IgG Production Research Articles

Immunomodulatory chitosan nanoparticles for Toxoplasma gondii infection: Novel application of chitosan in complex propranolol-hydrochloride as an adjuvant in vaccine delivery

The study aimed to investigate the immunomodulatory effects of propranolol hydrochloride (PRO) in combination with chitosan nanoparticles (CS NPs) as an adjuvant to develop an effective vaccine against T. gondii. A total of 105 BALB/c mice were randomly divided into seven equal groups including PBS alone, CS NPs, SAG1 (Surface antigen 1), CS-SAG1 NPs, CS-PRO NPs, SAG1-PRO, and CS-SAG1-PRO NPs. The immunostimulatory effect of each adjuvant used for vaccine delivery was evaluated in a mice immunization model. The results showed that the mice immunized with CS-SAG1-PRO NPs exhibited the highest lymphocyte proliferation rate, along with increased secretion of IFN-γ, TNF-α, IL-6, IL-12, IL-17, and IL-23, as well as elevated levels of protective cytokines such as TGF-β, IL-27, and IL-10. Although, the CS-SAG1-PRO NPs immunized mice showed the highest level of T. gondii specific IgG compared to the other groups, a significant production of IgG2a and IgG1 was observed in the sera of mice immunized with the CS-SAG1-PRO NPs compared to the other group (p <0.001). The higher IgG2a/IgG1 ratio observed in the CS-SAG1-PRO NPs group indicates a bias towards Th1 cell polarization, suggesting the promotion of Th1 cell-mediated immune responses. Considering the combination of the highest lymphocyte proliferation and survival rates, IgG2a/IgG1 ratio, and cytokine levels in the mice immunized with CS-SAG1-PRO NPs, this approach holds promise for immunostimulation and vaccine delivery against T. gondii infection.

SARS-CoV-2 S-RBD IgG & Neutralizing antibodies among different categories of health care workers post third dose BNT162b2 mRNA COVID-19 vaccine

ABSTRACT Neutralizing antibodies (NTAb) play a significant role in preventing and protecting against SARS-CoV-2 virus infection. Identifying NTAb is undoubtedly imperative in understanding the immunity toward COVID-19 better. However, it is interesting to note that the production of NTAb varies among individuals, especially among healthcare workers (HCWs), as they are exposed to the virus daily. Hence, we would like to investigate factors affecting the production of S-RBD IgG and NTAb among different categories of HCWs, particularly after receiving the third dose of the BNT162b2 mRNA COVID-19 Vaccine. A total of 361 HCWs from our hospital were prospectively enrolled and had their S-RBD IgG and NTAb titers measured. They were studied in relation to the degree of exposure to COVID-19, breakthrough infections, gender, age, race, household income, housing type, household number, and education levels. HCWs with the highest risk of exposure to COVID-19, breakthrough infections, and male gender displayed the highest median titers of both S-RBD IgG and NTAb, and the differences were statistically significant (p < .05). Age, race, household income, housing type, household number, and education levels were revealed to be insignificant. We concluded that the degree of exposure to COVID-19, breakthrough infections, and male gender are significant factors in NTAb production among HCWs.

FRI374 Immunomodulatory Effects Of Progesterone And Glucocorticoids In Pregnancy Immunity

Abstract Disclosure: A. Yasuda: None. T. Seki: None. H. Kashiwagi: None. N. Kitajima: None. Y. Kametani: None. Immune tolerance to a semi-allogeneic fetus is crucial for a successful pregnancy. However, the mechanisms of tolerance to semi-allografts in the co-existence with normal defenses against cancer and pathogens is not clear. During pregnancy, levels of pregnancy-related proteins and hormones such as progesterone (P4), estrogen, testosterone, and glucocorticoids (GC) increase. We hypothesized that the most abundant pregnancy related hormone in the placenta, P4, might play an important role in the local tolerance in the placenta. Thus, we aimed to compare the effects of P4 and cortisol (COR) on human lymphocytes in vivo, to clarify their role in the systemic regulation of immunity during pregnancy. Healthy donor peripheral blood mononuclear cells (PBMCs) were treated with P4 or COR for 6 h. These PBMCs were washed and transplanted intravenously into 8- to 9-week-old NOG-hIL-4-Tg (formal name, NOD.Cg-PrkdcscidIl2rgtm1Sug/Tg(CMV-IL4)/Jic) mice. Human epidermal growth factor receptor-2 (HER2) peptide was emulsified in complete Freund's adjuvant and administered intraperitoneally to these PBMC-NOG-hIL-4-Tg mice at the same day. As a negative control, an equal volume of PBS was added to the culture and transplanted into NOG-hIL-4-Tg mice. Boosters were administered using incomplete Freund's adjuvant 2 weeks after the primary immunization. Peripheral blood was collected 4 weeks after transplantation and 2 weeks after booster administration. T and B cell profiles were analyzed using FCM 28 days later. The results revealed that significantly higher numbers of human CD45+ cells engrafted in the spleens of P4-treated mice compared to COR-treated mice 4 weeks post-transplantation. Transplanted human CD45+ cells included T and B cells, and CD8+ T cells were significantly higher in P4-treated mice compared to both control and COR-treated mice. Moreover, antigen-specific IgG production was maintained in the P4-treated mice, suggesting that the T cell/B cell function was maintained in the mice. Compared to control and P4-treated mice, COR-treated mice tended to engraft fewer human CD45+ cells. Moreover, B cell engraftment tended to be lower in COR-treated mice than in control mice. Antigen-specific IgG production was not maintained. There results suggest that lymphocytes which experienced a high P4 environment maintain engraftment and function of human lymphocytes in the NOG-hIL-4-Tg mice, while high COR environment rather dampens the engraftment and function of them. The high-P4 environment limited in the placenta may support pregnant immunity to protect the semi-allogeneic fetus from pathogen-induced infectious disease or cancer. Presentation: Friday, June 16, 2023

Antiallergic Effects of Technologically Processed Antibodies to MHC II.

The risk of developing anaphylactic reactions to medications introduces additional difficulties for effective pharmacotherapy. Using a model of systemic anaphylaxis in mice, we showed that preventive administration of a preparation containing technologically processed antibodies (TPA) to MHC II induces an anti-anaphylactic effect comparable to that of dexamethasone (when assessing the severity of systemic anaphylaxis 30 and 60 min after challenge injection of the model antigen ovalbumin). The revealed activity may be related to the ability of TPA to MHC II to regulate the antigen presentation system and shift the immune response towards the production of IgG instead of IgE typical of anaphylactic reaction.

Pro-tumor Tfh2 cells induce detrimental IgG4 production and PGE2-dependent IgE inhibition in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) has a dismal prognosis and it is characterized by predominant pro-tumor Th2-type inflammation. T follicular helper (Tfh) cells are relevant immunoregulators in cancer, and often correlate with better survival. How the Th2-skewed microenvironment in PDAC modulates the differentiation of Tfh cells and their immunoregulatory function is unknown. We carried out high-dimensional flow cytometry and T-cell receptor- and RNA-sequencing, as well as bioinformatics, immunohistochemistry and invitro mechanistic studies. We identified Tfh1-, Tfh2-, and Tfh17-like cell clusters in the blood, tumors and tumor-draining lymph-nodes (TDLNs) of chemo-naïve PDAC patients and showed that high percentages of Tfh2 cells within the tumor tissue and TDLNs correlated with reduced patient survival. Moreover, only Tfh2 cells were highly activated and were reduced in frequency in patients who responded to neoadjuvant chemotherapy. RNA-sequencing analysis of immunoglobulin expression showed that tumor and TDLN samples expressed all immunoglobulin (IGH) isotypes apart from IGHE. Consistent with these findings, Tfh2 cells differentiated invitro by tumor microenvironment-conditioned dendritic cells promoted the production of anti-inflammatory IgG4 antibodies by co-cultured B cells, dependent on IL-13. Moreover, unexpectedly, Tfh2 cells inhibited the secretion of pro-inflammatory IgE, dependent on prostaglandin E2. Our results indicate that in PDAC, highly activated pro-tumor Tfh2 favor anti-inflammatory IgG4 production, while inhibit pro-inflammatory IgE. Thus, targeting the circuits that drive Tfh2 cells, in combination with chemotherapy, may re-establish beneficial anti-tumor Tfh-B cell interactions and facilitate more effective treatment. Research grants from the Italian Association for Cancer Research (AIRC) IG-19119 to MPP and the AIRC Special Program in Metastatic disease: the key unmet need in oncology, 5 per Mille no. 22737 to CB, MF, CD, MR and MPP; the ERA-NET EuroNanoMed III (a collaborative european grant financed by the Italian Ministry of Health, Italy) project PANIPAC (JTC2018/041) to MPP; the Fondazione Valsecchi to SC.

Accelerated blood clearance of PEGylated nanoparticles induced by PEG-based pharmaceutical excipients

PEGylated nanomedicines have been extensively developed and applied to cancer therapy. However, the antitumor efficacy of these nanoparticles is hampered by the accelerated blood clearance (ABC) effect caused by anti-PEG antibodies in vivo. There is still limited understanding about the cause of pre-existing anti-PEG antibodies in the human body. Herein, we discovered that PEG-based pharmaceutical excipients, commonly used in clinical and daily settings, could induce anti-PEG antibodies in vivo and lead to considerable potential clinical impacts on pharmacokinetics and pharmacodynamics of PEGylated nanoparticles. Specifically, we investigated the ability of poloxamer 188 (F68) and poloxamer 407 (F127), the two most frequently used PEG-based pharmaceutical excipients, to elicit the production of anti-PEG antibodies and influence the pharmacokinetics of PEGylated nanoparticles, with PEGylated liposome nanoparticles (L-NPs) as a model. Anti-PEG IgG and IgM levels were significantly boosted 3.8- and 32.2-fold, respectively, after pre-injection with F68, leading to rapid clearance of subsequently injected L-NPs from circulation due to the capture by neutrophils and monocytes. However, pre-injection of F127 did not induce the production of anti-PEG IgG, although there was a 7.7-fold increase in IgM level, which resulted in minimal effect on circulation time of L-NPs. Furthermore, the potential clinical impacts of F68 and F127 were further inspected for PEGylated liposomal doxorubicin (PLD). It was found that administering F68 prior to treatment led to over a one-third decrease in the antitumor effectiveness of PLD, while F127 had a negligible impact. Our study elucidates the mechanism by which PEG-based pharmaceutical excipients influence the effectiveness of PEGylated nanomedicines. It also highlights the significance of considering the potential for an ABC effect induced by PEG-based pharmaceutical excipients in patients.

Active inoculation with an inactivated Coxsackievirus A2 vaccine induces neutralizing antibodies and protects mice against lethal infection

Coxsackievirus A2 (CVA2) is one of the causative agents of hand-foot-and-mouth disease (HFMD), which poses a great challenge for global public health. However, presently, there are no available commercial vaccines or antivirals to prevent CVA2 infection. Here, we present an inactivated Vero cell-based whole CVA2 vaccine candidate and evaluate its safety and efficacy in this study. Neonatal BALB/c mice were vaccinated at 5 and 7 days old, respectively, and then challenged with either homologous or heterologous strain of CVA2 at a lethal dose at 10 days old. The inactivated whole CVA2 vaccine candidate showed a high protective efficacy. Additionally, our inactivated vaccine stimulated the production of CVA2-specific IgG1 and IgG2a antibodies in vivo and high titers of neutralization antibodies (NtAbs) in the serum of immunized mice. Maternal immunization with the inactivated CVA2 vaccine provided full protection to pups against lethal infection. Compared with mice inoculated with only alum, the viral loads were decreased, and pathological changes were relieved in tissue samples of immunized mice. Moreover, the transcription levels of some genes related to cytokines (IFN-γ and TNF-α, MCP-1, IL-6, CXCL-10 etc.) were significantly reduced. The number of immune cells and levels of cytokines in peripheral blood of mice inoculated with only alum were higher than that of immunized mice. It is noteworthy that this vaccine showed a good cross-immunity efficacy against Enterovirus A71 (EVA71) challenge. In conclusion, our findings suggest that this experimental inactivated CVA2 vaccine is a promising component of polyvalent vaccines related to HFMD in the near future.

Subcutaneous, Oral, and Intranasal Immunization of BALB/c Mice with Leishmania infantum K39 Antigen Induces Non-Protective Humoral Immune Response.

Visceral leishmaniasis is a high-burden disease caused by parasites of the Leishmania genus. The K39 kinesin is a highly antigenic protein of Leishmania infantum, but little is known about the immune response elicited by this antigen. We evaluated the humoral immune response of female BALB/c mice (n = 6) immunized with the rK39-HFBI construct, formed by the fusion of the K39 antigen to a hydrophobin partner. The rK39-HFBI construct was administered through subcutaneous, oral, and intranasal routes using saponin as an adjuvant. We analyzed the kinetics of IgG, IgG1, and IgG2a production. The groups were then challenged by an intravenous infection with L. infantum promastigote cells. The rK39-HFBI antigen-induced high levels of total IgG (p < 0.05) in all groups, but only the subcutaneous route was associated with increased production of IgG1 and IgG2a 42 days after immunization (p < 0.05), suggesting a potential secondary immune response following the booster dose. There was no reduction in the splenic parasite load; thus, the rK39-HFBI failed to protect the mice against infection under the tested conditions. The results presented here demonstrate that the high antigenicity of the K39 antigen does not contribute to a protective immune response against visceral leishmaniasis.

Identification of Colon Immune Cell Marker Genes Using Machine Learning Methods.

Immune cell infiltration that occurs at the site of colon tumors influences the course of cancer. Different immune cell compositions in the microenvironment lead to different immune responses and different therapeutic effects. This study analyzed single-cell RNA sequencing data in a normal colon with the aim of screening genetic markers of 25 candidate immune cell types and revealing quantitative differences between them. The dataset contains 25 classes of immune cells, 41,650 cells in total, and each cell is expressed by 22,164 genes at the expression level. They were fed into a machine learning-based stream. The five feature ranking algorithms (last absolute shrinkage and selection operator, light gradient boosting machine, Monte Carlo feature selection, minimum redundancy maximum relevance, and random forest) were first used to analyze the importance of gene features, yielding five feature lists. Then, incremental feature selection and two classification algorithms (decision tree and random forest) were combined to filter the most important genetic markers from each list. For different immune cell subtypes, their marker genes, such as KLRB1 in CD4 T cells, RPL30 in B cell IGA plasma cells, and JCHAIN in IgG producing B cells, were identified. They were confirmed to be differentially expressed in different immune cells and involved in immune processes. In addition, quantitative rules were summarized by using the decision tree algorithm to distinguish candidate immune cell types. These results provide a reference for exploring the cell composition of the colon cancer microenvironment and for clinical immunotherapy.

Interactive effect of booster vaccination and vitamin D status on antibody production of Omicron variant-infected adults: A real-world cohort study.

Effect of booster vaccination and vitamin D status on antibody production of Omicron variant-infected adults need to be further explored. A retrospective, longitudinal, real-world cohort study was performed. All included cases were divided into vitamin D deficiency (VDD) and non-VDD (control) groups according to baseline serum 25-hydroxyvitamin D [25(OH)D] concentration and then into unvaccinated, routinely vaccinated, and booster vaccinated VDD and control subgroups according to vaccination status. Antibody dynamics were observed within six time periods during hospitalization. A total of 204 adult cases were included, of which 121 (59%) were males; 23 (11%), 31 (15%), and 26 (13%) or 50 (25%), 35 (17%), and 39 (19%) were unvaccinated, routinely vaccinated, and booster vaccinated VDD cases or controls, respectively. The median (interquartile range) for age and baseline 25(OH)D concentration was 42.5 (31-53.5) years and 21.5 (18-25.4) ng/mL, respectively. The IgM titers within 3 to 7days and 7 to 14 days increased rapidly to 1.8-fold (P < 0.001) and 3.6-fold (P < 0.001) those within the first day; the IgG titers increased to 5.8-fold (P < 0.001) and 10.9-fold (P < 0.001). Booster vaccinated controls had higher first IgG titers compared with unvaccinated controls (3.1-fold; P = 0.001) or booster vaccinated VDD cases (2.1-fold; P = 0.02). Booster vaccination and non-VDD status may have an interactive boosting effect on IgG production of Omicron variant-infected adults. Further randomized clinical trials may be needed to determine whether booster vaccination combined with VDD correction improves the humoral immunity to Omicron variants.

Production and evaluation of rabbit IgG against IBDV in broiler chickens

Production and evaluation of rabbit IgG against IBDV in broiler chickens

The food additive titanium dioxide hinders intestinal production of TGF-β and IL-10 in mice, and long-term exposure in adults or from perinatal life blocks oral tolerance to ovalbumin.

Food hypersensitivities are increasing in industrialized countries, and foodborne nanoparticles (NPs) are suspected as co-factors in their aetiology. Food-grade titanium dioxide (fg-TiO2), a food colouring agent, is composed of NPs with immunomodulatory properties. We investigated whether fg-TiO2 may compromise the establishment of oral tolerance (OT) to food proteins using a model of OT induction to ovalbumin (OVA) in mice, and whether a perinatal exposure could trigger this effect. In pregnant mice fed a TiO2-enriched diet, ICP-MS and TEM-EDX analyses showed passage of TiO2 NPs into the foetus. When their weaned offspring were fed the same diet, a breakdown in OT to OVA was observed at adulthood, characterized by a high anti-OVA IgG production compared to controls. However, adult mice directly exposed to fg-TiO2 did not induce OT to OVA either, ruling out a developmental origin for these effects. When these mice were orally challenged with OVA, intestinal inflammation demonstrated hypersensitivity to OVA. In OVA-naïve mice, fg-TiO2 exposure impaired intestinal TGF-β and IL-10 production, of key role in OT induction and maintenance. These findings showed that long-term exposure to TiO2 as food additive alters anti-inflammatory cytokine profile, and leads to OT failure regardless of the timing of TiO2 exposure throughout life.

Prevalence of Immunoglobin G and M among children infected with Plasmodium falciparum in some Hospitals in Maiduguri, Borno State

The threat of Malaria to the public health especially in Sub-Saharan Africa is enormous and Nigeria in particular is considered a bit hotspot. The diseases are transmitted by Plasmodium species with severe disease outcome children under 5 years. In this study, we undertook a cross-sectional study using representative cohort of children in Maiduguri aged 5 59 months to determine the seroprevalence and risk factors associated with infection with P. falciparum in this vulnerable aged group. A cross-sectional study was conducted on participants from four hospitals in Maiduguri, Borno State. In total, plasma was collected from 182 and 91 participants for the detection of IgG and IgM antibodies, respectively using Enzyme Linked Immunosorbent Assay for the measurement of IgG and IgM antibody production against P. falciparum. The result indicates that the overall seroprevalence was (75.3%; 137/182) and (86.8%; 79/91) corresponding to IgG and IgM respectively. Based on gender, male 24(13.2%) and 8(8.8%) were positive with respect to IgG and IgM while 21(11.5%) and 4(4.4%) of the females were positive to IgG and IgM antibodies respectively. Additionally, both University of Maiduguri Teaching Hospital and State Specialist Hospital Maiduguri, recorded the highest prevalence of 15 (8.2%) for IgG while only UMTH recorded the highest prevalence of 5(5.5%) to IgM antibodies. In conclusion, the overall seroprevalence was found to be low for both IgG and IgM. However, our study observed differences in the seroprevalence of P. falciparium in children according to age and study locations for IgM and IgG respectively. Also, males have high seroprevalence for both IgG and IgM.

Milk antibody response after 3rd COVID-19 vaccine and SARS-CoV-2 infection and implications for infant protection

Little is known about the persistence of human milk anti-SARS-CoV-2 antibodies after 2nd and 3rd vaccine doses and infection following 3rd dose. In this study, human milk, saliva, and blood samples were collected from 33 lactating individuals before and after vaccination and infection. Antibody levels were measured using ELISA and symptoms were assessed using questionnaires. We found that after vaccination, milk anti-SARS-CoV-2 antibodies persisted for up to 8months. In addition, distinct patterns of human milk IgA and IgG production and higher milk RBD-blocking activity was observed after infection compared to 3-dose vaccination. Infected mothers reported more symptoms than vaccinated mothers. We examined the persistence of milk antibodies in infant saliva after breastfeeding and found that IgA was more abundant compared to IgG. Our results emphasize the importance of improving the secretion of IgA antibodies to human milk after vaccination to improve the protection of breastfeeding infants.

Development of a bivalent protein-based vaccine candidate against invasive pneumococcal diseases based on novel pneumococcal surface protein A in combination with pneumococcal histidine triad protein D.

Extensive efforts have been made toward improving effective strategies for pneumococcal vaccination, focusing on evaluating the potential of multivalent protein-based vaccines and overcoming the limitations of pneumococcal polysaccharide-based vaccines. In this study, we investigated the protective potential of mice co-immunization with the pneumococcal PhtD and novel rPspA proteins against pneumococcal sepsis infection. The formulations of each antigen alone or in combination were administered intraperitoneally with alum adjuvant into BALB/c mice three times at 14-day intervals. The production of antigen-specific IgG, IgG1 and IgG2a subclasses, and IL-4 and IFN-γ cytokines, were analyzed. Two in vitro complement- and opsonophagocytic-mediated killing activities of raised antibodies on day 42 were also assessed. Finally, the protection against an intraperitoneal challenge with 106 CFU/mouse of multi-drug resistance of Streptococcus pneumoniae ATCC49619 was investigated. Our findings showed a significant increase in the anti-PhtD and anti-rPspA sera IgG levels in the immunized group with the PhtD+rPspA formulation compared to each alone. Moreover, the results demonstrated a synergistic effect with a 6.7- and 1.3- fold increase in anti-PhtD and anti-rPspA IgG1, as well as a 5.59- and 1.08- fold increase in anti-PhtD and anti-rPspA IgG2a, respectively. Co-administration of rPspA+PhtD elicited a mixture of Th-2 and Th-1 immune responses, more towards Th-2. In addition, the highest complement-mediated killing activity was observed in the sera of the immunized group with PhtD+rPspA at 1/16 dilution, and the opsonophagocytic activity was increased from 74% to 86.3%. Finally, the survival rates showed that mice receiving the rPspA+PhtD formulation survived significantly longer (100%) than those receiving protein alone or PBS and exhibited the strongest clearance with a 2 log10 decrease in bacterial load in the blood 24h after challenge compared to the control group. In conclusion, the rPspA+PhtD formulation can be considered a promising bivalent serotype-independent vaccine candidate for protection against invasive pneumococcal infection in the future.

Effects of Dietary Supplementation of Lacticaseibacillus Chiayiensis AACE3 on Hepatic Antioxidant Capacity, Immune Factors and Gut Microbiology in Nandan Yao Chicks.

The growing issue of antibiotic resistance has restrained the utilization of antibiotics as growth enhancers in the poultry industry. Probiotics are candidates for replacing antibiotics in the poultry industry. However, probiotics are strain-specific and their efficacy needs to be investigated before applying them. The aim of this study was to assess the positive effects of Lacticaseibacillus chiayiensis AACE3 on the health and gut microbiota of Nandan Yao chicks. The results showed that compared with the blank control (NC) and aureomycin (PC) groups, L. chiayiensis AACE3 increased final body weight (BW), villus height and improved the ratio of villus height to crypt depth in chicken jejunal tissues. L. chiayiensis AACE3 also increased the activity of hepatic antioxidant enzymes (SOD, CAT and T-AOC) and reduced hepatic oxidative damage (MDA). Furthermore, compared to NC, L. chiayiensis AACE3, the activity of intestinal digestive enzymes (i.e., α-amylase, lipase and trypsin) was increased. L. chiayiensis AACE3 upregulated the production of IgA and IgG and downregulated the production of IL-6, IL-1β and TNF-α in chicken serum. Moreover, supplementation of L. chiayiensis AACE3 enhances the diversity of gut microbes. At the phylum level, the abundance of Actinobacteriota and Proteobacteria decreased with L. chiayiensis AACE3 supplementation, while the abundance of Verrucomicrobiota and Bacteroidetes increased. At the genus level, there was an increase in the abundance of potential probiotics Akkermansia, Romboutsia, Subdoligranulum, and Lactobacillus. This study confirms that L. chiayiensis AACE3 is an excellent feed additive as an alternative to aureomycin and offers various advantages for the healthy growth of chickens during the brooding period by positively affecting their gut microbiome.

Desensitization for the Prevention of Drug Hypersensitivity

Drug desensitization is a treatment strategy for patients with hypersensitivity to essential drugs without alternatives. The gradual increase in the drug dosage from low doses to therapeutic levels induces a transient immune tolerance to the culprit drug. Although desensitization has traditionally been recommended for IgE-mediated immediate hypersensitivity, this indication has recently been expanded to include non-IgE-mediated immediate responses, nonimmunological responses, and T-cell mediated delayed hypersensitivity reactions. Although the exact mechanism behind desensitization remains unclear, the process is thought to attenuate various intracellular signals in target cells through the high-affinity IgE receptor (FcɛRI) internalization, alteration in signaling pathways in mast cells and basophils, reduction in Ca2+ influx, and production of anti-drug IgG4 blocking antibody. Desensitization can be used for the safe administration of anti-neoplastic agents, antibiotics, aspirin, and nonsteroidal anti-inflammatory drugs. Various desensitization protocols have been proposed for each drug. The optimization of drug concentration, target dosage, administration interval, and route of administration is key to successful desensitization. In addition, the desensitization protocol should be individualized for each patient with consideration of the severity of the initial hypersensitivity response, the characteristics of the culprit drug, and the nature of the breakthrough reactions.

A TLR9 agonist synergistically enhances protective immunity induced by an Alum-adjuvanted H7N9 inactivated whole-virion vaccine

ABSTRACT Antigen sparing is an important strategy for pandemic vaccine development because of the limitation of worldwide vaccine production during disease outbreaks. However, several clinical studies have demonstrated that the current aluminum (Alum)-adjuvanted influenza vaccines fail to sufficiently enhance immune responses to meet licensing criteria. Here, we used pandemic H7N9 as a model virus to demonstrate that a 10-fold lower amount of vaccine antigen combined with Alum and TLR9 agonist can provide stronger protective effects than using Alum as the sole adjuvant. We found that the Alum/CpG 1018 combination adjuvant could induce more robust virus-specific humoral immune responses, including higher total IgG production, hemagglutination-inhibiting antibody activity, and neutralizing antibody titres, than the Alum-adjuvanted formulation. Moreover, this combination adjuvant shifted the immune response toward a Th1-biased immune response. Importantly, the Alum/CpG 1018-formulated vaccine could confer better protective immunity against H7N9 challenge than that adjuvanted with Alum alone. Notably, the addition of CpG 1018 to the Alum-adjuvanted H7N9 whole-virion vaccine exhibited an antigen-sparing effect without compromising vaccine efficacy. These findings have significant implications for improving Alum-adjuvanted influenza vaccines using the approved adjuvant CpG 1018 for pandemic preparedness.

Long-Term Culturing of FreeStyle 293-F Cells Affects Immunoglobulin G Glycome Composition.

Glycosylation of IgG regulates the effector function of this antibody in the immune response. Glycosylated IgG is a potent therapeutic used for both research and clinical purposes. While there is ample research on how different cell culture conditions affect IgG glycosylation, the data are missing on the stability of IgG glycome during long cell passaging, i.e., cell "aging". To test this, we performed three independent time course experiments in FreeStyle 293-F cells, which secrete IgG with a human-like glycosylation pattern and are frequently used to generate defined IgG glycoforms. During long-term cell culturing, IgG glycome stayed fairly stable except for galactosylation, which appeared extremely variable. Cell transcriptome analysis revealed no correlation in galactosyltransferase B4GALT1 expression with galactosylation change, but with expression of EEF1A1 and SLC38A10, genes previously associated with IgG galactosylation through GWAS. The FreeStyle 293-F cell-based system for IgG production is a good model for studies of mechanisms underlying IgG glycosylation, but results from the present study point to the utmost importance of the need to control IgG galactosylation in both in vitro and in vivo systems. This is especially important for improving the production of precisely glycosylated IgG for therapeutic purposes, since IgG galactosylation affects the inflammatory potential of IgG.

Long-term SARS-CoV-2 neutralizing antibody level prediction using multimodal deep learning: A prospective cohort study on longitudinal data in Wuhan, China.

The ongoing epidemic of SARS-CoV-2 is taking a substantial financial and health toll on people worldwide. Assessing the level and duration of SARS-CoV-2 neutralizing antibody (Nab) would provide key information for government to make sound healthcare policies. Assessed at 3-, 6-, 12-, and 18-month postdischarge, we described the temporal change of IgG levels in 450 individuals with moderate to critical COVID-19 infection. Moreover, a data imputation framework combined with a novel deep learning model was implemented to predict the long-term Nab and IgG levels in these patients. Demographic characteristics, inspection reports, and CT scans during hospitalization were used in this model. Interpretability of the model was further validated with Shapely Additive exPlanation (SHAP) and Gradient-weighted Class Activation Mapping (GradCAM). IgG levels peaked at 3 months and remained stable in 12 months postdischarge, followed by a significant decline in 18 months postdischarge. However, the Nab levels declined from 6 months postdischarge. By training on the cohort of 450 patients, our long-term antibody prediction (LTAP) model could predict long-term IgG levels with relatively high area under the receiver operating characteristic curve (AUC), accuracy, precision, recall, and F1-score, which far exceeds the performance achievable by commonly used models. Several prognostic factors including FDP levels, the percentages of T cells, B cells and natural killer cells, older age, sex, underlying diseases, and so forth, served as important indicators for IgG prediction. Based on these top 15 prognostic factors identified in IgG prediction, a simplified LTAP model for Nab level prediction was established and achieved an AUC of 0.828, which was 8.9% higher than MLP and 6.6% higher than LSTM. The close correlation between IgG and Nab levels making it possible to predict long-term Nab levels based on the factors selected by our LTAP model. Furthermore, our model identified that coagulation disorders and excessive immune response, which indicate disease severity, are closely related to the production of IgG and Nab. This universal model can be used as routine discharge tests to identify virus-infected individuals at risk for recurrent infection and determine the optimal timing of vaccination for general populations.