Avidity Index Research Articles

Avidity maturation of anti-spike IgG after vaccination in COVID-19 convalescent vs COVID-19 naïve patients.

Antibodies and avidity maturation contribute to long-lasting immunity, and previous COVID-19 seems to enhance the immune response after vaccination. The aim of this study was to compare the immune response after vaccination between COVID-19 convalescents and naïve patients. Blood samples from COVID-19 convalescents and naïve patients, taken 1, 3 and 6 months after the second dose of vaccine (mRNA-vaccine BNT162b2), were analysed for anti-spike IgG and avidity. Questionnaires concerning side effects were used. Thirty-one patients in the COVID-19 cohort and 30 patients in the naïve cohort were included. High levels of anti-spike IgG and avidity index were seen. Anti-spike IgG were significantly higher in the COVID-19 cohort and declining (median 1250, 566, 282 RU/ml vs 565, 187, 65 RU/ml). Avidity did not change over time (median at 6 months 78% vs 65%). The most common side effects were pain at the injection site, malaise and headache. In conclusion, high levels of anti-spike IgG after vaccination were seen and most patients developed high-avidity antibodies, although antibody levels and avidity were higher in the COVID-19 cohort. Over time, the levels of anti-spike IgG declined, yet avidity remained high. Side effects did not differ between groups and were of short duration.

The avidity of virus-specific antibodies obtained from <i>in vitro</i> stimulated memory b cells does not change one month after booster with Sputnik V or Comirnaty

The protective properties of long-term immunological memory after vaccination against COVID-19 are characterized by the neutralizing activity of serum antibodies and antibodies secreted by memory B cells upon repeated encounter with the antigen. Somatic hypermutations occurring in the immunoglobulin genes of memory B cells are one of the mechanisms for increasing the affinity of antibodies. At the moment, the effect of booster vaccination against COVID-19 with vector vaccines, on the maturation of memory B cells remains poorly understood. The purpose of this work was to determine how COVID-19 booster affects the affinity of RBD-specific IgG antibodies secreted by memory B cells. B lymphocytes were isolated from peripheral mononuclear blood cells of volunteers who had been revaccinated against COVID-19 with Sputnik V or Comirnaty. B cells were stimulated in vitro with CD40L expressed on the surface of A549 feeder cells and IL-21. Supernatants were concentrated 8-fold using centrifugal concentrators. In the obtained supernatants from stimulated memory B cells, the level of IgG antibodies specific to wild-type RBD was determined by enzyme-linked immunosorbent assay (ELISA). To determine the avidity index, ELISA with 7M urea was provided. It was shown that despite a general increase in the amount of antigen-specific IgG antibodies obtained from stimulated memory B cells, there was no change in the avidity of these antibodies one month after booster in both groups of donors. The obtained results contribute to the understanding of the mechanisms of memory B cell maturation after booster vaccinations against COVID-19 and may be useful for deciding on the strategy of booster vaccination.

Correlation of FDG PET/CT, tumor markers and Ki-67 index with EGFR mutation or positive ALK expression in patients with non-small cell lung cancer.

Epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) are the two most common druggable targets in non-small cell lung cancer (NSCLC). To investigate whether the EGFR mutation and ALK rearrangement could be predicted by the combination of FDG avidity, tumor markers and Ki-67 Index. A total of 168 newly diagnosed NSCLC patients who had undergone 18F-FDG PET/CT for staging were enrolled. PET/CT parameters of primary tumors including maximum standardized uptake value (pSUVmax), metabolic tumor volume (pMTV) and total lesion glycolysis (pTLG) were measured. Five serous tumor markers for lung cancer were recorded. Ki-67 labeling index was counted by immunohistochemical staining. EGFR mutation and ALK status were detected by ARMS-PCR and RT-PCR, respectively. Univariate and multivariate analyses were applied to identify the predictors of EGFR mutation and ALK positivity. EGFR mutation rate was 38.1% (64/168), which were found more frequently in female, ≤60 years old, non-smokers and adenocarcinoma patients, and were not related to lymph node involvements, distant metastases, stage and serum tumor markers. Low pSUVmax, pMTV, pTLG and Ki-67 were significantly associated with EGFR mutation. Logistic regression demonstrated that pSUVmax <6.75 and gender (female) were the independent factors affecting EGFR mutation, and the combination of them had a certain predictive value with the area under the curve of 0.784. ALK positive rate was 6.0% (10/168), all of them were adenocarcinoma patients, which were more common in non-smokers, low serum cytokeratin-19 fragment antigen (CYFRA21-1) and low Ki-67, and were not related to FDG activity. No independent factor for ALK positivity was found on Logistic regression. Low pSUVmax, rather than tumor markers or Ki-67, was correlated with EGFR mutation independently, which could be integrated with gender (female) to improve the identification for EGFR mutation in NSCLC patients.

An IgG1 single-dilution avidity ELISA predicts cross-protection against heterologous foot-and-mouth disease virus challenge after vaccination

This study aims to analyze if the results from different serological assays, used alone or combined, could match the outcome of challenge infection with foot-and-mouth disease virus (FMDV) after vaccination in cattle. Day-of-challenge sera from animals that had been vaccinated 21 days before with monovalent formulations containing inactivated A Iran 96 or A Iran 99 virus strains were used. Challenge and serology were performed with A22 Iraq strain. IgG1 titers and total-IgG avidity indexes were significantly higher in protected animals (p < 0.01) while IgG2-titers were not related to protection (p > 0.05). An IgG1 avidity ELISA was developed to analyze in one step, IgG1 levels and avidity. This assay estimated protection with 96 % accuracy. A strong agreement with challenge results was achieved (K = 0.85), suggesting a role of high-affinity IgG1 in protection against FMDV. These results support the assessment of the single dilution IgG1-Avidity ELISA to predict cross-protection in FMDV-vaccinated cattle.

Immunogenicity of Recombinant Zoster Vaccine: A Systematic Review, Meta-Analysis, and Meta-Regression.

The adjuvanted recombinant zoster vaccine (RZV), consisting of varicella-zoster virus glycoprotein E (gE) and the AS01B adjuvant system, effectively prevents herpes zoster (HZ). In the absence of a well-defined correlate of protection, it is important to monitor the RZV immune response, as a proxy of clinical effectiveness. This systematic review examined post-vaccination parameters: humoral and cell-mediated immunity, avidity index, geometric mean concentration of antibody (GMC), and immunity persistence. The meta-analysis used a random-effects model, and subgroup and meta-regression analyses were conducted. Among 37 included articles, after one month from RZV-dose 2, the pooled response rate for anti-gE humoral immunity was 95.2% (95%CI 91.9-97.2), dropping to 77.6% (95%CI 64.7-86.8) during immunosuppression. The anti-gE cell-mediated immunity-specific response reached 84.6% (95%CI 75.2-90.9). Varying factors, such as age, sex, coadministration with other vaccines, prior HZ, or live-attenuated zoster vaccine, did not significantly affect response rates. RZV induced a substantial increase in gE avidity. Immunity persistence was confirmed, with more rapid waning in the very elderly. This systematic review indicates that RZV elicits robust immunogenicity and overcomes immunocompromising conditions. The findings underscore the need for further research, particularly on long-term immunity, and have the potential to support HZ vaccination policies and programs.

Seroprevalence and sociodemographic characteristics of Toxoplasma gondii infection in patients with psychiatric disorders in Malaysia

Toxoplasma gondii is a neurotropic protozoan parasite that affects neuronal processing in the brain. This study aimed to investigate the prevalence of T. gondii infection in psychiatric disorder patients. We also investigated the potential association between sociodemographic, clinical manifestation, and behavior of Toxoplasma-seropositive patients with psychiatric disorders. Commercial ELISAs (IgG, IgM, and IgG avidity) using serum and PCR using buffy coat were performed on samples from 54 individuals in each of the following groups: patients diagnosed with depressive disorder, bipolar disorder, and schizophrenia, as well as psychiatrically healthy subjects (control group). They were recruited from the Hospital Universiti Sains Malaysia in Kelantan, Malaysia. Of 54 patients with depressive disorder, 24/54 (44.4 %) were seropositive for IgG, and four (16.7 %) were IgG+/IgM+. Among the latter, a high avidity index indicating a past infection was observed in half of the samples (50.0 %), and the other half (50.0 %) showed a low avidity index, indicating a possible recent infection. Meanwhile, 30/54 (55.6 %) patients with bipolar disorder were seropositive for IgG+, five (16.7 %) were IgG+/IgM+, and four of them had a high avidity index, and one had a low avidity index. Patients with schizophrenia showed 29/54 (53.7 %) seropositive for IgG, two of them (6.9 %) were IgG+/IgM+; one of latter had a high avidity index, and one had a low avidity index. Of 54 people in the control group, 37.0 % (20/54) were seropositive for T. gondii IgG antibodies. However, no significant difference was observed in seroprevalence between the control group and each patient group. No PCR-positive results were documented. A Chi-Square and multiple logistic regression showed that age (p = 0.031), close contact with cats/pets (p = 0.033) and contact with soil (p = 0.012) were significantly associated with Toxoplasma seropositivity in patients with psychiatric disorders. Additional research is needed to elucidate the causal relationships and underlying mechanisms.

Analysis of Suspected Measles Cases with Discrepant Measles-Specific IgM and rRT-PCR Test Results, Japan.

We investigated clinically suspected measles cases that had discrepant real-time reverse transcription PCR (rRT-PCR) and measles-specific IgM test results to determine diagnoses. We performed rRT-PCR and measles-specific IgM testing on samples from 541 suspected measles cases. Of the 24 IgM-positive and rRT-PCR--negative cases, 20 were among children who received a measles-containing vaccine within the previous 6 months; most had low IgG relative avidity indexes (RAIs). The other 4 cases were among adults who had an unknown previous measles history, unknown vaccination status, and high RAIs. We detected viral nucleic acid for viruses other than measles in 15 (62.5%) of the 24 cases with discrepant rRT-PCR and IgM test results. Measles vaccination, measles history, and contact history should be considered in suspected measles cases with discrepant rRT-PCR and IgM test results. If in doubt, measles IgG avidity and PCR testing for other febrile exanthematous viruses can help confirm or refute the diagnosis.

Adaptive immune responses to two-dose COVID-19 vaccine series in healthy Canadian adults ≥ 50 years: a prospective, observational cohort study

To evaluate immune responses to COVID-19 vaccines in adults aged 50 years and older, spike protein (S)-specific antibody concentration, avidity, and function (via angiotensin-converting enzyme 2 (ACE2) inhibition surrogate neutralization and antibody dependent cellular phagocytosis (ADCP)), as well as S-specific T cells were quantified via activation induced marker (AIM) assay in response to two-dose series. Eighty-four adults were vaccinated with either: mRNA/mRNA (mRNA-1273 and/or BNT162b2); ChAdOx1-S/mRNA; or ChAdOx1-S/ChAdOx1-S. Anti-S IgG concentrations, ADCP scores and ACE2 inhibiting antibody concentrations were highest at one-month post-second dose and declined by four-months post-second dose for all groups. mRNA/mRNA and ChAdOx1-S/mRNA schedules had significantly higher antibody responses than ChAdOx1-S/ChAdOx1-S. CD8+ T-cell responses one-month post-second dose were associated with increased ACE2 surrogate neutralization. Antibody avidity (total relative avidity index) did not change between one-month and four-months post-second dose and did not significantly differ between groups by four-months post-second dose. In determining COVID-19 correlates of protection, a measure that considers both antibody concentration and avidity should be considered.

Changes in the avids of IgG antibodies to the S protein of SARS-CoV-2 after coronavirus infection in medical workers of a temporary infections hospital

BACKGROUND: The effector capabilities of humoral immunity are determined not only by the amount of specific antibodies produced in response to an antigenic effect, but also by their qualitative characteristics, which include avidity ― the total strength of binding to the antigen, which determines the duration and effectiveness of post-infectious immunity to SARS-CoV-2.&#x0D; AIM: Is a selective study of the quantity and avidity of IgG antibodies to SARS-CoV-2 over time among medical workers of a temporary infectious diseases hospital in Kazan ― convalescents of COVID-19, during the period from July 2020 to July 2021.&#x0D; MATERIALS AND METHODS: Determination of IgG to the S antigen of SARS-CoV-2 by ELISA was carried out using the test system SARS-CoV-2-IgG quantitative-ELISA-BEST (Vector-Best, Russia) and expressed in BAU/ml (binding antibody units). Antibody avidity was determined using a 4.0 M urea solution and expressed as avidity indices. 1, 4 and 7 months after COVID-19 asymptomatic (n=34); mild severity (n=42); moderate severity (n=29); reinfected (n=34). When statistically processing the data, descriptive statistics methods and the Wilcoxon matched data test were used. Differences were considered significant at p 0.05.&#x0D; RESULTS: IgG avidity to SARS-CoV-2 depended on the severity of COVID-19. The highest rates of avidity indices were found in the group of those who had a moderate form of COVID-19. If in mild and asymptomatic forms there was a parallel decrease in avidity indices and IgG titer, then in moderate forms an increase in antibody titer was accompanied by a decrease in their avidity 4 months after the infection. 7 months after seroconversion, the IgG level decreased almost twofold, both in mild, asymptomatic and moderate forms. In the group of medical workers who had COVID-19 repeatedly, the initially low levels of avidity indices and antibody titers increased in parallel, while avidity indices after 7 months did not decrease, but remained high. Differences in avidity indices determined the subsequent formation of different trends in the development of the humoral immune response, which were mainly characterized by an uneven decrease in IgG and persistence of IgM antibodies for more than 1 month.&#x0D; CONCLUSIONS: The research results expand the understanding of the mechanisms of formation of the humoral immune response and the avidity of IgG antibodies against SARS-CoV-2 in the risk group ― medical workers. The level of humoral immunity decreases in the first six months and varies depending on the severity of COVID-19. The data obtained can be used to identify categories of increased risk of SARS-CoV-2 infection among healthcare workers, make decisions about immunorehabilitation and revaccination against COVID-19.

Intranasal administration of Escherichia coli Nissle expressing the spike protein of SARS-CoV-2 induces long-term immunization and prevents spike protein-mediated lung injury in mice

While current anti-Spike protein (SP) vaccines have been pivotal in managing the pandemic, their limitations in delivery, storage, and the inability to provide mucosal immunization (preventing infections) highlight the ongoing necessity for research and innovation. To tackle these constraints, our research group developed a bacterial-based vaccine using a non-pathogenic E. coli Nissle 1917 (EcN) strain genetically modified to express the SARS-CoV-2 spike protein on its surface (EcN-pAIDA1-SP). We intranasally delivered the EcN-pAIDA1-SP in two doses and checked specific IgG/IgA production as well as the key immune mediators involved in the process. Moreover, following the initial and booster vaccine doses, we exposed both immunized and non-immunized mice to intranasal delivery of SARS-CoV-2 SP to assess the effectiveness of EcN-pAIDA1-SP in protecting lung tissue from the inflammation damage. We observed detectable levels of anti-SARS-CoV-2 spike IgG in serum samples and IgA in bronchoalveolar lavage fluid two weeks after the initial treatment, with peak concentrations in the respective samples on the 35th day. Moreover, immunoglobulins displayed a progressively enhanced avidity index, suggesting a selective binding to the spike protein. Finally, the pre-immunized group displayed a decrease in proinflammatory markers (TLR4, NLRP3, ILs) following SP challenge, compared to the non-immunized groups, along with better preservation of tissue morphology. Our probiotic-based technology provides an effective immunobiotic tool to protect individuals against disease and control infection spread.

Fetal Cytomegalovirus Infection in the Absence of Maternal Cytomegalovirus-IgM Seropositivity

The aim of this study was to evaluate maternal serological status and fetal sonographic findings of Cytomegalovirus (CMV) infection. This is a retrospective study performed at Perinatology Department of Istanbul Başakşehir Çam and Sakura City Hospital. A computerized search was conducted to identify cases who underwent prenatal diagnosis of fetal CMV infection between September 2020 and December 2023. We identified nine cases with fetal CMV infection. The clinical data of the patients, gestational age at the time of diagnosis, serological, sonographic findings, and pregnancy outcomes were analyzed. A computer search of the database was made for the seroprevalance of CMV-IgM and CMV-IgG in our population. The CMV-IgM and IgG results of the 1235 patients who underwent CMV screening in the first trimester between September 2020 and December 2023 were evaluated. Fetal CMV infection was identified in nine patients. None of the 9 cases showed maternal CMV-IgM positivity. Seven of the 9 patients showed high IgG avidity index. Pregnant population had 98 % positivity for CMV-IgG. The evaluation of serologic tests for CMV is not straightforward in the second and third trimester. IgM and IgG avidity should be interpreted with caution in the second and third trimester. In the presence of ultrasound findings suggesting fetal CMV infection and CMV-IgG positivity, invasive diagnostic tests rather than serological test should be discussed with the patient, and non-primary infections should always be considered to minimize overlooked fetal cytomegalovirus infections and missed antiviral treatment opportunity.

Congenital cytomegalovirus infection in newborns suspected of congenital rubella syndrome in Iran: a cross-sectional study

BackgroundFollowing rubella virus control, the most important cause of congenital infections is human cytomegalovirus (HCMV). Congenital CMV (cCMV) may happen both in primary and non-primary maternal infections. The present study aimed to screen cCMV in symptomatic newborns suspected of congenital rubella syndrome (CRS) in Iran.MethodsOut of 1629 collected infants' serum samples suspected of CRS but negative for rubella IgM, 524 samples were selected regarding cCMV complications. These samples were divided into two age groups: 1- one month and younger, 2- older than 1 month up to one year. Anti-HCMV IgM detection was performed on these serums. Then HCMV IgG avidity assay and HCMV DNA detection were carried out on all samples with positive and borderline results in IgM detection.ResultsHerein, 3.67% of symptomatic infants aged one month and younger had positive and borderline HCMV IgM, 12.5% of which had a low avidity index (AI). HCMV IgM detection rate among symptomatic infants older than one month to one year was 14.5%. Identified genotypes in this study were gB-1(63.63%), gB2 (18.18%), and gB3 (18.18%), respectively.ConclusionsThis comprehensive study was performed on serum samples of symptomatic infants clinically suspected of cCMV from all over Iran. There was a good correlation between serology findings and PCR.

Easy assessment of the avidity of polyclonal allergen-specific serum antibodies.

Allergen-specific IgE-blocking IgG antibodies contribute to successful allergen immunotherapy (AIT), however, not much is known about their affinity. Since affinity measurements of polyclonal antibodies in serum are technically challenging we evaluated the applicability of acidic disruption of antibody-allergen complexes by a modified ELISA protocol with monoclonal antibodies (mAbs) specific for the relevant major allergens Betv1 and Mald1. Then, AIT-induced blocking and non-blocking Mald1-specific antibodies in sera from individuals with or without reduced apple allergy were compared. After testing their pH stability coated recombinant allergens were incubated with (i) mAbs diluted in PBS or human serum and (ii) sera from individuals after sublingual administration of Mald1 or Betv1 for 16 weeks. Immune complexes were exposed to buffers in the pH range of 6.4-3.4 and residual antibodies were measured. Avidity indexes (AI), defined as the pH removing 50% of antibodies, were compared to the dissociation constants (KD) of mAbs determined by surface plasmon resonance. The selected pH range was applicable to disrupt allergen complexes with highly affine mAbs without compromising allergen integrity. AIs of mAbs accorded with KD values and were unaffected by epitope specificity or the presence of serum proteins. The inter-assay variability was <4% CV. Protective Mald1-specific IgG antibodies from individuals with reduced apple allergy showed a higher collective binding strength than that of the non-protective antibodies of individuals without reduced apple allergy. Acidic disruption of allergen-antibody complexes may be used to estimate the net-binding force of polyclonal serum antibodies and eases the investigation of affinity-related research questions in AIT.

Evaluation of different cut-off points for IgG avidity and IgM in the diagnosis of acute toxoplasmosis in pregnant women participating in a congenital toxoplasmosis screening program.

The main social impact of toxoplasmosis stems from its ability to be vertically transmitted. Postnatally acquired infection is generally asymptomatic in approximately 70-90% of cases, making diagnosis often dependent on laboratory tests using serological methods to search for anti-T. gondii antibodies. This study aimed to investigate the ability of the VIDAS TOXO IgG avidity and VIDAS TOXO IgM assays to confirm recent toxoplasmosis. In total, 341 pregnant women with suspected acute toxoplasmosis were systematically monitored in the Program for Control of Congenital Toxoplasmosis in Minas Gerais State, Brazil. We conducted an observational analytical-descriptive cross-sectional study and grouped according to clinical and laboratory criteria as having acute or chronic toxoplasmosis. The VIDAS TOXO IgG avidity and VIDAS TOXO IgM assays were evaluated to investigate the capacity to identify acute infection. IgG avidity showed good performance in identifying acute toxoplasmosis when the IgG avidity index was lower than or equal to 0.1. Values greater than or equal to 3.16 according to the TOXO IgM kit were associated with a greater chance of acute infection. These results may contribute to a more adequate diagnosis of acute gestational toxoplasmosis and, consequently, the avoidance of inadequate or unnecessary treatments.

1726. Characterization of humoral immune responses to COVID-19 vaccination in children in Canada: interim analysis from the Severe acute respiratory syndrome-related coronavirus 2 PRevalence In children and youNG adults in British Columbia (SPRING) Study

Abstract Background A vaccine series consisting of two doses of coronavirus disease 2019 (COVID-19) mRNA vaccines plus one booster dose is currently recommended for healthy children aged 5-11 years in Canada. Additional studies are needed to understand the longitudinal immunity to COVID-19 vaccination in the pediatric population. The Severe acute respiratory syndrome-related coronavirus 2 PRevalence In children and youNG adults in British Columbia (SPRING) sub-study aimed to specifically investigate antibody responses to COVID-19 vaccination in children aged 5-11 years. Methods Fifty-four children without immunocompromising conditions or taking immunosuppressive medications were enrolled prior to dose one or dose two of their COVID-19 vaccine. Responses were quantified via: anti-index virus spike protein specific IgG (S-IgG) geometric mean concentrations (GMCs) (binding antibody units, BAU/mL) and S-IgG avidity reported as total relative IgG avidity index (TRAI) (avidity units, AU) at pre-dose two, as well as one and six months post-dose two. A Welch’s t-test compared responses between timepoints. Results The cohort consisted of 55% male and 45% female with a median age of 8 years. The interval between first and second doses ranged from 7 – 18 (median 11) weeks. Concentrations of S-IgG increased from pre-dose two to one month post-dose two (222 vs. 1152 BAU/mL, p &amp;lt; 0.0001). GMCs then decreased by six months post-dose two (1152 vs. 343 BAU/mL, p &amp;lt; 0.0001) to levels similar to pre-dose two (p = 0.0696). TRAI increased between time points. By six months post-dose two, S-IgG TRAI (68 AU) remained higher than pre-dose two (46 AU, p &amp;lt; 0.0001) and one month post-dose two (65 AU, p = 0.0495). This increase in avidity was due to higher concentrations of medium high, high and very high avidity S-IgG as well as a decrease in very low avidity S-IgG at six months post-dose two. Conclusion Concentrations of S-IgG waned significantly by six months post-dose two. The results suggest that due to repeated exposure to the S-protein, affinity maturation has resulted in the production of higher avidity antibodies post-dose two. This suggests that both S-IgG concentrations and avidity should be considered when determining protection against COVID-19 and need to be further explored to support future booster recommendations. Disclosures Sofia R. Bartlett, PhD, Abbvie: Advisor/Consultant|Abbvie: Grant/Research Support|Cepheid: Advisor/Consultant|Gilead: Advisor/Consultant|Gilead: Grant/Research Support Manish Sadarangani, BM BCh, FRCPC, DPhil, GlaxoSmithKline: Grant/Research Support|Merck: Grant/Research Support|Moderna: Grant/Research Support|Pfizer: Grant/Research Support|Sanofi Pasteur: Grant/Research Support|Seqirus: Grant/Research Support|Symvivo: Grant/Research Support|VBI Vaccines: Grant/Research Support

Toxoplasma gondii IgG avidity for the diagnosis of primary infection in pregnant women: Comparison between chemiluminescent microparticle immunoassay and enzyme-linked immunosorbent assay

IntroductionThis study evaluated whether IgG avidity measured by chemiluminescent microparticle immunoassay (CMIA) compared with enzyme-linked immunosorbent assay (ELISA) was useful to detect primary T. gondii infection during pregnancy and to estimate the risk for congenital T. gondii infection. MethodsOne hundred six women with positive tests for T. gondii IgG and T. gondii IgM, comprising 21 women (19.8%) with low (<30%), 6 (5.7%) with borderline (30%–35%), and 79 (74.5%) with high (>35%) IgG avidity measured by ELISA were selected. Their stored sera were used for T. gondii IgG avidity measurements by CMIA. ResultsIn CMIA, 72 (67.9%) women had low (<50%), 12 (11.3%) had borderline (50%–59.9%), and 22 (20.8%) had high (≥60%) IgG avidity. The ratio of low T. gondii IgG avidity index in CMIA was more than three-fold than that in ELISA. Eighteen (85.7%) of 21 women with ELISA low avidity also had CMIA low avidity, and 26 (96.3%) of 27 women with ELISA low or borderline avidity corresponded to CMIA low or borderline avidity, whereas 21 (26.6%) of 79 women with ELISA high avidity were diagnosed with CMIA low avidity. All three cases with congenital T. gondii infection showed coincidentally low IgG avidity in both methods. A positive correlation in IgG avidity indices was found between of ELISA and CMIA. ConclusionsCMIA for T. gondii avidity measurements compared with ELISA was clinically useful to detect pregnant women at a high risk of developing congenital T. gondii infection.

Immunomodulatory effect of Myrtenol on benzo (a) pyrene-induced lung cancer in Swiss albino mice via modulation of tumor markers, cytokines and inhibition of PCNA expression.

Lung cancer is one of the most common cancers in men. Although many diagnostic and treatment regimens have been followed in the treatment for lung cancer, increasing mortality rate due to lung cancer is depressing and hence requires alternative plant based therapeutics with with less side-effects. Myrtenol exhibits anti-inflammatory and antioxidant properties. Hence we intended to study the effect of Myrtenol on B(a)P-induced lung cancer. Our study showed that B(a)P lowered hematological count, decreased phagocyte and avidity indices, nitroblue tetrazolium (NBT) reduction, levels of immunoglubulins, antioxidant levels, whereas Myrtenol treatment restored them back to normal levels. On the other hand, xenobiotic and liver dysfunction marker enzymes and pro-inflammatory cytokines were elevated on B(a)P exposure, which retuned back to normal by Myrtenol. This study thus describes the immunomodulatory and antioxidant effects of Myrtenol on B[a]P-induced immune destruction.

Analysis of antibodies avidity for Tityus serrulatus scorpion venom in antivenom production and its potential for application as a potency test

Antivenoms are the only specific medication for neutralizing toxins present in venom of animals such scorpions and snakes through antigen-antibody binding. Several analyses are carried out throughout its production in order to ensure the quality and effectiveness of the antivenom that will be administered to the patient. One of these is the potency assay, which is performed to assess the ability of antivenoms to neutralize the toxic effects of the venom injected in mice. The substitution of in vivo for in vitro assays such as ELISA has been presented by other authors, bringing several advantages such as the reduction in the use of animals, in costs and in the duration of the assays. However, the avidity index of antivenom antibodies determined by ELISA has not yet been applied for this purpose. Therefore, the objective of this study was to evaluate the avidity of sera from hyperimmunized horses with crude Tityus serrulatus venom, a scorpion species associated with the most serious accidents in Brazil, and its potential for application as a potency test replacing the in vivo assay. The avidity ELISA proved to be interesting for monitoring the binding strength of antibodies produced by horses in hyperimmune plasma production programs. It was possible to verify oscillations in antibody avidity that occurred along the immunization cycles, differences between novice and veteran horses, maturation of antibody avidity, and correlation between avidity index and antibody titre. Similar results were obtained for crude venom and purified Ts1 toxin. In addition, the avidity ELISA apparently demonstrated potential for application as a potency test in the initial stage of antivenom production. However, more studies are necessary.

IgY Antibodies from Birds: A Review on Affinity and Avidity.

IgY antibodies are found in the blood and yolk of eggs. Several studies show the feasibility of utilising IgY for immunotherapy and immunodiagnosis. These antibodies have been studied because they fulfil the current needs for reducing, replacing, and improving the use of animals. Affinity and avidity represent the strength of the antigen-antibody interaction and directly influence antibody action. The aim of this review was to examine the factors that influence the affinity and avidity of IgY antibodies and the methodologies used to determine these variables. In birds, there are few studies on the maturation of antibody affinity and avidity, and these studies suggest that the use of an adjuvant-type of antigen, the animal lineage, the number of immunisations, and the time interfered with the affinity and avidity of IgY antibodies. Regarding the methodologies, most studies use chaotropic agents to determine the avidity index. Studies involving the solution phase and equilibrium titration reactions are also described. These results demonstrate the need for the standardisation of methodologies for the determination of affinity and avidity so that further studies can be performed to optimise the production of high avidity IgY antibodies.

Development of a multiassay algorithm (MAA) to identify recent HIV infection in newly diagnosed individuals in Indonesia

Ongoing HIV transmission is a public health priority in Indonesia. We developed a new multiassay algorithm (MAA) to identify recent HIV infection. The MAA is a sequential decision tree based on multiple biomarkers, starting with CD4+ Tcells >200/μL, followed by plasma viral load (pVL)>1,000 copies/ml, avidity index (AI)<0 · 7, and pol ambiguity <0 · 47%. Plasma from 140 HIV-infected adults from 19 hospitals across Indonesia (January 2018- June 2020) was studied, consisting of a training set (N= 60) of longstanding infection (>12-month) and a test set (N= 80) of newly diagnosed (≤1-month) antiretroviral (ARV) drug naive individuals. Ten of eighty (12 · 5%) newly diagnosed individuals were classified as recent infections. Drug resistance mutations (DRMs) against reverse transcriptase inhibitors were identified in two individuals: one infected with HIV subtype C (K219Q, V179T) and the other with CRF01_AE (V179D). Ongoing HIV transmission, including infections with DRMs, is substantial in Indonesia.