TABLE 1.
Summary of EBV deletion mutant cell lines tested for superantigen activitya
| EBV cell linesb | Superantigen activityc | Sequence deletions | Genes affected |
|---|---|---|---|
| IM-1 LCL | + | ? Unknown | Wild type (isolated from an infectious mononucleosis patient) (a gift from M. A. Epstein) |
| B95-8 marmoset | − | 13.6 kb at 154,012 | Prototype lab strain (first virus entirely sequenced; has a 13.6-kb deletion relative to most other strains) |
| B95-8 LCL/BL | + | 13.6 kb at 154,012 | Prototype lab strain |
| Raji BL | + | 98,805-102,116, 163,978-166,635 | EBNA-3C (latent); BZLF-2, BALF-1-2, BARF-1 (lytic) |
| P3HR1 BL | − | 45,644-52,450 | EBNA-2, EBNA-LP (truncated) (latent) |
| Mg68 LCL | + | 68,928-87,030, 117,609-163,415 | BPLF-1, BOLF-1, BORF-1-2, BaRF-1, BMRF-1-2, BMLF-1, BSLF-1-2, BSRF-1, BBLF-1-2, BBRF-3, BGLF-1-5, BGRF-1, BDLF-1-4, BDRF-1, BcLF-1, BcRF-1, BTRF-1, BXLF-1-2, BXRF-1, BVRF-1-2, BdRF-1, BILF-1-2, BALF-2-5 (lytic) |
| 253.30 LCL | + | 19,360-43,934, 56,082-79,657, 113,283-163,476 | EBNA-3A, EBNA-LP (truncated) (latent); BFLF-1-2, BFRF-1-3, BPLF-1, BOLF-1, BORF-1-2, BaRF-1, BBLF-1-4, BBRF-1-3, BGLF-1-5, BGRF-1, BDLF-1-4, BDRF-1, BcLF-1, BcRF-1, BTRF-1, BXLF-1-2, BXRF-1, BVRF-1-2, BdRF-1, BILF-1-2, BALF-2-5 (lytic) |
Results obtained with the different cell lines tested for functional activation of the TCRBV13 T-cell hybridoma are shown (Fig. 1A). The results indicate that a deletion of a combined total of 115 kb of the 172-kb EBV genome comprising the majority of lytic genes does not affect superantigen activity, indicating that these genes are not responsible for transactivation of the superantigen. On the other hand, a deletion of EBNA-2, the key latent gene transactivator, abolished superantigen activity. In addition, the B95-8 marmoset cell line was negative (−) for superantigen activity; marmosets are New World primates which do not have the HERV-K18 provirus.
BL, Burkitt's lymphoma.
A + indicates a cell line that was positive for superantigen activity; a − indicates a cell line that was negative for superantigen activity.