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PubMed1993

Clinical significance of low or negative titer of antibody to hepatitis B core antigen during the course of chronic hepatitis B virus infection in adolescents.

Antibody to hepatitis B core antigen (anti-HBc) was measured by radioimmunoassay in 127 asymptomatic hepatitis B surface antigen (HBsAg) carriers (ASC; mean age 19) who had normal serum alanine aminotransferase (ALT) levels and 16 patients with chronic hepatitis B (CH; 19). All 16 CH patients, who were positive for hepatitis B e antigen (HBeAg) and 5 ASC cases who were negative for both HBeAg and its antibody (anti-HBe), had high anti-HBc titers. Anti-HBc titers in 27 (56.3%) of the 48 HBeAg-positive ASC and 18 (24.3%) of the 74 anti-HBe-positive ASC were relatively low. Two of the ASC were HBeAg-positive/anti-HBc-negative. In a follow-up study of the 19 HBeAg-positive ASC with low or negative anti-HBc titers, 5 had abnormal serum ALT levels and increased anti-HBc titers. In contrast, in the other 14 of these subjects, serum ALT levels remained normal and the low anti-HBc titers remained unchanged and/or decreased. The serological profile of HBsAg-positive/low or negative anti-HBc titer and increased anti-HBc titer with abnormal serum ALT levels are not necessarily exceptional in HBeAg-positive adolescent ASC. It is suggested that anti-HBc is associated with the liver damage that occurs before adolescence in chronic hepatitis B virus infection.

Adolescent↗

PubMed2000

Simulating ozone detoxification in the leaf apoplast through the direct reaction with ascorbate.

This paper presents a mathematical model which enables the semi-quantification of ozone (O3) detoxification, based upon the direct reaction of the pollutant with ascorbate (ASC) located in the aqueous matrix associated with the cell wall (i.e. the apoplast). The model describes the uptake of ozone into the leaf and its direct reaction with ASC, taking into consideration the regeneration of dehydroascorbic acid in the cytosol, the rate of replenishment of cell wall ASC and the distribution of ASC between sub-cellular compartments based upon the permeability of biomembranes to the neutral species, ascorbic acid and the pH of various sub-cellular compartments. The importance of various physico-chemical characteristics (e.g. stomatal conductance, mesophyll cell wall thickness and tortuosity, chloroplast volume, apoplast pH, ASC:O3 reaction stoichiometry) in mediating the flux of ozone to the plasmalemma is analysed. Model simulations, supported by experimental observations, suggest that the ASC concentration in the leaf apoplast is high enough to scavenge a significant proportion of the O3 taken up into the leaf interior, under environmentally relevant conditions. However, there is considerable variation between taxa in the potential degree of protection afforded by apoplastic ASC, emphasizing the need for an improved understanding of the reaction chemistry of O3 in the cell wall.

Ascorbic Acid↗

PubMed2006

Pluripotency potential of human adipose-derived stem cells marked with exogenous green fluorescent protein.

Musculoskeletal tissues regeneration requires rapid expansion of seeding cells both in vitro and in vivo while maintaining their multilineage differentiation ability. Human adipose-derived stem cells (ASCs) are considered to contain multipotent mesenchymal stem cells. Monolayer cultures of human ASCs were isolated from human lipoaspirates and passaged 3 times and then infected with replication-incompetent adenoviral vectors carrying green fluorescent protein (Ad/GFP) genes. Then, Ad/GFP infected human ASCs were transferred to osteogenic, chondrogenic, adipogenic, and myogenic medium. The morphological characterization of induced cells was observed using phase-contrast microscopy and fluorescence microscopy. The expression of marker proteins or genes was measured by immunocytochemical and RT-PCR analysis. Osteopontin (OPN), and osteocalcin (OCN) were positive in osteogenic lineages, aggrecan and SOX9 were positive in chondrogenic ones, peroxisome proliferator-activated receptor (PPAR-gamma2) and lipoprotein lipase (LPL) were positive in adipogenic ones, and myogenin and myod1 was positive in myogenic ones. At the same time, the results of fluorescence microscopic imaging proved that the high level of GFP expression during ASCs differentiation maintained stable nearly 2 months. So the exogenous GFP and multilineage potential of human ASCs had no severe influences on each other. Since the human ASCs can be easily obtained and abundant, it is proposed that they may be promising candidate cells for further studies on tissue engineering. Imaging with expression of GFP facilitates the research on ASCs physiological behavior and application in tissue engineering during differentiation both in vitro and in vivo.

Adenoviridae↗

PubMed1991

Cation and harmaline interactions with Na(+)-independent dibasic amino acid transport system y+ in human erythrocytes and in erythrocytes from a primitive vertebrate the pacific hagfish (Eptatretus stouti).

Transport systems y+, asc and ASC exhibit dual interactions with dibasic and neutral amino acids. For conventional Na(+)-dependent neutral amino acid system ASC, side chain amino and guanido groups bind to the Na+ site on the transporter. The topographically equivalent recognition site on related system asc binds harmaline (a Na(+)-site inhibitor) with the same affinity as asc (apparent Ki range 1-4 mM), but exhibits no detectable affinity for Ha. Although also classified as Na(+)-independent, dibasic amino acid transport system y+ accepts neutral amino acids when Na+ or another acceptable cation is also present. This latter observation implies that the y+ translocation site binds Na+ and suggests possible functional and structural similarities with ASC/asc. In the present series of experiments with human erythrocytes, system y(+)-mediated lysine uptake (5 microM, 20 degrees C) was found to be 3-fold higher in isotonic sucrose medium than in normal 150 mM NaCl medium. This difference was not a secondary consequence of changes in membrane potential, but resulted from Na+ functioning as a competitive inhibitor of transport. Apparent Km and Vmax values for lysine transport at 20 degrees C were 15.2 microM and 183 mumol/l cells per h, respectively, in sucrose medium and 59.4 microM and 228 mumol/l cells per h in Na+ medium. Similar results were obtained with y+ in erythrocytes of a primitive vertebrate, the Pacific hagfish (Eptatretus stouti), indicating that Na(+)-inhibition is a general property of this class of amino acid transporter. At a permeant concentration of 5 microM, the IC50 value for Na(+)-inhibition of lysine uptake by human erythrocytes was 27 mM. Other inorganic and organic cations, including K+ and guanidinium+, also inhibited transport. In parallel with its actions on ASC/asc harmaline competitively inhibited lysine uptake by human cells in sucrose medium. As predicted from mutually competitive binding to the y+ translocation site, the presence of 150 mM Na+ increased the harmaline inhibition constant (Ki) from 0.23 mM in sucrose medium to 0.75 mM in NaCl medium. We interpret these observations as further evidence that y+, asc and ASC represent a family of closely related transporters with a common evolutionary origin.

Animals↗

PubMed1991

Different profiles of the human immune response to primary and secondary immunization with an oral Salmonella typhi Ty21a vaccine.

Human immune response to a secondary immunization by the oral route was studied by enumerating specific antibody-secreting cells (ASC) in the peripheral blood, believed to reflect the local immune response in the mucosa. The volunteers had been immunized 1-2 years earlier with live Salmonella typhi Ty21a given orally as three doses of vaccine in enteric-coated capsules (3 x E); their ASC and serum antibody responses have been published. In the present study 17 of the same volunteers received one booster dose of the same vaccine (B-E). Specific ASC appeared in the blood of all volunteers after vaccination, peaked on day 5 and faded away thereafter so that on day 9 specific ASC were detected in only seven subjects. The ASC responses to the single booster dose were significantly higher than those to one dose in primary immunization and at least as high as those of the same volunteers to three doses in primary immunization. Serum antibody responses were not seen in any of the vaccinees after secondary immunization, whereas after primary immunization 60% of these subjects responded. This study shows the presence of immunologic memory also in respect of the human ASC response, and confirms the separate nature of ASC and serum response.

Administration, Oral↗

PubMed2005

Ascorbate stimulates monooxygenase-dependent steroidogenesis in adrenal zona glomerulosa.

It is well known that ascorbic acid (Asc) is highly concentrated in the adrenal gland, but its function in the gland is not thoroughly elucidated. We therefore examined the possibility that Asc participates in steroidogenic monooxygenase systems of the adrenal cortex with the aid of the regenerating system including outer mitochondrial membrane cytochrome b (OMb). When Asc availability was limited in rat mutants unable to synthesize Asc, the increase in plasma aldosterone concentration under Na-deficiency was suppressed without effect on plasma corticosterone concentration. Aldosterone formation in the isolated mitochondrial fraction of the zona glomerulosa (zG) of the adrenal cortex was stimulated by the addition of Asc and NADH, while corticosterone formation was not. Consistently zG showed a high level of Asc regeneration activity and was rich in OMb among adrenocortical zones. Taken together, the enhanced aldosterone formation that is catalyzed by one of the steroidogenic monooxygenases, P450aldo, may be supported by Asc with its regenerating system.

Animals↗

PubMed2006

The appraisal of social concerns scale: psychometric validation with a clinical sample of patients with social anxiety disorder.

The Appraisal of Social Concerns (ASC) Scale was created by Telch et al. (2004) to improve upon existing self-report measures of social anxiety-related cognition. In a largely nonclinical sample, the ASC was found to possess three factors and was psychometrically sound. In a smaller clinical sample, the ASC demonstrated sensitivity to the effects of cognitive behavioral therapy. In the present study, the psychometric properties of the ASC were examined in a larger sample of patients with social anxiety disorder. In this sample, the ASC exhibited a 2-factor structure; the nature of the factors was similar to the primary factors originally reported by Telch et al. The ASC also demonstrated strong validity, internal consistency, and sensitivity to treatment effects. It is concluded that the ASC may be useful in the assessment of cognition and cognitive change in patients with social anxiety disorder.

Adult↗

PubMed2005

Is sudden death with vitamin C deficiency caused by lack of carnitine?

We investigated the effect of carnitine supplementation during vitamin C (ASC) deficiency by measuring the levels of ASC and carnitine in plasma and cardiac muscle cells (CMC), and histological analysis with electron microscopy. The levels of carnitine were significantly decreased in ASC-deficient rats in plasma and the heart than those in the control. In carnitine supplemented ASC-deficient rats, a significant increase of carnitine levels were observed in both plasma and heart. The number of lipid droplets significantly increased in the ASC-deficient rats compared to the control rats, but did not increase in carnitine supplemented rats. These results indicate that ASC deficiency causes a generalized mitochondrial abnormality and accumulation of lipid droplets in CMC as observed in carnitine deficiency, and supplementation of carnitine prevented these changes even in the presence of ASC deficiency.

Animals↗

PubMed2007

Exogenous proline and glycinebetaine increase NaCl-induced ascorbate-glutathione cycle enzyme activities, and proline improves salt tolerance more than glycinebetaine in tobacco Bright Yellow-2 suspension-cultured cells.

Up-regulation of the antioxidant system provides protection against NaCl-induced oxidative damage in plants. Antioxidants and activity of enzymes involved in the ascorbate-glutathione (ASC-GSH) cycle in tobacco Bright Yellow-2 (BY-2) were investigated to assess the antioxidant protection offered by exogenous proline and glycinebetaine (betaine from now on) against salt stress using cells grown in suspension culture. Reduced ascorbate (ASC) was detected in BY-2 cells but dehydroascorbate (DHA) was not. Large quantities of a reduced form of glutathione (GSH) and smaller quantities of an oxidized form of glutathione (GSSG) were detected in BY-2 cells. Salt stress significantly reduced the contents of ASC and GSH as well as activities of ASC-GSH cycle enzymes such as ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), and glutathione reductase (GR). Exogenous proline or betaine increased the activities of all enzymes except MDHAR involved in NaCl-induced ASC-GSH cycle. Levels of ASC and GSH in BY-2 cells under salt stress were lower in the presence of proline or betaine than in the absence of proline or betaine whereas there was no difference in redox status. Proline proved more effective than betaine in maintaining the activity of enzymes involved in NaCl-induced ASC-GSH cycle. Neither proline nor betaine had any direct protective effect on NaCl-induced enzyme activity involved in the antioxidant system; however, both improved salt tolerance by increasing enzyme activity. The present study, together with our earlier findings [Hoque MA, Okuma E, Banu MNA, Nakamura Y, Shimoishi Y, Murata Y. Exogenous proline mitigates the detrimental effects of salt stress more than exogenous betaine by increasing antioxidant enzyme activities. J Plant Physiol 2006;164:553-61.], suggests that proline offered greater protection against salt stress than betaine did because proline was more effective in increasing the activity of enzymes involved in the antioxidant system.

Antioxidants↗

PubMed1997

Detection of specific and 'constitutive' antibody secreting cells in the gills, head kidney and peripheral blood leucocytes of dab (Limanda limanda).

The relative immunological importance of the gills of fish was investigated in terms of antibody production by enumerating antibody secreting cells (ASC) in the gills, head kidney and blood of dab (Limanda limanda) using the ELISPOT assay. The contribution of 'constitutive' ASC in the gill appeared more substantial than that of elicited specific ASC. The gills were found to contain a mean (+/- SD) of 4227 +/- 1029 'constitutive' ASC/10(6) cells which was fewer than the head kidney which contained a mean (+/- SD) of 15617 +/- 3723 'constitutive' ASC/10(6) cells but more than peripheral blood leucocytes which contained a mean (+/- SD) of 2650 +/- 212 'constitutive' ASC/10(6) cells. The number of specific anti-human gamma globulin (HGG) ASC following parenteral or oral administration of HGG was also determined. Anti-HGG ASC were detected in all three tissues following parenteral immunization, peaking simultaneously, 4 weeks post-immunization. The strongest response was found in the head kidney. After oral immunization, responses were much weaker: again the head kidney was the most active but the gill response was barely detectable. These data were complemented by measurement of specific antibody in the serum by ELISA. Serum antibody titres following immunization were found to correlate closely with the number of specific ASC in the head kidney following parenteral immunization whereas serum antibody titres after oral administration of antigen most closely followed the number of specific ASC in the blood. In the light of these data it is suggested that the primary immunological role of the leucocytes in the gill may be in the earliest stages of defence against infection.

Animals↗

PubMed1999

Homing potentials of circulating antibody-secreting cells after administration of oral or parenteral protein or polysaccharide vaccine in humans.

The site of antigen encounter influences the Ig-distribution and homing potentials of circulating antibody-secreting cells (ASC) induced. After oral antigen administration, the majority ASC secrete the mucosal Ig-isotype, IgA, and all of them express the gut homing receptor (HR), alpha 4 beta 7, thus implying mucosal homing of these cells. Parenteral protein vaccine induces an IgG-dominated response with a low proportion of alpha 4 beta 7 expressing cells. However, a polysaccharide vaccine, even if administered parenterally, elicits an IgA-dominated response, hence suggesting homing to the mucosa. In order to study the influence of the nature of the antigen on the targeting of the ASC response, the present work compares the homing potentials of circulating ASC in humans after administration of an oral Salmonella Typhi Ty21a vaccine (antigen studied: O-9,12 polysaccharide), an oral recombinant cholera vaccine (antigen studied: cholera toxin B-subunit, CTB protein), a parenteral pneumococcal vaccine (antigen studied: Pnc capsular polysaccharide 19F) or a parenteral tetanus toxoid vaccine (antigen studied: TT protein). alpha 4 beta 7 was expressed on a higher proportion of ASC induced by oral O-9,12 (99%) and CTB (99%) than by parenteral Pnc (70%) or TT (63%). L-selectin, the peripheral lymph node HR, was expressed on a smaller proportion of ASC induced by O-9,12 (37%) or CTB (43%) than of those induced by Pnc (78%) or TT (81%). The results imply that even if the nature of the antigen has a profound effect on the Ig-distribution of the ASC response, it does not seem to influence the targeting of the response.

Administration, Oral↗

PubMed1999

Induction of immune responses in pigs following oral administration of purified F4 fimbriae.

An effective way of stimulating the mucosal immune system was examined in piglets, using F4 fimbriae of enterotoxigenic Escherichia coli (ETEC). It was demonstrated that purified F4 fimbriae, as opposed to ovalbumin (OVA), are powerful oral immunogens. Indeed, oral administration of purified F4 induced antigen-specific antibody-secreting cells (ASC) in the Peyer's patches, mesenteric lymph nodes (LN), blood and lamina propria 4, 7, 9 and 11 days postimmunization, respectively, indicating a stimulation of the mucosal immune system, whereas upon oral administration of OVA, no immune response was observed. Moreover, the induced F4-specific IgA and IgG antibody responses were comparable with those obtained upon oral infection with viable E. coli and intramuscular (i.m.) F4 injection, respectively. Furthermore, a priming of the mucosal immune system is better obtained by oral infection (ASC localized in mesenteric LN) than by i.m. F4 injection (ASC localized in spleen and retropharyngeal LN) since an oral boost with purified F4 induced a secondary response in the orally infected animal (mainly IgA and IgG ASC, rapid increase of IgA antibodies) while in the i.m. primed animal a secondary (more circulating antigen-specific ASC than in the unprimed animal) as well as a primary IgM and IgA response (mainly IgM ASC, slow increase of IgA antibodies), suggesting a primary mucosal response, were seen. An oral challenge of the naive control displayed a primary response (mainly IgM ASC, slow increase of IgA and IgG antibodies). The capacity of purified F4 to activate the mucosal immune system on oral administration, is of importance for the development of oral vaccines against ETEC infections.

Adhesins, Escherichia coli↗

PubMed1998

Modulation of UV-light-induced skin inflammation by D-alpha-tocopherol and L-ascorbic acid: a clinical study using solar simulated radiation.

OBJECTIVE: In this clinical trial we studied whether oral supplementation with D-alpha-tocopherol (alpha-Toc), L-ascorbic acid (Asc), or alpha-Toc combined with Asc influenced the solar simulated radiation (SSR) induced skin inflammation in healthy volunteers. METHODS: We investigated the following groups in a prospective, randomized and placebo controlled study: Group (1) alpha-Toc 2 g/day, group (2) Asc 3 g/day, group (3) alpha-Toc 2 g/day combined with Asc 3 g/day, and group (4) placebo. Before and 50 days after supplementation we analyzed alpha-Toc and Asc concentrations in keratinocytes. The dose response curve of UV erythema was determined by reflectance spectrophotometry and the minimal erythema dose (MED) by visual grading before and after supplementation. RESULTS: 50 days after supplementation alpha-Toc keratinocyte levels were increased in groups (1) and (3), Asc concentrations were elevated in groups (2) and (3), and the a/gamma-Toc ratio increased in groups (1) and (3). The dose response curve of UVR induced erythema showed a significant flattening and the MED increased from 103 +/- 29 mJ/cm2 (before supplementation) to 183 +/- 35 mJ/cm2 (after supplementation) in group (3), while there were no significant changes in groups (1) and (2) after vitamin supplementation. CONCLUSION: Alpha-Toc and Asc act synergistically in suppression of the sunburn reaction.

Administration, Oral↗

PubMed2003

Clinical characteristics of oral adenosquamous carcinoma: report of a case and an analysis of the reported Japanese cases.

We present a case of adenosquamous carcinoma (ASC) which developed in the floor of the mouth of a 72-year-old Japanese man, and review 19 reported ASC cases in Japan from between 1986 and 2001, including the subject case herein. These ASCs occurred at an average age of 63 years, with 74% of the ASCs occurring in the floor of the mouth (8) and the tongue (6); the other sites of occurrence were the palate (3) and mandibular alveolus (2). Chief complaints were painless mass formation (28%), pain and/or sensational abnormality (28%), painful ulcer or swelling (22%), simple ulcer (11%), and miscellaneous others (11%). The clinical presentations of ASC were tumor with ulceration (58%), tumorous mass (26%), and ulcer (16%). Tumor size at first examination varied from bean-size to approximately 65 x 40 mm. In the pretreatment period, 31.3% were known to have cervical lymph node involvement, and descriptions on distant metastasis were not noted in any of the 19 cases. Some of the ASCs were initially diagnosed as other types of lesions, such as squamous cell carcinoma (SCC; 41%), adenocarcinoma (Ad.C; 12%) mucoepidermoid carcinoma (MEC; 6%), and MEC or SCC (6%). After initial treatments, neck and distant metastases were ascertained in 47.1 and 17.6% of the cases, respectively. Generally, a surgical procedure was performed as one of the most critical methods of treatment. The overall 5-year survival rate was 57.0%, with that of patients who underwent active treatment at 60.6%. Our study demonstrates the extent of the varied nature of ASC.

Aged↗

PubMed2002

Very low vitamin C activity of orally administered L-dehydroascorbic acid.

The biological activity of L-dehydroascorbic acid (DHA), which is easily formed from L-ascorbic acid (ASC) during storage and cooking processes, has been considered to be equivalent to that of ASC on the basis of studies made several decades ago, when a specific method to determine ASC was not available. The nutritional activity of orally ingested DHA has now been evaluated by comparing ASC concentrations in 12 tissues of rats administered four different doses of ASC. Determinations were made by using the specific and sensitive method, which had been developed by us. Here it is shown that the efficiency of DHA was almost 10% of that of ASC on a molar basis, based on animal experiments using the inherently scorbutic ODS rat, which is a convenient human model animal to investigate the metabolism of vitamin C. On the basis of these findings, it is proposed that it is necessary to reevaluate the nutritional requirement of vitamin C based on both ASC and DHA contents of foods.

Administration, Oral↗

PubMed2003

Biochemical properties of black drum and sheepshead seabream skin collagen.

Acid-soluble collagen (ASC) and pepsin solubilized collagen (PSC) were isolated from the skins of black drum (Pogonias cromis) and sheepshead seabream (Archosargus probatocephalus) harvested in the Gulf of Mexico coastal waters. The yields of ASCs on dry basis from black drum and sheepshead were estimated at 2.3 and 2.6%, and the yields of PSCs were 15.8 and 29.3%, respectively. Analyses of molecular weight profile, amino acid composition, and secondary structure showed that the skin collagens from both species were typical type-I collagen. The molecular mass of alpha(1) and alpha(2) subunits, as determined by SDS-PAGE using Tris-Acetate gels, was 127 kDa and 116 kDa, respectively. The amino acid composition of ASC and PSC for both species was closer to calf skin ASC than to cod skin ASC. Thermal denaturation temperatures, measured by melting point using circular dichroism, gave the following values: black drum ASC, 34.2 degrees C; sheepshead ASC, 34.0 degrees C; black drum PSC, 35.8 degrees C; sheepshead PSC, 34.3 degrees C. The literature value for the heat stability of calf skin collagen is 36.3 degrees C. The potentials of collagens from black drum and sheepshead skins in the functional food, healthcare, and pharmaceutical industries are discussed.

Amino Acids↗

PubMed2001

The erosive effects of some mouthrinses on enamel. A study in situ.

BACKGROUND: There are both anecdotal clinical and laboratory experimental data suggesting that low pH mouthrinses cause dental erosion. This evidence is particularly relevant to acidified sodium chlorite (ASC) formulations since they have plaque inhibitory properties comparable to chlorhexidine but without the well known local side effects. AIM: Studies in situ and in vitro were planned to measure enamel erosion by low pH mouthrinses. The study in situ measured enamel erosion by ASC, essential oil and hexetidine mouthrinses over 15-day study periods. The study was a 5 treatment, single blind cross over design involving 15 healthy subjects using orange juice, as a drink, and water, as a rinse, as positive and negative controls respectively. 2 enamel specimens from unerupted human third molar teeth were placed in the palatal area of upper removable acrylic appliances which were worn from 9 a.m. to 5 p.m., Monday to Friday for 3 weeks. Rinses were used 2x daily and 250 ml volumes of orange juice were imbibed 4x daily. Enamel loss was determined by profilometry on days 5, 10 and 15. The study in vitro involved immersing specimens in the 4 test solutions together with a reduced acid ASC formulation for a period of 4 h under constant stirring; Enamel loss was measured by profilometry every hour. RESULTS: Enamel loss was in situ progressive over time with the 3 rinses and orange juice but negligible with water. ASC produced similar erosion to orange juice and significantly more than the two proprietary rinses and water. The essential oil and hexetidine rinses produced similar erosion and significantly more than water. Enamel loss in vitro was progressive over time, and the order from low to high erosion was reduced acid ASC, ASC, Essential oil, and hexetidine mouthrinses and orange juice. CONCLUSION: Based on the study in situ, it is recommended that low pH mouthrinses should not be considered for long term or continuous use and never as pre-brushing rinses. In view of the plaque inhibitory efficacy of ASC, short- to medium-term applications similar to those of chlorhexidine would be envisaged.

Adult↗

PubMed1995

Cell surface determinants on typhoid-specific B cells isolated from peripheral blood after oral Ty21a typhoid vaccination in humans.

Antigen specific B cells (ASC) that circulate after oral immunization with the typhoid vaccine Ty21a display cell surface determinants which are potentially involved in B cell differentiation and homing to mucosal sites. These ASC were isolated from peripheral blood after oral Ty21a, and dual labelled for binding of typhoid antigen and expression of various cell surface determinants: alpha 4 integrin (CD49d), CD45RO, CD45RA, L-selectin, CD44 and CD11a. Of particular interest was the finding of CD45RO expression on ASC. A comparison of cell surface determinants on typhoid-specific cells was also made following binding to high endothelial venules on peripheral and mesenteric lymph nodes, and venules in the lamina propria of the small intestine. Generally more typhoid ASC bound to mesenteric compared with peripheral lymph node. More ASC expressing CD45RO and alpha 4 integrin (CD49d) were bound to mesenteric lymph node and small intestine than to peripheral lymph node. When expressed as a fraction of total ASC, the difference was statistically significant only for CD45RO binding to small intestine versus peripheral lymph node. No differences in expression of other homing markers on bound ASC were seen.

Administration, Oral↗