DEVELOPMENT OF EPSTEIN-BARR VIRUS-SPECIFIC MEMORY T-CELL RECEPTOR CLONOTYPES IN ACUTE INFECTIOUS-MONONUCLEOSIS

The importance of cytotoxic T lymphocytes (CTLs) in the immunosurveill ance of Epstein-Barr virus (EBV)-infected B cells is firmly establishe d, and the viral antigens of CTL recognition in latent infection are w ell defined. The epitopes targeted by CTLs during primary infection ha ve not been identified, however, and there is only limited information about T cell receptor (TCR) selection. In the present report, we have monitored the development of memory TCR-beta clonotypes selected in r esponse to natural EBV infection in a longitudinal study of an HLA-B8( +) individual with acute infectious mononucleosis (IM). By stimulating peripheral blood lymphocytes with HLA-B8(+) EBV-transformed B lymphob lastoid cells, the primary virus-specific CTL response was shown to in clude specificities for two HLA-B8-restricted antigenic determinants, FLRGRAYGL, and QAKWRLQTL, which are encoded within the latent EBV nucl ear antigen EBNA-3. TCR-beta sequence analysis of CTL clones specific for each epitope showed polyclonal TCR-beta repertoire selection, with structural restrictions on recognition that indicated antigen-driven selection. Furthermore, longitudinal repertoire analysis revealed long -term preservation of a multiclonal effector response throughout conva lescence, with the reemergence of distinct memory T cell clonotypes sh aring similar structural restrictions. Tracking the procession of spec ific TCR-beta clonotypes and antigen-specific TCR-V beta family gene e xpression in the peripheral repertoire ex vivo using semiquantitative PCR strongly suggested that selective TCR-beta expansions were present at the clonotype level, but not at the TCR-V beta family level. Overa ll, in this first analysis of antigen-specific TCR development in IM, a picture of polyclonal TCR stimulation is apparent. This diversity ma y be especially important in the establishment of an effective CTL con trol during acute EBV infection and in recovery from disease.