RECOMBINANT FUSION PEPTIDES CONTAINING SINGLE OR MULTIPLE REPEATS OF A UBIQUITOUS T-HELPER EPITOPE ARE HIGHLY IMMUNOGENIC

Two recombinant mouse mammary tumor virus (MMTV) subunit vaccines have been constructed, in which linear sequences of the envelope gp 52 gly coprotein (EP3) or the superantigen (SAg) have been fused to single or multiple repeats of a T-cell epitope (P30) from tetanus toxin. Histid ine tags or glutathione-S-transferase (GST) sequences have been includ ed in the recombinant peptides in order to facilitate their purificati on by affinity chromatography. The EP3 or SAg recombinant polypeptides with four, one, or no T-cell epitopes were expressed in Escherichia c oli, purified and injected intramuscularly, with non-ionic block copol ymers as an adjuvant, into BALB/c mice. Following one or two boosts, t he B- and T-cell responses against the recombinant proteins were analy sed. The addition of T-cell epitopes considerably increased the immuno genicity of the subunit vaccines. The anti-EP3 response was maximum wi th four T-cell epitopes, while a single T epitope was optimal for the anti-SAg response. Copyright (C) 1996 Elsevier Science Ltd.