Identification of carboxymethyl (CM)-binding proteins derived from Lolium multiflorum pollen extract and antibody reactivity in Brazilian allergic patients.

Lolium multiflorum grass is the major pollen allergen source in the southern region of Brazil, but most of its allergens remain poorly characterized. The aim of this study was to investigate antibody reactivity to L. multiflorum crude and carboxymethyl-ligand extracts in allergic patients and healthy individuals. Ion exchange carboxymethyl (CM) chromatography (CM-Sepharose) was used to isolate proteins (S2) from L. multiflorum crude extract (S1), which were assessed by SDS-PAGE. S1- and S2-specific IgE and IgG4 levels were measured by ELISA using sera from 55 atopic and 16 non-atopic subjects. Reactive polypeptide bands in S1 and S2 were detected by immunoblotting, and the most prominent bands in S2 were analyzed by mass spectrometry (MS-MS). Similar IgE and IgG4 levels were observed to both S1 (IgE median absorbance: 1.22; IgG4 median absorbance: 0.68) and S2 (IgE median absorbance: 1.26; IgG4 median absorbance: 0.85) in atopic subjects. S1 and S2 had positive correlations for IgE and IgG4 (IgE: r=0.9567; IgG4: r=0.9229; P<0.0001) levels. Homology between S1 and S2 was confirmed by IgE (84%) and IgG4 (83%) inhibition. Immunoblotting revealed that the 29-32 kDa band was recognized by 100% of atopic subjects in both S1 and S2. MS-MS analysis identified similarity profile to groups 1 and 5 grass allergens. This study revealed that carboxymethyl-ligand fraction played an important role for pollen allergy diagnosis by containing clinically relevant allergens and constituted a promising candidate for allergen-specific immunotherapy.

Identification of carboxymethyl (CM)-binding proteins derived from Lolium multiflorum pollen extract and antibody reactivity in Brazilian allergic patients

Lolium multiflorum grass is the major pollen allergen source in the southern region of Brazil, but most of its allergens remain poorly characterized. The aim of this study was to investigate antibody reactivity to L. multiflorum crude and carboxymethyl-ligand extracts in allergic patients and healthy individuals. Ion exchange carboxymethyl (CM) chromatography (CM-Sepharose) was used to isolate proteins (S2) from L. multiflorum crude extract (S1), which were assessed by SDS-PAGE. S1- and S2-specific IgE and IgG4 levels were measured by ELISA using sera from 55 atopic and 16 non-atopic subjects. Reactive polypeptide bands in S1 and S2 were detected by immunoblotting, and the most prominent bands in S2 were analyzed by mass spectrometry (MS-MS). Similar IgE and IgG4 levels were observed to both S1 (IgE median absorbance: 1.22; IgG4 median absorbance: 0.68) and S2 (IgE median absorbance: 1.26; IgG4 median absorbance: 0.85) in atopic subjects. S1 and S2 had positive correlations for IgE and IgG4 (IgE: r=0.9567; IgG4: r=0.9229; P<0.0001) levels. Homology between S1 and S2 was confirmed by IgE (84%) and IgG4 (83%) inhibition. Immunoblotting revealed that the 29-32 kDa band was recognized by 100% of atopic subjects in both S1 and S2. MS-MS analysis identified similarity profile to groups 1 and 5 grass allergens. This study revealed that carboxymethyl-ligand fraction played an important role for pollen allergy diagnosis by containing clinically relevant allergens and constituted a promising candidate for allergen-specific immunotherapy.

Barrier proteins and eosinophilic esophagitis in children: the role of E-cadherin and filaggrin

This study aimed to assess the protein expression of E-cadherin and filaggrin (FLG) in the oesophagus of paediatric and adolescent patients diagnosed with eosinophilic esophagi-tis (EoE). It is a cross-sectional study conducted with 24 patients with EoE and 17 control patients, from June 2015 to June 2018. The histological analyses were performed by a trained pathologist. The protein expression of E-cadherin and FLG in oesophageal biopsy fragments was determined using an immunohistochemical technique. The epidemiological data were retrieved from medical records. There were no statistical differences in age and sex between case-patients and control patients. Food allergy was significantly higher in patients with EoE, as was the number of eosinophils present in the oesophageal biopsy materials. The immu-nohistochemical studies did not indicate FLG expression in any patient from the two groups. E-cadherin showed significantly reduced expression in patients with EoE. We concluded that FLG did not seem to play an important role in the mucosal alteration in EoE and that E-cadherin under expression could be a promising marker of epithelial damage in these patients.© 2022 Codon Publications. Published by Codon Publications (AU)

Usefulness of gel filtration fraction as potential biomarker for neurocysticercosis in serum: towards a new diagnostic tool.

There is an increasing interest in improving neurocysticercosis (NCC) diagnosis through the search of new and alternative antigenic sources, as those obtained from heterologous antigens. The aim of this study was to obtain potential biomarkers for NCC diagnosis after gel filtration chromatography [gel filtration fraction (GFF)] from the total saline extract (SE) from Taenia saginata metacestodes, followed by protein identification and application in immunodiagnostic. SE and GFF proteic profiles were characterized in gel electrophoresis, and diagnostic performance was verified by testing 160 serum samples through enzyme-linked immunosorbent assay and immunoblotting. Sensitivity (Se), specificity (Sp) and other diagnostic parameters were calculated. Polypeptides of interest in the diagnosis of human NCC present at GFF were analysed by mass spectrometry (MS) and B-cell epitopes were predicted. GFF had the best diagnostic parameters: Se 93·3%; Sp 93%; AUC 0·990; LR+ = 13·42 and LR- = 0·07, and proved to be useful reacting with serum samples in immunoblotting. Proteic profile ranged from 64 to 68 kDa and enolase and calcium binding protein calreticulin precursor were identified after MS. The enolase and calcium-binding protein calreticulin precursor showed 18 and 10 predicted B-cell epitopes, respectively. In conclusion we identified important markers in the GFF with high efficiency to diagnose NCC.

Ion-exchange protocol to obtain antigenic fractions with potential for serodiagnosis of strongyloidiasis.

The aim of this study was to fractionate and partially characterize the antigenic extract of filariform larvae of Strongyloides venezuelensis in ion-exchange resin diethylaminoethyl sepharose (DEAE), to obtain antigenic fractions potentially applicable in immunoassays. Somatic antigen (SA) and its fractions DEAE S1 and DEAE S2 - which interacted with the resin - were evaluated by 1-dimensional electrophoresis to obtain protein profiles. SA and its fractions were tested in serum samples for IgG detection by ELISA. Serum samples (n = 155) were analysed: 50 from strongyloidiasis patients (G1), 55 from patients with other parasitic infections (G2) and 50 from healthy volunteers. Sensitivity (Se), specificity (Sp), area under curve (AUC) and likelihood ratios (LR) were calculated. The DEAE S2 fraction provided a high diagnostic value for IgG detection (Se 92·0%, Sp 91·4%, AUC 0·981, LR+ 10·75, LR - 0·09). In conclusion, the DEAE S2 fraction would probably be a source of immunodominant polypeptides for IgG detection in human strongyloidiasis serodiagnosis.

Responses of IgE, IgG1, and IgG4 to concanavalin A-binding Blomia tropicalis antigens in allergic patients.

Blomia tropicalis (Bt) and Dermatophagoides pteronyssinus (Dp) are the prevalent house dust mites in tropical countries and are associated with allergic diseases. Glycosylated antigens are highly immunogenic and involved in different pathologies. We evaluated the presence of IgE, IgG1, and IgG4 to concanavalin A-binding antigens (Bt-Con-A) isolated from Bt-total extract in sera of allergic and non-allergic subjects. Bt-total and Bt-Con-A extracts were evaluated by SDS-PAGE and ELISA for reacting with IgE, IgG1, and IgG4 in sera of 121 patients with allergic rhinitis and 36 non-allergic individuals. All subjects were skin prick tested with Bt-total extract and inhibition tests were performed for IgE, IgG1, and IgG4 using both extracts (Bt-total and Bt-Con-A). Skin prick test showed that 58% of the patients were sensitized to Bt (Bt+), with 52% reactive to both mites (Bt and Dp) and 6% to Bt only. A broad spectrum of proteins (14-152 kDa) was visualized in Bt-total and components >27 kDa for the Bt-Con-A extract. ELISA showed a similar profile of IgE, IgG1 and IgG4 levels in response to Bt-total and Bt-Con-A extracts in different groups, although Bt+ patients showed a lower IgG4 reactivity to Bt-Con-A extract. Specific IgG1 levels were higher in Bt+ patients than in control subjects, and IgG4 levels showed no significant difference among groups. ELISA inhibition showed a partial IgE and total IgG1 and IgG4 cross-reactivity with Dp extract for Bt-total and Bt-Con-A extracts. We conclude that Con-A-binding components isolated from Bt constitute major allergens and are involved in both allergen sensitization (IgE response) and homeostasis maintenance (IgG1 and IgG4 responses).

Responses of IgE, IgG1, and IgG4 to concanavalin A-binding Blomia tropicalis antigens in allergic patients

Blomia tropicalis (Bt) and Dermatophagoides pteronyssinus (Dp) are the prevalent house dust mites in tropical countries and are associated with allergic diseases. Glycosylated antigens are highly immunogenic and involved in different pathologies. We evaluated the presence of IgE, IgG1, and IgG4 to concanavalin A-binding antigens (Bt-Con-A) isolated from Bt-total extract in sera of allergic and non-allergic subjects. Bt-total and Bt-Con-A extracts were evaluated by SDS-PAGE and ELISA for reacting with IgE, IgG1, and IgG4 in sera of 121 patients with allergic rhinitis and 36 non-allergic individuals. All subjects were skin prick tested with Bt-total extract and inhibition tests were performed for IgE, IgG1, and IgG4 using both extracts (Bt-total and Bt-Con-A). Skin prick test showed that 58 percent of the patients were sensitized to Bt (Bt+), with 52 percent reactive to both mites (Bt and Dp) and 6 percent to Bt only. A broad spectrum of proteins (14-152 kDa) was visualized in Bt-total and components >27 kDa for the Bt-Con-A extract. ELISA showed a similar profile of IgE, IgG1 and IgG4 levels in response to Bt-total and Bt-Con-A extracts in different groups, although Bt+ patients showed a lower IgG4 reactivity to Bt-Con-A extract. Specific IgG1 levels were higher in Bt+ patients than in control subjects, and IgG4 levels showed no significant difference among groups. ELISA inhibition showed a partial IgE and total IgG1 and IgG4 cross-reactivity with Dp extract for Bt-total and Bt-Con-A extracts. We conclude that Con-A-binding components isolated from Bt constitute major allergens and are involved in both allergen sensitization (IgE response) and homeostasis maintenance (IgG1 and IgG4 responses).

IgE, IgG1, and IgG4 antibody responses to Blomia tropicalis in atopic patients.

BACKGROUND: Allergens from house dust mites (HDMs), Dermatophagoides pteronyssinus and Blomia tropicalis are clinically relevant in atopic respiratory diseases in tropical countries. AIMS OF THE STUDY: To evaluate immunoglobulin (Ig)E, IgG1, and IgG4 antibody responses to B. tropicalis in Brazilian atopic patients. METHODS: About 110 patients with allergic rhinitis with/without asthma and 33 control subjects underwent skin prick testing (SPT) with HDM extracts, and their sera were tested for IgE and IgG subclass antibodies to D. pteronyssinus and B. tropicalis by enzyme-linked immunosorbent assay (ELISA) and immunoblotting. RESULTS: Most patients (56%) had positive SPT to B. tropicalis extract (B. tropicalis+ group), although 51% were reactive to both B. tropicalis and D. pteronyssinus and 6% were sensitized to B. tropicalis only. IgE-ELISA detected 43%B. tropicalis positivity with high-specific IgE levels in B. tropicalis+ patients. Specific IgG4 levels were higher in B. tropicalis+ than B. tropicalis- groups and correlated with specific IgE levels. The IgG1 levels to B. tropicalis were higher in patients than controls. The major allergenic B. tropicalis components recognized by B. tropicalis+ patient sera were the 54, 66, and 68 kDa proteins. The IgG4-binding protein profiles closely resembled that of IgE. The IgG1 antibodies recognizing multiple B. tropicalis protein species were detected in sera of all three patient groups. CONCLUSIONS: A large percentage of our allergic patients are B. tropicalis+. They are more frequently sensitized to high-molecular weight (HMW) B. tropicalis components than the major low-molecular weight (11-15 kDa) allergens detected in other studies. The results suggest that HMW B. tropicalis antigenic components are potential candidates for evaluating allergen exposure and sensitization, and for immunotherapy treatment.