Neuraminidase-treated cells

Most of the Neu5Ac residues are split off, while part of the neuraminidase molecules (black asterisks) is still bound to the cell surface. Further proliferation of the malignant cell is, if necessary, suppressed by cytostatic agents or radiation and finally the asialo -cells are reinjected into the animal (or human being). 

Besides, another detail of the experimental system renders it difficult or even impossible to compare and evaluate the different findings and observations properly, namely the number of desialylated tumor cells inoculated. Data summarized in Table 3 demonstrate unequivocally that only a narrow range of VCN-treated cells is suitable for therapy, while improper doses are either ineffective or increase the risk of metastases (Wilson et al. 1974, Sedlacek and Seiler 1978). Similarly, apart from other factors, the efficacy of intratumor injection of VCN depends on the amount applied so that the therapeutic effect can be positive, negative or is negligible (Sparks and Breeding 1974, Binder et al. 1975, Alley and Snodgrass 1977). 

3 X 104 cells complete protection against pulmonary metastases 1 X 104 cells 5 X 104 cells 

2 X 107 cells tumor regression, no metastases 2 X 106 cells transient effect 1 X 108 cells enhanced tumor growth 

In summary, tumor immunotherapy with neuraminidase-treated cells could improve medical treatment of cancer, if the following presuppositions are fulfilled (a) Low tumor burden or the tumor load has to be reduced by surgery, chemotherapy or irradiation, (b) a still immune-competent organism and (c) optimized doses of tumor cells and VCN, because—as Wilson (1974) has put it the greatest danger for clinical application of immunotherapy is the risk of stimulating tumor growth in a patient with only minimal residual disease . 

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Gitman, A.G., Kahane, L., and Loyter, A. (1985a) Use of virus-attached antibndies or insulin molecules to mediate fusion between Sendai virus envelopes and neuraminidase-treated cells. Biochemistry 24, 2762-2768. 

Figure 6. Variation of d with the molecular weight of dextrans (33), The data on Dx 20 (O) were obtained for neuraminidase-treated BBCs, and the results on larger dextrans were the same for normal and neuraminidase-treated cells. Vertical bars denote SEM.

Figure 11. Effects of dextrans on aggregation of normal RBCs (O) and neuraminidase-treatea RBCs (A) (24). A, B, C show results in Dextrans 20, 40, and 80, respectively. Note that neuraminidase-treated cells exhibit stronger aggregation than normal cells and do not show the characteristic disaggregation phase. The vertical bars represent SEM. I =...

The viral proteins HA and NA are essential for infection the HA of influenza viruses is responsible to bind the virus to cell-surface receptors during the infection sialic acids are the only known components of the receptors necessary to this interaction the virus does not bind or infect neuraminidase-treated cells [7,8], and binding is restored by re-sialation [9] or addition of sialated glycolipid [10,11],... 

Human epithelial-related antigen MOC-31 40-kD transmembrane glycoprotein present on most normal and malignant epithelial cells Neuraminidase treated cells from small cell carcinoma cell line Dako 1 50 HIER... 

Fig. 1. Basic procedure of immunotherapy with neuraminidase-treated cells.

Aggregation of Neuraminidase-Treated Red Cells by Dextrans. Following the depletion of RBC surface charge by neuraminidase treatment, the cells can be aggregated by Dx 20 with concentrations above... 

Cells were washed, and half were treated with neuraminidase (see Methods). Other half were treated identically in the absence of enzyme. Lipid extracts later made from neuraminidase-treated and control samples in the usual way, and extracts from 6 X Iff1 cells were compared by TLC. Plates stained with a-naphthol/sulfuric acid blue areas are bracketed. ( —) Controls (+) treated with neuraminidase. 

Use of a Synthetic Hapten in the Demonstration of the Thomsen Friedenreich (T) Antigen on Neuraminidase-Treated Human Red Blood Cells and Lymphocytes, J. Bray, R. U. Lemieux, and T. A. McPherson, J. Immunol., 126 (1981) 1966-1969. 

One approach to this problem would be to isolate the intact lectin-receptor molecules from the cell membranes and characterize them. Work in this direction has been initiated in our laboratory, and a method for the isolation of the peanut agglutinin receptor from membranes of neuraminidase-treated human erythrocytes on a column of peanut agglutinin-polyacryl-hydrazido-Sepharose has been developed (21). The amino acid composition, D-glucosamine ancHg-galac-tosamine content, and the electrophoretic mobility on polyacrylamide gel electrophoresis in sodium... 

Cell-binding studies on human erythrocytes, several human, urinary-bladder, carcinoma cell-lines, and an osteogenic-sarcoma cellline have been conducted.189 After treatment with neuraminidase, 80% of human lymphocytes will bind the H. pomatia lectin.5728 Neuraminidase-treated lymphocytes can also be fractionated on Helix pomatia hemagglutinin coupled to Sepharose beads.572b... 

Jancik J, Schauer R, Anders K H, et al. (1978). Sequestration of neuraminidase-treated erythrocytes. Cell Tiss. Res. 186 209-226. 

The relationships between bacterial neuraminidases and alterations in the immunological behaviour of neuraminidase-treated mammalian cells have been reviewed. ... 

The amoeba Acanthamoeba castellani has been shown to bind to equine erythrocytes by interaction with carbohydrates on the surface of the red cells. 4-Nitrophenyl tri-A-methyltyrosinate [ I]iodide has been used to label the outer surface of mature chicken erythrocytes. Two component glycoproteins, with subunits of molecular weight 5 x 10 and 1 x 10 , were identified. Neuraminidase-treated rat and rabbit erythrocytes were shown to be rapidly sequestered by the liver. Chemical studies of glycoproteins obtained from erythrocyte membranes from a number of sources have been reported. ... 

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