scholarly journals Kinetics of the Human Antibody Response against Salmonella enterica Serovars Enteritidis and Typhimurium Determined by Lipopolysaccharide Enzyme-Linked Immunosorbent Assay

2007 ◽  
Vol 14 (6) ◽  
pp. 741-747 ◽  
Author(s):  
Mette A. Strid ◽  
Tine Dalby ◽  
Kåre Mølbak ◽  
Karen A. Krogfelt
Keyword(s):  
Salmonella Enterica ◽  
Blood Donors ◽  
Enzyme Linked Immunosorbent Assay ◽  
Human Antibody ◽  
Specificity And Sensitivity ◽  
Iga Antibodies ◽  
Serovar Typhimurium ◽  
Antibody Levels ◽  
Kinetics Of ◽  
Very High

ABSTRACT Two indirect enzyme-linked immunosorbent assays (ELISAs) were employed to measure levels of immunoglobulin G (IgG), IgM, and IgA antibodies against Salmonella in sera from 303 Danish patients diagnosed by fecal culture with either Salmonella enterica serovar Enteritidis or Salmonella enterica serovar Typhimurium infections. The ELISAs were based on serovar Enteritidis lipopolysaccharide (LPS) and serovar Typhimurium LPS. The antibody levels were assessed approximately 1, 3, 6, and 12 months after the onset of salmonellosis. Sera from 164 healthy blood donors were analyzed to establish cutoff values for each analysis. One month after the onset of symptoms, the sensitivities of the assays were 95% for patients recovering from a serovar Enteritidis infection and 89% for patients recovering from a serovar Typhimurium infection. Three months after the onset of symptoms, these values had decreased to 85% and 55%. At 6 months they were 62% and 40%, and at 12 months they were 40% and 16%, respectively. The specificities of the assays were 97% for the serovar Enteritidis LPS ELISA and 94% for the serovar Typhimurium LPS ELISA. The high values for both sensitivity and specificity make these two ELISAs useful for serodiagnoses of Salmonella infection shortly after the acute phase of the infection and of Salmonella-associated reactive arthritis, as well as for seroepidemiological studies. A mixed ELISA consisting of both antigens, i.e., serovar Enteritidis and serovar Typhimurium LPS, was developed as a diagnostic tool with very high values for both specificity and sensitivity.

scholarly journals A network of Rab GTPases controls phagosome maturation and is modulated by Salmonella enterica serovar Typhimurium

2007 ◽  
Vol 176 (3) ◽  
pp. 263-268 ◽  
Author(s):  
Adam C. Smith ◽  
Won Do Heo ◽  
Virginie Braun ◽  
Xiuju Jiang ◽  
Chloe Macrae ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Dominant Negative ◽  
Rab Gtpases ◽  
Wild Type ◽  
Intracellular Growth ◽  
Non Invasive ◽  
Serovar Typhimurium ◽  
Guanosine Triphosphatase ◽  
Kinetics Of

Members of the Rab guanosine triphosphatase (GTPase) family are key regulators of membrane traffic. Here we examined the association of 48 Rabs with model phagosomes containing a non-invasive mutant of Salmonella enterica serovar Typhimurium (S. Typhimurium). This mutant traffics to lysosomes and allowed us to determine which Rabs localize to a maturing phagosome. In total, 18 Rabs associated with maturing phagosomes, each with its own kinetics of association. Dominant-negative mutants of Rab23 and 35 inhibited phagosome–lysosome fusion. A large number of Rab GTPases localized to wild-type Salmonella-containing vacuoles (SCVs), which do not fuse with lysosomes. However, some Rabs (8B, 13, 23, 32, and 35) were excluded from wild-type SCVs whereas others (5A, 5B, 5C, 7A, 11A, and 11B) were enriched on this compartment. Our studies demonstrate that a complex network of Rab GTPases controls endocytic progression to lysosomes and that this is modulated by S. Typhimurium to allow its intracellular growth.

scholarly journals IgM and IgA Antibody Responses in 12 Cases of Human Acquired Toxoplasmosis

1997 ◽  
Vol 39 (6) ◽  
pp. 327-332 ◽  
Author(s):  
Emília E. H. TAKAHASHI ◽  
Cláudio L. ROSSI
Keyword(s):  
Serological Test ◽  
Clinical Manifestations ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Igm Antibodies ◽  
Iga Antibodies ◽  
Direct Elisa ◽  
Acute Toxoplasmosis ◽  
Antibody Levels ◽  
Acquired Toxoplasmosis

The persistence, in some subjects, of specific IgM antibodies to Toxoplasma gondii for several months after the acute phase of infection has complicated the interpretation of serological test results for toxoplasmosis. Several reports have emphasized the value of the detection of Toxoplasma-specific IgA antibodies for the diagnosis of acute toxoplasmosis. In this article, we report the follow-up profiles of Toxoplasma-specific IgM and IgA antibodies in serum samples obtained from 12 patients at various intervals after the onset of the clinical manifestations of infection. IgM antibodies were detected by the indirect immunofluorescence (IIF) test, antibody capture enzyme-linked immunosorbent assay (cELISA) and enzyme-mediated chemilluminescent technique (CmL). IgA antibodies were quantified by the direct ELISA (dELISA) and cELISA procedures. As defined by the manufacturer of the cELISA test for IgA used, most patients with acute toxoplasmosis have antibody levels > 40 arbritary units per ml (AU/ml). At values > 40 AU/ml, the cELISA for IgA detected significant antibody levels for a shorter time than the other techniques used for IgM and IgA detection. However, IgA levels <FONT FACE="Symbol">£</font> 40 AU/ml do not exclude the possibility of acute toxoplasmosis since such levels can be reached very soon after infection with T. gondii. The results obtained in the present study show that the serological diagnosis of acute toxoplasmosis may not be such an easy task. Our data suggest that use of the IgA-cELISA concomitantly with IgM antibody screening could permit, in some circumstances, a more efficient diagnosis of acute acquired toxoplasmosis

scholarly journals Kinetics of Local and Systemic Immune Responses to an Oral Cholera Vaccine Given Alone or Together with Acetylcysteine

1998 ◽  
Vol 5 (2) ◽  
pp. 247-250 ◽  
Author(s):  
J. Kilhamn ◽  
M. Jertborn ◽  
A.-M. Svennerholm
Keyword(s):  
Immune Responses ◽  
Immunoglobulin A ◽  
Cholera Vaccine ◽  
B Subunit ◽  
Iga Antibodies ◽  
Oral Cholera Vaccine ◽  
Iga Antibody ◽  
Antibody Levels ◽  
Kinetics Of

ABSTRACT The possibility that a mucolytic drug, i.e., acetylcysteine, given orally may enhance the gut mucosal or systemic immune response to an oral B-subunit–whole-cell (B-WC) cholera vaccine was evaluated for 40 adult Swedish volunteers, and the kinetics of the immune responses were monitored for responding volunteers. Two doses of vaccine induced similar frequencies of immunoglobulin A (IgA) and IgG antitoxin responses (80 to 90%) and vibriocidal titer increases (60 to 65%) in serum irrespective of whether the vaccine was given alone or together with 2 g of acetylcysteine. In feces the frequencies of IgA antitoxin (67%) and antibacterial (33 to 40%) antibody responses were also comparable in the two immunization groups. Six months after vaccination, IgA and IgG antitoxin as well as vibriocidal antibody titer increases in serum could still be detected in approximately 80% of initially responding vaccinees. Significantly elevated fecal antitoxin and antibacterial IgA antibody levels were found in, respectively, 50 and 43% of those volunteers who initially had responded to the vaccine. Determination of IgA antibodies in feces does not seem to offer any advantages compared to determination in serum for assessment of immune responses after immunization with inactivated cholera vaccine.

scholarly journals Low Hepatitis E Virus Prevalence Among Blood Donor in Dali in China

2020 ◽  
Author(s):  
Ping Fu ◽  
Baochai Lin ◽  
Bingting Wu ◽  
Ling Ke ◽  
Tianfu Yang ◽  
...  
Keyword(s):  
Blood Transfusion ◽  
Ethnic Minority ◽  
Odds Ratio ◽  
Hepatitis E Virus ◽  
Blood Donors ◽  
Hepatitis E ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Iga Antibodies ◽  
Positive Rate

Abstract BACKGROUND: Hepatitis E virus (HEV) is a nonenveloped RNA virus causing Hepatitis E worldwide. An increasing transfusion transmission cases of HEV infections from asymptomatic blood donors which causing serious illnesses in immunosuppressed recipients have been reported in the past few years. China is one of the highly prevalent regions of HEV, it is important to evaluate the risk of HEV transmission from blood transfusion. METHODS: A total of 1864 serum samples from blood donors and demographic characteristics were randomly collected from Feb to Mar 2018 in Dali city. Anti-HEV IgG, IgM and IgA antibodies and HEV antigen were examined by enzyme-linked immunosorbent assay (ELISA). HEV RNA was detected by real-time PCR. Multivariable logistic regression modelling was used to examine risk factors associated with HEV prevalence.RESULTS: Overall, the positive rate of anti-HEV IgG, IgM, and IgA antibodies was 13.36% (249/1864), 1.13%(21/1864), and 1.82%(34/1864), respectively. However, none of the 1864 serum samples was detected as HEV antigen-positive nor HEV RNA positive. The positive rate of anti-HEV IgG antibody is high as 28.57% (2/7) in the donors with isolated elevated alanine aminotransferase (ALT). Females (16.69%) had a significantly higher HEV seroprevalence than males (13.04%) (odds ratio [OR]: 1.34 [95% CI, 1.02-1.75]). Other ethnic minority (24.32%) and Bai (18.85%) donors had a significantly higher HEV seroprevalence when compared to Han (12.21%) blood donors (odds ratio [OR], 2.25 [95% CI, 1.04-4.88] for other ethnic minority, 1.65 [95% CI, 1.24-2.19] for Bai). Conclusions: Dali, Yunnan province, China is an endemic region for HEV and have a relatively low risk of HEV transmission via blood transfusion. Whether to formulate the strategy for HEV screening in blood center needed further researched.

scholarly journals Flagellated but Not Hyperfimbriated Salmonella enterica Serovar Typhimurium Attaches to and Forms Biofilms on Cholesterol-Coated Surfaces

2010 ◽  
Vol 192 (12) ◽  
pp. 2981-2990 ◽  
Author(s):  
Robert W. Crawford ◽  
Kristin E. Reeve ◽  
John S. Gunn
Keyword(s):  
Salmonella Enterica ◽  
Biofilm Formation ◽  
Carrier State ◽  
Enzyme Linked Immunosorbent Assay ◽  
Cholesterol Gallstones ◽  
Serovar Typhimurium ◽  
Flagellar Proteins ◽  
Coated Surfaces ◽  
Biofilm Development ◽  
Chronic Carrier

ABSTRACT The asymptomatic, chronic carrier state of Salmonella enterica serovar Typhi occurs in the bile-rich gallbladder and is frequently associated with the presence of cholesterol gallstones. We have previously demonstrated that salmonellae form biofilms on human gallstones and cholesterol-coated surfaces in vitro and that bile-induced biofilm formation on cholesterol gallstones promotes gallbladder colonization and maintenance of the carrier state. Random transposon mutants of S. enterica serovar Typhimurium were screened for impaired adherence to and biofilm formation on cholesterol-coated Eppendorf tubes but not on glass and plastic surfaces. We identified 49 mutants with this phenotype. The results indicate that genes involved in flagellum biosynthesis and structure primarily mediated attachment to cholesterol. Subsequent analysis suggested that the presence of the flagellar filament enhanced binding and biofilm formation in the presence of bile, while flagellar motility and expression of type 1 fimbriae were unimportant. Purified Salmonella flagellar proteins used in a modified enzyme-linked immunosorbent assay (ELISA) showed that FliC was the critical subunit mediating binding to cholesterol. These studies provide a better understanding of early events during biofilm development, specifically how salmonellae bind to cholesterol, and suggest a target for therapies that may alleviate biofilm formation on cholesterol gallstones and the chronic carrier state.

scholarly journals Characterization of a Monoclonal Antibody Directed against Salmonella enterica Serovar Typhimurium and Serovar [4,5,12:i:−]

2009 ◽  
Vol 75 (5) ◽  
pp. 1345-1354 ◽  
Author(s):  
A. Rementeria ◽  
A. B. Vivanco ◽  
A. Ramirez ◽  
F. L. Hernando ◽  
J. Bikandi ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Western Blotting ◽  
Salmonella Enterica ◽  
Phase 1 ◽  
Enzyme Linked Immunosorbent Assay ◽  
Phase 2 ◽  
Serovar Typhimurium ◽  
Antigenic Complex ◽  
Dot Blotting

ABSTRACT Flagellar extracts of Salmonella enterica serovars expressing phase 2 H1 antigenic complex (H:1,2, H:1,5, H:1,6, and H:1,7) and a mutant flagellin obtained by site-directed mutagenesis of the fljB gene from serovar Typhimurium at codon 218, transforming threonine to alanine, expressed in Escherichia coli (fljB218 A ) were used to analyze the H1 antigenic complex. Cross-reactions were detected by Western blotting and dot blotting using commercial polyclonal antibodies against the different wild-type extracts and mutant FljB218A. Therefore, we produced a monoclonal antibody (MAb), 23D4, isotyped as immunoglobulin M, against H:1,2 S. enterica serovar Typhimurium flagellin. The mutant flagellin was not recognized by this MAb. When a large number of phase 1 and phase 2 flagellin antigens of different serovars were used to characterize the 23D4 MAb, only extracts of serovars Typhimurium and [4,5,12:i:−] reacted. The protein composition of phase 1 and phase 2 extracts and highly purified H:1,2 flagellin from serovar Typhimurium strain LT2 and extract of strain 286 (serovar [4,5,12:i:−]), which reacted with the MAb, was studied. Phase 2 flagellin (FljBH:1,2) was detected in phase 1 and phase 2 flagellar heat extracts of serovar Typhimurium and was the single protein identified in all spots of purified H:1,2 flagellin. FliC, FlgK, and other proteins were detected in some immunoreactive spots and in the flagellar extract of serovar [4,5,12:i:−]. Immunoelectron microscopy of complete bacteria with 23D4 showed MAb attachment at the base of flagella, although the MAb failed to recognize the filament of flagella. Nevertheless, the results obtained by the other immunological tests (enzyme-linked immunosorbent assay, Western blotting, and dot blotting) indicate a reaction against flagellins. The epitopes could also be shared by other proteins on spots where FljB is not present, such as aminopeptidase B, isocitrate lyase, InvE, EF-TuA, enolase, DnaK, and others. In conclusion, MAb 23D4 can be useful for detection and diagnostic purposes of S. enterica serovar Typhimurium and serovar [4,5,12:i:−] and could be also helpful for epitope characterization of flagellum-associated antigens.

scholarly journals Immunoglobulin G and A Antibody Responses to Bacteroides forsythus and Prevotella intermedia in Sera and Synovial Fluids of Arthritis Patients

2003 ◽  
Vol 10 (6) ◽  
pp. 1043-1050 ◽  
Author(s):  
Ketil Moen ◽  
Johan G. Brun ◽  
Tor Magne Madland ◽  
Turid Tynning ◽  
Roland Jonsson
Keyword(s):  
Immune Responses ◽  
Immunoglobulin G ◽  
Enzyme Linked Immunosorbent Assay ◽  
Prevotella Intermedia ◽  
Igg Antibodies ◽  
Serum Samples ◽  
Igg Antibody ◽  
Iga Antibodies ◽  
Iga Antibody ◽  
Antibody Levels

ABSTRACT The objective of the present study was to investigate immunoglobulin G (IgG) and IgA antibody immune responses to Porphyromonas gingivalis, Prevotella intermedia, Bacteroides forsythus, and Candida albicans in the sera of patients with rheumatoid arthritis (RA), the synovial fluid (SF) of patients with RA (RA-SF samples), and the SF of patients without RA (non-RA-SF samples). An enzyme-linked immunosorbent assay was used to determine IgG and IgA antibody levels in 116 serum samples from patients with RA, 52 RA-SF samples, and 43 non-RA-SF samples; and these were compared with those in SF samples from 9 patients with osteoarthritis (OA-SF samples) and the blood from 100 donors (the control [CTR] group). Higher levels of IgG antibodies against B. forsythus (P < 0.0001) and P. intermedia (P < 0.0001) were found in non-RA-SF samples than in OA-SF samples, and higher levels of IgG antibodies against B. forsythus (P = 0.003) and P. intermedia (P = 0.024) were found in RA-SF samples than in OA-SF samples. Significantly higher levels of IgA antibodies against B. forsythus were demonstrated in both RA-SF and non-RA-SF samples than in OA-SF samples. When corrected for total Ig levels, levels of IgG antibody against B. forsythus were elevated in RA-SF and non-RA-SF samples compared to those in OA-SF samples. Lower levels of Ig antibodies against B. forsythus were found in the sera of patients with RA than in the plasma of the CTR group for both IgG (P = 0.003) and IgA (P < 0.0001). When corrected for total Ig levels, the levels of IgG and IgA antibodies against B. forsythus were still found to be lower in the sera from patients with RA than in the plasma of the CTR group (P < 0.0001). The levels of antibodies against P. gingivalis and C. albicans in the sera and SF of RA and non-RA patients were comparable to those found in the respective controls. The levels of IgG and IgA antibodies against B. forsythus were elevated in SF from patients with RA and non-RA-SF samples compared to those in OA-SF samples. Significantly lower levels of IgG and IgA antibodies against B. forsythus were found in the sera of patients with RA than in the plasma of the CTR group. This indicates the presence of an active antibody response in synovial tissue and illustrates a potential connection between periodontal and joint diseases.

scholarly journals Specificity of Subcapsular Antibody Responses in Ethiopian Patients following Disease Caused by Serogroup A Meningococci

2008 ◽  
Vol 15 (5) ◽  
pp. 863-871 ◽  
Author(s):  
Gunnstein Norheim ◽  
Abraham Aseffa ◽  
Mohammed Ahmed Yassin ◽  
Getahun Mengistu ◽  
Afework Kassu ◽  
...  
Keyword(s):  
Acute Phase ◽  
Reference Strain ◽  
Antibody Responses ◽  
Enzyme Linked Immunosorbent Assay ◽  
Human Antibody ◽  
Igg Antibody ◽  
Future Studies ◽  
Antibody Specificities ◽  
Antibody Levels

ABSTRACT Dissecting the specificities of human antibody responses following disease caused by serogroup A meningococci may be important for the development of improved vaccines. We performed a study of Ethiopian patients during outbreaks in 2002 and 2003. Sera were obtained from 71 patients with meningitis caused by bacteria of sequence type 7, as confirmed by PCR or culture, and from 113 Ethiopian controls. Antibody specificities were analyzed by immunoblotting (IB) against outer membrane antigen extracts of a reference strain and of the patients' own isolates and by enzyme-linked immunosorbent assay for immunoglobulin G (IgG) levels against lipooligosaccharide (LOS) L11 and the proteins NadA and NspA. IB revealed that the main antigens targeted were the proteins PorA, PorB, RmpM, and Opa/OpcA, as well as LOS. MenA disease induced significant increases in IgG against LOS L11 and NadA. The IgG levels against LOS remained elevated following disease, whereas the IgG anti-NadA levels returned to acute-phase levels in the late convalescent phase. Among adults, the anti-LOS IgG levels were similar in acute-phase patient sera as in control sera, whereas anti-NadA IgG levels were significantly higher in acute-phase sera than in controls. The IgG antibody levels against LOS and NadA correlated moderately but significantly with serum bactericidal activity against MenA strains. Future studies on immune response during MenA disease should take into account the high levels of anti-MenA polysaccharide IgG commonly found in the population and seek to clarify the role of antibodies against subcapsular antigens in protection against MenA disease.

scholarly journals Evidence for Active Efflux as the Primary Mechanism of Resistance to Ciprofloxacin in Salmonella enterica Serovar Typhimurium

2000 ◽  
Vol 44 (5) ◽  
pp. 1223-1228 ◽  
Author(s):  
Etienne Giraud ◽  
Axel Cloeckaert ◽  
Dominique Kerboeuf ◽  
Elisabeth Chaslus-Dancla
Keyword(s):  
Outer Membrane ◽  
Salmonella Enterica ◽  
Efflux Pump ◽  
Enzyme Linked Immunosorbent Assay ◽  
Topoisomerase Iv ◽  
Efflux Pump Inhibitor ◽  
Active Efflux ◽  
Fluorimetric Method ◽  
Serovar Typhimurium ◽  
Acrab Efflux Pump

ABSTRACT The occurrence of active efflux and cell wall modifications were studied in Salmonella enterica serovar Typhimurium mutants that were selected with enrofloxacin and whose phenotypes of resistance to fluoroquinolones could not be explained only by mutations in the genes coding for gyrase or topoisomerase IV. Mutant BN18/21 exhibited a decreased susceptibility to ciprofloxacin (MIC = 0.125 μg/ml) but did not have a mutation in the gyrA gene. Mutants BN18/41 and BN18/71 had the same substitution, Gly81Cys in GyrA, but exhibited different levels of resistance to ciprofloxacin (MICs = 2 and 8 μg/ml, respectively). None of the mutants had mutations in the parC gene. Evidence for active efflux was provided by a classical fluorimetric method, which revealed a three- to fourfold decrease in ciprofloxacin accumulation in the three mutants compared to that in the parent strain, which was annuled by addition of the efflux pump inhibitor carbonyl cyanide m-chlorophenylhydrazone. In mutant BN18/71, a second fluorimetric method also showed a 50% reduction in the level of accumulation of ethidium bromide, a known efflux pump substrate. Immunoblotting and enzyme-linked immunosorbent assay experiments with an anti-AcrA antibody revealed that the resistance phenotype was strongly correlated with the expression level of the AcrAB efflux pump and suggested that decreased susceptibility to ciprofloxacin due to active efflux probably related to overproduction of this pump could occur before that due to gyrA mutations. Alterations were also found in the outer membrane protein and lipopolysaccharide profiles of the mutants, and these alterations were possibly responsible for the decrease in the permeability of the outer membrane that was observed in the mutants and that could act synergistically with active efflux to decrease the level of ciprofloxacin accumulation.

scholarly journals The C-Terminal Domain of Salmonella enterica Serovar Typhimurium OmpA Is an Immunodominant Antigen in Mice but Appears To Be Only Partially Exposed on the Bacterial Cell Surface

2003 ◽  
Vol 71 (7) ◽  
pp. 3937-3946 ◽  
Author(s):  
Shiva P. Singh ◽  
Yvonne U. Williams ◽  
Stephanie Miller ◽  
Hiroshi Nikaido
Keyword(s):  
Cell Surface ◽  
Outer Membrane ◽  
Bacterial Cell ◽  
Salmonella Enterica ◽  
Competitive Inhibition ◽  
Enzyme Linked Immunosorbent Assay ◽  
Intact Cells ◽  
Bacterial Cell Surface ◽  
Terminal Domain ◽  
Serovar Typhimurium

ABSTRACT We examined the way the major outer membrane protein OmpA of Salmonella enterica serovar Typhimurium is recognized by the mouse immune system, by raising a panel of 12 monoclonal antibodies (MAbs) against this protein. Interaction between OmpA and these MAbs is competitively inhibited with several-hundredfold dilutions of mouse polyclonal sera obtained by immunization with live or heat-killed whole cells, suggesting that OmpA is one of the immunodominant antigens of serovar Typhimurium. All of the MAbs were specific for an identical epitope(s) located on the C-terminal domain of OmpA, as indicated by the use of OmpA fragments generated by protease or cyanogen bromide treatment and by competitive inhibition enzyme-linked immunosorbent assay. This epitope was highly conserved within (but not outside) the family Enterobacteriaceae. The strong immunogenicity of this epitope was surprising because the C-terminal domain of OmpA, usually thought to be located in the periplasm, is not expected to be exposed on the bacterial cell surface. A MAb, however, reacted in a cytofluorometry assay more strongly with outer-membrane-permeabilized cells than with untreated cells, a result supporting the predominantly periplasmic localization of the epitope. Significant, though low-level, reactivity of intact cells nevertheless suggests that in some cells the C-terminal domain of OmpA is exposed on the surface, a result consistent with the proposal that OmpA can fold into one of the two alternate conformations.

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