The Immunological Development of the Human Fetus

Abstract

The immunogenesis of the human fetus has been investigated by means of the formation of immunoglobulins in vitro, immunofluorescence, morphological studies, and analysis of the immunoglobulins in the serum. Twenty fetuses which were born alive but died soon after delivery, were studied; their ages ranged from 13 to 31 weeks. The results of the spleen cultures demonstrated the synthesis of IgG and IgM, which starts at about the twentieth week of gestation. In the serum, IgM could be detected at about the same period. The immunofluorescent staining of the spleen tissue showed that medium sized and large lymphoid cells as well as plasma cells, even with Russell bodies, were positive for either IgG or IgM. The peripheral blood was also found to contain a small number of medium sized IgG and IgM-positive cells. Both the spleen and the peripheral blood showed a considerable number of fluorescent small lymphocytes which exclusively contained IgM. The relatively high ratio of IgM to IgG production prenatally as compared to the postnatal situation, agrees with a predominantly primary antibody response in fetal life. In general, the fetal thymus did not synthesize immunoglobulins. No indications for the synthesis of IgA and IgD during fetal life were found.

Subclasses of IgA antibodies in serum and saliva samples of newborns and infants immunized against rotavirus

“…With respect to ontogeny of the IgA imune response, most early reports indicated that normal infants are born with less than 1 mg IgA/100 ml serum in their cord blood [13][14][15][16], and it was assumed that this IgA was of maternal origin. More recently, exploiting genetic techniques and 'experiments of nature', Mellander et al and Cedarqvist & Litwin were able to demonstrate that newborn infants are capable of synthesizing IgA [17,18].…”

The clinical significance of immunoglobulin A deficiency

“…3 While both IgM and IgG plasma cells can usually be found by early second trimester, IgA-producing cells have not been observed before the 32nd week of pregnancy. 4 Serum IgA is usually undetectable at birth, and adult serum concentrations are not attained until around the time of puberty. In adults, the majority of human plasma cells produce IgA.…”

Onset of Lymphocyte Function in the Developing Human Fetus

“…Tlie onset of immunologic function in the developing human fetus has only recently heen studied systematically [11,12,16,32], ami existing data mainly concern imnninoglobulin synthesis. What is known about the onset of cellular immune function (delayed hypersensitivily) has been largely extrapolated from animal studies [15,23,32].…”