Abstract
Streptococcal preparation OK-432 is a bacterial immunopotentiator extensively used in Japan for adjuvant cancer therapy. Using C3H/He mice bearing MH-134 tumour cells, cytokine inductions of tumour necrosis factor-α, interleukin 1β interleukin 6 and interferon-γ were determined in spleen and tumour tissues by reverse transcriptase-polymerase chain reaction analysis. No significant induction of cytokine mRNA was observed after subcutaneous administration of OK-432 (OK-432, sc) or after intratumoural injection of IFN-γ (IFN-γ, it), compared with controls, either in spleen or tumour tissues. In contrast, subcutaneous administration of OK-432 followed by intratumoural OK-432 injection (OK-432, sc+it) was found to induce some cytokine mRNAs significantly. The mRNA levels of tumour necrosis factor α and interferon-γ in spleen tissue and those of interleukin 1β and interferon-γ in tumour tissues were significantly elevated in mice with OK-432, sc+it treatment compared with controls. These results suggest that treatment with OK-432, sc+it effectively induced splenic antitumour immunity as well as local immunity against tumour cells.
