Restorative effects of
levamisole on general and
tumor-associated cell-mediated immune responses were investigated following
aniline mustard (AM)
chemotherapy of BALB/c mice bearing ADJ-PC5
plasmacytoma. Total eradication of
tumor following AM
chemotherapy resulted in severe depression of lymphoproliferative (LP) responses which recovered after a prolonged period of 4-6 weeks. During this time, spleen cells from these treated mice were shown to be generally depressed to T- and B-cell
mitogens.
Levamisole, an
anthelmintic drug capable of enhancing depressed immune responses in mice and in man, was employed following AM
chemotherapy in an attempt to restore immunocompetency. Administration of
levamisole following AM had a significant effect on the ability of mice to resist rechallenge with ADJ-PC5
tumor and in
tumor cell neutralization. The enhanced resistance to
tumor cell challenge appeared to be associated with a faster recovery of the general T-cell immunocompetence as demonstrated in the LP assays among the mice receiving
chemotherapy followed by adjuvant
therapy.
Levamisole, when administered alone to
tumor-bearing mice, did not appear to possess a direct antitumor effect. In addition,
levamisole did not potentiate cellular immunity to higher than normal levels in nonimmunodepressed mice. These results demonstrate the efficacy of
levamisole as a restorative agent of the general and
tumor-associated immunocompetency in the immunodepressed host.