Abstract
Effect of various immunomodulators in combination with chemotherapeutic agents were studied using EN-L2C cell line, an acute lymphoblastic leukemia (ALL) of inbred strain-2 guinea pig.
Results obtained were followings.
1) Typical leukemic cells appeared in peripheral blood 12 days after the inoculation of 105 cells and the hosts died within 5 days. When EN-L2C cells were inoculated together with BCG or N-CWS (Nocardia rubra cell wall skeletones), the host survived significantly longer than controls.
2) Single injection of cyclophosphamide (CY ; 35 mg/kg, BW) 14 days after animals receiving inoculation of EN-L2C cells induced complete remission. However, it lasted 2 weeks. A repeated administration of BCG, N-CWS or irradiated EN-L2C cells plus BCG during the remission period did not prolong the period of remission.
3) Immunization of animals during the remission period with Mitomycin C-treated ENL2C cells either conjugated or mixed with PPD did not delay the relapse.
4) During hematological relapse, meningeal involvement was proven histologically. The animals received irradiation over cerebrospinal area with 60Co on the following day after they were given CY survived several days longer than the non-irradiated controls. An additional injection of N-CWS to the irradiation plus CY regimen did only slightly but significantly prolong the survival days. Passive transfer of specifically immunized lymphocytes to the animals after they received CY did only slightly but significantly prolong the survival days with or without the addition of craniospinal irradiation.
