Demonstration in vitro of cell mediated immunity to Epstein-Barr virus in cotton-top tamarins

In the course of developing an effective Epstein-Barr (EB) virus vaccine, the immune responses in cotton-top tamarins to a tumourigenic dose of EB virus were studied. Cell mediated responses were measured using a tissue culture 'growth inhibition' assay where peripheral blood lymphocytes were tested for their ability to inhibit the outgrowth of autologous EB virus transformed lymphoblastoid cells. This system has previously been recognized as a very sensitive assay for detecting cell-mediated responses to EB virus in man. Using this assay no cell-mediated immunity was detected up to the time of death in two tamarins following injection with a tumourigenic dose of EB virus. However, two other animals which had recovered from tumours induced by a first dose of EB virus 18 months previously when subsequently re-stimulated with a second tumourigenic dose did exhibit cell-mediated responses. These latter animals remained healthy following the re-challenge and did not show evidence of EB virus-induced disease.