kDa Antigen Research Articles

Comparison of the Diagnostic Performance of Antigen B Purified from Sheep Hydatid Cyst Fluid (HCF) with Commercial ELISA Kit.

Cystic echinococcosis (CE) is a zoonotic parasitic disease caused by the metacestode of Echinococcus granulosus. CE is a health problem in Middle Eastern countries, such as Iran. The purpose of this study was to purify subunit 8 KDa antigen B from crude sheep hydatid cyst fluid (HCF) and compare its sensitivity and specificity with a commercial human ELISA kit (PT-Hydatid-96). 28 sera samples were collected from hydatid cyst patients who had surgery for a hydatid cyst and had their disease confirmed by pathology after the surgery. Furthermore, 35 samples of healthy individuals with no history of hydatid cysts were collected, as were nine serum samples from parasite-infected non-CE patients. HCF was obtained from sheep fertile cysts at a Sari slaughterhouse and used as an antigen. In an indirect ELISA test, the B antigen was employed, and the results were compared to those from a commercial ELISA kit. The results of this study were analyzed using the Kappa test. The commercial ELISA kit showed 17 cases (23.6%) positive, 44 cases (61.1%) negative, and 11 cases (15.3%) borderline. B antigen showed that 18 (25%), 43 (59.7 %), and 11 (15.3%) were positive, negative, and borderline, respectively. One sample (1.4% of 72 total samples) of 35 serum samples from healthy individuals was positive using B antigen-based ELISA. In addition, all nine serum samples from parasite-infected non-CE patients were negative for both tests. The sensitivity and specificity of the commercial ELISA kit have been evaluated at 60.7% and 100%, respectively. For B antigenbased ELISA, these values are 64.3 and 97.7%, respectively. Antigen B produced from hydatid cyst fluid is a promising option for serological identification of hydatid cysts in both infected and healthy individuals. In an indirect ELISA test, hydatid fluid antigen could be used as a precise source of detection.

In silico design of Mycobacterium tuberculosis multi-epitope adhesin protein vaccines

Mycobacterium tuberculosis (Mtb) adhesin proteins are promising candidates for subunit vaccine design. Multi-epitope Mtb vaccine and diagnostic candidates were designed using immunoinformatic tools. The antigenic potential of 26 adhesin proteins were determined using VaxiJen 2.0. The truncated heat shock protein 70 (tnHSP70), 19 kDa antigen lipoprotein (lpqH), Mtb curli pili (MTP), and Phosphate transport protein S1 (PstS1) were selected based on the number of known epitopes on the Immune Epitope Database (IEDB). B- and T-cell epitopes were identified using BepiPred2.0, ABCpred, SVMTriP, and IEDB, respectively. Population coverage was analysed using prominent South African specific alleles on the IEDB. The allergenicity, physicochemical characteristics and tertiary structure of the tri-fusion proteins were determined. The in silico immune simulation was performed using C-ImmSim. Three truncated sequences, with predicted B and T cell epitopes, and without allergenicity or signal peptides were linked by three glycine-serine residues, resulting in the stable, hydrophilic molecules, tnlpqH-tnPstS1-tnHSP70 (64,86 kDa) and tnMTP-tnPstS1-tnHSP70 (63,96 kDa). Restriction endonuclease recognition sequences incorporated at the N- and C-terminal ends of each construct, facilitated virtual cloning using Snapgene, into pGEX6P-1, resulting in novel, highly immunogenic vaccine candidates (0,912–0,985). Future studies will involve the cloning, recombinant protein expression and purification of these constructs for downstream applications.

Molecular Identification of Spotted Fever Group Rickettsiae in Ticks in the Republic of Korea.

The Rickettsia species transmitted by ticks are mostly classified within the spotted fever group rickettsiae (SFGR), which causes tick-borne rickettsiosis. Although efforts have been made to investigate their prevalence in the Republic of Korea (ROK), research has been limited to certain areas. Furthermore, the pooling method for ticks does not fully reflect the exact infection rate. Therefore, we aimed to perform molecular identification of SFGR in ticks to elucidate the current prevalence of tick-borne rickettsiosis in the ROK. The SFGR of ticks was identified using polymerase chain reaction targeting the 17 kDa antigen, ompA, and gltA, followed by sequencing for species identification and phylogenetic analysis. In total, 302 ticks belonging to four species (Haemaphysalis flava, H. longicornis, Ixodes nipponensis, and Amblyomma testudinarium) were collected between April and November 2022. The overall SFGR infection rate was 26.8% (81/302 patients). Both adult and nymphal ticks and the SFGR infection rate increased during April-May, reaching their peaks in June, followed by a marked decline in August and July, respectively. Phylogenetic analysis revealed three species (R. monacensis, R. heilongjiangensis, and Candidatus R. jingxinensis) of SFGR. Thus, our results emphasize the importance of tick surveys for the prevention and management of tick-borne rickettsiosis.

Increased levels of IL-10 in the spleen after induction of pili protein 65.5 kDa Klebsiella pneumoniae

Background: One of the gram-negative bacteria often found as the cause of nosocomial infections is Klebsiella pneumoniae. This bacterium has a mortality rate of 28.3% due to ESBL strains that cause resistance to several antibiotics and the absence of a vaccine as a preventive measure. Objective: To determine the level of IL-10 in the spleen after induction of the protein pili K. pneumoniae 65.5 kDa in mice. Method: This study used mice spleen samples from 21 mice aged six to eight weeks in an experimental investigation with a randomised posttest-only control group design. There are three groups, K1 as a PBS-given control, 65.5 kDa antigen protein pills + Freund’s adjuvants are given to K2, and Freund's adjuvants are given to K3. Interleukin-10 concentrations were measured using the ELISA and analysed by a one-way ANOVA assay. Result: The research showed significant differences in each group at IL-10 levels after administration of the pili protein K. pneumoniae using one-way ANOVA (p = 0.036). The treatment group had the highest average levels of IL-10, so there was an increased association between exposure to pili protein and IL-10 levels in rats. A significant increase in IL-10 levels was found in the treatment group compared to the control and adjuvant groups. Conclusion: Induction of protein pili Klebsiella pneumoniae 65.5 kDa increases IL-10 levels in spleen mice.

Serological Investigation of Persistent Villous Atrophy in Celiac Disease.

Persistent villous atrophy (VA) is not uncommon in celiac disease (CeD) while patients take a gluten-free diet (GFD). We conducted a retrospective study with 122 serum samples collected from controls and patients with CeD either at the initial diagnosis or at the follow-up during endoscopy. These samples were assigned to 3 groups: nonceliac control, non-VA CeD (Marsh score 0-2), and VA CeD (Marsh score 3a-3c). We established an in-house multiplex assay to identify potential serological biomarkers for VA. We assessed autoantibodies reported to affect the small intestine, including IgA and IgG antibodies against tissue transglutaminase (tTG), interferons, villin, actin, autoimmune enteropathy-related 75 kDa antigen (AIE-75), and tryptophan hydroxylase (TPH)-1, as well as 27 cytokines. The apolipoproteins quantified included apo A1, apo B-100, and apo A4, which were produced predominantly by the intestinal epithelium or expressed specifically in villi. Autoantibody levels were high only for tTG antibodies, which performed well in initial CeD diagnosis, but suboptimally for VA prediction during follow-up, because 14.6% of the follow-up patients with VA had low tTG-IgA. Increasing dilution improved tTG-IgA quantification, particularly when the antibody levels were extremely high but did not significantly improve VA detection. Among those with low tTG-IgA and persistent VA, high proinflammatory cytokines were observed in 2 patients. Median low-density lipoprotein cholesterol levels were significantly lower in the VA CeD group ( P = 0.03). Apolipoprotein levels were similar in patients with and without VA but diverged between those on a GFD or not. tTG-IgA as a biomarker is suboptimal for VA prediction while on a GFD. Persistent VA is associated with low low-density lipoprotein cholesterol levels and partially related to persistent high proinflammatory cytokines.

Identification of serologically active Helicobacter pylori antigens related to alterations in serum pepsinogen levels

Gastric adenocarcinoma is associated with Helicobacter pylori infection. The transition to a carcinogenic process is preceded by glandular atrophy and serum levels of pepsinogen I and II (PGI and PGII) correlate with this type of gastric lesions. Possible associations of serum PG levels in relation to the frequency of serological activity against H. pylori antigens were studied. Serum samples from patients with gastric pathology associated with H. pylori (n=26) and asymptomatic individuals as controls (n=37) were used. Seroactive antigens were identified by immunoblot using a protein extract of H. pylori. The antibody titers anti-H. pylori and the concentration of PGs in serum was determined by ELISA. Thirty-one seroactive antigens were identified, nine of which exhibited a differential frequency between both groups (116.7, 68.8, 61.9, 54.9, 45.6, 38.3, 36.5, 33.8 and 30.1kDa) and only 3 were related to altered levels of PGs in serum. In the control group, the seropositivity of the 33.8kDa antigen was related to an increase in PGII, while the 68.8kDa antigen was related to normal PG values (decreased PGII and elevated PGI/PGII levels) indicating that seropositivity to this antigen could be a protective factor to gastric pathology. The seropositivity of the 54.9kDa antigen was related to altered values of PGs indicative of inflammation and gastric atrophy (increased in PGII and decreased in PGI/PGII). The identification of serum alterations in pepsinogen levels related to seropositivity to H. pylori 33.8, 54.9 and 68.8kDa antigens sets a precedent for further study as possible prognostic serological biomarkers.

Doubtful Clinical Value of Subtyping Anti-U1-RNP Antibodies Regarding the RNP-70 kDa Antigen in Sera of Patients with Systemic Lupus Erythematosus.

The detection of antinuclear antibodies is central to the diagnosis and prognosis of systemic lupus erythematosus (SLE), primary Sjögren's syndrome (pSS) and mixed connective tissue disease (MCTD). Anti-U1-RNP and anti-RNP70 antibodies were assayed in the sera of patients with SLE (n = 114), pSS (n = 54) and MCTD (n = 12). In the SLE group, 34/114 (30%) were anti-U1-RNP positive, and 21/114 (18%) were both anti-RNP70 positive and anti-U1-RNP positive. In the MCTD group, 10/12 (83%) were anti-U1-RNP positive, and 9/12 (75%) were anti-RNP70 positive. Only one individual with pSS was antibody positive (for both anti-U1-RNP and anti-RNP70). All anti-RNP70-positive samples were also anti-U1-RNP positive. Anti-U1-RNP-positive subjects with SLE were younger (p < 0.0001); showed lower concentrations of complement protein 3 (p = 0.03); had lower eosinophil (p = 0.0005), lymphocyte (p = 0.006) and monocyte (p = 0.03) counts; and had accrued less organ damage (p = 0.006) than the anti-U1-RNP-negative SLE patients. However, we observed no significant clinical or laboratory parameter differences between the anti-U1-RNP-positive individuals with/without anti-RNP70 in the SLE group. In conclusion, anti-RNP70 antibodies are not exclusive to MCTD but are rarely detected in pSS and healthy individuals. In SLE, anti-U1-RNP antibodies are associated with a clinical phenotype that resembles MCTD, with hematologic involvement and less damage accrual. Based on our results, the clinical value of subtyping anti-RNP70 in anti-U1-RNP-positive sera appears to be of limited value.

Sensitivity and specificity of an indirect ELISA using Hawaii 31 kDa Angiostrongylus cantonensisantigen in experimentally-infected rats (Rattus norvegicus)

Abstract The parasitic nematode Angiostrongylus cantonensisis the leading cause of neuroangiostrongyliasis, is an emerging tropical disease, and is the leading cause of eosinophilic meningitis worldwide. Diagnosis is generally presumptive and can be easily confused with other central nervous system disorders. Several studies have demonstrated the promise of immunodiagnosis, most frequently in the form of ELISA assays. Taking advantage of plasma samples from previous rat studies, we developed an indirect ELISA assay based on the 31 kDa antigen isolated from A. cantonensiscollected in Hawai’i. Using IgG, our assay showed 100% sensitivity, and specificity in diagnosing A. cantonensisinfection in lab-reared rats fed 50 live larvae six weeks previously. We saw diminishing sensitivity to IgM, IgA, and IgE, respectively, and no antibody response in rats fed killed A. cantonensislarvae. Our experiments validate the use of indirect ELISA with 31 kDa antigen as an effective immunodiagnostic assay for rats, and our use of different antibody isotypes provided an opportunity to investigate in more detail the humoral immune response in lab-reared rats to A. cantonensisinfection. Daniel K. Inouye College of Pharmacy, Hawaii State Legislature

Comparison of Antibody Isotype Response to Angiostrongylus cantonensis in Experimentally Infected Rats (Rattus norvegicus) Using Hawai'i 31 kDa Antigen in an Indirect ELISA.

Neuroangiostrongyliasis (NAS) is an emerging tropical disease in humans and some animals which is caused by infection with the parasitic nematode Angiostrongylus cantonensis. It is the leading cause of eosinophilic meningitis worldwide. Diagnoses in humans and susceptible animals are generally presumptive and easily confused with other central nervous system disorders. The 31 kDa antigen is currently the only NAS immunodiagnostic assay that has achieved 100% sensitivity. However, little is known about the humoral immune response against the 31 kDa antigen in NAS infections, which would be critical for widespread adoption of this assay. We used the Hawai'i 31 kDa isolate in an indirect ELISA assay to confirm the presence of immunoglobulin IgG, IgM, IgA, and IgE isotypes in six-week post-infection plasma from lab-reared rats infected with 50 live, third-stage, A. cantonensis larvae isolated from a wild Parmarion martensi semi-slug. Our results confirmed the presence of all four isotypes against the Hawaii 31 kDa isolate, with sensitivity ranging from 22-100%. The IgG isotype showed 100% sensitivity in detecting A. cantonensis infection, which validates the use of IgG indirect ELISA with 31 kDa antigen as an effective immunodiagnostic assay for rats six weeks post-infection. Given each isotype may be present at different times during NAS infections, our data provides preliminary information on the humoral immune response to A. cantonensis infection in lab-reared rats and serves as a baseline for future studies.

IEg67 kDa Bovine Hydatid Cyst Antigen: A Candidate for Developing Sero-Diagnostic Assays for Cystic Echinococcosis, a Disease of One Health Importance.

Cystic echinococcosis (hydatidosis) is a world-wide zoonotic disease of mainly humans, livestock and dogs, caused by Echinococcus granulosus. The disease can negatively impact food production and animal welfare and causes socio-economic hardship. Here, we aimed to identify the local bovine hydatid cyst fluid (BHCF) antigen for developing a sero-diagnostic assay to be used for the pre-slaughter screening of food animals. In total, 264 bovines approved for slaughter in Pakistan were subjected to serum collection and post-mortem screening for hydatid cysts. These cysts were assessed microscopically to assess fertility and viability, and by PCR for molecular confirmation of species. A BHCF antigen was identified from positive sera via SDS-PAGE, confirmed by Western blot, and quantified via a bicinchoninic acid (BCA) assay. The quantified crude BHCF antigen (iEg67 kDa) was then used in ELISA screening to test all sera collected from known positive and negative animals based on hydatid cyst presence/absence. Of the 264 bovines examined, 38 (14.4%) showed hydatid cysts during post-mortem examination. All of these individuals, plus an additional 14 (total: 52; 19.6%) tested positive based on less time-consuming ELISA examination. Based on ELISA, occurrence in females (18.8%) was significantly higher than in males (9.2%) and was higher in cattle (19.5%) compared to buffalo (9.5%). The infection rate increased with age in both host species: cumulatively, 3.6% in animals aged 2-3 years, 14.6% in 4-5-year-olds and 25.6% in 6-7-year-olds. The occurrence of cysts in cattle was significantly higher in the lungs (14.1%) compared to their livers (5.5%), whereas the opposite was true in buffalo (6.6% livers, 2.9% lungs). For both host species, most cysts in the lungs were fertile (65%), while the majority in the liver were sterile (71.4%). We conclude that the identified iEg67 kDa antigen is a strong candidate for the development of a sero-diagnostic screening assay for the pre-slaughter diagnosis of hydatidosis.

Detection of 16 kDa Protein from Mycobacterium Tuberculosis Using Interdigitated Electrode

In the past, researchers investigated the immune response acting against mycobacterial antigens in tuberculosis (TB). Several ELISA tests have been conducted for the diagnosis of tuberculosis. Other researchers manipulated 16 kDa antigen from Mycobacterium Tuberculosis to develop a tuberculosis diagnostic test while some others studied the subspecies of M. tuberculosis. In the present study, we explored the possibilities of detecting 16 kDa protein derived from M. tuberculosis, on an interdigitated electrode (IDE). Measurements with Electrochemical impedance spectroscopy and current-volt systems were demonstrated using antibody as the probe. Further, the involvement of gold nanoparticle for the signal-enhancement and high-performance are evidenced. The specificity in the serum containing samples is used to show the clinical relevancy. 16 kDa antigen used in this experiment is highly reliable for TB diagnosis as it largely expresses and can be implemented in other sensing system.

Identification and Prevalence of Brucella Species Circulating among Cattle Slaughtered in the Douala and Buea Municipalities of Cameroon

Brucellosis is a neglected zoonotic disease affecting the livestock sector in low‐income countries. Cameroon, a lower‐middle‐income country in sub‐Saharan Africa, has reported the prevalence of brucellosis in regions where livestock rearing is the principal economic activity. However, the presence of the disease has not been reported in southern regions receiving cattle for consumption by their population. In addition, there is no report on the Brucella species circulating in Cameroon. This study aimed to determine the prevalence of brucellosis in cattle slaughtered in the Buea and Douala slaughterhouses and identify the Brucella species circulating among these animals. A total of 576 cattle serum samples were collected from the Buea and Douala slaughterhouses and analysed by ELISA. Following the ELISA assay, all samples were subjected to polymerase chain reaction (PCR) analysis. The bcsp31 gene primers were used for the genus‐specific PCR. All bcsp31‐positive samples were subjected to species‐specific PCR. Primers targeting the IS711 gene sequence were used to identify the abortus‐melitensis‐ovis‐suis species. The prevalence of brucellosis in both locations was 3.1% and 5.4% using the ELISA and PCR assays, respectively. Out of the 18 ELISA‐positive samples, 5 (27%) were positive with PCR, while 26 (4.7%) of the ELISA‐negative samples were positive with PCR. The Brucella species in circulation were identified using the Sanger sequencing technique. The sequences were 99.3% to 100% identical to the B. abortus strain BJ1‐23 and the B. abortus strain BJ1‐1 of the 31 kDa antigen (bcsp31) gene from India. This is the first report on the genotypic characterisation of Brucella species in Cameroon and confirms brucellosis in cattle at the Buea and Douala slaughterhouses.

Evaluation of the immunogenic properties of the recombinant Histophilus somni outer membrane protein 40 kDa (rOMP40)

BackgroundGram-negative bacterial infections are a serious problem in beef and dairy cattle. Bacterial outer membrane proteins (OMPs) play a pivotal role in cellular survival and the host-bacterium interaction. Histophilus somni OMP40 was identified as a porin with homology between its N-terminal amino acid sequence and the sequences of porins of other gram-negative bacteria The aim of this study was to produce recombinant H. somni OMP40 (rOMP40), optimize its production and evaluate its immunogenic properties in calves. The cross-reactivity of anti-rOMP40 antibodies were also checked.ResultsThe highest overexpression of rOMP40 was demonstrated by Escherichia coli C41 using the autoinduction process. Double immunization of calves (20 μg rOMP40 per animal) induced a significant increase of anti-rOMP40 antibodies in the IgG1 (P ≤ 0.01) and IgG2 (P ≤ 0.01, after first immunization only) subclasses, but not IgM. ELISA revealed increased reactivity of the IgG against surface antigens of E. coli and Pasteurella multocida after the second immunization (P < 0.01). Cross reactivity of anti-rOMP40 antibodies with ~ 40 kDa antigens of most common gram-negative pathogens was shown by Western blotting.ConclusionImmunization with H. somni rOMP40 induced a humoral response in cattle with broad cross-reactivity with similar antigens of other species of Pasteurellaceae and Enterobacteriaceae families and the delayed-type hypersensitivity reaction. The obtained results encourage further study to evaluate the protective effect of the produced protein as a subunit vaccine in cattle.

Seroprevalence of Fasciola-infection using Enzyme-linked immunosorbent assay in large ruminants from Pakistan

Fasciolosis, caused by liver fluke species of the genus Fasciola, are well recognized because of its high veterinary impact. Stool examination for Fasciola eggs is not a sensitive method, and limited efforts to find a reliable and cheaper means of detection are available. The present study aimed to develop rapid diagnostic ELISA test against fasciolosis. The excretory/secretory (ES) and somatic (SA) products of Fasciola helminths were analysed using polyacrylamide gel electrophoresis (PAGE). Immunogenicity was evaluated by immunoblotting using hyperimmune sera raised in rabbits and seroprevalence was determined by indirect ELISA. The results of SA antigen of Fasciola species showed polypeptide bands ranged from 10kDa-100kDa, while ES antigen of Fasciola showed bands of 15kDa-55kDa. The immunoblotting results showed the most prominent bands against ES antibodies were 25, 35, 55-70, 100 and 250 kDa and SA antigens showed 10, 15-25, 35, 70, 100 and 250 kDa polypeptide bands. The sensitivity and specificity of developed indirect ELISA for SA antigens was 95.45% and 87.1%, while for ES antigens was 100% and 77.42% respectively. The overall seroprevalence recorded for fascioliasis based on SA antigen was 39.8% and 29.8% for ES antigen. The fasciolosis did not show significant association with host type, sex and age groups of examined animals, however significantly higher infection was found in months of September and October. The result provides sensitive in house immunodetection assay for diagnosis of fasciolosis alternative to commercial kits with high import cost.

Evaluation of indirect-ELISA using eluted antigens from Trichinella spiralis muscle larvae for diagnosis of swine trichinellosis

Trichinellosis is caused by Trichinella spiralis muscle larvae (TsML), which is transmitted to human when they eat infected raw or undercooked meat. T. spiralis infection is detected by an enzyme-linked immunosorbent assay (ELISA) using excretory–secretory antigens (ESAg); however, the preparation of ESAg is challenging, and yields are low, which hampers screening efforts. In this study, crude somatic antigens (CSAg) of TsML with molecular weights (MWs) of 43, 79 and 101 kDa have been identified in swine trichinellosis sera with less cross-reaction with uninfected sera and other parasitic infected sera. After that, the CSAg at MWs of 43, 79 and 101 kDa (TsCSAg-43, TsCSAg-79, and TsCSAg-101, respectively) were isolated from sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The eluted antigens were analyzed by IgG-ELISA for sensitivity and specificity, and specific antigens from the three regions were identified by two-dimensional polyacrylamide gel electrophoresis (2-DE) and liquid chromatography-tandem mass spectrometry (LC-MS-MS). The sensitivity of IgG-ELISA using the three eluted antigens was 100% with specificities of 97.77%, 95.54%, 90.63% and for TsCSAg-43, TsCSAg-79, and TsCSAg-101, respectively. The LC-MS-MS results of immunomics showed that 18/20 spots of the antigens with MWs of 43, 79, and 101 kDa represent 11 different proteins identified. TsCSAg-43 showed the highest specificity, indicating that the specific proteins identified, including 45 kDa antigen–trichina [fragment], DNA topoisomerase 2-alpha antigen targeted by protective antibodies, and a conserved hypothetical protein (gi339234223), should be developed and produced in large volumes for further immunodiagnostic studies.

Expression of immunogenic genes of Mycobacterium avium subsp. paratuberculosis

SUMMARY&#x0D; Johne’s disease is an economically important disease caused by Mycobacterium avium subsp. Paratuberculosis (MAP). Continuous efforts are being made to identify MAP genes with antigenic and immunogenic capabilities which may serve as vaccine candidates and diagnostic antigens. mptD and 35 KDa antigen genes of MAP amplified by Polymerase chain reaction resulted in 630bp and 830 bp products respectively. Both mptD and 35 KDa antigen genes were cloned in to pTZ57R/T cloning vector, and subsequently subcloned into pET22b and expressed in BL21 (DE3) host system. The expressed recombinant antigens could be tested in diagnostic assays and might open up the avenue for the development of newer diagnostics and vaccine candidates for Johne’s disease.

First evaluation of antibody responses to Culex quinquefasciatus salivary antigens as a serological biomarker of human exposure to Culex bites: A pilot study in Côte d'Ivoire.

BackgroundCulex mosquitoes are vectors for a variety of pathogens of public health concern. New indicators of exposure to Culex bites are needed to evaluate the risk of transmission of associated pathogens and to assess the efficacy of vector control strategies. An alternative to entomological indices is the serological measure of antibodies specific to mosquito salivary antigens. This study investigated whether the human IgG response to both the salivary gland extract and the 30 kDa salivary protein of Culex quinquefasciatus may represent a proxy of human exposure to Culex bites.Methodology/Principal findingsA multidisciplinary survey was conducted with children aged 1 to 14 years living in neighborhoods with varying exposure to Culex quinquefasciatus in the city of Bouaké, Côte d’Ivoire. Children living in sites with high exposure to Cx quinquefasciatus had a significantly higher IgG response to both salivary antigens compared with children living in the control site where only very few Culex were recorded. Moreover, children from any Culex-high exposed sites had significantly higher IgG responses only to the salivary gland extract compared with children from the control village, whereas no difference was noted in the anti-30 kDa IgG response. No significant differences were noted in the specific IgG responses between age and gender. Sites and the use of a bed net were associated with the level of IgG response to the salivary gland extract and to the 30 kDa antigen, respectively.Conclusions/SignificanceThese findings suggest that the IgG response to Culex salivary gland extracts is suitable as proxy of exposure; however, the specificity to the Culex genus needs further investigation. The lower antigenicity of the 30 kDa recombinant protein represents a limitation to its use. The high specificity of this protein to the Culex genus makes it an attractive candidate and other specific antibody responses might be more relevant as a biomarker of exposure. These epidemiological observations may form a starting point for additional work on developing serological biomarkers of Culex exposure.

Identification of a Novel Antigen for Serological Diagnosis of Scrub Typhus

Scrub typhus is an acute infectious disease caused by the bacterium Orientia tsutsugamushi, which is widely distributed in northern, southern, and eastern Asia. Early diagnosis is essential because the average case fatality rate is usually >10% but can be as high as 45% if antimicrobial treatment is delayed. Although an O. tsutsugamushi 56-kDa type-specific antigen (TSA) is commonly used for serological diagnosis of scrub typhus, the 56-kDa TSA shows variations among O. tsutsugamushi strains, which may lead to poor diagnostic results. Therefore, the discovery of new antigenic proteins may improve diagnostic accuracy. In this study, we identified an O. tsutsugamushi 27 kDa antigen through an immunoinformatic approach and verified its diagnostic potential using patient samples. Compared with the O. tsutsugamushi 56-kDa antigen, the new 27-kDa antigen showed better diagnostic specificity with similar diagnostic sensitivity. Therefore, the O. tsutsugamushi 27-kDa antigen shows potential as a novel serological diagnostic antigen for scrub typhus, providing higher diagnostic accuracy for O. tsutsugamushi than the 56-kDa antigen.

Diagnostic value of serum IgG by Eliza to detecting Mycobacterium tuberculosis, Original Article

Introduction: In developing countries, which is an endemic region in terms of tuberculosis, there is an urgent need for fast, accurate, and inexpensive serological testing. The aim of this study was to determine the diagnostic value of patient serum IgG antibodies by ELISA in the diagnosis of Mycobacterium tuberculosis. Method: This case-control study was performed on patients with pulmonary tuberculosis in 2017-2020. After selecting the case (n = 30) and control (n = 30) subjects according to inclusion criteria, their blood samples were obtained and analyzed in the reference laboratory by standard kits for immunoglobulin G against 16, 36, and 40 kDa antigens of mycobacterium tuberculosis. Results: The mean age of the subjects was 47.07 (15.57%). The majority of participants were 46 (51.1%) women. There was no significant difference between the two groups regarding sex and age. serological examination of patients with pulmonary tuberculosis showed 25 positive results and only 4 of the control group had a positive result. Sensitivity, specificity, positive and negative predictive values of serology test were 83.3%, 86.67%, 86.20% and 87.88% respectively. Conclusion: Despite the acceptable sensitivity of the serologic immunoglobulin G test, according to the statement of World health organization (WHO), it did not possess an acceptable specificity. It is recommended that a a wider range of different antigens to be studied also it is essential to evaluate the diagnostic value of the other immunoglobulins inpatient in different stages of the disease.

Immunoblot for the Diagnosis of Cutaneous Leishmaniasis in French Guiana.

.Cutaneous leishmaniasis (CL) is firmly established in South America. We aimed to assess the detection of IgG antibodies against 14 and/or 16 kDa antigens by immunoblot (IB) for CL serological diagnosis in French Guiana, an area where many endemic pathogens could interfere with it. This study was performed retrospectively on sera from 141 patients at the Cayenne tertiary hospital: 30 were patients with confirmed CL, 71 were diagnosed with various other endemic pathogens, 11 were diagnosed with an autoimmune disease, and 29 controls had no history of CL. Antibodies bound to the 14 and/or 16 kDa antigens in 27 of the 30 CL patients’ sera and in 39 of the 111 non-CL patients’ sera (26 from the infectious diseases group, four from the autoimmune diseases group, and nine from the dermatology department). The method tested showed a high sensitivity (90%) and a low specificity (66%), and a diagnosis odds ratio of 17.5 (95% CI [4.6–78.0]). This IB may be helpful to exclude the diagnosis of CL, prompting physicians to look for another diagnosis in the case of a negative IB.