Mario F. Venegas

Blood Group Antigen Expression on Vaginal and Buccal Epithelial Cells and Mucus in Secretor and Nonsecretor Women

Blood group antigens on epithelial cells may influence bacterial adherence to mucosal surfaces. In the urinary tract the presence of these genetically determined carbohydrate structures may affect bacterial colonization of the vaginal mucosa and subsequent urinary tract infection. In previous studies the detection of ABH and Lewis antigen expression and distribution in tissues have made use of semiquantitative immunohistochemical staining techniques. To determine the pattern and intensity of blood group antigens on epithelial cells and in the mucus overlying them, we developed quantitative immunoassays that use monoclonal antibodies to detect changes in the expression and intensity of ABH and Lewis antigens on cells and in mucus. Vaginal and buccal cell specimens from 23 healthy women (15 secretors and 8 nonsecretors) with no history of urinary tract infections and known blood group types were analyzed for the expression of these antigenic determinants. The profile of ABH antigen expression was generally consistent with the ABO phenotype of the individual and appeared to be influenced by the secretor status; the levels of A, B and H determinants were higher for secretors than nonsecretors. Lewis antigens were detected on vaginal and buccal cells, and mucus. Le(a) and Le(x) antigen expression was greater on cells and mucus from nonsecretors, whereas the expression of Le(b) and Le(y) was greater on cells and mucus from secretors. Variability in antigen expression was observed among individuals with the same blood type and secretor status. The patterns of antigen expression were similar for the vaginal and buccal cell, and mucus samples of an individual but the amount of antigen generally differed for the various samples. These findings document the variation of blood group antigen expression on vaginal epithelial cells and mucus, which may have a significant role in susceptibility to urinary tract infections in women.

Evidence that serum amyloid P component binds to mannose-terminated sequences of polysaccharides and glycoproteins.

Serum amyloid P component (SAP) is a normal human serum protein with pentraxin structure that has morphological and immunochemical identity to the amyloid P component found in normal tissue and amyloid deposits. In the presence of calcium, SAP binds to certain complex polysaccharides, including agarose and zymosan. While the binding of SAP to agarose involves interaction with a galactose pyruvate acetal, the ligand in zymosan has not been defined. In the present study we determined that SAP binds to ligand(s) in a soluble extract of zymosan prepared by alkaline hydrolysis, which contains the mannose oligosaccharide sequences alpha DMan1----3DMan and alpha DMan1----6DMan. SAP did not bind to the alkali-insoluble fraction of zymosan, which is predominantly a glucan polymer, and its binding to zymosan extract which had been absorbed with concanavalin A was markedly reduced, suggesting that mannose residues are involved in the binding of SAP to zymosan. We also demonstrated that SAP binds to the glycoproteins ovalbumin, thyroglobulin, beta-glucuronidase and C3bi, which contain mannose-terminated sequences, while it did not bind to native and desialized preparations of ovomucoid, alpha 1-acid glycoprotein and glycophorin, which lack terminal mannose residues. SAP did not bind to pneumococcal C polysaccharide or to N-acetylglucosamine oligosaccharides covalently linked to a protein carrier. The binding of SAP to ligand(s) in zymosan extract or ovalbumin was inhibited by the preincubation of SAP with either zymosan extract or ovalbumin glycopeptides, both of which share similar mannose oligosaccharide sequences. All of the SAP binding reactions required calcium, were maximal at approximately 1 mM calcium, and gave similar results whether purified SAP or SAP in serum was used. These findings indicate that mannose-terminated oligosaccharides of polysaccharides and glycoproteins represent a new class of ligands for SAP and suggest that SAP may function as a mannose-binding protein.

Relatedness of Escherichia coli colonizing women longitudinally.

PURPOSE The longitudinal colonization patterns by Escherichia coli of the vaginal introitus and urinary tract were investigated. MATERIALS AND METHODS Cultures of the vaginal introitus and midstream urine were collected once a week for 12 consecutive weeks from five women with (patients) and five without (controls) a history of urinary tract infection (UTI). RESULTS A total of 63 E. coli isolates was obtained from the 10 women, 26 from controls and 37 from patients. The bacterial counts of E. coli present in control individuals were uniformly low, < or = 200 E. coli/mL. The numbers in patients were higher and more variable, reaching > 10(5)/mL in urine and vaginal specimens. In 16 instances, E. coli was present in the urine and the vaginal introitus concurrently (matched isolates). Random amplified polymorphic DNA (RAPD) fingerprinting was used to characterize all matched E. coli isolates. Concurrent vaginal and urinary tract colonization was more common in the patient population, and usually, the same E. coli strain was present at both sites; only 15% of the matched isolates represented different strains. The RAPD fingerprinting was also carried out on selected isolates recovered from four patients and three control individuals over the 12-week study period. Colonization of the vaginal introitus and urinary tract in these individuals varied over time. Generally, however, a predominant E. coli strain was present in the vaginal milieu, urinary tract, or both, either continuously (for as long as 9 consecutive weeks in one patient) or intermittently. CONCLUSION The results support the concept that the vaginal mucosa acts as reservoir of E. coli which may enter the urinary tract.

Blood Group Antigen Expression on Vaginal Cells and Mucus in Women with and without A History of Urinary Tract Infections

Adherence of bacteria to carbohydrate receptors on the surface of vaginal epithelial cells is a critical event that precedes bacterial colonization of the vaginal mucosa and subsequent urinary tract infection. Blood group antigens, carbohydrate structures bound to lipids or proteins, constitute an important component of the uroepithelial cell membrane and may affect susceptibility to urinary tract infections. To determine if the ABH and Lewis antigen expression in women with a history of urinary tract infections differed from that of women without such a history, vaginal specimens from 87 women (42 patients and 45 controls) were analyzed for the detection of these antigenic determinants using monoclonal antibodies in quantitative immunoassays. The profile of ABH antigen expression was generally consistent with the ABO phenotype of the individual and appeared to be influenced by the secretor status. Secretors expressed higher levels of A, B and H determinants than nonsecretors. In addition, Lewis antigens were detected on vaginal cells and in mucus. Samples from nonsecretors expressed higher levels of Le(a) and Le(x) antigens, whereas secretors expressed higher levels of Le(b) and Le(y) antigens. The levels of antigen expression varied widely among individuals with the same blood type and secretor status. Comparisons between patient and control groups showed no significant differences in ABH or Lewis antigen expression overall, or when controlling for ABO or secretor phenotypes, respectively. These findings confirm our previous observations on healthy women, and document the heterogeneity of blood group antigen expression on vaginal epithelial cells and mucus from women with a history of urinary tract infections.

Variation of Blood Group Antigen Expression on Vaginal Cells and Mucus in Secretor and Nonsecretor Women

The expression of blood group antigens on the surface of urothelial cells and in mucus is controlled partly by the blood type and secretor status of the individual. To our knowledge, the possibility that the levels of these antigens vary with time has not been previously assessed. We determine if the pattern and/or intensity of blood group antigen expression on vaginal epithelial cells and mucus changed with time. Cell and mucus specimens were collected weekly for 3 months from 10 women: 5 (2 secretors and 3 nonsecretors) with and 5 (3 secretors and 2 nonsecretors) without a history of urinary tract infections. In addition, samples were collected on 5 consecutive days from 5 of these individuals. The cell and mucus samples were assayed for ABH and Lewis blood group antigens using monoclonal antibodies in cell concentration immunofluorescence and enzyme-linked fluorogenic assays, respectively. Although the pattern of antigen expression in the vaginal cell and mucus samples was consistent with the blood type and secretor status of an individual, in all women the level of antigen expression changed significantly and rapidly during the 3-month and 5-day periods. The results show a previously unrecognized phenomenon and demonstrate that the expression of blood group antigens on vaginal cells and in mucus is a dynamic process.

Purification and immunochemical characterization of ascitic fluid glycoproteins containing certain tumor-associated and blood group antigen markers

Ascitic fluids from patients with various types of cancer were screened for the CA 19-9 and CA 125 tumor-associated antigenic activities. Two fluids exhibiting the highest activities were tested for their binding to various lectin-Sepharose columns resulting in both being bound best to wheat germ agglutinin (WGA) Sepharose. The WGA column eluate of one fluid was further chromatographed by HPLC and three peaks were obtained with approximate molecular weights of 3.65 MDa, 664 kDa and 330 kDa, of which only the largest fraction contained the CA 19-9 activity. The fluids were also fractionated on a Sephacryl S-400 column with most of the activity being present in or near the void volume.Monoclonal antibodies were used to demonstrate that the purified glycoproteins also contained the blood group A determinant, the four Lewis determinants Lea, Leb, Lex and Ley, and the sialylated-Lex determinant, while other antibody analyses failed to detect other blood group and/or carbohydrate sequence determinants. Some of the blood group expressions could be separated from the CA 19-9 and CA 125 active glycoproteins by adsorption with various lectins other than the WGA.

Tumor-Associated Blood Group Antigen Expressions and Immunoglobulins Associated with Tumors

As outlined in Figures 1 and 2, the biosynthetic pathways for the expression of the A, B and H, and the Lewis determinant carbohydrate sequence structures, as well as sialylated structures, involves both type 1 and type 2 precursor chains (which may be present as glycolipids and N- or O-linked glycoproteins), and many glycosyltransferases. For tumor cells, there appears to be increased expressions of fucosyl- and sialyltransferases yielding such structures as the Le(x), sialyl-Le(a), and many other similar determinants, which are not found on the normal cell progenitor of the tumor. The types of structures expressed on tumor cells is dependent on the particular fucosyl-, sialyl- and other glycosyltransferase genes activated in the transformation and tumor progression events, the availability of the substrates for the glycosyltransferases (both the precursor sequences and the nucleotide-sugar substrates) which is partly dependent on metabolites available to the tumor mass, and on the genotype of the individual regarding particular glycosyltransferases. Both the loss of A, B and/or H blood group antigen expressions of tumor cells and the relative expressions of the Lewis and sialylated-oligosaccharide determinants may be a consequence of the competing biosynthetic pathways and the glycosyltransferases for common substrate sequences, as well as due to the loss of particular glycosyltransferases concomitant with transformation. All of these factors probably account for the variable expressions of the complex of carbohydrate sequence determinants when comparing tumor sections of different individuals as well as the heterogeneity of expression of particular determinants within a single tumor tissue section. As described above, the A, B and/or H determinants, and the precursor sequences, are also expressed to differing extents on epithelial cells depending on the tissue type and cellular location in the tissue. Thus, the differentiation state of the particular epithelial cell also determines the quantity and types of carbohydrate sequences expressed. However, because of the complex nature of the competing biosynthetic pathways for the carbohydrate sequences of glycolipids and glycoproteins, and the relative activations of fucosyl- and sialyltransferases of tumor cells, it would seem that simple deductions as to the state of differentiation of particular tumors with A, B, H and precursor sequence expressions is not warranted.(ABSTRACT TRUNCATED AT 400 WORDS)