Antibodies against IL-15 or IL-12 abrogated the effect of PSK and Trx80, respectively. (A) EBV-infected CBMCs were cultured with PSK or Trx80 in the presence of antibodies against IL-15 (10 μg/mL) or IL-12 (10 μg/mL). SAP expression was assayed on the sixth day. Panels Ai-iii are results from different experiments. Cultures containing PSK (i) without and with antibodies against IL-15, and (ii) without and with antibodies against IL-12; and (iii) cultures containing Trx80 without and with antibodies against IL-15 or IL-12. The results show 1 of 3 experiments. (B) ³H-thymidine incorporation of the cells in 12-day-old cultures containing neutralizing antibodies of IL-15 or IL-12. (i) Cultures without (□), or with PSK (▦), PSK and anti–IL-15 Ab (▨), or PSK and anti–IL-12Ab (▪); (ii) cultures without (□), or with Trx80 (▦), Trx80 and anti–IL-15Ab (▨), or Trx80 and anti–IL-12 Ab (▪). The results represent the mean ± SEM of 3 independent experiments. *P < .05 compared with untreated cultures. (C) EBV-infected monocyte-depleted populations were cultured. The monocytes without pretreatment or with PSK or Trx80 for 20 hours were reintroduced as indicated. To parallel IL-15 or IL-12, neutralizing antibodies were added. SAP expression was assayed in cells of 3-day-old cultures.