ANTIGENIC STRUCTURE OF NEPHROBLASTOMAS

The antigenic structure of 13 nephroblastomas was compared to that of differentiating nephrogenic mesenchyme of the foetal kidney by immunodiffusion and the fluorescent antibody technique using absorbed antisera against tumour, foetal kidney and postnatal kidney. No tumour‐specific antigens were demonstrated. Immunodiffusion experiments showed that undifferentiated tumour tissue contains common antigens present in a variety of normal tissues. Undifferentiated tumour contained, however, additional antigens associated with differentiated structures („differentiative antigens”). The metanephrogenic mesenchyme of foetal kidneys resembled undifferentiated tumour in lacking antigens associated with differentiated structures. These two tissues differed in that foetal antigens (not found in postnatal kidneys) were present in the metanephrogenic mesenchyme but absent from tumours. „Differentiative antigens” appear during the morphological differentiation of the metanephrogenic mesenchyme which will form the different parts of the nephron. An analogous situation was seen in nephroblastomas in regions where morphological differentiation had occurred. In the tumours „differentiative antigens” were observed in tubular structures, pseudoglomerules and muscle cells. Brush border antigen (s) normally present in the proximal secreting tubules were demonstrated in some tubular structures of the tumours. Glomerular epithelial antigen (s) were seen in pseudoglomeruli. Differentiation in tumours, however, does not proceed as far as in the kidney. This is shown by the absence of „kidney‐specific” brush border antigens. The results of the present investigation favour the hypothesis that nephroblastomas arise from cells that normally differentiate into kidney structures. Copyright © 1969 Wiley‐Liss, Inc., A Wiley Company