LATENT EPSTEIN-BARR-VIRUS INFECTION IN COTTONTOP TAMARINS - A POSSIBLE MODEL FOR EPSTEIN-BARR-VIRUS INFECTION IN HUMANS

The association of Epstein-Barr virus (EBV) with a growing number of h uman malignancies underlines the importance of efforts aimed at preven ting the infection with this potential carcinogen and of establishing animal models for human virus-associated tumors. Cottontop tamarins ha ve been used in EBV vaccine studies because virus infection regularly induces lymphomas similar to those seen in human immunocompromised ind ividuals. In recent years, several vaccines based on the gp340/220 env elope protein of EBV have been developed and shown to prevent the deve lopment of EBV-associated lymphomas in this model Using in situ hybrid ization and immunoh istology, we have characterized EBV infection in o ne nonimmunized and three immunized ani mals after challenge with a st andard tumorigenic dose of EBV. In the nonimmunized animal, EBV-infect ed lymphoid cells were detected in numer ous tissues showing no obviou s lymphoma infiltration. Surprisingly, variable numbers of virus-carry ing cells were also found in all three immunized animals that were pro tected against the development of virus-associated lymphoma This obser vation demonstrates that vaccination does not induce sterilizing immun ity against EBV infection in this model. Double labeling suggested a B cell phenotype of the majority of these cells. EBV infection of nonly mphoid cells was not observed Analysis of viral gene expression in imm unized animals suggested a restricted form of virus latency different from that seen in EBV-driven lymphomas in nonimmunized cottontop tamar ins. These results mise the possibility that immunized cottontop tamar ins protected against the development of EBV-driven lymphoma or animal s exposed to a sublymphomagenic dose of virus may serve as a model for EBV infection in humans.