Serum Immunoglobulin G Antibodies Research Articles

Quantity and Quality of Naturally Acquired Antibody Immunity to the Pneumococcal Proteome Throughout Life.

Young children and older adults are susceptible for invasive pneumococcal disease (IPD) caused by Streptococcus pneumoniae. Pneumococcal protein-specific antibodies play a protective role against IPD; however, not much is known about the pace of acquisition, maturation, and maintenance of these antibodies throughout life. Immunoglobulin G (IgG) and IgA levels, avidity, and/or specificity to the pneumococcal proteome in serum and saliva from healthy young children, adults, and older adults, with known carriage status, were measured by enzyme-linked immunosorbent assay (ELISA) and 2-dimensional western blotting against ΔcpsTIGR4. Eleven-month-old children, the youngest age group tested, had the lowest pneumococcal proteome-specific IgG and IgA levels and avidity in serum and saliva, followed by 24-month-old children and were further elevated in adult groups. Among adult groups, the parents had the highest serum and saliva IgG and IgA antibody levels. In children, antibody levels and avidity correlated with daycare attendance and presence of siblings, posing as proxy for exposure and immunization. Immunodominance patterns slightly varied throughout life. Humoral immunity against the pneumococcal proteome is acquired through multiple episodes of pneumococcal exposure. Low-level and low-avidity antiproteome antibody profiles in young children may contribute to their IPD susceptibility, while in overall antiproteome antibody-proficient older adults other factors likely play a role.

Evaluation of circulating IgG antibodies against Porphyromonas gingivalis or its gingipains as serological markers of periodontitis and carriage of the bacterium.

Increasing evidence indicates that periodontitis contributes to systemic low-grade inflammation. Porphyromonas gingivalis is strongly associated with periodontitis, and antibodies against the bacterium may be used as a serological proxy to account for periodontal status, when studying diseases associated with periodontitis. The aim of the present study is to identify an easily accessible and reliable serological biomarker for determination of periodontal status and oral carriage of the bacterium. Saliva and serum samples were collected from periodontally healthy controls (n=27), and patients with periodontitis stage II (n=12) or stages III or IV (n=44). Serum levels of immunoglobulin G (IgG) antibodies against intact and fragmented P. gingivalis, recombinant gingipains (RgpA and RgpB), and the bacteria Escherichia coli and Capnocytophaga ochracea as controls were quantified with a multiplex bead-based assay. P. gingivalis was identified in saliva using quantitative polymerase chain reaction (qPCR). Serum IgG antibodies against P. gingivalis whole bacteria were good indicators of periodontitis (area under the curve [AUC]: 0.75, 95% confidence interval [CI]: 0.64-0.85). The same was observed for levels of antibodies against P. gingivalis fragments (AUC: 0.78, 95% CI: 0.68-0.88). Likewise, levels of antibodies against P. gingivalis whole bacteria or P. gingivalis fragments were good indicators of oral carriage of P. gingivalis (AUC: 0.92, 95% CI: 0.86-0.98 and AUC: 0.96, 95% CI: 0.92-1, respectively). Conversely, antibodies against recombinant RgpA and RgpB were not good indicators of periodontitis or oral carriage of the bacterium. None of the antibody levels differed significantly between stage II and stage III or IV periodontitis. Serum IgG antibody levels against heat-inactivated whole P. gingivalis proved to be the preferable biomarker for periodontitis and oral carriage of the bacterium.

Bacterial DNA and serum IgG antibody titer assays for assessing infection of human-pathogenic and dog-pathogenic Porphyromonas species in dogs

Periodontal disease is highly prevalent in both humans and dogs. Although there have been reports of cross-infection of periodontopathic bacteria, methods for assessing it have yet to be established. The actual status of cross-infection remains to be seen. The purpose of this study was to evaluate the utility of bacterial DNA and serum immunoglobulin G (IgG) antibody titer assays to assess infection of human-pathogenic and dog-pathogenic Porphyromonas species in dogs. Four experimental beagles were used for establishing methods. Sixty-six companion dogs at veterinary clinics visiting for treatment and prophylaxis of periodontal disease were used and divided into healthy, gingivitis, and periodontitis groups. Periodontal pathogens such as Porphyromonas gingivalis and Porphyromonas gulae were investigated as target bacteria. DNA levels of both bacteria were measured using species-specific primers designed for real-time polymerase chain reaction (PCR). Serum IgG titers of both bacteria were measured by enzyme-linked immunosorbent assay (ELISA).PCR primers were confirmed to have high sensitivity and specificity. However, there was no relationship between the amount of bacterial DNA and the severity of the periodontal disease. In addition, dogs with periodontitis had higher IgG titers against both bacteria compared to dogs in the healthy and gingivitis groups; there was cross-reactivity between the two bacteria. Receiver operating characteristic (ROC) analysis of IgG titers against both bacteria showed high sensitivity (>90 %) and specificity (>75 %). Since both bacteria were distinguished by DNA assays, the combination of these assays may be useful in the evaluation of cross-infection.

Seroprevalence and risk factors of Borrelia burgdorferi sensu lato and Rickettsia species infection in humans in Mongolia, 2016-2020.

Borrelia burgdorferi sensu lato and Rickettsia spp. are worldwide causes of tick-borne infections. We aimed to estimate the seroprevalence of immunoglobulin G (IgG) antibodies against different tick-borne diseases (TBDs) and determine risk factors among Mongolians from 2016 to 2020. Blood samples were obtained from voluntary participants with a history of suspected tick bite who visited our hospital, and IgG antibodies against Rickettsia and Borrelia were detected using enzyme-linked immunosorbent assay (ELISA). The IgG antibody seropositivity rate against Rickettsia was 21.8% (1032/4724), while 3.4% (162/4724) of participants tested positive for serum IgG antibodies against Borrelia by ELISA.Binary logistic regression analysis was performed to evaluate risk factors for tick-borne rickettsiosis (TBR) and tick-borne borreliosis (TBB) using IgG serum sample. Age, occupation, and residence were significantly associated with these diseases; however, sex did not show any significant association. Seroprevalence was significantly higher among herders (40.6%, 95% confidence interval [CI]: 35.5-45.8; odds ratio [OR] 0.61; P < 0.001) and students (32.8%, 95% CI: 30.2-35.4; OR 0.75; P < 0.001) than among individuals with other occupations. The 25-29 age group had a slightly higher seroprevalence (35.1%, 95% CI: 28.1-42.6; OR 0.61; P < 0.006) than those in other age groups. Province was a stronger predictor of TBR than occupation and age group. In univariate subgroup analysis by age group, occupation, and residence were significantly associated with TBR seroprevalence, whereas age and province were associated with TBB seroprevalence. Thus, risk factors for TBD include residence, occupation, and age group. This study was conducted using samples from all Mongolian provinces and the capital city, and the risk factors and prevalence of Rickettsia and Borreliaare highlighted.

Circulating IgG antibodies to periodontal bacteria and lung cancer risk in the CLUE cohorts.

Oral health is a key indicator of overall health, well-being, and quality of life. Several studies have provided new evidence about the role of oral diseases, specifically periodontitis, in generating risk for various forms of cancers, including lung, colorectal, and pancreatic cancers. Incident lung cancer cases (n = 192) and matched controls (n = 192) were selected from participants of the CLUE I and CLUE II cohorts. Archived serum samples collected from participants in 1974 (in CLUE I) were analyzed using immunoblotting for immunoglobulin G (IgG) antibody levels to 13 bacteria of the periodontium. Associations between antibody levels and lung cancer were estimated using conditional logistic regression. Most of the periodontal bacterial antibodies measured were inversely associated with lung cancer risk; of these, 3 were statistically significant (Prevotellaintermedia, Actinomyces naeslundii, and Veillonella parvula). A statistically significant positive association was observed for one of the Porphyromonas gingivalis strains after adjusting for P. intermedia. The sum of the logarithm of antibodies against the 13 measured bacteria was inversely associated with risk of lung cancer when the analysis was restricted to a longer follow-up (31-44 years after blood collection, highest vs lowest quartile: odds ratio = 0.26, 95% confidence interval = 0.08 to 0.84). Findings from this study highlight the complexity of using serum IgG antibodies to periodontal bacteria to identify associations between oral pathogens and risk of lung cancer. The inverse associations observed for antibodies to periodontal bacteria suggest that these may represent markers of immunity that provide some advantage in reducing the development of lung cancer.

The SARS-CoV-2 specific IgG antibodies biophotonic sensor.

In this paper, we present the design and the principle of operation of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) specific immunoglobulin G (IgG) biophotonic sensor, which is based on the single-mode telecommunication fiber. We fabricated the sensor head at the face of the single mode fiber-28. Due to the process of bio-functionalization, our sensor has the ability to selectively detect the SARS-CoV-2 specific IgG antibodies. The results of preliminary tests allowed us to correctly determine the presence of antibodies in less than 1 min in 5 μl in a volume sample of concentration of 10 μg/ml, which according to studies, corresponds to the concentration of IgG antibodies in human serum. Additionally, the tested sample can be smaller than 5 μl in volume.

Examining the association between serum IgG of oral bacteria and metabolic syndrome.

AimThis investigation explored the relationship between oral bacteria and metabolic syndrome (METS).Materials and MethodsThere were 4,882 subjects enrolled in this cross-sectional study from the NHANES III database. The severity of periodontitis was classified into mild, moderate and severe. We measured oral bacterial antibodies. We examined the relationship between serum immunoglobulin G (IgG) antibodies of oral bacteria and METS via performing multivariate regression analysis. Mediation analysis of oral bacteria on the correlation between periodontitis and METS was also executed.ResultsAfter adjusting for covariates, the serum IgG antibodies of P. nigrescens, E. corrodens, and E. nodatum were associated with the presence of METS (p = 0.006, p = 0.014 and p = 0.018, respectively). Furthermore, serum IgG antibodies of P. intermedia, T. forsythia and V. parvula were positively associated with the presence of METS (p = 0.001, p = 0.011, and p = 0.002, respectively) and ≥4 features of METS (p = 0.019, p = 0.025, and p = 0.02, respectively). P. intermedia IgG mediated 11.2% of the relationship between periodontitis and METS.ConclusionSerological markers of oral pathogens were correlated with the presence and the number of METS features after multivariable adjustment. Oral bacteria acted as a mediator of the correlation between periodontitis and METS. Our study provided a biologically plausible explanation for the association between periodontitis and METS, which provides a comprehensive evaluation of periodontitis.

SARS-CoV-2 Spike Stem Protein Nanoparticles Elicited Broad ADCC and Robust Neutralization against Variants in Mice.

Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) has caused the global pandemic. The virus is rapidly evolving, characterized by the emergence of several major variants. Stable prefusion spike protein (Pre) is the immunogen in current vaccines but is limited in protecting against different variants. Here, the immune responses induced by the relatively conserved stem subunit (S2) of spike protein versus Pre are investigated. Pre generates the most robust neutralization responses against SARS‐CoV‐2 variants in vesicular stomatitis virus pseudovirus‐based assessment but elicits less antibody‐dependent cellular cytotoxicity (ADCC) activity than S2. By contrast, S2 induces the most balanced immunoglobulin G (IgG) antibodies with potent and broad ADCC activity although produces weaker neutralization. The immunogenicity of S2 and Pre improves by incorporating the two proteins into double‐layered protein nanoparticles. The resulting protein nanoparticles Pre/S2 elicit higher neutralizing antibodies than Pre alone, and stronger ADCC than S2 alone. Moreover, nanoparticles produce more potent and balanced serum IgG antibodies than the corresponding soluble protein mixture, and the immune responses are sustained for at least four months after the immunization. Thus, the double‐layered protein nanoparticles have the potential to be developed into broader SARS‐CoV‐2 vaccines with excellent safety profiles.

Luciferase Immunosorbent Assay Based on Multiple E Antigens for the Detection of Chikungunya Virus-Specific IgG Antibodies.

ABSTRACTIn recent years, the chikungunya virus (CHIKV) has continued to spread from local epidemics to nonnative habitats until eventually reaching pandemic status. Nonendemic areas such as China have also emerged as potential epidemic areas of CHIKV. Serological detection of CHIKV is the key to diagnosing and controlling the prevalence of this virus. In this study, we review the progress of the serological detection of the envelope (E) protein in CHIKV, and we provide a novel research assay and ideas for the serological detection of CHIKV. The luciferase immunosorbent assay (LISA) does not require species-specific labeled secondary antibodies for detection, making it universally suitable for tracking samples from various animals or carriers. At present, most research on CHIKV antigen detection technology tends to combine two or more proteins to avoid the decrease in detection ability caused by antigen mutation. Our results indicate that two or more kinds of CHIKV E antigens combined with LISA detection can improve the detection rate of anti-CHIKV immunoglobulin G (IgG) antibodies in CHIKV-infected patient sera and detect antibodies in the early stage of infection accurately and sensitively. After 235 days of infection, the anti-CHIKV IgG antibodies could still be detected in CHIKV-infected patients. All serum samples were tested with a detection rate of 100% after combining various recombinant CHIKV E antigens. Our proposed CHIKV-specific LISA could be a useful tool for serum diagnosis of CHIKV infection and serum epidemic research in areas where CHIKV is endemic, which would help to manage potential epidemics in the future.IMPORTANCE At present, chikungunya virus (CHIKV) is still circulating in some parts of the world, and mutated strains have emerged, making it easier for the virus to spread among humans. With the continuous variation of CHIKV, its antigen variation leads to the decline of detection ability. In addition, the risk of transmission of CHIKV in areas where CHIKV is not endemic, such as China, has increased dramatically, which compels us to enhance the detection capacity of CHIKV and continuously monitor CHIKV antibody levels in the population. Real-time quantitative PCR (RT-PCR) detection technology will not be reliable when the infection time is chronic or in subclinical infection due to decreases in virus concentration, and an antibody detection technology must be adopted. In this study, multiple CHIKV envelope (E) antigens were used to detect anti-CHIKV IgG antibodies in serum for the first time. The new assay is characterized by convenient operation, high detection rate, and high sensitivity and has significance for early warning and monitoring. Moreover, it contributes to the prevention and control of CHIKV.

Characterization of the Pathology, Biochemistry, and Immune Response in Kunming (KM) Mice Following Fasciola gigantica Infection.

As a putative model of Fasciola gigantica infection, detailed data in Kunming (KM) mice infected with F. gigantica are lacking. In this study, KM mice were orally infected with 15 metacercaria for 8 weeks. Macroscopic and microscopic changes, serum biochemistry, cytokine responses, and changes in parasite-specific immunoglobulin G (IgG) antibody levels were monitored at 1, 3, 5, 7, and 8 weeks post-infection (wpi), respectively. The serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) increased after infection, while that of albumin (ALB) decreased, which was positively correlated with the degree of liver damage. Between 5 and 7 wpi, the mice showed symptoms of anemia and weight loss, possibly caused by the decrease of alkaline phosphatase (ALP). Moreover, the changing tendencies of the levels of globulin (GLB) and parasite-specific IgG antibody were similar, suggesting a potential correlation between GLB production and adaptive immune response in the host. Coordinated variations in interferon gamma (IFN-γ) and interleukin 4 (IL-4) indicated a mixed T helper 1 (Th1)/Th2 cellular immune response. Furthermore, the serum IgG antibody increased after infection and peaked at 5 wpi, and it was positively correlated with the average parasite burdens. The worms collected from mice were approximately 1 cm in length at 8 wpi, their digestive and reproductive systems were well developed, and no eggs were found in the uterus. To the best of our knowledge, this is the first report describing detailed histological, biochemical, and immunological indices in KM mice infected with F. gigantica, which provides basic information on KM mice against infection with F. gigantica.

Liver or Kidney Transplantation After SARS-CoV-2 Infection: Prevalence, Short-term Outcome, and Kinetics of Serum IgG Antibodies.

Background.There is a paucity of data on the prevalence, adequate timing, and outcome of solid organ transplantation after severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection and the kinetics of immunoglobulin G (IgG) antibodies in these patients.Methods.SARS-CoV-2 antinucleocapsid (N) IgG and polymerase chain reaction via a nasopharyngeal swab were analyzed in all patients within 24 h before liver or kidney transplantation. Kinetics of IgG antibodies were analyzed and compared with an immunocompetent cohort.Results.Between May 1, 2020, and March 18, 2021, 168 patients underwent liver or kidney transplantation in our center, of which 11 (6.54%) patients with a previous SARS-CoV-2 infection were identified. The median interval between SARS-CoV-2 infection and transplantation was 4.5 mo (range, 0.9–11). After a median posttransplant follow-up of 4.9 mo, 10 out of 11 patients were alive without clinical signs of viral shedding or recurrent or active infection. One patient without symptom resolution at time of transplantation died after combined liver-kidney transplantation. In 9 out of 11 patients with previously polymerase chain reaction-confirmed infection, SARS-CoV-2 anti-N and antispike (S) IgG were detectable at day of transplantation. Absolute levels of anti-N and anti-S IgG were positively correlated, declined over time in all patients, and were significantly lower compared with immunocompetent individuals. All patients remained anti-S IgG positive until the last posttransplant follow-up, whereas 3 patients became anti-N negative.Conclusions.We observed an uncomplicated course of liver or kidney transplantation after SARS-CoV-2 infection in selected patients. Although having lower absolute IgG antibody levels than immunocompetent individuals, all seroconverted patients remained anti-S IgG positive. These encouraging data need validation in larger studies.

Colorectal Carcinoma Affected Patients Are Significantly Poor Responders Against the Oncogenic JC Polyomavirus.

BackgroundMany investigations reported the association between human tumors and JCPyV, a polyomavirus with oncogenic potential. The association has been supported by studies that found JCPyV footprints in CRC and gliomas of different types. Indeed, JCPyV footprints including its nucleic acids and Tag oncoprotein have been revealed in CRC tissues.MethodsHerein, sera from colorectal carcinoma (CRC) affected patients and healthy individuals (HS), employed as control, were analysed for immunoglobulin G (IgG) antibodies against specific JCPyV viral capsid protein 1 (VP1) antigens. The investigation was carried out employing an innovative immunological assay. Indeed, an indirect enzyme-linked immunosorbent assay (ELISA) with JCPyV VP1 mimotopes was used. JCPyV VP1 mimotopes consisted of synthetic peptides mimicking VP1 epitopes.ResultsSera from CRC affected patients, evaluated using indirect ELISAs with synthetic mimotopes, showed a significant lower prevalence of IgG antibodies against JCPyV VP1 mimotopes (26%) compared to HS (51%), p<0.005. These data were confirmed by another method, the hemagglutination inhibition (HAI) assay. Altogether these results, i.e. the prevalence of serum IgG antibodies against JCPyV VP1 mimotopes from patients with CRC is approximately 50% lower than in HS, are of interest.DiscussionOur data suggest that patients with CRC are significantly poor responders against JCPyV VP1 antigens. It is possible that CRC patients are affected by a specific immunological deregulation. This immunological dysfunction, revelled in CRC patients, may account for their predisposition to the colorectal carcinoma onset.

Periodontitis and the outcome of atrial fibrillation ablation: Porphyromonas gingivalis is related to atrial fibrillation recurrence.

Inflammation is one of the main causes of atrial fibrillation (AF) recurrence after ablation. Porphyromonas gingivalis is a key periodontal pathogen in the oral-systemic disease connection and serum immunoglobulin G (IgG) antibody titers against P. gingivalis reflect the clinical status of periodontitis. This study aimed to investigate the relationship between late recurrence of AF after radiofrequency catheter ablation (RFCA) and serum IgG antibody titers against P. gingivalis. A total of 596 AF patients (mean age, 64.9 ± 10.0 years; 69% male; 61% paroxysmal AF) who underwent a first session of RFCA were enrolled. Patients were carefully examined for late recurrence during a mean follow-up period of 17.1 ± 14.5 months. Serum IgG antibody titers against P. gingivalis (types I-IV) were measured using enzyme-linked immunosorbent assay. The results of serum antibody titers were divided into a high-value and a low-value group. Among the five P. gingivalis subtypes, serum antibody titer against P. gingivalis type IV was associated with late recurrence (odds ratio, 1.937; 95% confidence interval [CI], 1.301-2.884; p = .002). Multivariate Cox proportional-hazards regression analysis revealed that high-value serum antibody titer against P. gingivalis type IV independently predicted late recurrence (paroxysmal AF: adjusted hazard ratio [HR], 1.569; 95% CI, 1.010-2.427; p = .04; non-paroxysmal AF: adjusted HR, 1.909; 95% CI, 1.213-3.005; p = .004). Periodontitis was related to the late recurrence of AF after RFCA. P. gingivalis type IV may be pathogenic for AF recurrence after RFCA.

Evaluation of serum IgM and IgG antibodies in COVID-19 patients by enzyme linked immunosorbent assay.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is sweeping the world since the end of 2019. The titer change of antibodies against SARS-CoV-2 needs to be further clarified, the clinical and preventive value of antibodies still needs to be further investigated. An enzyme-linked immunosorbent assay (ELISA) was established by coating with SARS-CoV-2 recombinant spike protein and used to detect serum immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies against SARS-CoV-2 in coronavirus disease 2019 patients to evaluate the pattern of changes of antibodies. The specificity of the ELISA for detection SARS-CoV-2 IgM and IgG were 96% (144/150) and 100% (150/150), respectively. The sensitivity of ELISA was 100% (150/150) for IgM, and 99.3% (149/150) for IgG. SARS-CoV-2-SP-IgM and SP-IgG antibodies could be detected on Day 1 of hospitalization in 12.5% patients, and SP-IgM began to decrease after reaching its peak at around 22-28 days, and become negative at Month 3 in 30% patients and negative at Month 7 in 79% of these patients after onset; IgG reached its peak around Day 22-28 and kept at a high level within the longest observation period for 4 months, it dropped very sharply at 7 months. The positive rates of SP-IgM and SP-IgG were higher than those of reverse transcription-polymerase chain reaction on Day 7 and 4. The established indirect ELISA has good specificity and sensitivity. IgM and IgG against SARS-CoV-2 appeared almost simultaneously in the early stage, and the level of IgG antibodies could not maintain a high plateau in the observation period of 7 months. Our data will help develop the diagnosis and vaccine of SARS-CoV-2.

Symptomatic Severe Acute Respiratory Syndrome Coronavirus 2 Reinfection of a Healthcare Worker in a Belgian Nosocomial Outbreak Despite Primary Neutralizing Antibody Response.

Background It is currently unclear whether SARS-CoV-2 reinfection will remain a rare event, only occurring in individuals who fail to mount an effective immune response, or whether it will occur more frequently when humoral immunity wanes following primary infection.Methods A case of reinfection was observed in a Belgian nosocomial outbreak involving 3 patients and 2 health care workers. To distinguish reinfection from persistent infection and detect potential transmission clusters, whole genome sequencing was performed on nasopharyngeal swabs of all individuals including the reinfection case’s first episode. IgA, IgM, and IgG and neutralizing antibody responses were quantified in serum of all individuals, and viral infectiousness was measured in the swabs of the reinfection case.Results Reinfection was confirmed in a young, immunocompetent health care worker as viral genomes derived from the first and second episode belonged to different SARS-CoV-2 clades. The symptomatic reinfection occurred after an interval of 185 days, despite the development of an effective humoral immune response following symptomatic primary infection. The second episode, however, was milder and characterized by a fast rise in serum IgG and neutralizing antibodies. Although contact tracing and virus culture remained inconclusive, the health care worker formed a transmission cluster with 3 patients and showed evidence of virus replication but not of neutralizing antibodies in her nasopharyngeal swabs.ConclusionIf this case is representative of most Covid-19 patients, long-lived protective immunity against SARS-CoV-2 after primary infection might not be likely.

Association between serum IgG antibody titers against Porphyromonas gingivalis and liver enzyme levels: A cross-sectional study in Sado Island

BackgroundPrevious studies have reported associations between nonalcoholic fatty liver disease, periodontitis, and obesity. Serum immunoglobulin G (IgG) antibody titer against Porphyromonas gingivalis, a major pathogen of periodontitis, is an established indicator of periodontal infection. However, the relationship between the antibody titer and liver enzyme levels has not been clarified yet. A study in the elderly was needed to evaluate the effect of long-term persistent bacterial infection on liver function. The objective of this study was to investigate the association between liver function and infection by P. gingivalis, and the effect of obesity on the association. MethodsA cross-sectional study was conducted in adult outpatients visiting Sado General Hospital, in Niigata Prefecture, Japan, from 2008 to 2010. The final participants included 192 men and 196 women (mean age 68.1 years). Multivariable logistic regression analyses were performed to assess the association between the serum IgG antibody titer and the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and γ-glutamine transferase (GGT) levels. ResultsIn women, serum IgG antibody titers against P. gingivalis was associated with elevated ALT, but not with AST or GGT, independent of covariates (p = 0.015). No significant association was found between the antibody titer and the elevated liver enzymes in men. The effect of obesity on the relationship between antibody titer and liver enzyme levels was not statistically significant. ConclusionsA cross-sectional analysis of adult outpatients suggested an association between P. gingivalis infection and ALT levels in women. The effect of obesity on this association was not statistically significant.

Component Identification and Functional Analysis of Outer Membrane Vesicles Released by Avibacterium paragallinarum.

Avibacterium paragallinarum, the causative agent of infectious coryza, is known to release outer membrane vesicles (OMVs). In the present study, we investigated the composition, bioactivities, and functional properties of the OMVs of A. paragallinarum. Following extraction and purification, the OMVs were observed to be spherical in shape, with diameters ranging from 20 to 300 nm. The vesicles contained endotoxin as well as genomic DNA. The molecular weights of the OMV-contained protein fragments were mostly concentrated at 65 and 15 kDa. The components of the OMV proteins were mainly various functional enzymes (e.g., ATP-dependent RNA helicase), structural components (e.g., streptomycin B receptor and membrane protein), and some hypothetical proteins with unknown functions. The expression levels of inflammation-related factors, such as interleukin (IL)-2, IL-6, IL-1β, IL-10, and inducible nitric oxide synthase (iNOs), were significantly upregulated in chicken macrophage cells HD11 incubated with OMVs. Serum IgG antibodies were measured after two intramuscular injections of an OMV-based vaccine into specific pathogen-free (SPF) chickens. The vaccinated chickens were then challenged by A. paragallinarum of homologous and heterologous serovars. It was noted that the vaccinated chickens produced immunoglobulin G (IgG) antibodies against A. paragallinarum. The OMVs conferred an acceptable level of protection (70%), defined as an absence of colonization and of clinical signs, against the homologous strain (serovar A), while the cross-protection against heterologous challenge with serovars B and C was much weaker. However, the OMVS did provide significant protection against clinical signs for all three serovars. Overall, this study laid a foundation for further unraveling the functional roles of OMVs released by A. paragallinarum.

Seroprevalence of Immunoglobulin G Antibodies Against Mycobacterium avium subsp. paratuberculosis in Dogs Bred in Japan

In this study, the seroprevalence of immunoglobulin G (IgG) antibodies against Mycobacterium avium subsp. paratuberculosis (MAP) in dogs bred in Japan was evaluated. Ninety-two non-clinical samples were obtained from three institutes and fifty-seven clinical samples were obtained from a veterinary hospital in Japan. Serum titers of total IgG, IgG1 and IgG2 isotype antibodies against MAP were measured using an indirect enzyme-linked immunosorbent assay (ELISA). The IgG antibodies against MAP in non-clinical serum obtained from three institutes was observed to be 2.4%, 20% and 9.0%. Similarly, the IgG1 antibodies titers against MAP were observed to be 7%, 20% and 0%. Lastly, the IgG2 antibodies against MAP were observed to be 7%, 20% and 4.4%. No significance differences in these titers were observed among the three institutes. The IgG, IgG1 and IgG2 antibodies in serum obtained from a veterinary hospital were observed to be 55.3%, 42% and 42%, respectively. Significant differences were found between the non-clinical and clinical samples. The titers in the clinical samples showed a high degree of variance, whereas low variance was found in the non-clinical samples. The IgG antibody levels were thought to be induced following exposure to MAP-contaminated feed. The difference in titers between the clinical and non-clinical samples is likely to be related to the amount of MAP antigen contamination in dog foods.

Serum antibodies to phosphatidylcholine in MS.

ObjectiveTo evaluate the value of serum immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies reactive with phosphatidylcholine (PC) and lactosylceramide (LC) as biomarkers in MS.MethodsWe developed an ultrasensitive ELISA technique to analyze serum IgG and IgM antibodies to LC and PC, which we used to analyze samples from 362 patients with MS, 10 patients with non-MS myelin diseases (Non-MSMYDs), 11 patients with nonmyelin neurologic diseases (Non-MYNDs), and 80 controls. MS serum samples included clinically isolated syndrome (CIS, n = 17), relapsing-remitting MS (RRMS, n = 62), secondary progressive MS (SPMS, n = 50), primary progressive MS (PPMS, n = 37), and benign MS (BENMS, n = 36).ResultsWe detected higher levels of serum IgM antibodies to PC (IgM-PC) in MS than control samples; patients with CIS and RRMS showed higher IgM-PC levels than patients with SPMS, PPMS, and BENMS and controls. MS and control samples did not differ in serum levels of IgM antibodies reactive with LC, nor in IgG antibodies reactive with LC or PC.ConclusionsSerum IgM-PC antibodies are elevated in patients with MS, particularly during the CIS and RRMS phases of the disease. Thus, serum IgM-PC is a candidate biomarker for early inflammatory stages of MS.Classification of evidenceThis study provides Class III evidence that serum antibodies to PC are elevated in patients with MS. The study is rated Class III because of the case control design and the risk of spectrum bias: antibody levels in patients with MS were compared with healthy controls.

Detection of antibodies to recombinant truncated flagellin and sonicated whole cell antigen of Burkholderia pseudomallei in acute melioidosis and in healthy Bangladeshi individuals

Background and objectives: Several types of Burkholderia pseudomallei antigens have been used to determine the antibody response in acute and asymptomatic cases. In the present study, we have detected immunoglobulin G (IgG) antibody to recombinant truncated flagellin antigen (RTFA) of B. pseudomallei in the sera of acute melioidosis cases and healthy individuals from melioidosis endemic areas of Bangladesh by indirect enzyme-linked immunosorbent assay (ELISA). In parallel, IgG antibody to sonicated whole cell antigen (SWCA) of B. pseudomallei was determined to compare with anti-RTFA antibody.&#x0D; Methodology: Serum samples from culture confirmed melioidosis cases and from healthy individuals aged 21 years and above residing in melioidosis endemic rural areas were included in the study. Serum IgG antibody to RTFA and SWCA of B. pseudomallei was determined by indirect ELISA.&#x0D; Results: Out of 8 culture confirmed acute melioidosis cases, 7 (87.5%) and 8 (100%) were positive for anti-B. pseudomallei IgG antibodies by RTFA and SWCA methods respectively. Among 361 healthy individuals, the rate of seropositivity by RTFA-ELISA was significantly less than that of SWCA-ELISA (16.1% versus 26.8%; p = 0.001). The mean optical density (OD) of RTFA-ELISA of positive cases was significantly less than that of SWCA-ELISA in both melioidosis and healthy individuals (0.79±0.11 versus 2.4±0.08, p = 0.0001; 0.67±0.01 versus 1.27±0.02, p = 0.0001). The sensitivity and specificity of RTFA-ELISA were 88.9% and 100% respectively.&#x0D; Conclusion: Findings of the study suggest that multiple or combination of antigens should be used to study the seroprevalence of B. pseudomallei infection in a community. Also, prospective study is necessary to find out the duration of persistence of antibodies to different antigenic components of B. pseudomallei after exposure.&#x0D; Ibrahim Med. Coll. J. 2020; 14(1): 47-52