Effect of Human Chorionic Somatomammotrophin and Human Chorionic Gonadotropin on Phyto-haemagglutinin-induced Lymphocyte Transformation

Inability of highly purified preparations of human chorionic gonado‐tropin to inhibit the phytohemagglutinin‐induced stimulation of lymphocytes

“…The crude hCG which was used in our laboratory shows a similar inhibitory activity to that reported by Adcock et al [lo]. The hCG preparation used by Contractor et al [9] has a higher inhibitory activity, but a lower biological activity.…”

Effects of a placental hormone, human chorionic somatomammotropin on normal and malignant cells.

“…Similar results were also noted by earlier workers (Contractor and Davis, 1973;Pernitcheva and Morin 1976;Cerni et al, 1977). That a sudden fall in serum HCS titre in pregnancy marks the onset of parturition (Genazzani et al, 1972) suggests that the hormone may have a role in nonrejection of the foetus during pregnancy.…”

Ultrastructural Demonstration of the Negative Surface Charge on Human Trophoblast

“…Though this hypothesis was once presented by Kirby (27, 29) as a decidual protection, it was soon discarded based ont only on the natural experiment of an extrauterine pregnancy but also on several animal experiments (40, 44). Second, the immunological capacity of the mother may be reduced by certain substances during pregnancy so as to prevent rejection of the fetus (1,5,14,21,22,23,26,37,39,41,49,51,52,55,58). Other evidence, such as the suppressed repsonse to PPD (50), increased isolation of cytomegalovirus (33) and decreased resistance to infectious diseases (18,20,34,46,54) during pregnancy has suggested that the immunological competency of the mother is impaired during pregnancy.…”

“…The uterus was once described as the immunologically privileged site for conceptus, protecting it from the host (29). There are also several reports in which maternal immunity is considered to be impaired by the pregnancy induced increase of some immunosuppressive substances in the blood, such as steroid hormones (5,22,37), human chorionic gonadotropin (HCG) (1,14,21,26,49), or some other factors (23, 39, 41, 51, 52, 55, 58), thus resulting in tolerance for the allogeneic graft (fetus). There is also an alternative explanation that the peritrophoblastic fibrinoid layer acts as an immuno-SURFACE CHARGE ON HUMAN TROPHOBLAST 255 logical barrier between the fetus and mother (3 , 9, 15, 28, 57).…”