The serum protein levels of newborn African infants.

It has been shown (Holmes, Stanier, Semambo and Jones, 1951) that the concentration of y-globulin in the serum of apparently healthy adult Africans is considerably higher than that of Europeans. It is also known (Longsworth, Curtis and Pembroke, 1945) that, in white infants, the level of y-globulin of the serum of umbilical cord blood is higher than that of the maternal blood taken on the day of delivery. The question arises whether the newborn African infant has as high a level of y-globulin as the adult African, or whether it is born with the same level of y-globulin as the white infant, and subsequently increases its y-globulin to the African adult level. This question was particularly interesting because unpublished observations by one of us (M.D.T.) suggested that apparently healthy African infants aged 2-4 years, without active infections and without evidence of malnutrition, had y-globulin levels nearly as high as those of adult Africans. Certain mammals are known to absorb large amounts of y-globulin from the colostrum and early milk. Thus, Hansen and Phillips (1947) showed that the serum of the calf at birth contained no protein with the mobility of y-globulin, but such a protein rapidly appeared if the animal was fed colostrum within 24 hours of birth. Similarly, Mason, Dalling and Gordon (1930) measured antibodies of ewe's serum and colostrum and lamb's serum, and showed that the lamb obtained its antibody only by suckling. As it is now known that antibodies are modified y-globulins (Tiselius and Kabat, 1939), this must have meant an increase in the lamb's y-globulin level. It is highly improbable that such a process occurs in man, but it would be useful to exclude this possibility, which might be invoked to account for the high y-globulin levels found even in young African children. Another difference in the serum protein pattern of apparently normal adult Africans from the