scholarly journals Detection of cross-reactive immunoglobulin A against the severe acute respiratory syndrome-coronavirus-2 spike 1 subunit in saliva

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0249979
Author(s):  
Keiichi Tsukinoki ◽  
Tatsuo Yamamoto ◽  
Keisuke Handa ◽  
Mariko Iwamiya ◽  
Juri Saruta ◽  
...  
Keyword(s):  
Breast Milk ◽  
Immunoglobulin A ◽  
Cross Reactivity ◽  
University Hospital ◽  
Enzyme Linked Immunosorbent Assay ◽  
Angiotensin Converting Enzyme 2 ◽  
Mucosal Surfaces ◽  
Polymerase Chain ◽  
The Cross ◽  
Age Range

Abundant secretory immunoglobulin A (SIgA) in the mucus, breast milk, and saliva provides immunity against infection of mucosal surfaces. Pre-pandemic breast milk samples containing SIgA have been reported to cross-react with SARS-CoV-2; however, it remains unknown whether SIgA showing the cross-reaction with SARS-CoV-2 exists in saliva. We aimed to clarify whether SIgA in saliva cross-reacts with SARS-CoV-2 spike 1 subunit in individuals who have not been infected with this virus. The study involved 137 (men, n = 101; women, n = 36; mean age, 38.7; age range, 24–65 years) dentists and doctors from Kanagawa Dental University Hospital. Saliva and blood samples were analyzed by polymerase chain reaction (PCR) and immunochromatography for IgG and IgM, respectively. We then identified patients with saliva samples that were confirmed to be PCR-negative and IgM-negative for SARS-CoV-2. The cross-reactivity of IgA-positive saliva samples with SARS-CoV-2 was determined by enzyme-linked immunosorbent assay using a biotin-labeled spike recombinant protein (S1-mFc) covering the receptor-binding domain of SARS-CoV-2. The proportion of SARS-CoV-2 cross-reactive IgA-positive individuals was 46.7%, which correlated negatively with age (r = –0.218, p = 0.01). The proportion of IgA-positive individuals aged ≥50 years was significantly lower than that of patients aged ≤49 years (p = 0.008). SIgA was purified from the saliva of patients, which could partially suppress the binding of SARS-CoV-2 spike protein to the angiotensin converting enzyme-2 receptor. This study demonstrates the presence of SARS-CoV-2 cross-reactive SIgA in the saliva of individuals who had never been infected with the virus, suggesting that SIgA may help prevent SARS-CoV-2 infection.

scholarly journals Detection of cross-reactive IgA against SARS-CoV-2 spike 1 subunit in saliva

2021 ◽  
Author(s):  
Keiichi Tsukinoki ◽  
Tatsuo Yamamoto ◽  
Keisuke Handa ◽  
Mariko Iwamiya ◽  
Juri Saruta ◽  
...  
Keyword(s):  
Breast Milk ◽  
Recombinant Protein ◽  
University Hospital ◽  
Spike Protein ◽  
Secretory Iga ◽  
Enzyme Linked Immunosorbent Assay ◽  
Receptor Binding Domain ◽  
Blood Samples ◽  
Milk Samples ◽  
Mucosal Surfaces

AbstractAbundant secretory IgA (sIgA) in mucus, breast milk, and saliva provides immunity that prevents infection of mucosal surfaces. sIgA in pre-pandemic breast milk samples have been reported to cross-react with SARS-CoV-2, but whether it also occurs in saliva and, if so, whether it cross-reacts with SARS-CoV-2, has remained unknown. We aimed to clarify whether sIgA in saliva cross-reacts with SARS-CoV-2 spike 1 subunit in individuals who have not been infected with this virus. The study included 137 (male, n = 101; female, n = 36; mean age, 38.7 [24–65] years) of dentists and doctors in the Kanagawa Dental University Hospital. Saliva and blood samples were analyzed by PCR and immunochromatography for IgG and IgM, respectively. We then identified patients with saliva samples that were confirmed as PCR- and IgM-negative for COVID-19. Proportions of SARS-CoV-2 cross-reactive IgA-positive individuals were determined by enzyme-linked immunosorbent assay using a biotin-labeled spike S1-mFc recombinant protein covering the receptor-binding domain of SARS-CoV-2. The proportion of SARS-CoV-2 cross-reactive IgA-positive individuals was 46.7%, and this correlated negatively with age (r = −0.218, p = 0.01). The proportion of IgA-positive individuals ≥ 50 y was significantly lower than that of patients aged ≤ 49 y (p = 0.008). sIgA was purified from the saliva of all patients, and the salivary sIgA was found to suppress the binding of SARS-CoV-2 spike protein to the ACE-2 receptor. We found SARS-CoV-2 cross-reactive sIgA in the saliva of some participants who had never been infected with the virus, suggesting that sIgA helps prevent SARS-CoV-2 infection.

scholarly journals Correlations between Antibody Immune Responses at Different Mucosal Effector Sites Are Controlled by Antigen Type and Dosage

2000 ◽  
Vol 68 (7) ◽  
pp. 3830-3839 ◽  
Author(s):  
Dörthe Externest ◽  
Barbara Meckelein ◽  
M. Alexander Schmidt ◽  
Andreas Frey
Keyword(s):  
Cholera Toxin ◽  
Plasma Cells ◽  
Immunoglobulin A ◽  
Secretory Iga ◽  
Enzyme Linked Immunosorbent Assay ◽  
Routine Diagnostics ◽  
Significant Relationships ◽  
Serum Igg ◽  
Mucosal Surfaces ◽  
Secretory Immunoglobulin

ABSTRACT Monitoring specific secretory immunoglobulin A (IgA) responses in the intestines after mucosal immunization or infection is impeded by the fact that sampling of small intestinal secretions requires invasive methods not feasible for routine diagnostics. Since IgA plasma cells generated after intragastric immunization are known to populate remote mucosal sites as well, secretory IgA responses at other mucosal surfaces may correlate to those in the intestines and could serve as proxy measures for IgA secretion in the gut. To evaluate the practicability of this approach, mice were immunized intragastrically with 0.2, 2, and 20 mg of ovalbumin plus 10 μg of cholera toxin, and the antigen-specific local secretory IgA responses in duodenal, ileal, jejunal, rectal, and vaginal secretions, saliva, urine, and feces, as well as serum IgG and IgA responses were analyzed by enzyme-linked immunosorbent assay. Correlation analysis revealed significant relationships between serum IgG and IgA, urinary IgA, salivary IgA, and secretory IgA in duodenal, jejunal, ileal, and rectal secretions for the 0.2-mg but not for the 20-mg ovalbumin dose. Fecal samples were poor predictors for intestinal antiovalbumin IgA responses, and no correlations could be established for cholera toxin, neither between local anti-cholera toxin levels nor to the antiovalbumin responses. Thus, specific IgA in serum, saliva, or urine can serve as a predictor of the release of specific IgA at intestinal surfaces after intragastric immunization, but the lack of correlations for high ovalbumin doses and for cholera toxin indicates a strong dependency on antigen type and dosage for these relationships.

scholarly journals A Rapid and International Applicable Diagnostic Device for Cobra (Genus Naja) Snakebites

Toxins ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 572
Author(s):  
Jing-Hua Lin ◽  
Wang-Chou Sung ◽  
Jiunn-Wang Liao ◽  
Dong-Zong Hung
Keyword(s):  
Detection Limits ◽  
Rapid Test ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Immunochromatographic Test ◽  
Tissue Destruction ◽  
Diagnostic Device ◽  
Life Threatening ◽  
The Cross ◽  
Geographical Characteristics

Cobra snakes (genus Naja) are some of the most dangerous snake species in Asia and Africa, as their bites cause severe life-threatening respiratory failure and local tissue destruction, especially in the case of late diagnosis. The differential diagnosis of snakebite envenomation still mainly relies upon symptomatology, the patient’s description, and the experience of physicians. We have designed a rapid test, immunochromatographic test of cobra (ICT-Cobra), which obtained fair results in improving the diagnosis and treatment of Naja (N.) atra snakebites in Taiwan. In this study, we further investigated the feasibility of applying the kit for the detection of other cobra venoms based on the potential interspecies similarity. We firstly demonstrated the cross-reactivity between eight venoms of medically important cobra species and the rabbit anti-N. atra IgG that was used in ICT-Cobra by Western blotting and sandwich enzyme-linked immunosorbent assay. Then, ICT-Cobra was used to detect various concentrations of the eight venoms to elucidate its performance. Noticeable correlations between the cross-reactivity of venoms from genus Naja snakes and existing geographical characteristics were found. ICT-Cobra could detect venoms from other Asian cobras with variable detection limits comparable to those observed for N. atra, but the kit was less successful in the detection of venom from African cobras. The similar but slightly different venom components and the interaction between venom and rabbit anti-N. atra IgG led to variations in the detection limits. The transcontinental usage of ICT-Cobra might be possible due to the cross-reactivity of antibodies and similarities among the larger-sized proteins. This study showed that the close immunological relationships in the genus Naja could be used to develop a venom detection kit for the diagnosis of cobra envenomation in both Asian and African regions. Additional clinical studies and technical adjustments are still needed to improve the efficacy and broadening the application of ICT-Cobra in the future.

scholarly journals Allergenic Characterization of Tropomyosin from the Dusky Brown Cockroach, Periplaneta fuliginosa

2004 ◽  
Vol 11 (4) ◽  
pp. 680-685 ◽  
Author(s):  
Kyoung Yong Jeong ◽  
Heeyu Hwang ◽  
Jongweon Lee ◽  
In-Yong Lee ◽  
Dong Soo Kim ◽  
...  
Keyword(s):  
Recombinant Protein ◽  
Periplaneta Americana ◽  
Immunoglobulin E ◽  
Expression System ◽  
Specific Ige ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Inhibitor Concentration ◽  
The Cross ◽  
Elisa Inhibition

ABSTRACTHousehold arthropods are one of the most common causes of allergic diseases. Four species of cockroaches are found to reside in Korean homes, but published work deals almost exclusively with the German and American cockroaches. This study was undertaken to investigate the cross-reactive allergenic components of the dusky brown cockroach,Periplaneta fuliginosa. Enzyme-linked immunosorbent assay (ELISA) inhibition and immunoblot analyses for the dusky brown cockroach were performed withBlattella germanicaandDermatophagoides farinaeallergic sera. cDNA encoding tropomyosin, which is a well known cross-reactive pan-allergen, was cloned by reverse transcriptase PCR, and recombinant protein was produced by using a pET-28b expression system. Native tropomyosin was purified by ammonium sulfate fractionation and electroelution. The immunoglobulin E (IgE) reactivities of native and recombinant tropomyosins were compared by an ELISA inhibition study. All 30 sera tested showedP. fuliginosa-specific IgE, and the IgE-binding reactivity of theP. fuliginosaextract was inhibited as much as 79.4% by aB. germanicaextract and as much as 63.3% by aD. farinaeextract. The deduced amino acid sequence of cloned cDNA was identical with that ofPeriplaneta americanatropomyosin (98.5% nucleotide sequence identity). Seven of 26 (26.9%) allergic sera had IgE specific for recombinant protein, and the maximum inhibition ofP. fuliginosa-specific IgE achieved with recombinant tropomyosin was 37.7% at an inhibitor concentration of 10 μg/ml. Native tropomyosin inhibited the binding of IgE to theP. fuliginosa,B. germanica, andD. farinaeextracts by 65.0, 51.8, and 39% at an inhibitor concentration of 1 μg/ml.P. fuliginosaappears to possess allergens that are highly cross-reactive with allergens ofB. germanicaandD. farinae. Tropomyosin was found to be a major allergenic component accounting for the cross-reactivity between cockroaches and dust mites.

scholarly journals Impairment by Mucosal Adjuvants and Cross-Reactivity with Variant Peptides of the Mucosal Immunity Induced by Injection of the Fusion Peptide PADRE-ELDKWA

2003 ◽  
Vol 10 (6) ◽  
pp. 1103-1108 ◽  
Author(s):  
Nipa Decroix ◽  
Perayot Pamonsinlapatham ◽  
Cahn P. Quan ◽  
Jean-Pierre Bouvet
Keyword(s):  
Immunoglobulin A ◽  
Cell Epitope ◽  
Oral Poliovirus Vaccine ◽  
Fusion Peptide ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Native Form ◽  
Mucosal Transmission ◽  
Viral Epitope ◽  
Industrial Level

ABSTRACT Secretory immunity protects against mucosal transmission of viruses, as demonstrated with the oral poliovirus vaccine. In a previous study we showed that this immunity could be induced in mice by injection of a fusion peptide consisting of an unnatural peptide-like sequence (PADRE) and a viral epitope (ELDKWASLW). PADRE is a T-helper-cell epitope able to bind most major histocompatibility complex class II molecules of different haplotypes in mice and humans and to increase antibody responses. ELDKWA is a well-known consensual sequence of gp41 involved in a key structure of human immunodeficiency virus (HIV) type 1. Here, the antibody response to the native form of ELDKWA was mainly of the immunoglobulin A isotype and selectively occurred in mucosa. Adjuvants, such as cholera toxin and cytosine polyguanine, were useless and even competed with PADRE for the response. Interestingly, these antibodies were cross-reactive with the three major variants of the epitope, as shown both by direct enzyme-linked immunosorbent assay and by inhibition. This unconventional route of mucosal immunization allows control of the administered dose. The lack of adjuvant and the cross-reactivity of the antibodies increase the safety and the spectrum of the candidate vaccine, respectively. The drug-like nature of the construct suggests further improvements by synthesis of more antigenic sequences. The reasonable cost of short peptides at the industrial level and their purity make this approach of interest for future vaccines against mucosal transmission of HIV or other pathogens.

scholarly journals Development of an Immunoassay for the Detection of Amyloid Beta 1-42 and Its Application in Urine Samples

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Anurak Wongta ◽  
Surat Hongsibsong ◽  
Somporn Chantara ◽  
Mookda Pattarawarapan ◽  
Ratana Sapbamrer ◽  
...  
Keyword(s):  
Amyloid Beta ◽  
Limit Of Detection ◽  
Cross Reactivity ◽  
Urine Samples ◽  
Enzyme Linked Immunosorbent Assay ◽  
Inexpensive Method ◽  
Amyloid Beta Peptides ◽  
Beta Peptides ◽  
The Cross ◽  
Sequence Similarities

Amyloid beta peptides (Aβ1-42) have been found to be associated with the cause of Alzheimer’s disease (AD) and dementia. Currently, methods for detecting Aβ1-42 are complicated and expensive. The present study is aimed at developing an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) to detect Aβ1-42 by using a polyclonal antibody from alpaca, an application used in urine samples. The serum was collected from the alpaca after immunizing it with Aβ1-42 at 500 μg/injection 5 times. The ic-ELISA was developed and showed a half-maximal inhibitory concentration ( I C 50 ) of 103.20 ng/ml. The limit of detection (LOD) was 0.39 ng/100 μl. The cross-reactivity was tested with Aβ1-40 and 8 synthesized peptides that had sequence similarities to parts of Aβ1-42. The cross-reactivity of Aβ1-40 and peptide 1 (DAEFRHDSGYE) was 55% and 69.4%, respectively. The ic-ELISA was applied to analyze Aβ1-42 in the urine and precipitated protein urine samples. This method can be used for detecting a normal level of total soluble Aβ (approximately 1 ng in 5 mg of precipitated urine protein) and can be used for detecting the early stages of AD. It is considered to be an easy and inexpensive method for monitoring and diagnosing AD.

scholarly journals Multiplex lateral flow immunochromatographic assay is an effective method to detect carbapenemases without risk of OXA-48-like cross reactivity

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Hadas Kon ◽  
Shirin Abramov ◽  
Sammy Frenk ◽  
David Schwartz ◽  
Ohad Shalom ◽  
...  
Keyword(s):  
Gold Standard ◽  
Clinical Microbiology ◽  
Cross Reactivity ◽  
Control Measures ◽  
Chain Reaction ◽  
Infection Control Measures ◽  
Carbapenem Resistant ◽  
Highly Sensitive ◽  
Polymerase Chain ◽  
The Cross

Abstract Background It is essential to detect carriers of carbapenemase-producing Enterobacterales in order to implement infection control measures. The objectives of this study was to evaluate the NG-Test® CARBA 5 (CARBA 5) assay for detection of five carbapenemases and to assess the cross reactivity of other OXA-type carbapenemases with the OXA-48-like specific antibodies. Methods A total of 197 Enterobacterales isolates were tested. To evaluate the cross reactivity, 73 carbapenem-resistant A. baumannii, harboring OXA-type variants, were tested. Polymerase chain reaction (PCR) served as gold standard for carbapenemase identification. Results Excellent agreement was found between PCR and CARBA 5, for all but one isolate. The single false positive result (a blaSME positive S. marcescens isolate) was incorrectly positive for blaOXA-48 by CARBA 5. No cross reactivity was observed. The sensitivity and specificity were 100.0% and 98.0%, respectively. Conclusions The CARBA 5 assay is highly sensitive and specific and is recommended as a tool for the detection of the main carbapenemases of interest in clinical microbiology laboratories.

Breast Milk and Saliva Lactoferrin Levels and Postnatal Cytomegalovirus Infection

2020 ◽  
Author(s):  
Kristin E. D. Weimer ◽  
Hunter Roark ◽  
Kimberley Fisher ◽  
C. Michael Cotten ◽  
David A. Kaufman ◽  
...  
Keyword(s):  
Breast Milk ◽  
Very Low Birth Weight ◽  
Quantitative Polymerase Chain Reaction ◽  
Neutralization Assay ◽  
Enzyme Linked Immunosorbent Assay ◽  
Lactating Mothers ◽  
Life Threatening ◽  
Polymerase Chain

Abstract Objective Very low birth weight preterm infants are at risk for life-threatening infections in the NICU. Breast milk protects against infections but carries the risk of infection by cytomegalovirus (CMV) shed in mother's milk. Lactoferrin is a breast milk and saliva protein with potent neutralizing activity against CMV. Study Design VLBW, maternal breast milk fed infants in the NICU and their lactating mothers were enrolled and followed for 3 months/discharge. Breast milk and infant saliva samples were collected biweekly. Maternal CMV status was determined on breast milk. CMV was measured using quantitative polymerase chain reaction and lactoferrin by enzyme-linked immunosorbent assay. Results In an in vitro neutralization assay, the IC90 of purified human lactoferrin against CMV was 2.08 ng/mL. Bovine lactoferrins were more potent, IC90s > 10-fold higher. Lactoferrin was detected in all breast milk (median: 3.3 × 106 ng/mL) and saliva (median: 84.4 ng/swab) samples. Median CMV load in breast milk was 893 copies/mL. There was no correlation between breast milk lactoferrin concentration and CMV load. Five infants acquired postnatal CMV. There was no difference in saliva or breast milk lactoferrin concentration for mother–infant pairs and postnatal CMV acquisition. Conclusion Lactoferrin neutralizes CMV in vitro, but concentrations in breast milk and saliva are likely too low for effective neutralization in vivo.

Production and Function of Immunoglobulin A

2021 ◽  
Vol 39 (1) ◽  
pp. 695-718
Author(s):  
Timothy W. Hand ◽  
Andrea Reboldi
Keyword(s):  
Immunoglobulin A ◽  
Intestinal Bacteria ◽  
Secretory Component ◽  
Cross Reactivity ◽  
Antigen Binding ◽  
Effector Functions ◽  
Mucosal Surfaces ◽  
Enteric Infections ◽  
And Function ◽  
Exquisite Specificity

Among antibodies, IgA is unique because it has evolved to be secreted onto mucosal surfaces. The structure of IgA and the associated secretory component allow IgA to survive the highly proteolytic environment of mucosal surfaces but also substantially limit IgA's ability to activate effector functions on immune cells. Despite these characteristics, IgA is critical for both preventing enteric infections and shaping the local microbiome. IgA's function is determined by a distinct antigen-binding repertoire, composed of antibodies with a variety of specificities, from permissive polyspecificity to cross-reactivity to exquisite specificity to a single epitope, which act together to regulate intestinal bacteria. Development of the unique function and specificities of IgA is shaped by local cues provided by the gut-associated lymphoid tissue, driven by the constantly changing environment of the intestine and microbiota.

scholarly journals Incorporation of IgG Depletion in a Neutralization Assay Facilitates Differential Diagnosis of Zika and Dengue in Secondary Flavivirus Infection Cases

2018 ◽  
Vol 56 (6) ◽  
Author(s):  
Amanda E. Calvert ◽  
Karen L. Boroughs ◽  
Janeen Laven ◽  
Janae L. Stovall ◽  
Betty E. Luy ◽  
...  
Keyword(s):  
Differential Diagnosis ◽  
Dengue Virus ◽  
Neutralizing Antibody ◽  
Laboratory Diagnosis ◽  
Cross Reactivity ◽  
Definitive Diagnosis ◽  
Health Concern ◽  
Enzyme Linked Immunosorbent Assay ◽  
Global Public Health ◽  
The Cross

ABSTRACTZika virus (ZIKV) has emerged as a major global public health concern due to its link as a causative agent of human birth defects. Laboratory diagnosis of suspected ZIKV infections by serological testing of specimens collected a week or more after symptom onset primarily relies on detection of anti-ZIKV-specific IgM antibodies by enzyme-linked immunosorbent assay coupled with detection of ZIKV-specific neutralizing antibody by neutralization tests. A definitive diagnosis based on serological assays is possible during primary ZIKV infections; however, due to the cross-reactivity of antibodies elicited during flaviviral infections, a definitive diagnosis is not always possible, especially among individuals who have previously been exposed to closely related flaviviruses, such as dengue virus (DENV). Here, we investigated the neutralizing IgM antibody profiles of 33 diagnostic specimens collected from individuals with suspected primary and secondary flaviviral infections acquired when visiting areas experiencing active ZIKV transmission in 2015 and 2016. Specimens collected between 1 day and 3 months postexposure were tested for ZIKV and dengue virus type 1 (DENV1) and type 2 (DENV2) by the plaque reduction neutralization test (PRNT) before and after IgG depletion. We found that IgG depletion prior to neutralization testing had little effect in differentiating samples from individuals with secondary infections taken less than 3 weeks postexposure; however, IgG depletion significantly reduced the cross-reactive neutralizing antibody titers and increased the percentage of cases discernible by PRNT from 15.4% (95% confidence interval [CI], 4.3 to 42.2%) to 76.9% (95% CI, 49.7 to 91.8%) for samples collected between roughly 3 and 12 weeks postexposure. These results highlight the potential of IgG depletion to improve the specificity of PRNT for better confirmation and differential diagnosis of flavivirus infections.

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