Published in Cancer Detection and Prevention 2001; 25(5):470-478.

Anti-Lymphoma Immunity: Relative Efficacy of Peptide and Recombinant DNA Vaccine

So-Yon Lim, BS, Sreenivas Laxmanan, MS, Gary Stuart; BS, and Swapan K. Ghosh, PhD

Department of Life Sciences, Indiana State University, Terre Haute, Indiana.

Address all correspondence and reprint request to Swapan K. Ghosh. PhD. Department of Life Sciences. Indiana State University, Terre Haute, IN 47809, USA

ABSTRACT The efficacy of vaccines consisting of (1) Ig idiopeptides of a murine B-lymphoblastoma, 2C3, and (2) a corresponding scFV-expressing DNA construct was determined on the basis of their ability to induce anti-tumor immune response and protection against tumor growth. Peptide-KLH complexes and a plasmid expressing single-chain variable fragment (scFv) corresponding to 2C3 Ig VH and VL chains were used separately as vaccines. Immunized BALB/c mice were bled and then challenged with live 2C3 tumor. Survival of various challenged groups was also determined. The results indicate that CDR3-H (VH3) peptides, and the plasmid DNA when given with GM-CSF, only moderately retarded tumor growth, whereas killed 2C3 tumor vaccine induced lasting protection, as shown earlier. Both peptides and scFv-plasmid induced circulating anti-Id antibodies, but no specific cytotoxic T-cell (CTL) activity was detected. However, in spite of their inability to induce CTL activity, both idiopeptides and the scFv-expressing plasmid DNA displayed epitopes recognized by an Id-specific long-term splenic CTL line (A 102) obtained from mice vaccinated with killed 2C3 tumor.

KEY WORDS: scFv plasmid DNA, cytotoxic T-cells, vaccine, B-lymphoblastoma.