Serum Antibody Titers Research Articles

Effect of Aging on the Immune Response to Core Vaccines in Senior and Geriatric Dogs.

Elderly dogs are steadily increasing worldwide as well as veterinarians' and owners' interest in their health and wellness. Aging is not a disease, but a combination of changes negatively affecting the organism in general and the immune system in particular, resulting in a decline in protection over time. The aim of this study was to measure the specific serum antibody titers against the main dangerous and widespread viral diseases preventable by core vaccinations in senior and geriatric dogs using the in-practice test VacciCheck. A cohort of three hundred fifty elderly dogs was analyzed for Protective Antibody Titers (PATs) against CPV-2, CDV and CAdV-1. The age ranged from 5 to 19 years, with two hundred fifty-eight seniors (73.7%) and ninety-two geriatrics (26.3%), and 97.4% of them were vaccinated at least once in their lives. More than half of the entire study population (52.9%) had PATs simultaneously for all three diseases, with 80.5% seniors and 19.5% geriatrics. Specific PATs were found in 88.6% of aging dogs for CPV-2, 82.3% for CadV-1 and 66.0% for CDV, demonstrating that unprotected aging dogs represent a minority. Unexpectedly, the larger elderly dogs resulted as more protected than smaller ones for CPV-2. Protection then decreases over time, with geriatric dogs less protected than senior ones. Veterinary practitioners should therefore always consider whether to maintain core vaccinations in aging dogs as in adults on a three-year basis or opt instead for closer boosters (every 1 or 2 years). PATs for core vaccines could then represent a good biomarker of protection and their titration could become a standard of care, especially in such a sensitive period of the dogs' life.

Self-assembled nanoparticle with E protein domain III of DTMUV based on ferritin as carrier can induce a more comprehensive immune response and against DTMUV challenge in duck

Duck Tembusu virus (DTMUV) causes severe reduction in egg production and neurological symptoms in ducklings. Vaccination is the primary measure used to prevent DTMUV infections. In this study, self-assembled nanoparticles with the E protein domain III of DTMUV, using ferritin as a carrier (EDⅢ-RFNp), were prepared using a prokaryotic expression system. Ducks were intramuscularly vaccinated with EDⅢ-RFNp, EDⅢ protein, an inactivated vaccine HB strain (InV-HB), and PBS. At 0, 4, and 6 weeks post-primary vaccination, the EDIII protein-specific antibody titre, IL-4, and IFN-γ concentrations in serum were determined by ELISA, and neutralising antibodies titres in sera were determined by virus neutralising assay. Peripheral blood lymphocytes proliferation was determined by CCK-8 kit. Following challenge with the virulent DTMUV strain, the clinical signals and survival rate of the vaccinated ducks were recorded, and DTMUV RNA levels in the blood and tissues of the surviving ducks were determined by real-time quantitative RT-PCR. The near-spherical EDⅢ-RFNp nanoparticles with 13.29 ± 1.43 nm diameter were observed by transmission electron microscope. At 4 and 6 weeks post-primary vaccination, special and Virus neutralisation (VN) antibodies, lymphocyte proliferation (stimulator index, SI), and concentrations of IL-4 and IFN-γ in the EDⅢ-RFNp group were significantly higher than in the EDⅢ and PBS groups. In the DTMUV virulent strain challenge test, the EDⅢ-RFNp-vaccinated ducks showed milder clinical signs and higher survival rates than EDⅢ- and PBS-vaccinated ducks. The DTMUV RNA levels in the blood and tissues of EDⅢ-RFNp-vaccinated ducks were significantly lower than those in EDⅢ- and PBS-vaccinated ducks. Additionally, the EDⅢ protein-special and VN antibodies, SI value, and concentration of IL-4 and IFN-γ in the InV-HB group was significantly higher than that of the PBS group at 4 and 6 weeks post-primary vaccination. InV-HB provided more efficient protection than PBS based on a higher survival rate, milder signals, and lower levels of the DTMUV virus in the blood and tissues. These results indicated that EDⅢ-RFNp effectively protected ducks against DTMUV challenge and could be a vaccine candidate to prevent DTMUV infection.

Antimicrobial and Immunomodulatory Action of Probiotic Composition of Bacilli on Bacterial Vaginitis in Mice

The purpose of this study was to investigate the antimicrobial and immunomodulatory action of a probiotic composition of Bacillus subtilis and B. megatherium strains (UnicaUro, Sirion (Ukraine)) for experimental bacterial vaginitis. Methods. Experimental studies were conducted on female BALB/c mice; we used Staphylococcus aureus strain B-918 (ATCC 6538) to induce bacterial vaginitis. The strain was vaginally introduced into mice before treatment with probiotic bacteria. In the vagina of mice, aerobic and optionally anaerobic bacteria, including representatives of the genera Staphylococcus, Streptococcus, Lactobacillus, Bifidobacterium, Pseudomonas, coliform bacteria, and microscopic fungi were identified in different periods of observation using generally accepted microbiological methods. Serum antibody titer to S. aureus was determined by the bacterial agglutination reaction. The phagocytic activity and oxygen-dependent bactericidal activity of peritoneal exudate macrophages (PEM) were evaluated using generally accepted immunological methods. Results. The formation of bacterial vaginitis in the BALB/c mice line infected with S. aureus B-918 (ATCC 6538) was evidenced by the appearance of external clinical manifestations of the infectious and inflammatory process against the background of the increased number of aerobic and optionally anaerobic microorganisms, including representatives of the genus Staphylococcus and Streptococcus, microscopic fungi, and decreased number of lactobacilli in different observation periods. The probiotic introduction to mice with bacterial vaginitis led to a dynamic change in the vaginal microbiota: the number of aerobic and optionally anaerobic microorganisms decreased, primarily due to the normalization of the number of representatives of Staphylococcus genus accompanied by a decrease in the antibody titer to staphylococcus in the blood serum. The effective therapeutic action of the probiotic was confirmed by the gradual disappearance of the external clinical signs of the infectious-inflammatory process in the vagina against the background of the functional activity of PEM. Conclusions. The probiotic composition of B. subtilis and B. megatherium (UnicaUro, Sirion, Ukraine) is a promising antimicrobial formulation that may be used in the treatment of bacterial vaginitis; however, further studies are required to confirm its therapeutic, antimicrobial, and immunomodulatory efficacy.

Evaluation of Clostridium septicum hemolytic activity, administration route, and dosage volume of a clostridial dermatitis (cellulitis) bacterin-toxoid on humoral immune response in commercial turkeys

Clostridial cellulitis or dermatitis affects commercial turkey flocks, primarily as they approach market age. In the field, this disease has been effectively controlled with antibiotics, but alternatives to antibiotics are needed. Bacterin-toxoid vaccination programs have been shown to prevent clostridial diseases in other species, including humans. Results from previous field studies indicate that vaccination with an experimental whole-cell Clostridium septicum (CS) bacterin-toxoid oil emulsion vaccine reduced clostridial dermatitis-associated mortality and antibiotic usage for some commercial turkey flocks, but vaccination was not always efficacious. To improve vaccine efficacy, studies were conducted to optimize the antigenic component of the experimental vaccine and to determine the appropriate antigen to adjuvant ratio, route, and volume for vaccine administration. It was determined that the phase of culture at time of formalin inactivation played a key role in serum antibody titer and larger volume vaccine doses produced higher serum antibody immune response regardless of antigen:adjuvant formulation ratio or route of injection. No significant differences (P > 0.05) were found between formulation ratios or between the subcutaneous and tail head injection sites. Based on these results, we propose to look further into the relationship between culture phase and antigenic components produced by CS under different culture conditions.

Unraveling Mechanisms of Autoimmune Skin Blistering: Applying Single-Cell Transcriptomics to Pemphigus B Cells

Unraveling Mechanisms of Autoimmune Skin Blistering: Applying Single-Cell Transcriptomics to Pemphigus B Cells

Development of a vaccine adjuvant based on squalene and study of its adjuvant properties

The use of modern subunit vaccines involves adjuvant introduction into their composition. Currently, the search for new and improvement of existing adjuvant systems is actively underway. Squalene- based adjuvants are well-known and approved in a number of countries for clinical use in influenza vaccines. Our study was devoted to the development of an adjuvant composition on the basis of squalene. The resulting adjuvants were composed in a form of oil emulsion containing a hydrophilic and hydrophobic phase. The stability of the emulsion was achieved by treating it with ultrasound at a frequency of 22 kHz. Particle sizes of the obtained emulsions were examined with the use of an electron microscope. The particle size was calculated to be 50-80 nm for the majority of particles (84%). Adjuvant activity was evaluated in 100 male Balb/C mice, weighing 16-18 g. To assess the humoral immune response, immunization was performed twice, with a 14-day interval, by intramuscular injection of 200 mL per animal. The receptor-binding domain (RBD) of the surface S protein of the severe acute respiratory syndrome coronavirus 2 (Delta variant (B.1.617.2)) or ovalbumin (OVA) from chicken eggs were used as antigens. RBD was administered at a dose of 50 mg/animal; OVA was administered at two doses (1 mg or 5 mg/animal). An antigen with aluminum hydroxide was used as a positive control; a saline solution was used as a negative control. The effectiveness of the obtained adjuvants was determined by measuring the titers of specific antibodies in mouse sera in ELISA assays using the recombinant RBD of SARS-CoV-2 S-protein or ovalbumin from chicken eggs. It was shown that the use of squalene-based adjuvants increased the antigens’ immunogenicity. The average titers of specific antibodies against RBD in the experimental group were 4 times higher than in the group immunized with RBD adjuvanted with aluminum hydroxide. An increase in immunogenicity of the antigen adjuvanted with squalene was also observed in the experimental OVA-group. Thus, it was shown that the developed squalene-based adjuvant compositions could be an alternative to the traditional adjuvants based on aluminum salts.

Study of the adjuvant properties of preparations containing recombinant human granulocyte-macrophage colony stimulating factor

The relevance of the search for new vaccine adjuvants is growing along with the increase in the number of current vaccine preparations, especially those developed on the basis of proteins. Some cytokines are known to exert adjuvant properties. The present work is devoted to the study of adjuvant activity of recombinant human granulocyte-macrophage colony stimulating factor (rhGM-CSF) and constructs based on it. Earlier, we developed a technology for isolation and purification of GM-CSF from the E. coli SG20050/p280_2GM producer strain, as well as a technology for conjugating polyglucin:spermidine complexes with rhGM-CSF. Double-stranded RNA was used to obtain molecular constructs on the basis of rhGM-CSF conjugate. To assemble constructs, the ratio of the components was calculated for one dose of the preparation to contain 5-40 mg of rhGM-CSF and 100 mg of double-stranded RNA. The effectiveness of the formation of molecular constructs was evaluated by dsRNA electrophoretic mobility shift in a 1% agarose gel. The effectiveness of the resulting adjuvants was determined in ELISA assays by measuring the titers of specific antibodies in mouse sera against ovalbumin or recombinant receptor-binding domain of the surface S protein of the severe acute respiratory syndrome coronavirus 2 (Delta variant (B.1.617.2). The experiments were carried out in 100 male BALB/c mice weighing 16-18 g. Mice were immunized twice, with a 14-day interval, by intramuscular injection of 200 mL per animal. Recombinant receptor-binding domain of the surface protein of SARS-CoV-2 was administered at a dose of 50 mg/animal, ovalbumin – at two doses – 1 mg or 5 mg/animal. Corresponding antigen was used as a positive control, a saline solution – as a negative control. It was shown that the maximum effect was achieved by immunization with a construct based on double-stranded RNA and rhGM-CSF conjugated to polyglucin-spermidine. The use of a conjugate without double-stranded RNA as an adjuvant also improved humoral response. The use of native rhGM-CSF did not increase the titers of specific antibodies. Thus, it was found that rhGM-CSF being a part of a polysaccharide conjugate or a molecular construct exerted an ability to enhance the humoral immune response to protein antigens.

Assessment of the In Vitro and In Vivo Antitumor Activity of Hemocyanins from Helix aspersa, Helix lucorum, and Rapana venosa in a Graffi Myeloid Tumor Model.

Hemocyanins are oxygen-transporting glycoproteins in the hemolymph of some invertebrate species that attracted scientific interest as potential anticancer agents. The present study aims to assess the in vitro and in vivo anticancer activity of hemocyanins isolated from Helix aspersa, Helix lucorum, and Rapana venosa in the Graffi myeloid tumor model. The in vitro antitumor activity of the hemocyanins was determined by a MTT test and cytomorphological analysis by fluorescent and transmission electron microscopy. The in vivo effects of the hemocyanins were examined in hamsters transplanted with Graffi tumor. The serum antibody titers against the tested hemocyanins and tumor antigen were determined by ELISA. Histopathological assessment of the morphological features related to antitumor effect, immune system response, and toxicity in some internal organs was performed. The results of in vitro studies indicated that the tested hemocyanins induced significant antiproliferative and apoptogenic effects. The in vivo investigations demonstrated a protective antitumor effect, expressed in reduced transplantability, suppression of tumor growth and metastasis, reduced mortality, prolonged survival time, and absence of toxic side effects. The present study indicated that the antitumor activity of the studied hemocyanins was due to both immune stimulation and direct effects on the tumor cells, and they displayed their potential as therapeutic agents against hematological malignances.

Durability of immune responses to mRNA booster vaccination against COVID-19.

BackgroundMaintaining durable immunity following vaccination represents a major challenge, but whether mRNA booster vaccination improves durability is unknown.MethodsWe measured antibody responses in 55 healthy adults, who received a booster dose of the Pfizer-BioNTech or Moderna vaccine against SARS-CoV-2 and calculated the half-life of the antibody titers. We also measured memory B and T cell responses in a subset of 28 participants. In 13 volunteers who received a second booster vaccine, we measured serum antibody titers and memory B and T cell responses.ResultsThe booster (third immunization) dose at 6 to 10 months increased the half-life of the serum-neutralizing antibody (nAb) titers to 76 days from 56 to 66 days after the primary 2-dose vaccination. A second booster dose (fourth immunization) a year after the primary vaccination further increased the half-life to 88 days. However, despite this modestly improved durability in nAb responses against the ancestral (WA.1) strain, there was a loss of neutralization capacity against the Omicron subvariants BA.2.75.2, BQ.1.1, and XBB.1.5 (48-, 71-, and 66-fold drop in titers, respectively, relative to the WA.1 strain). Although only 45% to 65% of participants demonstrated a detectable nAb titer against the newer variants after the booster (third dose), the response declined to below the detection limit in almost all individuals by 6 months. In contrast, booster vaccination induced antigen-specific memory B and T cells that persisted for at least 6 months.ConclusionThe durability of serum antibody responses improves only marginally following booster immunizations with the Pfizer-BioNTech or Moderna mRNA vaccines.

Is It Lupus? Is It Neuromyelitis Optica Spectrum Disorder (NMOSD)?—Why Not Both?

Multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD) are among the commonly considered differential diagnoses in patients with inflammatory central nervous system (CNS)-diseases. Formerly diagnosed competing autoimmune diseases might impair diagnostics and treatment. Here, we report on a 41-year-old woman admitted to our hospital with primary manifestation of NMOSD (paresthesia, paralysis of the lower extremities, and urinary incontinence) while undergoing treatment for a diagnosed systemic lupus erythematosus (SLE) with hydroxychloroquine. CNS manifestation of the disease was considered. Magnetic resonance imaging (MRI) of the cranium and spinal cord showed multiple supratentorial lesions of the white matter and massive intramedullary lesions with contrast enhancement. Cerebrospinal fluid (CSF) showed pleocytosis (20/µL), positive antinuclear antibodies (ANA), antiphospholipid antibodies, and SSA/Ro antibodies, while formerly positive dsDNA antibodies were negative. Further diagnostics revealed a 1:10,240 serum titer of Aquaporine-4 antibodies. The patient received intravenous methylprednisolone for three days (2 g per day), which led to an escalation to plasmapheresis and to an improved EDSS from 8.0 to 4.0. Because of the comorbidity, a combined relapse prophylaxis with satralizumab and mycophenolate mofetil was established. Rehabilitation and continued treatment improved EDSS to 1.0 with no impairment of mobilization. Although formerly diagnosed SLE could have explained the symptoms, it is important to reconsider competitive diseases in order to establish adequate immunotherapy.

Immune response of large yellow croaker Larimichthys crocea towards a recombinant vaccine candidate targeting the parasitic ciliate Cryptocaryon irritans.

Cryptocaryon irritans, a parasitic ciliate, pose a major threat to marine teleost fish aquaculture. So far, no effective and safe control method is available. In this study, the protective efficacy of a recombinant truncated surface antigen of C. irritans (rCiSA32.6t) for large yellow croaker (Larimichthys crocea) against the parasite challenge with a sub-lethal dose of the infective theronts was evaluated by comparing the relative percent survivals (RPS), the specific antibody titers in sera, and the expression levels of the immune-related genes among the negative or adjuvant control fish, fish intraperitoneally immunized with rCiSA32.6t. The results showed that a RPS of 50.1% in rCiSA32.6t-immunized fish was achieved in comparison to negative control fish against C. irritans. A significant increase was noted in the antigen-specific immunoglobulin M (IgM) and immunoglobulin T (IgT) antibody levels in the sera of the rCiSA32.6t-vaccinated fish. Compared to the negative control fish, quantitative real-time PCR analysis indicated that the interleukin-1beta, IgT, and IgM heavy chain mRNA level in the fish head kidney, spleen, gill, and skin tissue were upregulated post-rCiSA32.6t immunization. This study indicates that the rCiSA32.6t can provide a high level of immune protection against C. irritans infection in grouper and is therefore pursued as a candidate C. irritans vaccine.

Mannosylated chitosan nanoparticles loaded with ABP antigen server as a novel nucleic acid vaccine against Nocardia Seriolae infection in Micropterus Salmoides

Largemouth bass (Micropterus Salmoides) is an important cultured fish in south China with a large scale of cultivation. However, bacterial disease has badly damaged the healthy development of the breeding industry. Nocardia Seriolae (N. seriolae), a gram-positive bacterial widely existing in soil and water, mainly infects bass and snakehead. This bacterial has caused a large financial loss in China. However, efficient methods to control this pathogeny still remain largely unexplored. Previous study suggested that vaccine was efficient method to prevent fish from bacterial infection. In this study, based on reverse vaccinology, a new DNA vaccine named pcDNA-ABP was obtained by genetic engineering technology. Furthermore, to enhance the stability and target ability, mannosylated chitosan (Mcs) was used to package the nucleic acid vaccine. In order to evaluate the immunoprotection effect of this vaccine, a total of 300 fish (N = 5) were vaccinated with PBS (50 μL per fish), pET32a-ABP (10 μg per fish), pcDNA (10 μg per fish), pcDNA-ABP (20 μg per fish), Mcs-pcDNA-ABP (20 μg per fish). After 28 days' vaccination, experiment fish were challenged with live N. seriolae. Then, some immune-related indexes were measured to evaluate the variation of fish's immunity. Results showed the highest relative percentage survival (RPS) was 80.73% in Mcs-pcDNA-ABP group. What's more, the serum antibody titer, enzyme activity in vaccinated group were significantly increased compared to that of control group. Furthermore, some innate immune-related genes (IL-1β, CD4, TNF-α) and adaptive immune-related gene (IgM) were significantly up-regulated in kidney and spleen. In a word, in this study, a new DNA vaccine packaged with mannosylated chitosan was developed. Results suggested that this vaccine could significantly enhance the immunity of fish after vaccination, and increase the survival rate after live bacterial infection. This research might provide some basic information for the development of N. seriolae vaccine, and make a contribution to the control of bacterial diseases in aquaculture.

The effect of metformin on influenza vaccine responses in nondiabetic older adults: a pilot trial

BackgroundAging is associated with progressive declines in immune responses leading to increased risk of severe infection and diminished vaccination responses. Influenza (flu) is a leading killer of older adults despite availability of seasonal vaccines. Geroscience-guided interventions targeting biological aging could offer transformational approaches to reverse broad declines in immune responses with aging. Here, we evaluated effects of metformin, an FDA approved diabetes drug and candidate anti-aging drug, on flu vaccination responses and markers of immunological resilience in a pilot and feasibility double-blinded placebo-controlled study.ResultsHealthy older adults (non-diabetic/non-prediabetic, age: 74.4 ± 1.7 years) were randomized to metformin (n = 8, 1500 mg extended release/daily) or placebo (n = 7) treatment for 20 weeks and were vaccinated with high-dose flu vaccine after 10 weeks of treatment. Peripheral blood mononuclear cells (PBMCs), serum, and plasma were collected prior to treatment, immediately prior to vaccination, and 1, 5, and 10 weeks post vaccination. Increased serum antibody titers were observed post vaccination with no significant differences between groups. Metformin treatment led to trending increases in circulating T follicular helper cells post-vaccination. Furthermore, 20 weeks of metformin treatment reduced expression of exhaustion marker CD57 in circulating CD4 T cells.ConclusionsPre-vaccination metformin treatment improved some components of flu vaccine responses and reduced some markers of T cell exhaustion without serious adverse events in nondiabetic older adults. Thus, our findings highlight the potential utility of metformin to improve flu vaccine responses and reduce age-related immune exhaustion in older adults, providing improved immunological resilience in nondiabetic older adults.

Sex disparities in pathological features and autoimmunity in high fat diet associated lupus mouse model

Abstract Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that is more common in women than men. SLE has been reported with diverse clinical phenotypes of varying severity, which may be caused by sex hormones and environmental factors. Our recent studies showed that high-fat diet (HFD) exacerbated lupus development in MRL/lpr lupus-prone mice. Here we explored the gender difference in lupus progress and autoimmune response to HFD. Twenty male and twenty female MRL/lpr mice were evenly grouped and fed with a regular diet (RD, 10% fat) or HFD (60% fat) for 14 weeks. Body weights were recorded weekly. SLE progression was monitored by skin lesions, urine protein, titers of anti-dsDNA antibody in serum. Kidney and skin from the dorsum of the neck were embedded for H&E, PAS, and Masson’s staining quantified as kidney index and skin score. Immune cells in the spleens were identified by immunofluorescence staining and flow cytometry. HFD induced a greater weight gain in female mice than male mice (p<0.01). Skin rash showed up as early as week 6 in female HFD group with a greater histopathological skin score (p<0.01). Splenomegaly, proteinuria, and anti-dsDNA level were increased only in male HFD group. Kidney pathological changes were more severe in male HFD mice with significant increase of kidney index (p<0.05). Significant increases of germinal center B cells, plasma cells, and T follicular helper cells were observed in HFD mice (p<0.05). SLE progression is sexually dimorphic in lupus-prone mice in response to HFD. Our results parallel many known clinical lupus phenotypes and sexual dimorphism in which male patients are more likely to have severe disease (such as nephritis) than female lupus patients who may have a broader range of lupus symptoms. None

Unmasking Arterial-resident Autoreactive B cells involved in Atherosclerosis and Peripheral Artery Disease Progression

Abstract Atherosclerosis activates the immune system, including B cells which secrete antibodies that bind antigens released by necrotic cells within plaques and may promote inflammation. To identify these antibodies, we isolated activated B cells from atherosclerotic ApoE-deficient mice aortas and human tibial arteries with peripheral artery disease post-amputation. Single-cell sequencing of the B cell receptors identified 35 mouse and 48 human overrepresented disease-relevant heavy and light chain pairings, which were sequentially expressed as antibody. Epitope determination was performed by human proteome array, and 14 mouse and 21 human protein targets were found with significant affinity and specificity. Mouse antigens were scrutinized by immunohistochemistry to confirm presence in inflamed plaques, and expression of these proteins were used to interrogate autoreactive antibody titers in diseased sera by ELISA. ApoE-deficient mice were immunized with the 6 most promising antigens. Serum antibody measurement showed strong, rapid, and early onset of antigen-specific antibody responses in the immunized mice compared to an adjuvant only control group. Strikingly, we saw decreased plaque accumulation in the immunized animals, suggesting antigen responses may clear pathogenic antigens before disease develops. Likewise, human antigen ELISAs comparing antigen-specific serum antibody titers to patient Framingham score for cardiovascular risk supported a role for two antigens in disease. To confirm these antigens as potential biomarkers, we will characterize the emergence of their antibody counterparts using a historical library of serum samples from individuals enrolled in the Baltimore Longitudinal Study on Aging. This work is directly funded by the National Institutes of Health – National Institute on Aging’s Intramural Research Program in the Lab of Molecular Biology and Immunology

Association between SARS-CoV-2 anti-spike antibody titers and the development of post-COVID conditions: A retrospective observational study.

The symptoms that persist after an acute coronavirus disease 2019 (COVID-19) are referred to as post- COVID conditions. Although the cause of post-COVID conditions remains unclear, the host immune response to SARS-CoV-2 may be involved. Hence, we aimed to investigate the effect of serum antibody titers against SARS-CoV-2 on the development of post-COVID conditions. We conducted a retrospective observational study of COVID-19-recovered individuals who attended the clinic at the National Center for Global Health and Medicine between January 2020 and April 2021. Serum SARS-CoV-2 anti-spike antibody titers were measured and a questionnaire survey was used to collect information on the presence of post-COVID conditions and demographic characteristics of the participants. Participants were then divided into two groups: high peak antibody titer group [≥ 0.759 OD450 value], and low peak antibody titer group [< 0.759 OD450 value] and compared their frequency of post-COVID conditions. Of 526 individuals attending the clinic, 457 (86.9%) responded to the questionnaire. We analyzed the data of 227 (49.7%) participants with measurements of serum antibody titers during the peak period. The incidence of depressed mood was significantly higher in the group with higher antibody titers (odds ratio: 2.34, 95% CI: 1.17-4.67, p = 0.016). There was no significant difference in the frequency of the remaining symptoms between the two groups. Among post-COVID conditions, the depressed mood was more frequent in the group with high serum antibody titers which suggests a difference in pathogenesis between depressive mood and other post-COVID conditions that requires further investigation.

Storage time and temperature of filter paper strips affect anti-West Nile virus antibody detection in 2 galliform species.

The effects of filter paper strip (FPS) storage time and temperature on antibody detection are poorly understood despite widespread use in wildlife research. We collected sera and FPSs from 23 wild turkeys (Meleagris gallopavo) and 20 northern bobwhites (Colinus virginianus) experimentally infected with West Nile virus (WNV) to compare FPS storage methods with WNV plaque reduction neutralization test (PRNT) sensitivity. FPS storage methods included: immediate elution after drying, and storage at -20°C for 3 mo, -20°C for 6 mo, room temperature (RT) for 3 mo, and RT for 6 mo prior to elution. FPS eluates and sera were co-titrated to determine endpoint antibody titers, which were compared between FPS sera eluted immediately and sera, and among FPS eluates that underwent different storage conditions. Antibody titers were ~4-fold less in FPS sera eluted immediately versus sera, and dropped more frequently below PRNT detection threshold in northern bobwhites, which had ~10-fold lower serum antibody titers than wild turkeys. Antibody titers were lower in FPS samples stored at RT and for 6 mo. WNV serologic surveys may result in falsely low seroprevalence estimates if FPSs are stored at RT for ≥ 3 mo before elution.

Neutralizing antibody titer after recommended early vaccination against Japanese encephalitis

Objective Following the case of a 10-month-old with Japanese encephalitis in Chiba in 2015, the Chiba Pediatric Association and Chiba Medical Association recommended that children receive the Japanese encephalitis vaccine at six months of age. In this study, we investigated early vaccinations and standard vaccinations of children in a patient outbreak area. Additionally, we examined changes in the timing of vaccination initiation and the acquisition and maintenance of protective immunity before and after the early vaccination recommendation.Methods With the cooperation of the medical institution designated for Type II Infectious Diseases, which treated affected children in 2015, the history and timing of vaccinations for children who visited the hospital between October 2018 and March 2020 were investigated, and serum samples were collected. The data obtained in this study and the Ministry of Health, Labour and Welfare's Community Health Service Report were used to investigate the timing of vaccinations. Neutralizing antibody titers in serum were quantified with the focus measurement method and examined with respect to the number of vaccinations, doses, and number of days since vaccination.Results A total of 154 samples were obtained, with 89 from the vaccinated group and 65 from the unvaccinated group. There was no difference in the percentage of children based on the age of first vaccination between Japan, Chiba Prefecture, and the study subjects until FY2015, but from FY2016 onward, the percentage of children vaccinated early was higher among the study subjects, as well as for children from Chiba Prefecture and Japan, in that order. The antibody possession rate by vaccination frequency was 9.2% for the unimmunized, 87.5% for those vaccinated once, 95.1% for those vaccinated twice, and 100% for those vaccinated three times. In the group vaccinated twice, antibody titers of children who received half the vaccine dose were significantly lower than those of children who received the normal dose.Conclusion In the districts targeted in this study, significantly more children under three years of age were vaccinated before the early vaccination recommendation, suggesting the effectiveness of that recommendation. In addition, the high rate of antibody positivity among unvaccinated children suggests that it is important to promote early vaccination in areas at high risk for Japanese encephalitis. In this study, there was no evidence of attenuation of antibody titers over time after early immunization, but the possibility remains that the children who completed early immunization received a booster due to pathogen exposure and maintained antibody titers, given that Japanese encephalitis was endemic in the target area.

Post Infectious Triggered Anti-Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease (MOGAD) via CMV in an Immunocompetent Host (P10-5.030)

<h3>Objective:</h3> N/A <h3>Background:</h3> A previously healthy, immunocompetent 38-year-old female presented with initial complaints of subacute, waxing and waning high grade fevers, general malaise, and muscle aches for two weeks. Acutely she developed severe lumbar radiculopathy with significant urinary retention and bilateral lower extremity weakness leading to ED presentation. The patient was subsequently admitted with rapidly progressive lower extremity paraplegia and brisk reflexes over a 24-hour span. MRI imaging was notable for longitudinally extensive transverse myelitis (LETM) over continuous cervical and thoracic segments with significant gray matter involvement and left parahippocampal FLAIR hyperintensities Serum subsequently demonstrated positive anti-CMV IgM/IgG antibodies with a PCR load of 61 copies/mL indicative of a CMV infection with low viremia. LP CSF was CMV PCR negative with mildly elevated opening pressures and trace neurotrophic pleocytosis. Given stagnant clinical changes after five days of IV steroids, plasmapheresis was initiated with marked improvements in functional lower extremity strength. Soon afterwards, initial presenting lab work resulted, demonstrating high serum titers (1:2560) of anti-MOG antibodies. <h3>Design/Methods:</h3> N/A <h3>Results:</h3> N/A <h3>Conclusions:</h3> In immunocompetent hosts, CMV infection itself is a rarely described cause of inflammatory myelopathy with only 14 prescribed cases. With both deep gray matter FLAIR hyperintensities and cervical and thoracic LETM, a concomitant para-infectious CMV and new MOGAD is unlikely in our clinical setting. Additionally, systemic findings typically indicative of severe CMV infections such as retinitis, pericarditis/myocarditis, transaminitis, thrombocytopenia, and leukopenia were absent. Given prior reports of sequence similarities between MOG T-cell epitopes and a major capsid protein of CMV, molecular mimicry between antigen presenting cells has been hypothesized. Here we detail a first described case report of a possible post-infectious MOG antibody transverse myelitis triggered presumptively via CMV infection. Furthermore, presenting in an immunocompetent host, our case report highlights a further wrinkle into the pathophysiology and presence of post infectious triggered autoimmunity for MOGAD. <b>Disclosure:</b> Dr. Chen has nothing to disclose. Dr. Kwon has nothing to disclose.

A Case series with comparative analysis of children and young adults with Anti-N-Methyl-D-Aspartate Receptor Encephalitis (P5-5.004)

<h3>Objective:</h3> To compare clinical presentation of 5 patients of various age groups with Anti-N-Methyl-D-Aspartate (NMDA) Receptor Encephalitis <h3>Background:</h3> Anti-NMDA-receptor antibody encephalitis is a treatable neurological condition hypothesized to be secondary to immune response initiated by an ovarian tumor or a non-specific infectious etiology. The immune mediated trigger produces antibodies that cross the compromised blood brain barrier where they interact with NR1/NR2 subunits of NMDA receptor resulting in encephalitis. Clinical presentation can vary according to the age and can include psychiatric symptoms, cognitive impairment, seizures, autonomic instability, and movement disorders. <h3>Design/Methods:</h3> Medical chart review of patients seen in a university hospital with varied presentations and subsequent diagnosis of Anti-NMDA-receptor antibody encephalitis <h3>Results:</h3> We describe 5 cases of Anti-NMDA-receptor antibody encephalitis seen at a university hospital between 2016 and 2022. Three were children under 5 years of age (youngest is 2.5 months) with abnormal choreo-athetoid movements and two were young women with psychiatric symptoms. Two of the infants had a preceding infectious exposure while both the young women had ovarian cysts. Except one infant, all cases had seizures during their disease course. All cases had CSF antibody positivity except one. Management included high dose IV methyl prednisolone with good response, followed by IVIG and/or Rituximab infusions in resistant cases. <h3>Conclusions:</h3> Clinicians should have high suspicion for Anti-NMDA-receptor antibody encephalitis in patients presenting with abnormal movements or nonspecific sudden onset psychological symptoms in the presence or absence of a preceding infectious prodrome. Aggressive testing with serum and CSF NMDA antibody titers is warranted when EEG is not consistent with seizures as Anti-NMDA-receptor antibody encephalitis is a treatable neurological condition with high morbidity and mortality if left untreated. <b>Disclosure:</b> Dr. Vasireddy has nothing to disclose. Qutubuddin Khan has nothing to disclose. Dr. Guduru has nothing to disclose.