An Initial Investigation of Lymphocyte Antibody Activity through Pregnancy and in Eluates Prepared from Placental Material

Abstract

Lymphocyte cytotoxic antibody specificity and activity were studied through seven pregnancies. Maternal and neo‐natal samples were HL‐A typed and eluates prepared from placental material. In six cases where neo‐natal lymphocytes reacted with maternal antisera, antibody activity was found in the placental eluate but not in the neo‐natal serum. In the seventh case no reaction was obtained with neo‐natal lymphocytes, antibody activity was not detected in the placental eluate but was found in neo‐natal serum. The role of the placenta as a defence mechanism for the foetus against HL‐A antibodies is discussed.

Some Parameters of Lymphocyte Antibody Activity through Pregnancy and Further Eluates of Placental Material

“…In Table 4 the data of a further 40 placental eluates can be seen, confirming the findings of Doughty & Gelsthorpe (1974). Where the foetus possesses the corresponding antigens to the antibody present in the maternal serum, antibody is found in the placental eluate and not the foetal serum.…”

“…Both features are demonstrated simultaneously in the one pregnancy of Mrs. CIS. Consequently, the 'hypothesis' stated previously (Doughty & Gelsthorpe 1974) that the placenta prevents antibody from reaching the foetal circulation by absorption, and that the process of escape from sensitization (Miyajima et al 1972) allows the placenta to regenerate further antigens for antibody absorption, is still maintained. A further finding which supports the above view is that, in all cases, the auto test of neo-natal serum against neonatal lymphocytes by the cytotoxic technique is negative.…”

“…Serum sample collection, lymphocytotoxic technique, HLA typing of maternal and neo-natal lymphocytes, placental elution, IgG and IgM separation of maternal sera and eluates, titration method and the term titration score are as previously described (Doughty & Gelsthorpe 1974).…”

Transfer of anti‐HLA‐DR antibodies from the mother to the child Are DR antigens expressed on the placenta?

“…It is well known that anti-HLA-A and/or B antibodies induccd by a pregnancy are not usually found in the neonatal cord blood but can be eluted from the placenta; contrarily, antibodies induced by an antigen other than those of the current pregnancy can be detected i n the neonatal cord blood but cannot he eluted from the placenta (Doughty & Gelsthorpe 1974, Tongio & Mayer 1971, 1975, Jeannet et al 1977. Less work has been done o n the rnaterno-l'uetal transfer of anti-HLA-DR antibodies.…”