Serum protein concentrations in pregnancy. II. Concentrations in cord serum and amniotic fluid

Complement in human reproduction: activation and control

The behaviour of the complement system during human reproduction is now the focus of much scientific attention. The presence of antisperm antibodies in the reproductive tracts of some infertile individuals, and of complement in cervical and ovarian follicular fluid, suggests that complement-mediated damage of spermatozoa is involved in some cases of infertility. Further, deposition of maternal IgG and of complement in the extrafetal tissues indicates that complement activation occurs within the fetoplacental unit. Recently, three complement-regulatory proteins--decay-accelerating factor, membrane cofactor protein and CD59--have been detected on spermatozoa and in the extrafetal tissues. It is likely that these inhibitors are essential for normal reproductive function. This article reviews current understanding of the interaction of the complement system with cells and tissues involved in reproduction, with emphasis on the nature and function of the controlling proteins.

Human amnion as a model for IgG transport

The ability of fresh human amnion to bind and internalize horseradish peroxidase-labeled IgG (IgG-HRP) was examined in an in vitro Ussing chamber system. The amnion demonstrated unique cell membrane receptors for the Fc portion of IgG molecules (Fc gamma R). The Fc gamma R exhibit exquisite specificity and affinity for IgG monomers as demonstrated by staining with labeled IgG. Labeled IgA, IgM, F(ab')2 fragments of IgG, aggregated IgG, and antigen-antibody complexes all failed to bind to the amnionic epithelial cells. Binding was only minimally affected by changes in ionic strength or pH when viewed at the light microscopic level. The Fc gamma R are located on both the apical and basal cell membranes. The binding of IgG-HRP to the amnion cell membrane was detectable within 1 min, and internalization of the ligand occurred within 5 min. No binding of IgG-HRP was observed following treatment of the membrane with 0.25% trypsin for 30 min at room temperature. Incubation of the amnion at 4 degrees C or in the presence of colchicine or cytochalasin D prevented internalization of the IgG-HRP. These experiments demonstrate Fc gamma R on human amnionic epithelial cells that both bind and internalize IgG, thus allowing the amnion to be used as a model system for studying IgG transport.

Quantitation of immunoglobulin A in the human chorioamniotic membrane

Thirty-eight chorioamniotic membranes were obtained from normal patients divided into three groups according to time of rupture. A protein extract was obtained by destruction and differential centrifugation and immunoglobulin A was measured by the method of Mancini. The authors demonstrated that it is possible to quantitate immunoglobulin A. No statistically significant differences were observed between groups.

Expression of Fc gamma binding sites on human extraplacental membranes

Binding sites for the Fc portion of immunoglobulin G (IgG) molecules (Fc gamma BS) were identified on amnionic epithelial cells and chorionic trophoblast cells in human extraplacental membranes using direct immunofluorescence with labeled human IgG. The binding sites are similar to FC gamma BS on placental trophoblast in their specificity and high degree of relative binding affinity for IgG monomers. Neither immunoglobulin A (IgA) nor IgM bound to a significant degree to the membranes. Binding was completely inhibited with unlabeled IgG but not F(ab')2 fragments of IgG. Studies on isolated amnion cells demonstrated that the binding sites are expressed on the cell membrane. At the level of sensitivity of the immunohistologic methods used, aggregated IgG or antigen-antibody complexes failed to bind amnionic epithelial cells or chorionic trophoblasts. This is in contrast to Fc gamma BS on macrophages which, being present in the same tissue, failed to exhibit significant binding of deaggregated IgG but bound complexes avidly.

Intrauterine infection by non-capsulated Haemophilus influenzae in a case of maternal immunodeficiency

A 29-year-old woman with an upper respiratory tract infection due to Haemophilus influenzae, gave birth to a premature infant who died after 3 h. The mother's strain was non-capsulated, as were the strains cultured from the infant's blood, lungs, nose, and throat. Antigen analyses revealed, however, that the strains were not identical. The infant probably acquired the infection via the transplacental route. The uncommon infection was in this case attributed to a transient dysgammaglobulinemia in the mother.

IgG levels in maternal and umbilical cord serum after vaginal delivery and after elective Caesarean section

Concentrations of IgG is maternal serum and in umbilical cord blood were determined in two groups of patients: one group had spontaneous vaginal deliveries and the other elective Caesarean sections. Mean umbilical cord serum IgG after vaginal delivery was significantly higher than the mean value after elective Caesarean section. The difference between the maternal serum IgG livel and the umbilical cord serum IgG level increased as did the duration of labour.

Serum immunoglobulins in multiple pregnancy

The concentrations of immunoglobulins (Ig) G.A.M. and E were determined in paired umbilical cord and maternal sera in 50 twin pregnancies. Mean IgG levels were higher in cord than maternal sera and in most cases the cord IgG level related more closely to that of the other twin than to either maternal level or birthweight, and was in the range for singletons of the same gestational age. The three cases of fetofetal transfusion syndrome were exceptional in the large difference between IgG concentrations in recipient and donor twins. The discrepancy was much greater than that found between the levels of proteins produced by the fetus, suggesting a disturbance in maternofetal placental transfer. IgM was detected in all cord sera, with one exception, and the level was not related to order of birth. IgA was detected in 16% of cord sera, 13% in sera from first borns. IgE was detected in only 8% of cord sera and there was no evidence of placental transfer.