IgG Ab Research Articles

Burden of Chikungunya Virus Infection during an Outbreak in Myanmar.

Chikungunya virus (CHIKV) infection is a re-emerging arboviral disease with no approved vaccine, although numerous options are in development. Before vaccine implementation, disease burden, affected age group, and hospitalization rate information should be documented. In 2019, a sizeable outbreak of the East Central South African genotype of CHIKV occurred in Myanmar, and during this period, a cross-sectional study was conducted in two regions, Mandalay and Yangon, to examine the molecular and seropositivity rate of the CHIKV infection. The participants (1124) included dengue-suspected pediatric patients, blood donors, and healthy volunteers, who were assessed using molecular assays (quantitative real-time RT-PCR), serological tests (anti-CHIKV IgM capture and IgG indirect enzyme-linked immunosorbent assays), and neutralization tests. The tests confirmed the following positivity rates: 11.3% (127/1124) for the molecular assay, 12.4% (139/1124) for the anti-CHIKV IgM Ab, 44.5% (500/1124) for the anti-CHIKV IgG Ab, and 46.3% (520/1124) for the CHIKV neutralizing Ab. The highest rate for the molecular test occurred with the dengue-suspected pediatric patients. The seroprevalence rate through natural infection was higher in the healthy volunteers and blood donors than that in the pediatric patients. The results of this study will help stakeholders determine the criteria for choosing appropriate recipients when a CHIKV vaccine is introduced in Myanmar.

Are high avidity antibodies to Plasmodium falciparum antigens preferentially transferred across the placenta of premature and term babies?

IntroductionTransplacental transport of maternal IgG via the neonatal Fc receptor (FcRn) provides babies with passive immunity. Several factors are reported to influence transport, including the avidity of antibodies (Abs) for their cognate antigens. Unfortunately, information on the role of antibody (Ab) avidity is limited. This study investigated if i) antibodies (Abs) with high avidity for 6 Plasmodium falciparum antigens and tetanus toxoid (TTx) were preferentially transferred to premature and term Cameroonian babies and ii) if Ab avidity was increased in babies whose mothers had placental malaria (PM), implicating the involvement of immune complexes. MethodsTotal IgG (mg/ml) and Abs to malarial antigens (AMA1, EBA-175, MSP1-42, MSP2, MSP3, DBL5 of VAR2CSA) and TTx were measured in paired mother-cord samples obtained from premature and term deliveries in Cameroon. Half the women had PM at delivery. Avidity Indices (AIs) were determined by treating antigen-bound-Abs with different molar concentrations of NH4SCN and calculating 50% endpoints. ResultsTotal IgG and antigen-specific Abs increased in cord blood with gestational age; however, AIs did not. AIs in paired maternal-cord blood samples were strongly associated for all antigens (r = 0.77–0.96). However, no significant different in AIs was found between paired mother-cord blood samples for any of the antigens (p values > 0.05). Similarly, Ab avidity was not increased in cord blood of babies whose mothers had PM or hypergammaglobulinemia. DiscussionOverall, there was no evidence that higher avidity Abs to any of the malarial antigens or TTx were preferentially transferred to Cameroonian babies.

Prevalence of Hepatitis B Virus among Renal Dialysis Patients in Diyala Province, Iraq

Background: One of the main public health challenges in the globe is the prevalence of the hepatitis B virus (HBV). Objectives: The curent study aimed to determine the prevalence of hepatitis B virus in renal dialysis patients in Diyala province, Iraq. Methods: Ninety of renal dialysis patients attended Ibn-Sina Dialysis Center were screened for HBsAg, HBc IgG, HBc IgM and HBe Ab using ELISA technique, and then positive results were retested by conventional PCR for detection of HBs gene and HB core gene. Demographic data of study population were recorded. Simple statistical analysis was done using SPSS Version 25. Results: Among studied samples, the seroprevalence of HBsAg, Anti-HBc Ab, Anti-HBc IgM and Anti-HBe Ab were 4.4%, 17.8%, 2.2% and 5.6% respectively. The results of conventional PCR showed that only 1(1.1%) of HBs gene at 417 bp in renal dialysis patients were positive. Whereas, the HBc gene at 791 bp was not detected in all included study population. Conclusion: The prevalence of HBV was relatively high among renal dialysis in Diyala province/Iraq.

A Case Report of Hyper-IgM Syndrome Patient with Normal Serum IgA Level

Hyper IgM syndromes are a group of disorders characterized by defective T and B cell interactions resulting in the lack of Immunoglobulin class switching. The most common hyper IgM syndrome is CD40 ligand (CD40L) deficiency. Patients with CD40L deficiency present with recurrent infection, neutropenia, and autoimmunity. These patients typically have absent serum IgA and IgG due to the class switch defect. Here we present a case of CD40L deficiency who presented with oral ulcers, failure to thrive, and recurrent fever. His laboratory evaluation was notable for intermittent neutropenia, elevated IgM (397mg/dl), normal IgA (78mg/dl) and low IgG (51mg/dl). Antibody responses to tetanus and measles were undetectable despite full vaccination. Whole exome sequencing showed a likely pathologic variant in CD40LG (c.674 T>C, p.L225S). This case highlights the importance of considering the diagnosis of hyper IgM syndrome in the appropriate clinical setting, even if the patient has a normal serum IgA level.

A Serological Analysis of the Humoral Immune Responses of Anti-RBD IgG, Anti-S1 IgG, and Anti-S2 IgG Levels Correlated to Anti-N IgG Positivity and Negativity in Sicilian Healthcare Workers (HCWs) with Third Doses of the mRNA-Based SARS-CoV-2 Vaccine: A Retrospective Cohort Study.

With SARS-CoV-2 antibody tests on the market, healthcare providers must be confident that they can use the results to provide actionable information to understand the characteristics and dynamics of the humoral response and antibodies (abs) in SARS-CoV-2-vaccinated patients. In this way, the study of the antibody responses of healthcare workers (HCWs), a population that is immunocompetent, adherent to vaccination, and continuously exposed to different virus variants, can help us understand immune protection and determine vaccine design goals. We retrospectively evaluated antibody responses via multiplex assays in a sample of 538 asymptomatic HCWs with a documented complete vaccination cycle of 3 doses of mRNA vaccination and no previous history of infection. Our sample was composed of 49.44% males and 50.56% females, with an age ranging from 21 to 71 years, and a mean age of 46.73 years. All of the HCWs' sera were collected from April to July 2022 at the Sant'Elia Hospital of Caltanissetta to investigate the immunologic responses against anti-RBD, anti-S1, anti-S2, and anti-N IgG abs. A significant difference in age between HCWs who were positive and negative for anti-N IgG was observed. For anti-S2 IgG, a significant difference between HCWs who were negative and positive compared to anti-N IgG was observed only for positive HCWs, with values including 10 (U/mL)-100 (U/mL); meanwhile, for anti-RBD IgG and anti-S1 IgG levels, there was only a significant difference observed for positive HCWs with diluted titers. For the negative values of anti-N IgG, among the titer dilution levels of anti-RBD, anti-S1, and anti-S2 IgG, the anti-S2 IgG levels were significantly lower than the anti-RBD and anti-S1 levels; in addition, the anti-S1 IgG levels were significantly lower than the anti-RBD IgG levels. For the anti-N IgG positive levels, only the anti-S2 IgG levels were significantly lower than the anti-RBD IgG and anti-S1 IgG levels. Finally, a logistic regression analysis showed that age and anti-S2 IgG were negative and positive predictors of anti-N IgG levels, respectively. The analysis between the vaccine type and mixed mRNA combination showed higher levels of antibodies in mixed vaccinated HCWs. This finding disappeared in the anti-N positive group. Most anti-N positive HCWs showed antibodies against the S2 domain and were young subjects. Therefore, the authors suggest that including the anti-SARS-CoV-2-S2 in antibody profiles can serve as a complementary testing approach to qRT-PCR for the early identification of asymptomatic infections in order to reduce the impact of potential new SARS-CoV-2 variants. Our serological investigation on the type of mRNA vaccine and mixed mRNA vaccines shows that future investigations on the serological responses in vaccinated asymptomatic patients exposed to previous infection or reinfection are warranted for updated vaccine boosters.

1490-P: Levels of Specific Antibodies (Ab) for Sars Cov2 after Vaccination and Its Relationship with Clinical and Metabolic Variables in People with Type 2 Diabetes vs. Controls without Diabetes

Introduction: The COVID-19 pandemic has affected people all over the world, and even more seriously people with chronic pathologies. Objectives: Primary: To evaluate the humoral immune response (IgG Ab specific for SARS CoV-2) in adults with DM2 versus controls. Secondary: To evaluate the relationship between Ab IgG levels and the presence of other clinical variables and comorbidities. Materials and Methods: The study was carried out in January 2022 in Argentina. Adults with DM2 and controls who had received first and second doses of any SARS Cov-2 vaccines were included. Titers of Ac IgG were performed through the assay of IgG anti RBD (receptor binding domain in the host cell). Multiple Logistic Regression and Multiple Linear Regression were used. p value <0.05 was considered statistically significant. Results: N 144 participants (91 with DM2 and 53 controls). Median from the second dose of a vaccine to the measurement of Ab: 141 days in controls and 144 in diabetics (p=0.451). The logarithm of the Ab titers were significantly lower in patients with DM2 vs. controls (p<0.01). Univariate analysis: Ab levels were positively and significantly related to BMI (p<0.01). They were also significantly associated with age (p<0.001) and with the presence of rheumatic diseases (p= 0.02). Multivariate analysis: Ab levels were only significantly and negatively associated with age (p<0.01) and the presence of rheumatologic bone disease (p=0.02). No differences were found between the type of vaccines used. Conclusion: Although the Ab titers registered in DM2 were significantly lower vs. controls, the adjustment for various covariates have not allowed to sustain the significance of this association in multivariate analysis. The role of age, BMI, the presence of rheumatic diseases and other factors should be explored in other studies in order to evaluate their potential role as confounders. Disclosure M.L.Pomares: None. A.Figuerero: None. C.Gomez martin: None. S.Gorban de lapertosa: None. G.Cuzziol: None. C.E.Lopez: None. S.Kremer sendros: None. D.Pomares: None. M.Ojeda: None. V.Wolffenbuttel carloto: None. R.M.Tejada: None. G.A.Ojeda: None.

Efgartigimod restores muscle function in a humanized mouse model of immune-mediated necrotizing myopathy.

Immune-mediated necrotizing myopathies (IMNMs) are severe forms of myositis often associated with pathogenic anti-3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) autoantibodies (aAbs). Efgartigimod is an engineered human IgG1 Fc fragment that antagonizes the neonatal Fc receptor (FcRn), thereby preventing recycling and promoting lysosomal degradation of IgG, including aAbs. We evaluated the therapeutic effects of IgG reduction by efgartigimod in a humanized murine model of IMNM. Disease was induced in C5-deficient (C5def) or Rag2-deficient (Rag2-/-) mice receiving co-injections of anti-HMGCR+ IgG from an IMNM patient and human complement. C5def mice were treated in a preventive setting with s.c. injections of efgartigimod and Rag2-/- mice in a curative setting after disease was induced by anti-HMGCR+ IgG injections. Anti-HMGCR aAbs levels were monitored in mouse serum and muscle tissue. Histological analysis was performed on muscle sections. Muscle force was assessed by grip test or measurement of gastrocnemius strength upon electrostimulation. Administration of efgartigimod rapidly reduced total IgG levels, including the level of pathogenic anti-HMGCR aAbs, in both serum (P < 0.0001) and muscle (P < 0.001). In the preventive setting, efgartigimod prevented myofibre necrosis (P < 0.05), thus precluding loss of muscle strength (P < 0.05). In the therapeutic setting, efgartigimod prevented further necrosis and allowed muscle fibre regeneration (P < 0.05). Hence, muscle strength returned to normal (P < 0.01). Efgartigimod reduces circulating IgG levels, including pathogenic anti-HMGCR+ IgG aAbs, in a humanized mouse model of IMNM, preventing further necrosis and allowing muscle fibre regeneration. These results support investigating the therapeutic efficacy of efgartigimod through a clinical trial in IMNM patients.

#5076 MONOCLONAL GAMMOPATHY IN C3 GLOMERULOPATHY: DOES THE BUCKET STOP THERE?

Abstract Background and Aims C3 glomerulopathy (C3G) is a rare diagnosis, characterized by dysregulation of the alternative pathway of complement, classically presenting in children and young adults. Recently, it has been reported the association between the production of a monoclonal protein and the development of C3G, affecting a larger age span. Method We report the case of a 53-year-old male patient, that attended the emergency department due to persistent holocranial headache. He was an IV drug abuser with a history of treated Hepatitis C infection and free lambda light chain monoclonal protein, being studied by the Haematology Department. On admission, he was hypertensive (187/98 mmHg), and labs showed an acute on chronic kidney disease (serum creatinine 2.35 mg/dL from a basal of 1.5 mg/dL) with an active urinary sediment (38 erythrocytes/field, with dysmorphia), a urinary protein/creatinine ratio of 626 mg/g, and C3 consumption (0.52 g/L). The patient was admitted, and a kidney biopsy was performed. Results Further lab results confirmed a serum IgG Lambda monoclonal protein. Autoantibodies screening (ANCAs, ANAs, Anti-GBM), ASLO and Rheumatoid Factor were negative. Cryoglobulinemia was detected, and the cryoprecipitate's immunofixation revealed monoclonal proteins IgG Lambda and IgM Kappa. HCV viral load was negative. Bone marrow biopsy revealed a small population (&amp;lt; 3%) of plasma cells with Lambda light chain restriction. Kidney biopsy's light microscopy showed increased mesangial matrix and cells, endocapillary hypercellularity, and some glomeruli with lobulated appearance. Five out of 15 glomeruli presented fibrocellular crescents. Immunofluorescence showed C3 dominant staining on capillary walls and in the mesangium, with absent IgG and light chain deposits. A presumptive diagnosis of C3 glomerulopathy was made and the patient was empirically started on corticosteroids (3 pulses of intravenous methylprednisolone, followed by oral prednisolone 1mg/Kg/day), which was followed by paraprotein-directed chemotherapy with bortezomib, cyclophosphamide and dexamethasone (VCD). The patient is currently on the third VCD cycle, presenting both renal and haematological responses: recovery of serum creatinine to basal levels (1.54 mg/dL), resolution of haematuria and proteinuria, normalisation of C3 levels. Serum immunofixation is currently negative for monoclonal protein, with normal serum immunoglobulin levels. Electron microscopy revealed electron-dense deposits in the mesangium, and mesangium-capillary transition, supporting the diagnosis of C3 glomerulonephritis. Genetic testing of complement-related genes revealed a rare missense variation of unknown significance (c.4855A&amp;gt;C) on the C3 gene, that has been previously reported in association with C3 glomerulopathy and atypical Haemolytic-Uremic syndrome. Conclusion This case represents a monoclonal gammopathy associated-C3 glomerulonephritis with a favourable response to paraprotein-directed chemotherapy. Although the association between monoclonal gammopathy and C3G rests on epidemiologic findings, experimental evidence suggests that several monoclonal proteins have complement dysregulation features, which may enhance alternate complement pathway activation. Our patient's response is in line with observational data that have shown improved renal outcomes in patients who achieve a haematological response following clone-directed chemotherapy, which further supports the role of monoclonal gammopathy in C3G pathogenesis [1]. Interestingly, the genetic variation identified in our patient might have provided a favourable genetic background for the development of C3G, which is thought to rely upon a complex interaction of triggering events, such as a monoclonal gammopathy, and underlying complement abnormalities, such as genetic variants in complement genes.

Baseline autoantibody profiling in patients with NSCLC with pre-existing autoimmune diseases or who had received prior anti-PD-1 therapy before enrolling in the TAIL study.

2512 Background: Patients (pts) with pre-existing autoimmune diseases (AID) and prior immune checkpoint inhibitor (ICI) experience were historically excluded from studies with ICIs. Moreover, about 50% pts with pre-existing autoimmunity have a flare up when given ICI therapies (1). In this post-hoc exploratory analysis, we characterized the baseline autoantibody (AAb) profiles and evaluated its correlation with efficacy and safety outcomes in NSCLC pts with either pre-existing AID or who had prior ICI therapy and received atezolizumab in the TAIL study (2). Methods: Plasma samples were obtained from 57 NSCLC pts prior to receiving atezolizumab (TAIL study, NCT03285763). AAb testing was performed using tailored immuno-oncology bead-based antigen arrays comprising 1,340 tumor, AID and immune pathway antigens (3, 4). The cohort includes 39 pts with prior ICI therapy or prior AID (experimental group) and 18 pts without prior ICI therapy or AID (control group). Differences in IgG AAbs were compared between the experimental and control group in pts with or w/o irAE and overall survival (OS) longer or shorter than 11.1 months (median OS in overall population in TAIL). Furthermore, the AAb profiles of a subgroup of pts with therapeutic benefit (OS ≥ 11.1 months) and no or low grade irAEs (standard toxicity grade ≤ 2) were analyzed. Statistical analysis included 2-way permutation-based ANOVA (factors: outcome, study group) and Significance Analysis of Microarrays (SAM). Results: While pre-treatment AAbs were detected in the overall cohort, significant differences in AAb were observed between the experimental and control group at baseline, which were associated with OS and irAEs. In experimental group pts, pre-existing AAbs to AQP4 and NCOA1 predicted the development of irAEs. Differences were also observed in AAbs predicting longer OS. AAbs to CENPT were specifically identified in pts in the experimental group with longer OS, whereas AAbs to SOX5 were elevated in pts of the control group with longer OS. In the subgroup of pts with therapeutic benefit and no or low risk of irAE, AAbs to IL6, CENPT and the cancer testis antigens NY-ESO-2 and MAGEB2 were elevated in the experimental group. Conclusions: This AAb analysis provides important preliminary data in helping to understand the drivers of clinical outcomes with ICIs in pts with pre-existing AID and prior ICI therapy. The findings seem biologically plausible as some of the identified antigens refer to the breach of tolerance to classical AAb targets e.g. CENPT, AQP4 and to an immune response to classic tumor antigens e.g. NY-ESO-2 and MAGEB2. Further validation of the AAb profiling approach is warranted to shed insights on potential therapeutically actionable antigens and generate data orthogonal to efforts to identify biomarkers that are predictive of efficacy and safety outcomes with ICI therapies.

Поширеність антитіл до SARS-CoV-2 у дітей та підлітків: одноцентрове дослідження

Despite the fact that children with COVID-19 are usually asymptomatic or mild, infection with SARS-CoV-2 is more likely to lead to the development of an antibody response. Understanding humoral immunity to SARS-CoV-2, including in children, is critical for future public health and vaccination strategies. Children with chronic diseases deserve special attention. Purpose - to study the prevalence of positive antibodies to SARS-CoV-2 in children and adolescents who were in paediatric hospital without signs of viral disease to develop future healthcare strategies. Materials and methods. In 32 children aged 6-17 years (14 (43.8%) boys and 16 (56.2%) girls) quantitative determination of IgG antibodies to SARS-CoV-2 in blood serum was carried out by enzyme immunoassay using commercial SARS-CoV-2 S1\RBD IgG Ab ELISA (TECAN, IBL International GmbH, Germany). Results. The majority (n=27, 84.4%) of children had a positive level of class G antibodies to SARS-CoV-2. 7 (25.9%) children had a positive PCR test in their anamnesis, 6 (18.8%) persons provided information about the infection transmitted by family members. Clinical manifestations characteristic of SARS-CoV-19 were present in 2 (7.4%) children. Parents of 18 (66.7%) children claimed that their children had no symptoms of COVID-19, while family members of 6 (33.3%) children had cases of the disease. All children (n=6, 18.8%) who were vaccinated with two doses of Comirnaty® vaccine had positive IgG antibodies to SARS-CoV-2. Antibodies to SARS-CoV-2 were absent in 5 (15.4%) people, all of them were patients with type 1 diabetes. Conclusions. The study of the prevalence of antibodies to SARS-CoV-2 provides important information about circulating antibodies against SARS-CoV-2 in children and adolescents, in particular those with chronic diseases. The obtained results showed the predominant seropositivity of children, which is formed regardless of the clinical manifestations of the disease. A high level of antibodies under the conditions of revaccination confirms the benefit of revaccination of children to strengthen memory formation. The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethics Committee of the participating institution. The informed consent of the patient was obtained for conducting the studies. No conflict of interests was declared by the authors.

Correlates of COVID-19 mRNA vaccine humoral immune responses in men living with HIV-1

Abstract It is important that people with HIV-1 (PWH) receive an FDA-approved vaccine for COVID-19. Because PWH are known to elicit less effective immune responses to other licensed vaccines, we assessed the humoral immune response to the novel COVID-19 mRNA vaccines in 139 fully vaccinated male participants (45 with HIV-1 [MWH] and 94 without HIV-1 [MWOH]) of the MACS/WIHS Combined Cohort Study. Levels of anti-nucleocapsid (N) and anti-spike 1 (S1) IgG and IgA were determined using ELISA and the MSD electro-chemiluminescence multiplex assay platform, to classify natural infection and vaccination status, and quantify binding IgG. Functional characterization of antibodies (Ab) was determined by measuring neutralizing Ab levels against WA, Delta, and Omicron strains, and immune complex complement activation capacity by complement component 3 (C3) deposition. We found that MWH who received two standard doses of mRNA vaccines had lower levels of vaccine-induced anti-S1 IgG and neutralizing Ab against the Washington, Delta, Omicron variants compared to MWOH, and these Ab titers were boosted in the context of natural SARS-CoV-2 infection for MWH. Interestingly, Ab in MWH promoted more potent C3 deposition. In all participants the Moderna mRNA-1273 vaccine induced significantly higher levels of binding IgG and neutralizing Abs against the variants. Importantly, preexisting immunity to the endemic human coronaviruses, participant age, and blood biochemical measurements correlated with these vaccine responses. Our data indicate that COVID-19 mRNA vaccine-induced humoral responses are impaired in MWH. Further studies are needed to define the long-term effects of this impairment on prevention and control of SARS-CoV-2 infection in MWH. Supported by grants from NIH: Pitt AIDS Research Training (PART) (NRSA 5T32AI065380-15) to DJT, NIH (NHLBI 5U01HL146208) and OAR/NHLBI Supplement (U01HL146208-03S2/S3), MWCCS Concepts X21033 and X20124, and NIH NIAID (R01-AI167711).

SRF617 Is a Potent Inhibitor of CD39 with Immunomodulatory and Antitumor Properties.

CD39 (ENTPD1) is a key enzyme responsible for degradation of extracellular ATP and is upregulated in the tumor microenvironment (TME). Extracellular ATP accumulates in the TME from tissue damage and immunogenic cell death, potentially initiating proinflammatory responses that are reduced by the enzymatic activity of CD39. Degradation of ATP by CD39 and other ectonucleotidases (e.g., CD73) results in extracellular adenosine accumulation, constituting an important mechanism for tumor immune escape, angiogenesis induction, and metastasis. Thus, inhibiting CD39 enzymatic activity can inhibit tumor growth by converting a suppressive TME to a proinflammatory environment. SRF617 is an investigational, anti-CD39, fully human IgG4 Ab that binds to human CD39 with nanomolar affinity and potently inhibits its ATPase activity. In vitro functional assays using primary human immune cells demonstrate that inhibiting CD39 enhances T-cell proliferation, dendritic cell maturation/activation, and release of IL-1β and IL-18 from macrophages. In vivo, SRF617 has significant single-agent antitumor activity in human cell line-derived xenograft models that express CD39. Pharmacodynamic studies demonstrate that target engagement of CD39 by SRF617 in the TME inhibits ATPase activity, inducing proinflammatory mechanistic changes in tumor-infiltrating leukocytes. Syngeneic tumor studies using human CD39 knock-in mice show that SRF617 can modulate CD39 levels on immune cells invivo and can penetrate the TME of an orthotopic tumor, leading to increased CD8+ T-cell infiltration. Targeting CD39 is an attractive approach for treating cancer, and, as such, the properties of SRF617 make it an excellent drug development candidate.

Recombinant Bacillus Calmette-Guérin Expressing SARS-CoV-2 Chimeric Protein Protects K18-hACE2 Mice against Viral Challenge.

COVID-19 has accounted for more than 6 million deaths worldwide. Bacillus Calmette-Guérin (BCG), the existing tuberculosis vaccine, is known to induce heterologous effects over other infections due to trained immunity and has been proposed to be a potential strategy against SARS-CoV-2 infection. In this report, we constructed a recombinant BCG (rBCG) expressing domains of the SARS-CoV-2 nucleocapsid and spike proteins (termed rBCG-ChD6), recognized as major candidates for vaccine development. We investigated whether rBCG-ChD6 immunization followed by a boost with the recombinant nucleocapsid and spike chimera (rChimera), together with alum, provided protection against SARS-CoV-2 infection in K18-hACE2 mice. A single dose of rBCG-ChD6 boosted with rChimera associated with alum elicited the highest anti-Chimera total IgG and IgG2c Ab titers with neutralizing activity against SARS-CoV-2 Wuhan strain when compared with control groups. Importantly, following SARS-CoV-2 challenge, this vaccination regimen induced IFN-γ and IL-6 production in spleen cells and reduced viral load in the lungs. In addition, no viable virus was detected in mice immunized with rBCG-ChD6 boosted with rChimera, which was associated with decreased lung pathology when compared with BCG WT-rChimera/alum or rChimera/alum control groups. Overall, our study demonstrates the potential of a prime-boost immunization system based on an rBCG expressing a chimeric protein derived from SARS-CoV-2 to protect mice against viral challenge.

Progressive Multifocal Leukoencephalopathy Secondary to Possible Covert Administration of Osimertinib, a Case Report. (P13-10.004)

<h3>Objective:</h3> to report a case of rapidly progressive multifocal leukoencephalopathy with unclear cause, possibly secondary to covert administration of Osimertinib. <h3>Background:</h3> Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease that was first reported in 1958. It is caused by reactivation of the John Cunningham (JC) virus. Drug-induced PML is increasingly reported in the era of molecular anti-neoplastic targeted therapy. Osimertinib, a tyrosine kinase inhibitor (TKI) was described in one case report to be associated with rapidly progressive PML, we believe our case to be the second. <h3>Design/Methods:</h3> Case report, N/A <h3>Results:</h3> 47-year-old-male with pulmonary sarcoidosis presented with worsening confusion and jerking episodes for nine months. Examination was significant for pseudobulbar affect, left sided weakness, and hyperreflexia. MRI brain showed multiple hyperintense FLAIR lesions in the subcortical white matter without enhancement. MRI cervical, thoracic, and lumbar spine was unremarkable. CT chest abdomen and pelvis was negative for malignancy but showed findings consistent with pulmonary sarcoidosis. CSF showed normal cell count and protein. CSF viral studies, bacterial studies, fungal studies, N-methyl-D-Aspartate Receptor Ab IgG CSF, NMO IgG, CSF were negative. He was found to have low total CD4 count of 118. Blood tests for infectious (including HIV), autoimmune, and paraneoplastic causes were unremarkable. He was noted to have. Brain biopsy confirmed the diagnosis of PML. There was reported concern about covert administration of Osimertinib which was available at home. The patient’s course was complicated by sepsis and he passed away after a month of hospitalization. <h3>Conclusions:</h3> This case demonstrates a challenging presentation of PML in an originally supposed immunocompetent patient. Inhibition of tyrosine kinase-dependent pathways can potentially aid in the replication of JC virus. Holding immunosuppressive therapy remains the mainstay for management for non-HIV related PML. Early recognition of this fatal etiology and its subcategory would help guide clinical management. <b>Disclosure:</b> Dr. Centofanti has nothing to disclose. Dr. Alkhoujah has nothing to disclose. Dr. Bishja has nothing to disclose.

Development of C1q Affinity Chromatography for the Study of C1q-IgG Interactions.

The classical complement system represents a central effector mechanism of Abs initiated by the binding of C1q to target bound IgG. Human C1q contains six heterotrimeric globular head groups that mediate IgG interaction, resulting in an avidity-driven binding event involving multiple IgG molecules binding a single C1q. Accordingly, surface bound IgG molecules are thought to assemble into noncovalent hexameric rings for optimal binding to the six-headed C1q. To study the C1q-Fc interaction of various Abs and screen for altered C1q binding mutants, we developed, to our knowledge, a novel HPLC-based method. Employing a single-chain form of C1q representing one C1q head group, our HPLC methodology was able to detect the interaction between the single-chain monomeric form of C1q and various ligands. We show that, despite a narrow window of specific binding owing to the low affinity of the monomeric C1q-IgG interaction, this approach clearly distinguished between IgG subclasses with established C1q binding properties. IgG3 displayed the strongest binding, followed by IgG1, with IgG2 and IgG4 showing the weakest binding. Fc mutants known to have increased C1q binding through oligomerization or enhanced C1q interaction showed greatly increased column retention, and IgG glycovariants displayed a consistent trend of increasing retention upon increasing galactosylation and sialylation. Furthermore, the column retention of IgG isotypes and glycovariants matches both the cell surface recruitment of C1q and complement-mediated cytotoxicity induced by each variant on an anti-CD20 Ab backbone. This methodology therefore provides a valuable tool for testing IgG Ab (glyco)variants for C1q binding, with clear relevance for therapeutic Ab development.

Clinical characterization and placental pathology of mpox infection in hospitalized patients in the Democratic Republic of the Congo

We describe the results of a prospective observational study of the clinical natural history of human monkeypox (mpox) virus (MPXV) infections at the remote L'Hopital General de Reference de Kole (Kole hospital), the rainforest of the Congo River basin of the Democratic Republic of the Congo (DRC) from March 2007 until August 2011. The research was conducted jointly by the Institute National de Recherche Biomedical (INRB) and the US Army Medical Research Institute of Infectious Diseases (USAMRIID). The Kole hospital was one of the two previous WHO Mpox study sites (1981-1986). The hospital is staffed by a Spanish Order of Catholic Nuns from La Congregation Des Soeurs Missionnaires Du Christ Jesus including two Spanish physicians, who were members of the Order as well, were part of the WHO study on human mpox. Of 244 patients admitted with a clinical diagnosis of MPXV infection, 216 were positive in both the Pan-Orthopox and MPXV specific PCR. The cardinal observations of these 216 patients are summarized in this report. There were three deaths (3/216) among these hospitalized patients; fetal death occurred in 3 of 4 patients who were pregnant at admission, with the placenta of one fetus demonstrating prominent MPXV infection of the chorionic villi. The most common complaints were rash (96.8%), malaise (85.2%), sore throat (78.2%), and lymphadenopathy/adenopathy (57.4%). The most common physical exam findings were mpox rash (99.5%) and lymphadenopathy (98.6%). The single patient without the classic mpox rash had been previously vaccinated against smallpox. Age group of less than 5 years had the highest lesion count. Primary household cases tended to have higher lesion counts than secondary or later same household cases. Of the 216 patients, 200 were tested for IgM & IgG antibodies (Abs) to Orthopoxviruses. All 200 patients had anti-orthopoxvirus IgG Abs; whereas 189/200 were positive for IgM. Patients with hypoalbuminemia had a high risk of severe disease. Patients with fatal disease had higher maximum geometric mean values than survivors for the following variables, respectively: viral DNA in blood (DNAemia); maximum lesion count; day of admission mean AST and ALT.

Serological Cross Reaction among Sonle Causative Agents of WomenAbortions (Toxoplasma gondii &amp; Cytomegalo Virus &amp; Rubella Virus),rvith the Incidence of Hepatitis Virus (B &amp;C)

Primary maternal infection with infectious agents of abortions in women is frequently associated with transplacental transmission to the fetus. This study was conducted to test the utility ELISA assay to detect recent infection with Toxoplasma (TOXO), Rubella virus (RV), Cytomegalovirus (CMV), the incidence of viral hepatitis B (HBS) &amp; C (HCV) in addition the determination of cross reactivity among serological tests. Three hundred forty three women with high risk of pregnancy (who had previous recurrent abortion &amp; congenital abnormalities) &amp; 60 normal pregnancies (control) were tested for the presence of the tests that described in above. The all rate of infectious agents was 22.15 % that divided into 8.88%, 8.02% &amp; 4.84 % for RV, CMV, &amp; Toxo antibodies respectively. Igm Ab of RV(31.5%) was higher than CMV( 17.6%) &amp; Toxo( 3.39% ) P&lt;0.05.While IgG Ab shows the reveres as 17% for Toxo, followed by 6.75% &amp; 7.89 % for RV&amp; CMV respectively P&lt;0.05. Relationship between distribution of Toxo Ab concerning age was not significant P&gt;0.05. incidence of HCV shows equality rates 2.63% within sero-positive Toxo,RV&amp;CMYV, while HBS shows high occurrence in sero-positive for RV ( 5.26%) than in sero- positive for Toxo &amp; CMV(1.31% )P&lt;0.05. Relationship between frequency of abortions &amp; stillbirthsé&amp; infectious agents was significant P&lt;0.05. In addition .relationship between women occupations &amp; frequency of scro-positive reveals significance P&lt;0.05 especially in sera of homemakers (housewives) than other women occupations. Control groups were negative for viral hepatitis &amp;Toxo, except few cases&gt;0.05.

Antibodies for β2-Microglobulin and the Heavy Chains of HLA-E, HLA-F, and HLA-G Reflect the HLA-Variants on Activated Immune Cells and Phases of Disease Progression in Rheumatoid Arthritis Patients under Treatment

Rheumatoid arthritis (RA) is a progressive, inflammatory, autoimmune, symmetrical polyarticular arthritis. It is characterized by synovial infiltration and activation of several types of immune cells, culminating in their apoptosis and antibody generation against "altered" autoantigens. β2-microglobulin (β2m)-associated heavy chains (HCs) of HLA antigens, also known as closed conformers (Face-1), undergo "alteration" during activation of immune cells, resulting in β2m-free structural variants, including monomeric open conformers (Face-2) that are capable of dimerizing as either homodimers (Face-3) or as heterodimers (Face-4). β2m-free HCs uncover the cryptic epitopes that can elicit antibodies (Abs). We report here the levels of IgM and IgG Abs against both β2m and HCs of HLA-E, HLA-F, and HLA-G in 74 RA patients receiving immunosuppressive drugs. Anti-β2m IgM was present in 20 of 74 patients, whereas anti-β2m IgG was found in only 8 patients. Abs against β2m would be expected if Abs were generated against β2m-associated HLA HCs. The majority of patients were devoid of either anti-β2m IgM or IgG but had Abs against HCs of different HLA-Ib molecules. The paucity of anti-β2m Abs in this cohort of patients suggests that Abs were developed against β2m-free HLA HCs, such as Face-2, Face-3, and Face-4. While 63 of 68 patients had IgG Abs against anti-HLA-F HCs, 36 and 50 patients showed IgG Ab reactivity against HLA-E and anti-HLA-G HCs, respectively. Evidently, anti-HLA-F HC Abs are the most predominant anti-HLA-Ib HC IgG Abs in RA patients. The incidence and intensity of Abs against HLA-E, HLA-F, and HLA-G in the normal control group were much higher than those observed in RA patients. Evidently, the lower level of Abs in RA patients points to the impact of the immunosuppressive drugs on these patients. These results underscore the need for further studies to unravel the nature of HLA-F variants on activated immune cells and synoviocytes of RA patients.

Simple prediction of COVID-19 convalescent plasma units with high levels of neutralization antibodies

BackgroundHyperimmune convalescent COVID-19 plasma (CCP) containing anti-SARS-CoV-2 neutralizing antibodies (NAbs) was proposed as a therapeutic option for patients early in the new coronavirus disease pandemic. The efficacy of this therapy depends on the quantity of neutralizing antibodies (NAbs) in the CCP units, with titers ≥ 1:160 being recommended. The standard neutralizing tests (NTs) used for determining appropriate CCP donors are technically demanding and expensive and take several days. We explored whether they could be replaced by high-throughput serology tests and a set of available clinical data.MethodsOur study included 1302 CCP donors after PCR-confirmed COVID-19 infection. To predict donors with high NAb titers, we built four (4) multiple logistic regression models evaluating the relationships of demographic data, COVID-19 symptoms, results of various serological testing, the period between disease and donation, and COVID-19 vaccination status.ResultsThe analysis of the four models showed that the chemiluminescent microparticle assay (CMIA) for the quantitative determination of IgG Abs to the RBD of the S1 subunit of the SARS-CoV-2 spike protein was enough to predict the CCP units with a high NAb titer. CCP donors with respective results > 850 BAU/ml SARS-CoV-2 IgG had a high probability of attaining sufficient NAb titers. Including additional variables such as donor demographics, clinical symptoms, or time of donation into a particular predictive model did not significantly increase its sensitivity and specificity.ConclusionA simple quantitative serological determination of anti-SARS-CoV-2 antibodies alone is satisfactory for recruiting CCP donors with high titer NAbs.

CD4 T Cell-Dependent and -Independent Roles for IFN-γ in Blood-Stage Malaria.

Production of IFN-γ by CD4 T cells is widely theorized to control Plasmodium parasite burden during blood-stage malaria. Surprisingly, the specific and crucial mechanisms through which this highly pleiotropic cytokine acts to confer protection against malarial disease remain largely untested invivo. Here we used a CD4 T cell-restricted Cre-Lox IFN-γ excision mouse model to test whether and how CD4 T cell-derived IFN-γ controls blood-stage malaria. Although complete absence of IFN-γ compromised control of the acute and the chronic, recrudescent blood-stage infections with P. c. chabaudi, we identified a specific, albeit modest, role for CD4 T cell-derived IFN-γ in limiting parasite burden only during the chronic stages of P. c. chabaudi malaria. CD4 T cell IFN-γ promoted IgG Ab class switching to the IgG2c isotype during P. c. chabaudi malaria in C57BL/6 mice. Unexpectedly, our data do not support gross defects in phagocytic activity in IFN-γ-deficient hosts infected with blood-stage malaria. Together, our data confirm CD4 T cell-dependent roles for IFN-γ but suggest CD4 T cell-independent roles for IFN-γ in immune responses to blood-stage malaria.