The genomic DNA sequence of herpes simplex virus type 2 (HSV-2) strain HG52 was determined as 154,746 bp with a G+C content of 70.4%. A total of 74 genes encoding distinct proteins was identified; three of these were each present in two copies, within major repeat elements of the genome. The HSV-2 gene set corresponds closely with that of HSV-1, and the HSV-2 sequence prompted several local revisions to the published HSV-1 sequence (D. J. McGeoch, M. A. Dalrymple, A. J. Davison, A. Dolan, M. C. Frame, D. McNab, L. J. Perry, J. E. Scott, and P. Taylor, J. Gen. Virol. 69:1531–1574, 1988). No compelling evidence for the existence of any additional protein-coding genes in HSV-2 was identified.

The herpes simplex virus (HSV) immediate early protein ICP47 inhibits the transporter associated with antigen processing (TAP)-dependent peptide translocation. As a consequence, empty major histocompatibility complex (MHC) class I molecules are retained in the endoplasmic reticulum and recognition of HSV-infected cells by cytotoxic T lymphocytes is abolished. We chemically synthesized full-length ICP47 (sICP47) and show that sICP47 inhibits TAP-dependent peptide translocation in human cells. Its biological activity is indistinguishable from that of recombinant ICP47 (rICP47). By using synthetic peptides, we mapped the core sequence of ICP47 minimally required for TAP inhibition to residues 2–35. This segment is located within the region of the molecule conserved between ICP47 from HSV-1 and HSV-2. Through alanine scanning substitution we identified three segments within this region that are critical for the ability to inhibit TAP function. The interaction of ICP47 with TAP is unlikely to mimic precisely that of the transported peptides, as deduced from differential labeling of the TAP1 and TAP2 subunits using sICP47 fragments with chemical cross-linkers.

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An extensive analysis of the class II (I-Ad)-restricted T cell repertoire for influenza hemagglutinin (HA) of the H3 subtype, elicited by natural infection, has shown that majority of CD4+ memory T cell clones focus on antibody-binding regions of HA, sites B and E, and are sensitive to the residue substitutions that have occurred in these regions during antigenic drift. The proliferative responses of CD4+ clones to synthetic peptides have identified T cell epitopes within site B, HA1 177-199 and HA1 182-199, and site E. HA1 56-76. The recognition specificity of T cell clones for antibody-selected mutant viruses, with single amino acid substitutions within these recognition sites identified residues 63, 189, 193 and 198 as being important for T cell recognition and thus established that BALB/c, CD4+ T cell clones were sensitive to the same substitutions known to abrogate BALB/c antibody recognition of the native HA. Our findings indicate extensive commonality of the B cell and T cell repertoires for HA, which may be relevant to an understanding of the immune pressures for antigenic drift, and, moreover, suggest that the antigen-specific B memory cell may be instrumental in selection of the peripheral T cell repertoire.