IDENTIFICATION AND MOLECULAR CHARACTERIZATION OF 2 DIAGNOSTICALLY RELEVANT MARKER PROTEINS OF THE EPSTEIN-BARR-VIRUS CAPSID ANTIGEN COMPLEX

The molecular specificity of the IgG response against Epstein-Barr vir us (EBV) was studied in 345 randomly collected sera of normal healthy individuals. The sera were tested on immunoblots containing antigens o f the cell line HH514.c16 (a superinducible derivate of P3HR1), nonind uced or induced for the expression of early antigens (EA) or viral cap sid antigens (VCA), and from the EBV-negative cell line Ramos-Nut. Thi s study reveals a remarkable similar antigen recognition pattern of Ig G class antibodies in sera of healthy EBV carriers. The protein bands recognized predominantly have molecular weights of 18 kD, 36/38 kD, 40 kD, 72 kD, and 160 kD. The 72 kD and 36/38 kD bands were identified a s EBNA1 and ''Zebra,'' respectively, using reading frame-specific anti sera. The bands at 160 kD (major capsid protein), 40 kD, and 18 kD wer e identified as VCA-class proteins. Of all EBV-seropositive sera teste d, 98% reacted with either p18 or p40 or both. The synthesis of the an tigens p18 and p40 was inhibited by phosphonoacetic acid, indicating t hat these were true late proteins. The detection of p18 and p40 in pur ified virion and capsid preparations confirms that these proteins are structural components of viral capsid antigen complex.