The TF, Tn, and SiaTn glycotopes are frequently expressed in cancer-associated mucins. Antibodies to these glycotopes were found in human serum. A set of polyacrylamide (PAA)--based glycoconjugates ...was applied to the direct and competitive enzyme-linked immunosorbent assays (ELISA) to characterize the specificity of serum IgG antibodies. The anti-TF, -Tn and -SiaTn IgG were affinity purified from serum of cancer patients and characterized using PAA-conjugates and free saccharides. The anti-TF and -Tn antibodies were shown to be specific. The anti-TF IgG bound both Galbeta1-3GalNAcalpha- and Galbeta1-3GalNAcbeta-PAA, the latter was three-four times more effective inhibitor of antibody binding. The anti-Tn IgG reacted only with GalNAcalpha-PAA. The anti-SiaTn IgG cross-reacted with Tn-PAA but SiaTn-PAA was five-six times more effective inhibitor in a competitive assay. The IC50 values for PAA-conjugates with the corresponding antibodies typically ranged from 2 to 5 x 10(-8) M. The antibodies display a low specificity to mucin-type glycoconjugates in comparison with PAA-conjugates as was shown for mucins isolated from human malignant tumor tissues, ovine submaxillary mucin (OSM) and asialo-OSM. The unusual IgG-antibody specificity to GalNAcbeta and GalNAcbeta1-3GalNAcbeta ligands was found in human serum.
The Galα1-3Galβ (αGal) hapten is xenogeneic for humans; natural anti-αGal antibodies are present in human serum. To study the possible abnormal expression of the αGal in humans and the ...pathophysiological role of antibodies, the method of affinity purification of human anti-αGal IgG was developed. The specificity of antibodies was evaluated using polyacrylamide (PAA)-based glycoconjugates in direct and competitive enzyme-linked immunosorbent assays (ELISA). The purified antibodies exhibited αGal-restricted specificity. The IC
50
value for αGal-PAA was equal to 4 × 10
−8
M. In a competitive assay, the Galα1-3(Fucα1-2)Galβ-PAA (trisaccharide of blood group B) was found to be one hundred times less active inhibitor than αGal-PAA. The multivalent αGal-PAA was 1100 times more potent an inhibitor than the monovalent spacered αGal-saccharide. The antibodies did not show any reactivity to the negatively charged antigens (DNA, human tumor-derived mucins). At a concentration of 2 µg/mL, the antibodies agglutinated rabbit erythrocytes but not hare erythrocytes. The high reactivity of antibodies to the αGal-glycosphingolipids of rabbit erythrocytes and the pig kidney was shown by a modified sensitive method of thin-layer chromatography with immunodetection.
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Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Changes in the glycosylation in cancer may lead to an aberrant expression of A, B incompatible or xenogeneic blood group related antigens. To characterize the specificity of IgG antibodies to A, B, ...and related glycans in sera of gastrointestinal cancer patients, serum probes and affinity-isolated antibodies were analyzed in the indirect and competitive ELISA using a set of homogenous polyacrylamide (PAA) glycoconjugates. Monoreactive antibodies recognizing A
di
(I) and cross-reactive antibodies to A
di
/B
di
/B
tri
(II) or A
di
/A
tri
/Fs
di
/Core5 (III) were affinity-isolated on A
di
-PAA-Sepharose. The population I showed a higher affinity to A
di
-PAA than cross-reactive antibodies. The antibodies II were more specific to B
di
and may belong to the core alpha-Gal reactive antibodies but are also capable of recognizing A
di
. The antibodies III were more specific to A
tri
; they agglutinated A-erythrocytes and belong to anti-A isoantibodies reactive to xenogeneic oligosaccharides. The purified antibody samples were non- or faintly reactive to Tn. The IC
50
values of PAA glycoconjugates ranged from 6 × 10
−8
to 7 × 10
−6
M. No or weak binding of antibodies to the unrelated antigens used in the detection of polyreactivity (ferritin, casein, and DNA) was observed.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Earlier we found two unusual IgG-antibody specificities to GalNAc beta and GalNAc beta1-3GalNAc beta (para-Forssman disaccharide, PFdi) carbohydrate ligands in human serum. The aim of the study was ...to evaluate whether elevated antibody levels are related to the progression of gastrointestinal cancer and the histopathological grading.
Specific IgG levels were tested in 159 patients with gastric cancer, 88 patients with colorectal cancer and 96 blood donors by the ELISA using synthetic polyacrylaamide (PAA) conjugates, GalNAc beta-PAA and PFdi-PAA. Biochemical and haematological analyses were performed using automatic equipment.
The anti-PFdi IgG levels were significantly higher in patients with gastric and colorectal cancer than in donors: in stages II-IV, P = 0.0002 - 0.04 (U-test). The elevated anti-PFdi IgG level was associated with the advanced gastric cancer: in stages II, III, IV vs stage I (P = 0.004 - 0.06) and in case of the tumor size T2 + T3 vs T1 (stages I, II; P = 0.03). Differences in anti-GalNAc beta IgG level were insignificant. No relation between antibody levels and the regional and distant metastases of gastric or colorectal cancer was found. The lower anti-GalNAc beta IgG level was associated with lower-differentiated carcinomas (P = 0.01 - 0.04). Prolonged postoperative changes in the levels of both antibodies during the follow-up were established. An elevation of both antibody levels in patients with gastrointestinal cancer was revealed after a surgical removal of G3-tumors (P = 0.003 - 0.01). The anti-PFdi IgG levels correlated with the levels of the C-reactive protein: r = 0.50, P = 0.003. The anti-GalNAc beta IgG levels correlated with the percentage of peripheral blood monocytes: r = 0.42, P = 0.002.
The association of the anti-PFdi IgG level with cancer progression suggests the implication of antibodies in the pathogenesis of gastrointestinal cancer. Further studies are required to identify natural targets of antibodies, their relation to other diseases, prognostic significance in cancer.
The soluble E-receptor (SER) of lymphocytes that is related to CD2 was detected in human plasma and serum using immunoelectrophoresis with sheep antiserum. All plasma samples (n=18) demonstrated ...reactivity with antiserum, whereas the reactivity of the corresponding sera remained low or undetectable. The depletion of SER in clotting is associated with fibrinogen, as shown by crossed-affinity immunoelectrophoresis with antisera to plasma proteins. The SER-associated fibrinogen was purified and analysed by the SDS-polyacrylamide gel electrophoresis and immunoblotting. A band close to 66 kDa was detected with monoclonal antibodies to CD2. The association of CD2 and other soluble receptors with fibrinogen via domains is suggested. It is recommended that the fresh plasma, not serum, should be used to study circulating receptors because coagulation may appreciably diminish their physiological level in blood samples.
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Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Serum anti-(GalNAcβ) and anti-para-Forssman disaccharide (PF(di), GalNAcβ1--3GalNAcβ) IgG levels were earlier found to be related to histological grading and progression of gastrointestinal cancer.
...To study the relation of serum antibodies level to survival in patients with gastrointestinal cancer.
The level of anti-GalNAcβ, and PF(di) IgG was analysed in the serum of patients with gastric (n = 78) and colorectal (n = 48) cancers in the long-term follow-up using ELISA with polyacrylamide glycoconjugates. Survival rate and hazard ratio (HR) were assessed by the Kaplan -- Meier method and Cox univariate analysis in different patho-morphological groups.
Better survival was observed in patients with an increased preoperative level of GalNAcβ antibodies. These were the gastrointestinal group in stages II, III or tumors T2--4 (n = 90--104, P = 0.007, HR = 0.48--0.49, 95% CI 0.27--0.83, and the group with gastric cancer in stages I, II (n = 49, P = 0.051, HR = 0.39, 95% CI 0.14-1.04). The survival time was significantly longer in the gastrointestinal group in patients whose GalNAcβ antibodies level rose in dynamics (stage III or N1--2: p = 0.031--0.039, HR = 0.29--0.31, 95% CI 0.09--1.00). No significant difference in survival of patients was observed in the evaluation of PF(di) antibodies. We suggest that the level of antibodies and its change reflect the enteric microbiota colonization, which may influence cancer progression via different interrelations between microbiota, the tumor and immune system.
The preoperative level of GalNAcβ antibodies and its dynamics may be of prognostic significance for clinical outcome assessment.
T CrB is a symbiotic star that experiences nova outbursts every \(\sim\) 80~yr. The next, long-anticipated nova outburst should occur during the 2024-2026 period. Here, we present results of ...high-resolution optical spectroscopy of T CrB in the period 2016 - 2023. In these spectra, we measured the equivalent widths of the H\(\alpha\), H\(\beta\), HeI and HeII emission lines. The maximum equivalent width (EW) was recorded on May 2021, when the EW of \(H\alpha\) reached -44.6 \AA and H\(\beta\) = -21.5 \AA. At the other extreme, the minimum of EW(\(H\alpha\))= -2.9 \AA was recorded in October 2023. After October 2023, the B-band emission brightened, suggesting a re-appearance of the orbital modulation. In addition to the optical data, we study the X-ray behaviour in the same period. We find a strong correlation between \(EW(H\alpha)\) and X-ray flux with a correlation coefficient -0.78 and a significance of 2.6\(\times 10^{-5}\).
Based on the Gaia EDR3 astrometric parameters and our new systemic radial velocity of the high-mass X-ray binary 4U 2206+54/BD+53 2790, we studied the trace back motion of the system and propose that ...it originated in the subgroup of the Cepheus OB1 association (Age~4-10 Myr) with its brightest star BD+53 2820 (B0V; L~\(10^{4.7}\)L\(_\odot\)). The kinematic age of 4U 2206+54 is about 2.8\(\pm\)0.4 Myr, it is at a distance of 3.1-3.3 kpc and has a space velocity of 75-100 km/s with respect to this member star (BD+53 2820) of the Cep OB1 association. This runaway velocity indicates that the progenitor of the neutron star hosted by 4U 2206+54 lost about 4-9 \(M_{\odot}\) during the supernova explosion and the latter one received a kick velocity of at least 200-350 km/s. Since the high-mass X-ray binary 4U 2206+54/BD+53 2790 was born as a member of a subgroup of Cep OB1, the initially most massive star in the system terminated its evolution within ~7-9 Myr, corresponding to an initial mass >= 32\(M_{\odot}\).
We present an extensive recent multi-band optical photometric observations of the blazar S5 0716+714 carried out over 53 nights with two telescopes in India, two in Bulgaria, one in Serbia, and one ...in Egypt during 2019 November -- 2022 December. We collected 1401, 689, 14726, and 165 photometric image frames in B, V, R, and I bands, respectively. We montiored the blazar quasi-simultaneously during 3 nights in B, V, R, and I bands; 4 nights in B, V, and R; 2 nights in V, R, and I; 5 nights in B and R; and 2 nights in V and R bands. We also took 37 nights of data only in R band. Single band data are used to study intraday flux variability and two or more bands quasi-simultaneous observations allow us to search for colour variation in the source. We employ the power-enhanced F-test and the nested ANOVA test to search for genuine flux and color variations in the light curves of the blazar on intraday timescales. Out of 12, 11, 53, and 5 nights observations, intraday variations with amplitudes between ~3% and ~20% are detected in 9, 8, 31 and 3 nights in B, V, R, and I bands, respectively, corresponding to duty cycles of 75%, 73%, 58% and 60%. These duty cycles are lower than those typically measured at earlier times. On these timescales color variations with both bluer-when-brighter and redder-when-brighter are seen, though nights with no measurable colour variation are also present. We briefly discuss possible explanations for this observed intraday variability.
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