Differentiation of kidneys antigens in the human foetus.

The appearance of new antigens in the embryo during differentiation has been investigated by a number of authors. Among the proteins studied were myosin (Holtzer, 1961; Ebert, 1962), Jens crystallin (Ten Cate & Van Doorenmaalen, 1950), chick embryo haemoglobin (Wilt, 1962), and keratin during feather formation in chick embryo (Ben-Or & Bell, 1965). The development of liver proteins in the chick embryo was studied by D'Amelio, Mutolo & Piazza (1963). Okada & Sato (1963) and Okada (1965) studied the appearance of a 'kidneyspecific antigen in the developing mesonephros. Lahti & Saxen (1966) demonstrated the appearance of mouse kidney-specific tubule antigens during development both in vivo and in vitro. 'Kidney-specific' antigens are found in the metanephric proximal secreting tubules of various mammals (Hill & Cruickshank, 1953; Weiler, 1956; Groupe & Kaplan, 1967; Nairn, Ghose & Maxwell, 1967), including man (Nairn, Ghose, Fothergill & McEntegart, 1962), and in the mesonephric tubules of birds and fish (Nairn et al. 1967). In addition cross-reacting membrane antigens (Dumonde, 1966; Weinberger & Boss, 1966) have been demonstrated in the basement membranes and reticular fibres of many organs, including kidney (Cruickshank & Hill, 1953). These are implicated in the glomerulonephritis induced by antikidney serum (Masugi, 1933). The appearance of kidney antigens in the human foetus has not previously been investigated. The purpose of the present investigation was to relate the appearance of new antigens to the morphological differentiation of the metanephrogenic mesenchyme of the human kidney using immunodiffusion and immunofluorescence techniques. MATERIAL AND METHODS