-defined cytopathic viruses (e.g., polio viruses) that induce strictly non-cross-reactive nAb titers, LCMV, a noncytopathic RNA virus, represents a dynamic multiplicity of personal serological submutants. Together, these mutants form a generally recognized “public” serotype. These findings may help to explain aspects of human infections and Ab responses against hepatitis B virus, hepatitis C virus, and HIV.

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