Location and characterization of the antigenic portion of the FMDV immunizing protein.

Purified foot-and-mouth disease virus (FMDV) to type O1K was treated with several endopeptidases of differing specificity. The immunizing protein VPThr was cleaved into two detectable fragments by all enzymes except for glutamic acid-specific Staphylococcus aureus V8 protease. The longest fragments were generated by mouse submaxillary gland protease and the shortest by trypsin treatment of the intact virion.

Cloning of cDNA of major antigen of foot and mouth disease virus and expression in E. coli.

Double-stranded DNA copies of the single-stranded genomic RNA of foot and mouth disease virus have been cloned into the Escherichia coli plasmid pBR322. A restriction map of the viral genome was established and aligned with the biochemical map of foot and mouth disease virus. The coding sequence for structural protein VP1, the major antigen of the virus, was identified and inserted into a plasmid vector where the expression of this sequence is under control of the phage lambda PL promoter.

Suppressor cells for in vivo cytotoxic responses--regulation of the in vivo activation of cytotoxic T-lymphocytes by suppressive cells.

A significant in vivo activation of cytotoxic T-lymphocytes (CTL) against trinitrophenyl (TNP)-modified autologous cells and of a DNA-synthesis response in the peripheral lymphnodes is observed in cyclophosphamide (CyP) treated mice after skinpainting with trinitrochlorbenzene (TNCB) or after injection of TNP-coupled spleen cells (TNP-Spl) into the footpads. The activation of these responses can be suppressed by the transfer of spleen cells or lymphnode cells from skinpainted normal mice, but not from skinpainted mice that had been pretreated with CyP. Suppressive activity is also induced by injections of TNP-Spl i.