Serum Antibody Titers Research Articles

Comparison of antibody responses of heterologous and homologous Covid-19 booster vaccination: an observational study.

Pakistan has been seriously affected by the COVID-19 pandemic, with numerous waves of infection. Using different vaccine and booster doses was a key component to control and combat this pandemic. This study aims to monitor the heterologous and homologous booster vaccination doses that generate immune responses in healthy adults after 9 months of vaccination. In this cross-sectional, observational study a total of 173 samples were collected. Participants from both genders (Male and Female) between the ages of 18 to 25 years were enrolled for the study. Participants who had booster shots of homologous Sinopharm BBIBP CorV and heterologous Pfizer-BioNTech vaccines were included only, with the use of a Roche Cobas-e601 analyzer, the antibody titers in the blood serum were quantified by the ECLIA method. IBM SPSS 22 was utilized for descriptive statistical analysis and P< 0.05 was considered significant. In this study the IgG antibody levels were measured against the full length of receptor binding domain (RBD) of the spike (S) protein. The mean antibody titer in the Pfizer group was 9764 ± 10976 U/mL and 5762 ± 4302 U/mL in the Sinopharm group. The Mean IgG antibody levels of the Pfizer-vaccinated group were significantly higher than the Sinopharm-vaccinated group (P=0.000, each). Comparing the Sinopharm BBIBP CorV booster dosage to the Pfizer booster, Pfizer BNT162b2demonstrated a stronger immune response. However, there were no immunological gender-specific significant differences. The administration of a third dosage of Pfizer BNT162b2 after two doses of BBIBP CorV. The administration of a third dosage of Pfizer BNT162b2 after two doses of BBIBP-CorV is recommended to boost the humoral immune response in the general population while there was no gender-specific difference observed. More effectiveness can be attained by administering additional doses due to the antibody decay.

Possible rapid reduction of anti-RBD antibody titre after SARS-CoV-2 mRNA vaccination in pregnant women: Multicentre prospective study.

Pregnant women are at increased risk for severe illness associated with coronavirus disease 2019 (COVID-19) compared to nonpregnant women. The aim of this multicenter prospective study was to assess the current COVID-19 vaccination status of pregnant women in the southern Osaka district and to compare their antibody titers with those of nonpregnant women. Serum antibody titers of anti-NCP antibodies (antibodies against the SARS-CoV-2 nucleocapsid) and anti-RBD antibodies (the receptor binding domain of the S1 subunit of the spike protein) were evaluated in 753 pregnant women at 34-35 weeks of gestation from October 2021 to March 2022. Anti-RBD antibody titre was also investigated in 1003 health care workers at Kindai University hospital 3 and 6 months after a second dose of the vaccine from March 2021 to April 2021. 519 (68.9%) pregnant women were vaccinated during pregnancy, of whom 497 (95.8%) received two doses. The COVID-19 infection rate calculated from the number of pregnant women with a positive anti-NCP antibody titre or with confirmed diagnosis was 5.1% (12/234) in the unvaccinated and 3.5% (18/519) in the vaccinated. The estimated half-life calculated from anti-RBD antibody titers and the number of days between vaccination and antibody testing was 39.9 days. The antibody titre and half-life in pregnant women were significantly lower and shorter than in nonpregnant women aged 20-39 years (109.4 days). Our study showed that pregnant women may have lower vaccine-acquired COVID-19 immunity than nonpregnant women.

Evaluation of Infectivity, Length of Infection, and Immune Response of Avian Reovirus Variants in Egg-laying Hens.

ABSTRACTWe conducted research studies on avian reovirus (ARV) infectivity in egg-laying hens, focusing on three variants (δC genotypes 2, 3, and 5) detected in layer chickens in Pennsylvania to date. Day-old chicks (Hy-Line North America, LLC, PA), raised at the Poultry Education and Research Center of Penn State University Park campus, showed healthy growth and normal egg production after 20 weeks of age. ARV variants were propagated in LMH cell cultures, with concentrations measured at TCID50/mL. Each group of 10 hens received a 1.0 mL dose containing 103 to 104 TCID50/mL of one ARV variant through oral, nasal, and ocular routes. Infected hens showed normal egg production, with minimal symptoms of watery droppings in the first-week post-inoculation (pi). Cloacal and oral pharyngeal swabs were collected daily in the first week pi and every other day in the second-week pi to monitor virus shedding. Virus shedding began 24 hours pi through feces, peaked at 2 to 4 days pi, decreased by 5 to 7 days pi, and ceased after 12 to 14 days pi. A few birds' oral pharyngeal swabs were weakly positive for 1 to 3 days pi, then all turned negative. Infected hens developed high serum and egg yolk antibody titers at 2 to 3 weeks pi, showing 100% protection against subsequent infections with the same variant strain, demonstrating a 100% protection rate.

Hypericum perforatum L. (St. John's Wort) in broilers diet improve growth performance, intestinal microflora and immunity

Hypericum perforatum L. (St. John's Wort) extract (HPE), powdered H. perforatum (PHP), and selenium (Se) on growth, intestinal flora, and immunity of broiler chicks were investigated. In total, 504 one-day-old broiler chicks were randomly allocated into 6 dietary treatments, which were then denoted as negative control (NC) group (basal diet), containing organic Se 0.2% in the starter and grower period as positive control (PC), containing 1% PHP in the starter and grower period, and HPE I, HPE II, and HPE III groups containing respectively, 1.5, 3.0, and 4.5 mL / kg HPE in the starter and grower period. The results on performance showed that a significant (P < 0.05) higher body weight of chickens in the HPE III group was observed when compared with that of the NC and PHP groups. Although average daily weight gain and feed intake are significant in the HPE III group, the difference in terms of total feed conversion rate was insignificant (P > 0.05). The liver weights in PC and HPE III were lower compared to HPE I (P < 0.05). The difference in total lactic acid bacteria count (TLABC) between the NC group and all HPE groups was found to be significant (P ˂ 0.05), in addition to TLABC was higher in the HPE III group than other groups (P = 0.001). The highest serum antibody titers to the Newcastle disease vaccine were determined in the HPE III group on the 24th, 35th, and 42nd days of age. IL-1B and IL-6 were found to be insignificant between the groups in chickens (P ˃ 0.05). TNF-α in the HPE III group was greatly increased than the other groups and significant compared to the NC and HPE I groups (P = 0.018). In conclusion, 4.5 mL / kg HPE, which has a low production cost and is easy to extract and without causing environmental problems, varied significantly in their impact on growth performance, intestinal microflora, and immunity of growing broilers.

Strain- and Subtype-Specific Replication of Genotype 3 Hepatitis E Viruses in Mongolian Gerbils

Since Mongolian gerbils are broadly susceptible to hepatitis E virus (HEV), including genotypes 1, 4, 5, and 8 (HEV-1, HEV-5, HEV-5, and HEV-8) and rat HEV, they are a useful small animal model for HEV. However, we have observed that the subtypes HEV-3k and HEV-3ra in genotype 3 HEV (HEV-3) were not infected efficiently in the gerbils. A small-animal model for HEV-3 is also needed since HEV-3 is responsible for major zoonotic HEV infections. To investigate whether gerbils can be used as animal models for other subtypes of HEV-3, we injected gerbils with five HEV-3 subtypes (HEV-3b, -3e, -3f, -3k, and -3ra) and compared the infectivity of the subtypes. We detected viral RNA in the gerbils’ feces. High titers of anti-HEV IgG antibodies in serum were induced in all HEV-3b/ch-, HEV-3f-, and HEV-3e-injected gerbils. Especially, the HEV-3e-injected animals released high levels of viruses into their feces for an extended period. The virus replication was limited in the HEV-3b/wb-injected and HEV-3k-injected groups. Although viral RNA was detected in HEV-3ra-injected gerbils, the copy numbers in fecal specimens were low; no antibodies were detected in the sera. These results indicate that although HEV-3′s infectivity in gerbils depends on the subtype and strain, Mongolian gerbils have potential as a small-animal model for HEV-3. A further comparison of HEV-3e with different genotype strains (HEV-4i and HEV-5) and different genera (rat HEV) revealed different ALT elevations among the strains, and liver damage occurred in HEV-4i- and HEV-5-infected but not HEV-3e- or rat HEV-infected gerbils, demonstrating variable pathogenicity across HEVs from different genera and genotypes in Mongolian gerbils. HEV-4i- and HEV-5-infected Mongolian gerbils might be candidate animal models to examine HEV’s pathogenicity.

Obtaining from the cell walls of Saccharomyces cerevisiae yeast and assessing their adjuvant properties in a subunit vaccine model

Background. Polysaccharides are known to possess adjuvant properties, they are biodegradable, safe, and are of low-labor production. In this regard, the development of polysaccharide-based adjuvants is an urgent task.The aim. To develop a method for obtaining mannans from the cell walls of Saccharomyces cerevisiae yeast and to study their adjuvant properties using subunit vaccine model.Materials and methods. The preparation of mannans was obtained from the Saccharomyces cerevisiae yeast by enzymatic and alkaline hydrolysis. Its adjuvant properties were assessed in BALB/c mice immunized with the recombinant receptor-binding domain (RBD) of the SARS-CoV-2 (S) protein (Delta (B.1.617.2)). The titers of specific antibodies in the blood sera were determined by ELISA assays using the recombinant RBD (Wuhan-Hu-1 and Delta), and the recombinant (S) protein (Wuhan-Hu-1, Delta and Omicron) as antigens. The titers of virus-neutralizing antibodies were determined using virus-neutralization tests with the SARS-CoV-2 virus strains Wuhan – hCoV19/Australia/VIC01/2020 (Wuhan-Hu-1), Delta – hCoV-19/Russia/PSK-2804/2021 (Delta (B.1.617.2)), and Omicron 1 – hCoV-19/Russia/Moscow171619-031221/2021 (Omicron (B.1.1.529)).Results. The developed scheme allowed for obtaining up to 200 mg of mannans from 10 g of yeast cell debris. Double, with a two-week interval, immunization with RBD (50 μg) in combination with mannans (40 μg and 10 μg) induced the production of specific antibodies in titers from 1:2477330 to 1:188360. The titer of virus-neutralizing antibodies to the Delta – hCoV-19/Russia/PSK-2804/2021 was 1:485 (40 μg of mannans per mouse).Conclusions. We developed a scheme for obtaining a low-toxic preparation of mannans from the Saccharomyces cerevisiae yeast. The highest adjuvant activity was achieved when using mannans at the dose of 40 µg per mouse. Blood sera obtained from the immunized animals neutralized both homologous and heterologous SARS-CoV-2 strains.

Variant-specific neutralising antibodies levels induced by the PHH-1 V SARS-CoV-2 vaccine (Bimervax®) by HIPRA

SARS-CoV-2 virus variants continue to emerge at an alarming rate due to spontaneous genetic mutations, particularly in the spike protein receptor-binding domain (RBD) portion, which render the virus more likely to escape immunity. So far, the immunity obtained through global primary and/or booster immunisation campaigns has been sufficient to protect the population from new emerging variants of the Omicron lineage. The current approach to update vaccines' antigen composition to new variants to boost immunity may not be sustainable in the long term. It might also be potentially redundant if the mutations are giving rise to variants which induce milder infections and existing vaccines, such as Bimervax®, are still sufficiently protective, as Covid is slowly becoming a seasonal illness. Through measuring neutralising antibody titres in sera from subjects boosted with Bimervax®, we have demonstrated the ability of Bimervax® to induce immune responses against a variety of SARS-CoV-2 variants, ranging from earlier variants inducing more serious infections to more recent variants which have been found to produce milder infections.

Bats generate lower affinity but higher diversity antibody responses than those of mice, but pathogen-binding capacity increases if protein is restricted in their diet.

Bats are reservoirs of many zoonotic viruses that are fatal in humans but do not cause disease in bats. Moreover, bats generate low neutralizing antibody titers in response to experimental viral infection, although more robust antibody responses have been observed in wild-caught bats during times of food stress. Here, we compared the antibody titers and B cell receptor (BCR) diversity of Jamaican fruit bats (Artibeus jamaicensis; JFBs) and BALB/c mice generated in response to T-dependent and T-independent antigens. We then manipulated the diet of JFBs and challenged them with H18N11 influenza A-like virus or a replication incompetent Nipah virus VSV (Nipah-riVSV). Under standard housing conditions, JFBs generated a lower avidity antibody response and possessed more BCR mRNA diversity compared to BALB/c mice. However, withholding protein from JFBs improved serum neutralization in response to Nipah-riVSV and improved serum antibody titers specific to H18 but reduced BCR mRNA diversity.

Two-dose priming immunization amplifies humoral immunity by synchronizing vaccine delivery with the germinal center response.

Prolonging exposure to subunit vaccines during the primary immune response enhances humoral immunity. Escalating-dose immunization (EDI), administering vaccines every other day in an increasing pattern over 2 weeks, is particularly effective but challenging to implement clinically. Here, using an HIV Env trimer/saponin adjuvant vaccine, we explored simplified EDI regimens and found that a two-shot regimen administering 20% of the vaccine followed by the remaining 80% of the dose 7 days later increased TFH responses 6-fold, antigen-specific germinal center (GC) B cells 10-fold, and serum antibody titers 10-fold compared with bolus immunization. Computational modeling of TFH priming and the GC response suggested that enhanced activation/antigen loading on dendritic cells and increased capture of antigen delivered in the second dose by follicular dendritic cells contribute to these effects, predictions we verified experimentally. These results suggest that a two-shot priming approach can be used to substantially enhance responses to subunit vaccines.

Lung-Kidney Axis in Cystic Fibrosis: Early Urinary Markers of Kidney Injury Correlate with Neutrophil Activation and Worse Lung Function.

Adult people with cystic fibrosis (PwCF) have a higher risk of end-stage kidney disease than the general population. The nature and mechanism of kidney disease in CF are unknown. This study quantifies urinary kidney injury markers and examines the hypothesis that neutrophil activation and lung infection are associated with early kidney injury in CF. Urinary total protein, albumin, and markers of kidney injury and neutrophil activation, normalized to creatinine, as well as urinary immune cells, were quantified in CF (n = 48) and healthy (n = 33) cohorts. Infection burden and chronicity were defined by sputum culture and serum titers of anti-bacterial antibodies. PwCF had increased urinary protein levels, consisting of low-molecular-weight tubular injury markers, independent of glomerular filtration rate (eGFR). This finding suggests subclinical renal injury processes. Urinary analysis of the CF cohort identified different associations of urinary injury markers with aminoglycoside exposure, lung function, and neutrophil activation. High urinary KIM-1 levels and increased prevalence of neutrophils among urine immune cells correlated with decreased lung function in PwCF. The relationship between tubular injury and decreased lung function was most prominent in patients harboring chronic Pseudomonas aeruginosa infection. Increased urinary tubular injury markers in PwCF suggest early subclinical renal injury not readily detected by eGFR. The strong association of high urinary KIM-1 and neutrophils with diminished lung function and high Pseudomonas aeruginosa burden suggests that pulmonary disease may contribute to renal injury in CF.

The genetic resistance of sows to Escherichia coli F4 adhesion reduces their response to a vaccine containing F4 fimbriae but does not affect the preweaning performance of their susceptible piglets.

Pigs without intestinal receptors for F4 fimbriae are congenitally resistant to F4 fimbriae-bearing enterotoxigenic Escherichia coli (ETEC F4). In general, 50 % and 100 % of piglets born to resistant (RR) sows crossed with hetero- or homozygous susceptible (SR, SS) boars, respectively, are susceptible but do not receive colostral antibodies against F4 fimbriae unless the sows have been vaccinated. The question arises as to whether resistant sows produce protective amounts of F4 antifimbrial antibodies after vaccination. The serum and colostrum antibody titres of 12 resistant and 12 susceptible vaccinated gilts were compared. The effect of the receptor status of the dam and sire on the preweaning performance of 5027 piglets was evaluated using Agroscope's recordings. The sows of the experimental herd, where ETEC F4 was circulating, were vaccinated against ETEC twice during the first pregnancy and once during each following pregnancy. The log2 transformed F4 antibody titres in the serum obtained after the second vaccine injection as well as in the colostrum of the 12 resistant animals were lower than the titres of the susceptible animals (serum: F4ab 11,19 ± 1,44 vs. 12,18 ± 1,33, P = 0,096; F4ac 10,03 ± 1,58 vs. 11,59 ± 1,43, P = 0,019; colostrum: F4ab 12,20 ± 2,41 vs. 14,02 ± 1,31, P = 0,033; F4ac 10,93 ± 2,46 vs. 13,03 ± 5,21, P = 0,006). The heat labile enterotoxin (LT) antibody titres after vaccination did not differ between susceptible and resistant animals (p > 0,10). Preweaning mortality in the offspring of RR sows × SS boars was slightly lower than in the offspring of SS sows × RR boars (P = 0,04), suggesting that the disease risk of susceptible piglets born to vaccinated resistant sows was not increased, even though they received colostrum with a slightly reduced content of antibody against F4 fimbriae.

Chicken Immunization followed by RNA Extraction and cDNA Synthesis for Antibody Library Preparation.

Effective isolation of specific antibodies from immunological repertoires requires the generation of a diverse library against a specific antigen of interest, as well as efficient selection procedures, such as bio-panning and phage ELISA. Key to this is the generation of a good immune response in the host, followed by preparation of high-quality RNA and cDNA from which a library can be constructed by the amplification and cloning of immunoglobulin heavy and light chain genes. The first step in the construction of such an "immune library" is a successful course of immunization. Detection of a strong serum antibody titer will theoretically then result in a pool of extracted RNA that is enriched for transcripts of genes encoding the antibody of interest. Chicken antibodies have been widely used for research and diagnostic purposes, largely because of both their cross-reactivity to epitopes shared by humans, mice, primates, and other mammals, and their simple characteristics, with chickens featuring single functional copies of V H /J H and V λ /J λ gene pairs. In chickens, antibodies against an antigen of interest can be detected in the serum as soon as 5-7 d after immunization. Once the antibody titer reaches an appropriate level in the serum, the spleen, bursa of Fabricius, and bone marrow are then harvested, and antibody libraries can be prepared from extracted RNA. Here, we describe a protocol for chicken immunization with an antigen of interest, followed by RNA extraction from the relevant tissues and cDNA synthesis, which users can use for antibody library construction.

Primary SARS-CoV-2 variant of concern infections elicit broad antibody Fc-mediated effector functions and memory B cell responses.

Neutralization of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) by human sera is a strong correlate of protection against symptomatic and severe Coronavirus Disease 2019 (COVID-19). The emergence of antigenically distinct SARS-CoV-2 variants of concern (VOCs) and the relatively rapid waning of serum antibody titers, however, raises questions about the sustainability of serum protection. In addition to serum neutralization, other antibody functionalities and the memory B cell (MBC) response are suggested to help maintaining this protection. In this study, we investigate the breadth of spike (S) protein-specific serum antibodies that mediate effector functions by interacting with Fc-gamma receptor IIa (FcγRIIa) and FcγRIIIa, and of the receptor binding domain (RBD)-specific MBCs, following a primary SARS-CoV-2 infection with the D614G, Alpha, Beta, Gamma, Delta, Omicron BA.1 or BA.2 variant. Irrespectively of the variant causing the infection, the breadth of S protein-specific serum antibodies that interact with FcγRIIa and FcγRIIIa and the RBD-specific MBC responses exceeded the breadth of serum neutralization, although the Alpha-induced B cell response seemed more strain-specific. Between VOC groups, both quantitative and qualitative differences in the immune responses were observed, suggesting differences in immunogenicity. Overall, this study contributes to the understanding of protective humoral and B cell responses in the light of emerging antigenically distinct VOCs, and highlights the need to study the immune system beyond serum neutralization to gain a better understanding of the protection against emerging variants.

LGI1 encephalitis: potentially complement-activating anti-LGI1-IgG subclasses 1/2/3 are associated with the development of hippocampal sclerosis

Two-thirds of published patients with anti-leucine rich, glioma inactivated 1 (LGI1) encephalitis develop hippocampal sclerosis (HS). It is likely that this contributes to residual cognitive long-term deficits and the risk of epilepsy. Almost all patients harbor anti-LGI1-immunoglobulin G-(IgG-) subclass 4, which is considered a “benign”, non-destructive subclass. In contrast, neuropathological case studies have suggested that the classical complement cascade may contribute to mediotemporal cell death in patients with LGI1 antibodies. IgG subclasses 1, 2, or 3 are required to initiate this cascade. We hypothesized that patients with these anti-LGI1-IgG1/2/3 in addition to IgG4 have a higher risk of developing HS than patients with anti-LGI1-IgG4 alone. We retrospectively assessed all anti-LGI1 encephalitis patients from this center with anti-LGI1-IgG-subclass information and follow-up MRI available. Nine out of 20 patients had developed HS (45%). Volumetric FreeSurfer analysis confirmed the visual HS diagnoses. HS and a lower hippocampal volume were associated with anti-LGI1-IgG1/2/3. All six patients with this IgG subclass status developed HS. There was no association with older or younger age at onset, female sex, longer latency from disease onset to start of immunotherapy, less intense immunotherapy, higher serum titers of LGI1 antibodies, LGI1 antibodies in CSF or higher LGI1-specific antibody indices. There was no association between anti-LGI1-IgG1/2/3 status and neuropsychological performance, epilepsy, or general neurological performance. This confirms our hypothesis that anti-LGI1-IgG1/2/3 in serum puts patients at risk of developing HS. If these findings can be confirmed and clinically corroborated, patients with anti-LGI1-IgG1/2/3 might become candidates for anti-complement-directed immunological treatments.

Production of a monoclonal antibody specific to the IgM heavy chain of Asian seabass (Lates calcarifer Bloch, 1790) and its application in assessing health status following vaccination and challenges with Flavobacterium covae and Streptococcus iniae

Immunoglobulin M (IgM) shows potential as a significant immunological marker in Asian seabass (Lates calcarifer), accentuating the importance of developing specific monoclonal antibodies (mAbs) for immunological studies. In this study, we investigated the antigenicity of the IgM heavy chain (IgMH), particularly the Cμ3 region of IgMH (IgMHCμ3), and synthesized a peptide for anti-IgMHCμ3 mAb production. The synthesized peptide was used to generate a specific mAb in rabbits. The produced mAb demonstrated high specificity and affinity for Asian seabass IgMH, as confirmed through indirect ELISA, Western blot analysis, indirect immunofluorescence assay (IIFAT) and flow cytometry analysis. In addition, an indirect ELISA was developed and optimized to measure anti-Flavobacterium covae and anti-Streptococcus iniae antibody titers in Asian seabass serum. The monoclonal antibody (mAb) was subsequently used to assess the health status of Asian seabass post-vaccination and challenge with these pathogens, demonstrating its potential as a valuable tool for immunological studies and health assessments in Asian seabass. Vaccination and postchallenge fish exhibited a pronounced increase in specific antibodies and total serum IgM and IgM+ cell populations. Thus, this study establishes a foundational platform for using the anti-IgMHCμ3 mAb as an essential tool for evaluating and understanding the immune responses and health status of Asian seabass, especially in the context of bacterial infections and vaccinations, and paves the way for more studies in fish immunology.

Association between human herpesvirus 8 and lipid profile in northwest China: A cross-sectional study.

Human herpesvirus 8 (HHV-8) infection shows obvious regional and ethnic differences. Although studies have shown that these differences may be associated with lipid metabolism, to date, no large-scale studies have explored this. This study explored the seropositivity rate of HHV-8 among 2516 residents from 10 regions of northwest China and then the correlates of HHV-8 infection with lipid profile. The HHV-8 serological positivity rate was 15.6% among all residents. The HHV-8 seroprevalence ranged 11.2-27.6% among different ethnicities. Across different BMI levels, the positive rates of HHV-8 were 27.6%, 16.9%, and 13.6% for a BMI < 18.5, 18.5-24.9, and ≥25, respectively. HHV-8 seropositivity rate was lower for hypertensive people (12.6%) than for non-hypertensive people (16.7%). Univariate logistic regression analyses revealed that age, hypertension, systolic blood pressure, BMI, total cholesterol, and high-density lipoprotein cholesterol (HDL-C) significantly correlated with HHV-8 seropositivity (p < 0.05). Multivariate logistic regression analysis after adjusting for confounding factors showed that HDL-C (odds ratio [OR]: 0.132, 95% confidence interval [CI], 0.082-0.212; p < 0.001) and BMI (OR: 0.959, 95% CI 0.933-0.986; p = 0.003) were associated with HHV-8 seropositivity. Subgroup analyses concerning ethnicity, sex, or age demonstrated a consistent relationship with HDL-C. The results of HHV-8 seropositivity and BMI were inconsistent in the subgroups. However, Spearman's correlation analysis between HHV-8 serum antibody titer and HDL-C levels showed no linear relationship among HHV-8 seropositive individuals (ρ = -0.080, p = 0.058). HHV-8 serum antibody titers were also not significantly correlated with BMI (ρ = -0.015, p = 0.381). Low HDL-C levels may be an independent risk factor for HHV-8 infection, but there is no significant correlation between HDL-C levels and HHV-8 antibody titers.

Clinical characteristics of COVID-19 clusters in three schools in Beijing, China: A retrospective study

BackgroundThis retrospective analysis aims to investigate the clinical characteristics of students infected with the SARS-CoV-2 Omicron variant in three Beijing schools. Additionally, we explore the dynamic trends of nucleic acid cycle threshold values (Ct values) and serum antibody titers throughout the disease course. MethodsDemographic, clinical, nucleic acid Ct values, and antibody titer data were collected from cases in a COVID-19 cluster in Beijing Ditan Hospital, Capital Medical University, spanning from September 6 to October 1, 2022. ResultsA total of 107 students infected with Omicron (BA.5.2 and BA.2.76) were identified across three schools. Primary clinical manifestations included fever and upper respiratory symptoms (85/107, 79.4 %), with the majority being classified as mild cases (96/107, 89.7 %). Notably, middle school students in the second school exhibited a higher peak body temperature compared to college students in the first and third schools (39.5 °C vs. 38.4 °C, adjusted P = 0.005; 39.5 °C vs. 38.6 °C, adjusted P = 0.002). Analysis of dynamic changes in Ct values revealed the lowest median Ct value in nasopharyngeal swabs on the third day of illness, reaching 35 after 9–11 days. Oropharyngeal swab nucleic acid median Ct value reached 35 approximately 3–5 days post-onset. Serum antibody detection showed continuous negativity of IgM antibody titers from days 1–10, while IgG antibody titers were positive on the first day and increased rapidly after one week. ConclusionsThe three COVID-19 cluster school outbreaks primarily resulted from Omicron infections, with no severe or fatal cases observed. Clinically, the selection of different types of SARS-CoV-2 nucleic acid swabs for virus detection can be tailored based on the infection's course.

Study of the adjuvant properties of beta-glucans from &lt;i&gt;Saccharomyces Cerevisiae&lt;/i&gt; yeast

To increase the effectiveness and immunogenicity of modern vaccines, especially subunit ones, it is required to use adjuvants. Polysaccharides, due to their safety and biocompatibility, are desirable candidates for the creation of vaccine adjuvants. The aim of our study was to develop a method for obtaining beta-Glucans from the yeast Saccharomyces cerevisiae cell wall, and evaluate their adjuvant properties. The high purity and non-toxicity of the resulting preparation was achieved by using enzyme complexes of cellulase and protease in combination with ultrasound (22 kHz) at the purification stage. The developed scheme allows for the yield of beta-Glucans up to 2 g from 100 g of the biomass of wet cells. The adjuvant properties of beta-Glucans were studied in 50 male BALB/c mice, weighing 16–18 g. Immunization was performed twice, with a 14-day interval, intramuscularly, 200 μl per animal. The recombinant receptor-binding domain (RBD) of the surface S protein of the SARS-CoV-2 virus (Wuhan-Hu-1 and B.1.617.2 (Delta)) was used as an antigen, at a dose of 50 μg per animal. A positive control group was administered with the antigen combined with aluminum hydroxide. As a negative control, mice injected with the saline solution were used. The titers of specific antibodies in the blood sera were determined by ELISA assays. RBD (Wuhan-Hu-1 and Delta), and S protein (Wuhan-Hu-1, Delta and Omicron) were used as antigens. The titers of virus-neutralizing antibodies were measured in neutralization tests using SARS-CoV-2 virus strains Wuhan-Hu-1, Delta (B.1.617.2) and Omicron (B.1.1.529). The results of the study have shown that beta-Glucans have the ability to enhance the production of specific and virus-neutralizing antibodies in mice immunized with RBD. The titers of specific and virus neutralizing antibodies are comparable to their levels in the group immunized with RBD and Al(OH)₃. It has been found in the experiments in white outbred ICR mice that the preparation belongs to practically non-toxic substances. Therefore, it can be concluded that the use of beta-Glucans could become a preferable alternative to the conventional adjuvants based on aluminum salts, being biocompatible, biodegradable and non-toxic substances of low labor-intensive production.

Bioproduction and immunogenic evaluation of SARS-CoV-2 prototype vaccine in silkworm BmN cells

COVID-19, caused by the novel coronavirus SARS-CoV-2, has presented a significant challenge to global health, security, and the economy. Vaccination is considered a crucial measure in preventing virus transmission. The silkworm bioreactor has gained widespread usage in antigen presentation, monoclonal antibody preparation, and subunit vaccine development due to its safety, efficiency, convenience, and cost-effectiveness. In this study, we employed silkworm BmN cells and the silkworm MultiBac multigene co-expression system to successfully produce two prototype vaccines: a recombinant baculovirus vector vaccine (NPV) co-displaying the SARS-CoV-2 virus capsid protein and a capsid protein virus-like particle (VLP) vaccine. Following the purification of these vaccines, we immunized BALB/c mice to evaluate their immunogenicity. Our results demonstrated that both VLP and NPV prototype vaccines effectively elicited robust immune responses in mice. However, when equal inoculation doses between groups were compared, the recombinant NPV vaccine exhibited significantly higher serum antibody titers and increased expression of spleen cytokines and lymphocyte immune regulatory factors compared to the VLP group. These results suggested an increased immune efficacy of the recombinant NPV vaccine. Conversely, the VLP prototype vaccine displayed more pronounced effects on lymphocyte cell differentiation induction. This study successfully constructed two distinct morphological recombinant vaccine models and systematically elucidated their differences in humoral immune response and lymphocyte differentiation rate. Furthermore, it has fully harnessed the immense potential of silkworm bioreactors for vaccine research and development, providing valuable technical insights for studying mutated viruses like coronaviruses.

Broader anti-EBV TCR repertoire in multiple sclerosis: disease specificity and treatment modulation.

Epstein-Barr virus (EBV) infection has long been associated with the development of multiple sclerosis (MS). MS patients have elevated titers of EBV-specific antibodies in serum and show signs of CNS damage only after EBV infection. Regarding CD8+ T-cells, an elevated but ineffective response to EBV was suggested in MS patients, who present with a broader MHC-I-restricted EBV-specific T-cell receptor beta chain (TRB) repertoire compared to controls. It is not known whether this altered EBV response could be subject to dynamic changes, e.g., by approved MS therapies, and whether it is specific for MS. 1317 peripheral blood TRB repertoire samples of healthy donors (n=409), patients with MS (n=710) before and after treatment, patients with neuromyelitis optica spectrum disorder (n=87), myelin-oligodendrocyte-glycoprotein antibody-associated disease (n=64) and Susac's syndrome (n=47) were analyzed. Apart from MS, none of the evaluated diseases presented with a broader anti-EBV TRB repertoire. In MS patients undergoing autologous hematopoietic stem-cell transplantation, EBV reactivation coincided with elevated MHC-I-restricted EBV-specific TRB sequence matches. Therapy with ocrelizumab, teriflunomide or dimethyl fumarate reduced EBV-specific, but not CMV-specific MHC-I-restricted TRB sequence matches. Together, this data suggests that the aberrant MHC-I-restricted T-cell response directed against EBV is specific to MS with regard to NMO, MOGAD and Susac's Syndrome and that it is specifically modified by MS treatments interfering with EBV host cells or activated lymphocytes.