Biomedical subjects

R G Sutcliffe

Publications and source records attributed to R G Sutcliffe.

At least 55 records · Page 3Linked to original sources

PubMed1982

Immune responsiveness against the human placenta. II. Response with xenogeneic lymphocytes in culture.

Human placental plasma membrane vesicles were cultured for up to 5 days in the presence of spleen cells from (BALB/c X C57BL/6By) F1 hybrid mice. The membrane preparations either inhibited the uptake of [3H]-thymidine ([3H]-TdR) by destroying the viability of the T-cell population or stimulated weak lymphocyte division which was primarily an expansion of the T-cell population. This differential effect was dependent on the membrane concentration in culture and the length of time the membrane preparation had been stored. Membrane preparations that inhibited [3H]-TdR uptake could be converted into stimulatory-type membranes by preincubating them at 37 degrees for several days. This conversion coincided with a change in status concerning membrane susceptibility to disruption by cytotoxic non-T-cells present in the spleen of unimmunized animals. The conversion from stimulating-type membrane into inhibitory-type was never observed. Throughout these cultures the generation of cell-mediated cytolysis could not be detected.

Animals↗

PubMed1982

Immune responsiveness against the human placenta. I. Generation of cellular and humoral activity in experimental animals.

Using a new adaptation of the 51Cr release assay, it was found that plasma membrane vesicles from the human placental microvillous surface were not only capable of eliciting both cellular and humoral immunity in mice, but were also susceptible to lysis by these immune components. The production of cytotoxic cells and circulating antibody in immunized animals was only observed in the presence of Freund's complete adjuvant. The cells exhibited reactivity only against vesicles from a limited range of placentae, while the antibodies showed reactions against vesicles from a wider range of placentae. These vesicles were also susceptible to lysis by antisera raised against placental alkaline phosphatase but were resistant to attack by antibodies raised against normal human serum and HLA (multispecific) determinants and by a cytotoxic monoclonal antibody against human beta 2-microglobulin. The cellular cytotoxicity in the spleens of immunized animals could be abrogated if the cells were pretreated with AKR anti-C3H antiserum and complement. Further, in the spleens of in immunized animals, a population of cells was detected that exhibited a 'natural' cytotoxicity against several of the membrane preparations. This cytotoxicity was heat-labile, being abrogated if the cells were preincubated at 37 degrees for 4 hr before the assay, but was resistant to attack by the anti-Thy 1 antiserum. The results indicate that the use of 51Cr-labelled placental microvillous vesicles is a useful way of searching for anti-trophoblast immunity which may now be applied to the search for immune responses in pregnancy.

Animals↗

PubMed1981

Examination of different preparations of human placental plasma membrane for the binding of insulin, transferrin and immunoglobulins.

Plasma membrane was prepared from human placental tissue by two standard methods. The preparations, termed PVM and PPM, examined by electron microscopy and polyacrylamide gel electrophoresis, were characterized with respect to their binding properties for insulin, transferrin, alpha 2-macroglobulin and the immunoglobulins, IgM and IgG1. By means of sucrose density-gradient centrifugation, it was possible to fractionate the PVM into two distinct fractions. The first fraction, under the conditions used, was heavier (density greater than 1.080 g . cm-3) and was obtained as a pellet. It bound transferrin and IgM and had low specific activities for 5'-nucleotidase and for the binding of IgG1. The lighter fraction (density range 1.048-1.050 g . cm-3) had a high specific activity for 5'-nucleotidase and for IgG1 binding. Transferrin and IgM did not bind to this fraction. Insulin bound to both the fractions with comparable levels of specific binding activity, while alpha 2-macroglobulin binding was undetectable. The PPM preparation was found to have binding properties similar to those of the light fraction of PVM.

Cell Fractionation↗

PubMed1980

Studies on human pregnancy-associated plasma protein A. Purification by affinity chromatography and structural comparisons with alpha 2-macroglobulin.

Pregnancy-associated plasma protein-A (PAPP-A) has been purified by a combination of methods including antibody-affinity chromatography. The resultant protein, obtained in 16% yield from maternal serum, appeared as a single major component on non-denaturing polyacrylamide and SDS/polyacrylamide gel electrophoresis. The protein showed a single component when analysed by isoelectric focusing under denaturing conditions in the presence and absence of reduction and had a pI of 4.34 and 4.42 respectively. These pI values were indistinguishable from those of alpha 2-macroglobulin (alpha 2M). The molecular weight of the PAPP-A polypeptide as shown by SDS/polyacrylamide-gel electrophoresis was 187000, with a minor component of mol.wt. 82500 that was attributed to proteolysis. Since native PAPP-A had a molecular weight on gel chromatography very similar to that of alpha 2M (620000--820000), it was concluded that PAPP-A was a homotetramer. In the absence of reduction, a high-molecular-weight (420000) protomer of PAPP-A was found. It was deduced that PAPP-A, like alpha 2M, is a dinner, whose protomers are composed of disulphide-linked polypeptide chains. It was found that the molecular weight of the PAPP-A polypeptide exceeded that of alpha 2M by 3.3%, but that the total carbohydrate content of PAPP-A exceeded that of alpha 2M by 10% and that its neutral carbohydrate content exceeded that of alpha 2M by between 7.4 and 9.0%. The significance of the estimated molecular weights of alpha 2M (181000) and its major tryptic fragments is discussed in the light of published values. A tryptic fragment alpha 2M (82500 mol.wt.) was apparently the same size as the major tryptic fragment of PAPP-A.

Carbohydrates↗

PubMed1980

Purification of human alpha uterine protein.

Human alpha uterine protein (AUP) has been prepared from extracts of decudua by antibody affinity chromatography, DEAE Sepharose chromatography and by filtration through Sephadex G-150. This procedure yielded a protein fraction containing AUP, which was labelled with 125I by chloramine T. When analysed by SDS gel electrophoresis this radioiodinated protein fraction was found to contain predominantly a single species of protein which was precipitated by antibodies against AUP in antibody-antigen crossed electrophoresis. Rabbit anti-AUP precipitated 55-65% of the tracer in a double-antibody system. Sephadex G150 gel filtration of AUP obtained before and after affinity chromatography provided a molecular weight estimate of 50000. Since SDS gel electrophoresis revealed a polypeptide molecular weight of 23000-25000, it is suggested that AUP is a dimer.

Chromatography, Affinity↗

PubMed1978

Fetal- and uterine-specific antigens in human amniotic fluid.

Removal of the major maternal serum proteins from second trimester amniotic fluid by antibody affinity chromatography revealed various soluble tissue antigens, of which two were fetal-specific skin proteins and another, of alpha2-mobility, was specific to the uterus, and was therefore designated alpha-uterine protein (AUP). These proteins could not be detected in maternal serum by antibody-antigen crossed electrophoresis. The concentration of AUP in amniotic fluid reached a maximum between 10 and 20 weeks of gestation, suggesting that there is an influx of uterine protein into the amniotic fluid at this stage of pregnancy.

Amniotic Fluid↗

PubMed1975