High avidity cytotoxic T lymphocytes to a foreign antigen are efficiently activated following immunization with a recombinant paramyxovirus, simian virus 5.

Our previous work has shown that high avidity cytotoxic T lymphocytes (CTL) are optimal for virus clearance in vivo and thus it is necessary that an effective vaccine is capable of eliciting high avidity CTL. To determine if vaccination with the paramyxovirus simian virus 5 (SV5) elicits a high avidity response to a model foreign antigen, a recombinant virus was engineered to express chicken ovalbumin (rSV5-Ova). To compare the CTL response elicited with rSV5-Ova and a recombinant vaccinia virus expressing ovalbumin (rVV-Ova), mice were vaccinated intranasally with various doses of each vector and the Ova-specific CTL response was determined by ELISPOT analysis. Here, it has been shown that rSV5 can be equally as effective as rVV in eliciting antigen-specific CTL, in terms of both the total number of CTL and the number of high avidity cells. This has implications for both the design of vaccine vectors and the route utilized for vaccine administration for the elicitation of high avidity CTL responses. The advantages and future potential use of rSV5 vaccine vectors are discussed.