MILK PROTEIN ntigen binding s● c Figure 4.28 Model of the basic 7S immunoglobulin(Ig) molecule showing two heavy and two region: C, constant region: L, lig CHO, carbohydrate groups; Fab refers to the(top)antigen-specific portion of the Ig Fc refers to the cell-binding effector portion of the lg molecule(from Larson, 1992). kling and persist for about 3 months, although the calf is able synthesize its own Ig within about 2 weeks. It is, therefore, essential that a calf should receive colostrum within a few hours of birth. otherwise it will probably die. The human baby obtains Ig in utero and hence, unlike the calf, is not as dependent on Ig from milk (in fact its intestine is impermeable to g). However, the Ig in human colostrum is beneficial to the baby, e.g. it reduces the risk of intestinal infections As regards the type and function of Ig in colostrum, mammals fall into three groups(Figure 4.30)-those like the cow (i.e. other ruminants), those like the human, and some, e.g. the horse, with features of the other two groups(Larson, 1992)MILK PROTEINS 197 Figure 4.28 Model of the basic 7s immunoglobulin (Ig) molecule showing two heavy and two light chains joined by disulphide bonds: V, variable region; C, constant region; L, light chain; H, heavy chain; 1, 2 and 3 subscripts refer to the three constant regions of the heavy chains; CHO, carbohydrate groups; Fab refers to the (top) antigen-specific portion of the Ig molecule; Fc refers to the cell-binding effector portion of the Ig molecule (from Larson, 1992). suckling and persist for about 3 months, although the calf is able to synthesize its own Ig within about 2 weeks. It is, therefore, essential that a calf should receive colostrum within a few hours of birth, otherwise it will probably die. The human baby obtains Ig in utero and hence, unlike the calf, is not as dependent on Ig from milk (in fact its intestine is impermeable to Ig). However, the Ig in human colostrum is beneficial to the baby, e.g. it reduces the risk of intestinal infections. As regards the type and function of Ig in colostrum, mammals fall into three groups (Figure 4.30) - those like the cow (i.e. other ruminants), those like the human, and some, e.g. the horse, with features of the other two groups (Larson, 1992)