Enhancing activity of synthetic polynucleotides on the induction of anti-hapten antibody response.

The enhancing activity of synthetic polynucleotides on the secondary anti-hapten antibody response was studied by using an adoptive transfer system of hapten-primed cells in mice. Hapten-primed B cells were effectively stimulated to produce anti-hapten antibody on challenge with hapten—heterologous carrier in the presence of an appropriate dose of polynucleotides. The enhancing activity of polynucleotides was most effective when administered at the same time as the second antigen and the activity was consistently observed either when these agents were administered or when hapten-primed cells were treated with the second antigen and these agents. Polynucleotides enhanced mainly the development of 7S plaque-forming cells (PFC) rather than 19S PFC. The enhancing effect of polynucleotides was not observed in hapten-primed cells from ATS-treated mice, but it was restored by the addition of non-primed lymph node cells or thymus-derived spleen cells from lethally irradiated mice reconstituted with thymocytes. These results clearly indicate that polynucleotides enhance the anti-hapten antibody response of hapten-primed B cells to the hapten—heterologous carrier through activation of non-primed T cells specific for the heterologous carrier and do not directly affect hapten-primed B cells. The mechanism of the stimulation of T cells by polynucleotides is discussed.