Sv. Komissarenko et al., SELECTIVE KILLING OF TUMOR-CELLS IN-VITRO BY IMMUNOTOXIN COMPOSES OF ANTITUMOR ANTIBIOTIC STREPTONIGRIN AND POLYCLONAL SPECIFIC ANTIBODIES, International journal of immunopharmacology, 16(12), 1994, pp. 1053-1058
Streptonigrin N-hydroxysuccinimide ester (STN-COONSu) was obtained by
carbodiimide synthesis. Poly-L-lysine (PLL) was loaded with STN-COONSu
and conjugated to polyclonal rabbit immunoglobulin G (IgG) activated
with sodium periodate. Non-specific IgG and IgG against Ehrlich carcin
oma cells were used to construct non-specific and specific immunotoxin
s. Immunotoxins contained 100 molecules of streptonigrin per 1 molecul
e of IgG. The streptonigrin concentration that caused 50% of inhibitio
n of [H-3]thymidine incorporation in Ehrlich carcinoma cells (IC50) wa
s 0.8 mu g/ml for specific immunotoxin, 16 mu g/ml for non-specific im
munotoxin, and 20 mu g/ml for the poly-L-lysine-streptonigrin conjugat
e (PLL-STN) used as the initial water-soluble form of antibiotic. Our
results demonstrate that the toxicity for target cells of streptonigri
n conjugated to specific IgG was 25 times higher than that of the init
ial water soluble form of antibiotic. This specific immumotoxin was no
n-toxic for non-target cells.