Pregnancy associated plasma protein A in Down's syndrome.
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Down Syndrome↗
Biomedical subjects
B Teisner
Publications and source records attributed to B Teisner.
First trimester concentrations of pregnancy associated plasma protein A and placental protein 14 in Down's syndrome.
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Down Syndrome↗
Calcium-dependent and calcium-independent signals in the conglutinin-binding assay (KgBa) for immune complexes. Influence of anti-collagen-antibodies.
A solid phase ELISA conglutinin-binding assay (KgBa) was evaluated for the detection of circulating immune complexes. ELISA wells were coated with purified bovine conglutinin and incubated with test sera. Bound IgG was detected with enzyme labelled anti-immunoglobulin. Heat aggregated IgG which had been "solubilized" (i.e., complement treated by incubation with serum) was employed as a reference. The binding of the complement-reacted IgG to solid phase conglutinin was found to be calcium-dependent and inhibitable with N-acetyl-D-glucosamine (GlcNAc). Prolonged incubation (4 days) of aggregated IgG with serum at 37 degrees C abolished the binding to conglutinin, a finding consistent with the complete degradation of deposited C3b to C3c and C3d. The solubilized IgG that bound to solid phase conglutinin was found by gel chromatography to be of high molecular weight (greater than 600 kDa). Binding of IgG to solid phase bovine conglutinin was also observed to a variable degree in normal and pathological sera. However, in this situation the IgG binding was largely calcium-independent, was not inhibited by GlcNAc and did not decrease after prolonged incubation of the serum at 37 degrees C. The reactive IgG eluted on gel chromatography at the position of monomeric IgG suggesting binding via the antigen binding sites. Binding of this IgG was inhibited by both collagen type II and purified conglutinin. These observations suggest that the assay detects cross-reacting autoantibodies against collagen epitopes, or, alternatively, antibodies against the dietary antigen, bovine conglutinin.
Acetylgalactosamine↗
Fetal antigen 2 (FA2) in human fetal osteoblasts, cultured osteoblasts and osteogenic osteosarcoma cells.
Immunohistochemical staining techniques used on an 11-week-old fetus showed that fetal antigen 2 (FA2) was present intracellularly in endochondral and perichondral osteoblasts, and the immunoreaction was extended into the adjacent bone matrix. Osteoclasts and chondroblasts were found to be FA2 negative. A granular perinuclear intracytoplasmic FA2 immunoreaction was found in cultured osteoblasts and osteogenic osteosarcoma cells, and immunoelectron-microscopical examination revealed a granular immunoreaction product in the rough endoplasmic reticulum. These findings indicate that FA2 is synthesized by osteoblasts and osteogenic osteosarcoma cells. A reaction of immunological identity was found between FA2 purified from second trimester amniotic fluid and serum-free supernatants of cultured osteogenic osteosarcoma cells. This shows that an antigen recognized by the anti FA2 antibody is secreted by these malignant cells. Thus, FA2 may represent a marker for altered bone metabolism, and have a potential in the classification of osteogenic osteosarcoma/chondrosarcoma.
Bone and Bones↗
Quantification of fetal antigen 2 (FA2) in supernatants of cultured osteoblasts, normal human serum, and serum from patients with chronic renal failure.
Fetal antigen 2 (FA2) was found within the cytoplasm of osteoblasts and in osteoid material, in a bone biopsy with morphological changes of renal osteodystrophy. An ELISA technique for FA2 quantification was developed, and the specificity confirmed by comparison with electroimmunoassay. The intra- and interassay coefficient of variations (%) were 8.3 and 9.7 respectively, and the detection limit 0.0004 arbitrary units FA2/1 using second-trimester human amniotic fluid as reference (1 AU FA2/1). FA2 was detected in serum-free supernatants from osteoblast cultures. Following size chromatography, the FA2 distribution (two peaks eluted corresponding to Mw 30 kDa and 100 kDa) in serum from a patient with chronic renal failure complicated with secondary hyperparathyroidism and in human amniotic fluid were identical. Probably due to the detection limit, only one peak fraction (30 kDa) was seen in normal human serum. Significantly greater FA2 concentrations were found in sera (n = 14) from patients with chronic renal failure (median: 11.9 mAU FA2/1; range: 5.2-49.0 mAU FA2/1) compared to normal healthy individuals (n = 23) (median: 4.1 mAU FA2/1; range 2.4-9.4 mAU FA2/1) (P less than 0.00001). A close correlation was found between serum FA2 and alkaline phosphatase (R(s) = 0.761; P = 0.006), c-terminal fraction of PTH (R(s) = 0.872; P = 0.003) and intact PTH(1-84) (R(s) = 0.904; P = 0.011) in the haemodialysis patients. These data indicate that FA2 is synthesized by osteoblasts and may represent a new marker for metabolic bone changes.
Cells, Cultured↗
Changes induced in serum protein profiles by ovarian stimulation during in-vitro fertilization--embryo transfer treatment: a comparison between conception and non-conception cycles.
The profiles of plasma protein concentrations during the follicular phase in unstimulated women and in women undergoing ovarian stimulation for in-vitro fertilization--embryo transfer (IVF-ET) treatment are described. Plasma protein concentrations are correlated with those of total oestradiol (protein-bound and free) and total progesterone. In addition, 10 conception cycles and 18 non-conception cycles are compared in an attempt to identify predictors of successful treatment. Ovarian stimulation caused a significant increase in follicular phase in serum concentrations of sex hormone binding globulin (SHBG), cortisol binding protein (CBP) and insulin-like growth factor binding protein 1 (IGFBP1). In contrast no increase was observed in unstimulated cycles. Serum levels of endometrial protein PP14 decreased significantly during the follicular phase in both stimulated and unstimulated cycles. Levels of pregnancy zone protein (PZP) were more than doubled at the time of oocyte aspiration compared to the unstimulated cycles. Albumin concentrations were unchanged by the stimulation. Throughout the follicular phase, levels of SHBG were significantly higher, and total oestradiol significantly lower in women who became pregnant, than in those who did not. Therefore, a low concentration of free, biologically active oestradiol seemed to favour pregnancy, as the concentration of albumin is similar in the two groups. The endometrial protein PP14 was significantly lower during the follicular phase in conception than in non-conceptional cycles. On day 2 of the treatment cycle, the PP14 concentration showed a 75% correct prediction of conception and non-conception cycles. These results suggest that levels of PP14 may predict successful IVF cycles even before hormonal treatment is commenced.
Adult↗
Foetal antigen 2 (FA2) in relation to wound healing and fibroblast proliferation.
During wound healing of human skin the deposition of foetal antigen 2 (FA2) and basement membrane (BM) components collagen type IV and collagen VII was followed. FA2 appeared on day 8 in the cytoplasm of proliferating fibroblasts and around newly formed blood vessels. As granulation tissue was formed, FA2 was seen diffusely in the loose matrix and in proliferating fibroblasts. Re-establishment of FA2 as a broad diffuse band along the BM at the dermo-epidermal junction was seen on day 22. In contrast, type IV and VII collagen were found along the BM and in the basal cells of the newly formed epithelium and a continuous linear BM distribution of these two components were re-established by days 12 and 14, respectively. The molecular weight (Mr) analysis of FA2, isolated from human skin fibroblast culture supernatants using SDS-PAGE, revealed a Mr of 27 kDa, corresponding to that of FA2 isolated from amniotic fluid. The presence of FA2 in proliferating fibroblasts and diffusely in the newly formed matrix of granulation tissue, as well as its late appearance at the BM after this had become established, suggests that FA2 takes part in connective tissue metabolism and perhaps tissue morphogenesis.
Amniotic Fluid↗
Foetal antigen 2 (FA2) in the stromal reaction induced by breast carcinoma.
An indirect immunoperoxidase technique was used to examine the distribution of foetal antigen 2 (FA2), a recently described basement membrane (BM)-associated antigen, in invasive breast carcinoma (n = 34), fibroadenoma (n = 5) and normal breast tissue (n = 5), and to compare its distribution with that of laminin and collagen type IV. In normal breast tissue, FA2 was detected in the intralobular stroma as a broad band around acini and ducts, but was not present in the interlobular stroma. In areas of carcinoma in situ, FA2 was present diffusely around and in close contact with the glandular elements, the staining being more intense than that found around normal glandular structures. Two distinct patterns of FA2 distribution were found in adenocarcinomas of the breast. In the fibroblast reaction type, fibroblast staining dominated, whilst in the stromal reaction type, intense and extensive staining of the surrounding stroma dominated. Significant correlation was found between the degree of fibroblast activity and the degree of anaplasia (p = 0.005). FA2 extracted from breast carcinoma tissue was shown to be immunologically identical to FA2 fractions extracted from second trimester amniotic fluid (AF). The Mr of FA2 isolated from AF was estimated to be 26 kD, whereas the Mr of FA2 extracted from breast carcinoma tissue was slightly higher. The apparent Mr under reducing conditions were higher and three bands ranging from 26 to 29 kD were seen. FA2 was found to be immunologically distinct from collagen types I, III and IV, laminin, fibronectin and fibrinogen. The increased production and widespread distribution of FA2 in breast carcinomas suggest that FA2 is involved in the stromal changes which occur in response to tumour growth and/or invasion.
Adenocarcinoma↗
Serum levels of fetal antigen 2 in hyperthyroidism and primary hyperparathyroidism.
Serum concentration of fetal antigen 2 (FA2) in patients with hyperthyroidism (n = 18) (median: 12.9 mAU/l; range: 3.2-22.4 mAU/l) was significantly (p < 0.002) higher than in age- and sex-matched healthy controls (median: 4.1 mAU FA2/l; range: 2.4-10.0 mAU FA2/l). Serum FA2 was positively correlated with thyroxine (T4) (Rs = 0.51; p < 0.05), triiodothyronine (T3) (Rs = 0.64; p < 0.01), bone-Gla protein (BGP) (Rs = 0.70; p < 0.01), total alkaline phosphatase (total-AP) (Rs = 0.62; p < 0.01), bone isoenzyme alkaline phosphatase (bone-AP) (Rs = 0.63; p < 0.01), N-terminal procollagen type III (PIIINP) (Rs = 0.65; p < 0.01) and urine OH-proline (OHP) (Rs = 0.79; p < 0.01). In patients with hyperparathyroidism the pretreatment levels of FA2 (n = 8) (median: 17.6 mAU/l; range: 5.2-35.0 mAU/l) were significantly (p < 0.001) higher than those of age- and sex-matched controls (median: 3.7 mAU FA2/l; range: 3.4-9.0 mAU/l). The pretreatment level of FA2 was positively correlated with the parathyroid hormone (PTH) (Rs = 0.80; p < 0.05). Following surgical treatment the serum concentrations of FA2, PTH, and BGP decreased compared to pretreatment levels and the fall in these three parameters revealed parallelism. These data indicate that serum FA2 can be used as a marker in the evaluation of metabolic bone diseases.
Adult↗
Fetal antigen 2: an amniotic protein identified as the aminopropeptide of the alpha 1 chain of human procollagen type I.
Fetal antigen (FA2) was purified from second trimester human amniotic fluid by immunospecific chromatography, gel filtration and reversed-phase chromatography. Gel filtration revealed two molecular forms of FA2 eluting at volumes corresponding to an M(r) of approximately 100 kDa and 30 kDa. SDS-PAGE analysis gave an M(r) = 27 kDa under reducing and non-reducing conditions for both forms, whereas the exact M(r) determined by mass spectrometry was 14,343 +/- 3 Da. FA2 was N-terminally blocked and after tryptic digestion the amino acid composition and sequences of the peptides showed identity with the aminopropeptide of the alpha 1 chain of human procollagen type I as determined by nucleotide sequences. After oxidative procedures normally employed for radio-iodination (iodogen and chloramine-T), FA2 lost its immunoreactivity. An antigen which cross-reacted with polyclonal rabbit anti-human FA2 was demonstrated in fetal calf serum. Gel filtration with analysis of fractions by inhibition ELISA showed that the bovine homologue was present in the same molecular forms as those in human amniotic fluid, and immunohistochemical analysis with anti-human FA2 showed that its distribution in bovine skin was identical to that of FA2 in human skin. FA2 is a circulating form of the aminopropeptide of the alpha 1 chain of procollagen type I, and this is the first description of its isolation and structural characterization in humans.
Amino Acid Sequence↗
Tissue localization of conglutinin, a bovine C-type lectin.
The distribution of bovine conglutinin (BK) in sections of frozen bovine tissues was studied by the indirect immunoperoxidase technique using a monospecific rabbit anti-BK antibody. BK was found in the cytoplasma of all hepatocytes, indicating that the liver is a major site of synthesis of BK. In the germinal centres of the spleen, tonsils and lymph nodes the anti-BK staining was restricted to a population of cells with a distribution and morphology characteristic of follicular dendritic cells. Macrophages in lung and thymus, and glia cells in cerebrum, revealed a granular staining reaction within the cytoplasma. Endothelial cells of blood vessels reacted with anti-BK. The intensity of this reaction varied greatly between the organs, the most pronounced reaction being seen in the glomeruli of the kidney, and in the capillary sinusoides of the cortex of the adrenal gland. The high endothelial venules of lymph nodes and tonsils were also stained. These findings suggest that BK, which until now has been described only as a circulating molecule, may exhibit a biological function within the BK-positive tissues.
Adrenal Cortex↗
Immunohistochemical studies on the localization of fetal antigen 2 (FA2), laminin, and collagen type 4 in basal cell carcinoma.
The localization of fetal antigen 2 (FA2), a recently described basement membrane (BM) associated antigen, was studied by immunohistochemical techniques in 21 basal cell carcinomas (BCC). In both superficial and infiltrating BCC, FA2 was located in a broad diffuse band around the tumor elements and in close contact with the BM. Compared to normal skin, a more extensive distribution of FA2 was seen in BCC. In the infiltrating BCC, FA2 staining was also present in the interstitial stroma between the tumor islands. FA2 was absent in areas with inflammatory cell infiltrates and elastoid degeneration. Epithelial and tumor cells were FA2 negative. The distribution of FA2 was clearly different from that of laminin and collagen type 4. Collagen type 4 and laminin were present as a continuous linear band corresponding to the BM surrounding the tumors. The close contact to the BM and the increased content of FA2 in the reactive stroma around BCC suggest that FA2 is involved in the matrix and/or BM changes taking place during tumor growth and invasion.
Antigens↗
Fetal antigen 2 in primary and secondary brain tumors.
Immunohistochemical deposition and distribution of fetal antigen 2 (FA2) was examined in normal brain tissue and in primary and metastatic tumors of the brain. In normal brain tissue FA2 was exclusively found linearly around the vessels, along pia and in arachnoidea. A similar localization was seen in primary brain tumors except in gliosarcoma where FA2 was distributed diffusely in the sarcoma region and was absent in the glioma region. In metastatic carcinoma with tumor stroma a diffuse staining reaction was seen in the stroma and with a basement membrane (BM) like staining at the tumor cell/stroma interface. Intracytoplasmic FA2 staining of the tumor cells was seen in areas without tumor stroma. In metastatic melanoma a BM like FA2 staining was seen around and between individual tumor cells. The staining patterns seen in the metastatic tumors were in accordance with that of the corresponding primary tumors.
Biomarkers, Tumor↗
Immunohistochemical analysis of the binding of human IgM to secretory component present in normal adult colon epithelia, but not in colon cancer and fetal colon epithelia.
We have analysed the binding of human IgM to fetal, normal adult and malignant colo-rectal tissues. Using an indirect immunoperoxidase technique on sections of frozen tissues human IgM binds to all normal adult colo-rectal epithelia (n = 15) tested. By contrast, 9 out of 25 colo-rectal adenocarcinomas were negative, and in the remaining 16 the staining reaction varied from staining of all the cancer areas to focal staining of a few areas. Human IgM did not bind to 14 samples of fetal intestinal epithelium (gestational age of 6-14 weeks). The binding of IgM was found to be mediated by secretory component (SC) as anti-SC antibody (anti-SC) showed a similar staining pattern as IgM and the IgM binding could be blocked by anti-SC. SC was also demonstrated in glandular epithelia of sections of all normal breast epithelia but only in 10 out of 15 breast adenocarcinomas. The loss of IgM binding and SC could not be correlated to the morphology of the adenocarcinomas. The observations on fetal, normal adult and malignant tissue suggest that IgM binding and SC may be gradually lost during dedifferentiation of normal cells, to malignant colo-rectal or breast epithelia.
Adenocarcinoma↗
A baboon model for pregnancy-associated antigens (PAPP-A, PP5, PP14).
By radioimmunoassays established on human derived antigens, PAPP-A, PP5 and PP14 immunoreactivity was detected in placental extracts and blood of pregnant baboons. None of the serial dilution curves suggested parallelism between respective human and baboon samples. Based on slopes of regressed logit-log transformed binding data, PAPP-A demonstrated the greatest degree of interspecies immunological crossreactivity. PP14 showed the least conservation of antigenic determinants. Physicochemical characterization on heparin, zinc chelate and bovine thrombin affinity matrices could not distinguish human from baboon-derived antigens. As in the human, baboon PAPP-A and PP5 were not detected in blood of male or non-pregnant animals. PP14 was detected in baboon follicular fluid, and only PP5 immunoreactivity was measured in culture media of baboon embryos. Of the three antigens, PAPP-A was detected in pregnant baboons at about 61 days gestation, that is, 4 weeks before PP5 and PP14. With the exception of PP14 which attained peak concentration at 118 days of pregnancy, PAPP-A and PP5 concentrations were greatest at term. In conjunction with physicochemical and immunological criteria, these physiological kinetics clearly support a role for developing a baboon model to serve for further studies into feto-maternal signals, particularly antigens such as PAPP-A and PP5.
Animals↗
Identification of specific serum proteins synthesized de novo by monolayer cultures of glandular cells of gestational endometrium.
Monolayer cell cultures (n = 3) of glandular epithelium of gestational endometrium obtained from three apparently healthy women undergoing elective termination of pregnancy (7-9 weeks gestation) were established. De novo synthesis of eight serum proteins (albumin, alpha 1-antitrypsin, ceruloplasmin, beta-lipoprotein, alpha 2-macroglobulin, fibronectin and complement factors C3 and C4) was demonstrated by the incorporation of radiolabelled substrate ([35S]methionine) employing autoradiography (AR) in combination with crossed immunoelectrophoresis (XIE), referred to as ARXIE, and line immunoelectrophoresis (LIE), referred to as ARLIE. By contrast, there was no evidence for de novo synthesis of IgA, haptoglobin and orosomucoid. Our findings suggest that the gestational endometrium may contribute to the production of several proteins considered to be synthesized and secreted mainly by the liver and reticulo-endothelial system. The simple techniques used here to identify the de novo synthesis of human serum proteins could be applied to investigate protein synthesis by a wide range of tissues and cells.
Blood Proteins↗
Zinc ions inhibit factor I-mediated release of CR1-bound immune complexes and degradation of cell-bound complement factors C3b and C4b.
ZnCl2 exerted a dose-dependent inhibition of citrate-phosphate-dextrose (CPD) plasma-induced release of 125I-labelled BSA-anti-BSA immune complexes (IC) bound to complement receptor type 1 (CR1, CD35) in human whole blood. Maximal inhibition was observed at 10 mM of ZnCl2. Furthermore, the release of IC bound to erythrocyte (E)-CR1 by purified factor I, factor I-deficient serum plus purified factor I, or normal human serum was reduced by approximately 90%, 64%, and 52%, respectively, in the presence of 10 mM ZnCl2. The effect of ZnCl2 on factor I-mediated degradation of cell-bound C3b/C4b was also investigated employing CPD blood or E from a factor I-deficient donor. These cells expressed covalently bound C3b and C4b as demonstrated by a simple agglutination technique. Upon incubation of CPD whole blood with purified factor I, or of E with purified factor I or normal CPD plasma, the C-fragments were cleaved and the cells were no longer agglutinated by antibodies to C3c and C4c. The presence of ZnCl2 prevented this factor I-mediated degradation of C3b and C4b, as evidenced by the unaffected agglutination of the cells by the antibodies. We conclude that ZnCl2 inhibited factor I activity since: (1) release of complement-preopsonized IC from E-CR1 by purified factor I was markedly inhibited (90%) in the presence of ZnCl2, (2) preincubation of the cells with ZnCl2 caused only a moderate inhibition (32-38%) of the IC release, and (3) degradation by purified factor I of covalently cell-bound C3b and C4b was abrogated in the presence of 10 mM ZnCl2.
Animals↗
Immune complex binding to erythrocyte-CR1 (CD 35), CR1 expression and levels of erythrocyte-fixed C3 fragments in SLE outpatients.
Erythrocytes (E) from a cross-sectional group of 22 outpatients with systemic lupus erythematosus (SLE) and/or mixed connective tissue disease (MCTD), the majority without active disease (n = 14), were analyzed for CR1 antigen expression and capacity to bind complement opsonized, radiolabelled immune complexes (IC). Furthermore, E-bound C3 fragments and the plasma C3d concentration were determined. E-bound C3b/iC3b fragments were not elevated in patients with SLE, whereas E from 11 out of 22 SLE patients had increased C3d levels which correlated with the plasma C3d concentration (Rs 0.73, p less than 0.001). E-fixed C3d fragments did not affect the binding of Mab or preopsonized IC to E-CR1 and were not correlated with disease activity or medical treatment. Antigen expression of E-CR1 measured by ELISA or agglutination showed positive correlation with the IC binding capacity of E-CR1 (Rs 0.92 and 0.72 respectively, p less than 001). The IC binding capacity of E-CR1 from SLE patients was significantly reduced (p less than 0.005), whereas the antigen expression of CR1 (ELISA) on E from the patients did not differ from that of E from healthy donors (p greater than 0.1). E-CR1 antigen was measured by Mab reacting with an epitope outside the IC-binding site of E-CR1. E-CR1 antigen expression or IC binding showed no correlation either with disease activity or prednisolone treatment. However, 4 og 5 patients with MCTD and 4 of 5 patients receiving Imurel were found to have low E-CR1 expression and capacity to bind IC. Thus, measurement of antigenic E-CR1 in a cross-sectional group of SLE outpatients by use of Mab reacting with an epitope outside the ligand-binding region of CR1 did not reveal a significantly reduced CR1 expression. However, an assay for CR1-mediated IC binding showed a clearly reduced E-CR1 function.
Antigen-Antibody Complex↗