Evidence for and Characterization of Suppressor Cells in BALB/c Mice Bearing ADJ-PC5 Plasmacytomas

• Published in: JNCI : Journal of the National Cancer Institute 1979-01, Vol.62 (5), p.1235-1241
• Main Authors: Padarathslngh, M. L., Dean, J. H., Jerrels, T. R., McCoy, J. L., Lewis, D. D., Northing, J. W.
• Format: Article
• Language: English
• ISSN: 0027-8874; 1460-2105
• DOI: 10.1093/jnci/62.5.1235

Suppressor cells were demonstrated in the spleens of BALB/c mice bearing progressively growing mineral oil-Induced plasmacytomas ADJ-PC5. Lymphoprollferative responses of spleen cells to general T- and B-cell mitogens became depressed with progressive tumor growth. Correlation of splenic macrophage concentrations with tumor size was demonstrated in ADJ-PC5 tumor-bearing mice by esterase staining. Thus spleen cells from mice bearing large subcutaneous ADJ-PC5 tumors (25–30 mm In diameter) contained more esterase-positive staining cells than did those from mice bearing small (8–12 mm In diameter) to medium-size (15–20 mm In diameter) ADJ-PC5 tumors and also correlated with the degree of depressed lymphoproliferative responses observed. In addition, the proportion of spleen cells bearing Fc receptors increased with progressive tumor growth In ADJ-PC5 tumor-bearing mice. Treatment of spleen cells from tumor-bearing mice by passagethrough Sephadex G-10 columns or by Incubation on plastic surfaces for 2 hours at 37° C to remove adherent cells also restored mitogeninduced lymphoproll-ferative responses to normal levels. Admixing of plastic-adherent cells or G-10 column-adherent cells from tumor-bearing mice with cultures of normal spleen cells likewise reduced the proliferative responses of these cells to mitogen. These data suggest that esterase-positive staining adherent cells were involved In the suppressed proliferative responses to T- and B-cell mitogens observed in plasmacytoma-bearing mice.