High IgG Titers Research Articles

Immunization with EmCRT-Induced Protective Immunity against Echinococcus multilocularis Infection in BALB/c Mice

Alveolar echinococcosis (AE) is a severe parasitic zoonosis caused by the larval stage of Echinococcus multilocularis. The identification of the antigens eliciting acquired immunity during infection is important for vaccine development against Echinococcus infection. Here, we identified that E. multilocularis calreticulin (EmCRT), a ubiquitous protein with a Ca2+-binding ability, could be recognized by the sera of mice infected with E. multilocularis. The native EmCRT was expressed on the surface of E. multilocularis larvae as well as in the secreted products of metacestode vesicles and protoscoleces (PSCs). The coding DNA for EmCRT was cloned from the mRNA of the E. multilocularis metacestode vesicles and a recombinant EmCRT protein (rEmCRT) was expressed in E. coli. Mice immunized with soluble rEmCRT formulated with Freund’s adjuvant (FA) produced a 43.16% larval vesicle weight reduction against the challenge of E. multilocularis PSCs compared to those that received the PBS control associated with a high titer of IgG, IgG1 and IgG2a antibody responses as well as high levels of Th1 cytokines (IFN-γ and IL-2) and Th2 cytokines (IL-4, IL-5 and IL-10), produced by splenocytes. Our results suggest that EmCRT is an immunodominant protein secreted by E. multilocularis larvae and a vaccine candidate that induces partial protective immunity in vaccinated mice against Echinococcus infection.

A SARS-CoV-2 vaccine based on conjugation of SARS-CoV-2 RBD with IC28 peptide and mannan

SARS-CoV-2 is a particularly transmissible virus that causes a severe respiratory disease known as COVID-19. Safe and effective vaccines are urgently needed to combat the COVID-19 pandemic. The receptor-binding domain (RBD) of SARS-CoV-2 spike protein elicits most neutralizing antibodies during viral infection and is an ideal antigen for vaccine development. In particular, RBD expressed by E. coli is amenable to low cost and high-yield manufacturability. The adjuvant is necessitated to improve the immunogenicity of RBD. IC28, a TLR5-dependent adjuvant, is a peptide from bacterial flagellin. Mannan is a ligand of TLR-4 or TLR-2 and a polysaccharide adjuvant. Here, IC28 and mannan were both covalently conjugated with RBD from E. coli. The conjugate (RBD-IC28-M) elicited high RBD-specific IgG titers, and a neutralization antibody titer of 201.4. It induced high levels of Th1-type cytokines (IFN-γ) and Th2-type cytokines (IL-5 and IL-10), along with high antigenicity and no apparent toxicity to the organs. The mouse sera of the RBD-IC28-M group competitively interfered with the interaction of RBD and ACE2. Thus, conjugation with IC28 and mannan additively enhanced the humoral and cellular immunity. Our study was expected to provide the feasibility to develop an affordable, easily scalable, effective vaccine SARS-CoV-2 vaccine.

The evolution of humoral immune responses to past and novel influenza virus strains gives evidence for antigenic seniority.

The high genetic and antigenic variability of influenza virus and the repeated exposures of individuals to the virus over time account for the human immune responses toward this pathogen to continuously evolve during the lifespan of an individual. Influenza-specific immune memory to past strains has been shown to affect the immune responses to subsequent influenza strains and in turn to be changed itself through the new virus encounter. However, exactly how and to what extent this happens remains unclear. Here we studied pre-existing immunity against influenza A virus (IAV) by assessing IAV binding (IgG), neutralizing, and neuraminidase-specific antibodies to 5 different IAV strains in 180 subjects from 3 different age cohorts, adolescents, adults, and elderly, over a 5-year time span. In each age cohort, the highest neutralizing antibody titers were seen for a virus strain that circulated early in their life but the highest increase in titer was found for the most recent virus strains. In contrast, the highest IgG titers were seen against recent virus strains but the biggest increase in titer occurred against older strains. Significant increases in neutralizing antibody titers against a newly encountered virus strain were observed in all age cohorts demonstrating that pre-existing immunity did not hamper antibody induction. Our results indicate that the evolution of influenza-specific humoral immunity differs for rather cross-reactive virus-binding antibodies and more strain-specific neutralizing antibodies. Nevertheless, in general, our observations lend support to the antigenic seniority theory according to which the antibody response to influenza is broadened with each virus encounter, with the earliest encountered strain taking in the most senior and thus dominant position.

Determination of Immunological Response among Vaccinated Individuals with Pfizer COVID-19 Vaccine in Garmian District, Iraq

Background: Worldwide, a coronavirus disease called COVID-19 has affected sizable populations. Although there has been a lot of excitement about vaccines, little is known about their negative effects or how antibody titters change following injections. The objective of the study is to evaluate post-vaccine IgG titters, WBCs count after Pfizer COVID-19 Vaccine and side effects in the Garmian District. Materials and Method: The data were collected from Sherwana primary health center in Kalar, Kurdistan region, Iraq, from September 25th to December 23rd 2021, which included 120 unvaccinated controls and 115 general population participants were enrolled in a COVID-19 vaccination campaign. A questionnaire form was used which included is socio-demography, clinical history, vaccine side effects. All 115 participants underwent two Pfizer COVID-19 vaccines and blood samples were collected 4 weeks after the 1st dose and 6–8 weeks after the 2nd dose of vaccination, and then the laboratory tests for the immunological (IgG) and white blood cells were performed. Result: The level of antibodies increased significantly after the 2nd dose of vaccines compared to the 1st dose. Younger age, non-chronic disease participant, COVID-19 positive, smoking, and AB blood group type, significantly associated with higher IgG titres after Pfizer COVID-19 vaccination. The non-vaccinated severe infected group had significantly higher antibody titters and WBC counts than the mild and moderate infected groups. Individuals with the 1st dose vaccinated have a higher level of side effects compared to vaccinated individuals with the 2nd dose at vaccine. Conclusion: After receiving two doses of the Pfizer COVID-19 vaccine, all research participants developed antibodies. The research population appears to be at no risk from the Pfizer COVID-19 vaccine, and the antibody titer rose following the two rounds of immunization. The participants' aging and the presence of non-chronic conditions are blamed for the rise in antibody titter.

Immunization with the lipoprotein FtsB stimulates protective immunity against Streptococcus pyogenes infection in mice.

Streptococcus pyogenes is one of the main pathogenic bacteria that causes disease in humans. It is reported that over 18 million cases of S. pyogenes disease occurred in the world, and more than 500,000 deaths occur annually worldwide. An effective vaccine is widely regarded as the most reliable way to control and prevent streptococcal infections. However, there is currently no approved vaccine for S. pyogenes. In this study, we evaluated the potential of lipoprotein FtsB as a new vaccine candidate to prevent S. pyogenes infection. Mice vaccinated with purified FtsB protein elicited high titers of IgG, IgG1 and IgG2a antibodies in mouse serum. Vaccinated with FtsB can reduce bacterial systemic dissemination in the blood, heart, and spleen and reduce organ damage in the mouse bacteremia model. In addition, active immunization with FtsB protected against streptococcal abscess formation. Furthermore, immunization with FtsB was efficient in inducing a mixed cellular immune response and promoting the maturation of dendritic cells in mice. The lipoprotein HtsA was served as a positive control because it has been reported to protect mice from S. pyogenes infection in both active and passive immunization. These findings demonstrated that lipoprotein FtsB may serve as a candidate vaccine for the prevention of S. pyogenes infection.

Impact of adjuvants on the biophysical and functional characteristics of HIV vaccine-elicited antibodies in humans

Adjuvants can alter the magnitude, characteristics, and persistence of the humoral response to protein vaccination. HIV vaccination might benefit from tailored adjuvant choice as raising a durable and protective response to vaccination has been exceptionally challenging. Analysis of trials of partially effective HIV vaccines have identified features of the immune response that correlate with decreased risk, including high titers of V1V2-binding IgG and IgG3 responses with low titers of V1V2-binding IgA responses and enhanced Fc effector functions, notably antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP). However, there has been limited opportunity to compare the effect of different adjuvants on these activities in humans. Here, samples from the AVEG015 study, a phase 1 trial in which participants (n = 112) were immunized with gp120SF-2 and one of six different adjuvants or combinations thereof were assessed for antibody titer, biophysical features, and diverse effector functions. Three adjuvants, MF59 + MTP-PE, SAF/2, and SAF/2 + MDP, increased the peak magnitude and durability of antigen-specific IgG3, IgA, FcγR-binding responses and ADCP activity, as compared to alum. While multiple adjuvants increased the titer of IgG, IgG3, and IgA responses, none consistently altered the balance of IgG to IgA or IgG3 to IgA. Linear regression analysis identified biophysical features including gp120-specific IgG and FcγR-binding responses that could predict functional activity, and network analysis identified coordinated aspects of the humoral response. These analyses reveal the ability of adjuvants to drive the character and function of the humoral response despite limitations of small sample size and immune variability in this human clinical trial.

A Pseudovirus Nanoparticle-Based Trivalent Rotavirus Vaccine Candidate Elicits High and Cross P Type Immune Response.

Rotavirus infection continues to cause significant morbidity and mortality globally. In this study, we further developed the S60-VP8* pseudovirus nanoparticles (PVNPs) displaying the glycan receptor binding VP8* domains of rotavirus spike proteins as a parenteral vaccine candidate. First, we established a scalable method for the large production of tag-free S60-VP8* PVNPs representing four rotavirus P types, P[8], P[4], P[6], and P[11]. The approach consists of two major steps: selective precipitation of the S-VP8* proteins from bacterial lysates using ammonium sulfate, followed by anion exchange chromatography to further purify the target proteins to a high purity. The purified soluble proteins self-assembled into S60-VP8* PVNPs. Importantly, after intramuscular injections, the trivalent vaccine consisting of three PVNPs covering VP8* antigens of P[8], P[4], and P[6] rotaviruses elicited high and broad immunogenicity in mice toward the three predominant P-type rotaviruses. Specifically, the trivalent vaccine-immunized mouse sera showed (1) high and balanced IgG and IgA antibody titers toward all three VP8* types, (2) high blocking titer against the VP8*-glycan receptor interaction, and (3) high and broad neutralizing titers against replications of all P[8], P[4], and P[6] rotaviruses. Therefore, trivalent S60-VP8* PVNPs are a promising non-replicating, parenteral vaccine candidate against the most prevalent rotaviruses worldwide.

Early and Long-Term HIV-1 Immunogenicity Induced in Macaques by the Combined Administration of DNA, NYVAC and Env Protein-Based Vaccine Candidates: The AUP512 Study.

To control HIV infection there is a need for vaccines to induce broad, potent and long-term B and T cell immune responses. With the objective to accelerate and maintain the induction of substantial levels of HIV-1 Env-specific antibodies and, at the same time, to enhance balanced CD4 and CD8 T cell responses, we evaluated the effect of concurrent administration of MF59-adjuvanted Env protein together with DNA or NYVAC vectors at priming to establish if early administration of Env leads to early induction of antibody responses. The primary goal was to assess the immunogenicity endpoint at week 26. Secondary endpoints were (i) to determine the quality of responses with regard to RV144 correlates of protection and (ii) to explore a potential impact of two late boosts. In this study, five different prime/boost vaccination regimens were tested in rhesus macaques. Animals received priming immunizations with either NYVAC or DNA alone or in combination with Env protein, followed by NYVAC + protein or DNA + protein boosts. All regimens induced broad, polyfunctional and well-balanced CD4 and CD8 T cell responses, with DNA-primed regimens eliciting higher response rates and magnitudes than NYVAC-primed regimens. Very high plasma binding IgG titers including V1/V2 specific antibodies, modest antibody-dependent cellular cytotoxicity (ADCC) and moderate neutralization activity were observed. Of note, early administration of the MF59-adjuvanted Env protein in parallel with DNA priming leads to more rapid elicitation of humoral responses, without negatively affecting the cellular responses, while responses were rapidly boosted after repeated immunizations, indicating the induction of a robust memory response. In conclusion, our findings support the use of the Env protein component during priming in the context of an heterologous immunization regimen with a DNA and/or NYVAC vector as an optimized immunization protocol against HIV infection.

Assessment of neutralizing antibody responses after natural SARS-CoV-2 infection and vaccination in congolese individuals

BackgroundAssessing immune responses after vaccination is part of the evaluation package of vaccine effectiveness in the real world. Regarding SARS-CoV-2, neutralizing antibody levels has been shown to be a good indicator of antibody immune response boosting. So far, limited data have been reported from Africa including in Central Africa. The objective of this study was to provide data on anti-S1 spike total IgG and neutralizing antibodies in vaccinated and non-vaccinated including naturally infected Congolese population during B.1.214.1 and B.1.617.2 variant waves.MethodsRecruited patients were divided into 4 groups: (1) Naturally infected by the B.1.214.1 variant on January 2021 and followed up until September 2021. These patients have been vaccinated at month 07 and then followed up for 2 months post vaccination; (2) Naturally infected by the B.1.617.2 variant from June 2021; (3) unvaccinated SARS-CoV-2 individuals with no history of prior SARS-CoV-2 infection; (4) fully vaccinated individuals with sinopharm/BBIP-CorV or Janssen/Ad26.COV2.S. SARS-CoV-2 was detected by qRT-PCR and sequenced using Next-Generation Sequencing. ELISA method was used for detecting IgG, and neutralizing Antibody against SARS-CoV-2 antigens using commercial neutralizing assay.ResultsIndividuals infected by the B.1214.1 variant elicited consistently high IgG titers at 02, 03 and 06 months. Two months post vaccination with BBIP-CorV, participants showed a significant increase by × 2.5 fold (p < 0.0001) of total IgG and X1.5 fold for neutralizing antibody capacity. This study showed that natural infection with B1.617.2 (delta) variant was more immunogenic compared to those being infected with B1.214.2 variant.We found a significantly higher concentration in anti-SARS-CoV-2 IgG (p < 0.0002) and antibodies neutralization capacity (P < 0.0001) in fully vaccinated compared to unvaccinated participants. Two months post vaccination, individuals who received Janssen/Ad26.COV2.S presented higher (p = 0.01) total IgG to spike protein compared to BBIP-CorV.ConclusionBoth natural infection and vaccination with BBIP-CorV and Janssen/Ad26.COV2.S induced antibody response in Congolese population. In addition, Janssen/Ad26.COV2.S was more immunogenic than Sinopharm/BBIP-CorV. There is a need to investigate the duration of these antibodies both in previously infected and naive vaccinated Congolese to allow public heath stakeholders to make evidence-based decision on vaccine schedule for the Congolese population.

Influence of immunity intensity to opportunistic infections on in vitro fertilization efficiency

BACKGROUND: The number of infertile couples and women seeking in vitro fertilization is on the rise worldwide. At the same time, the probability of pregnancy after one in vitro fertilization attempt is 2540%. Among the various causes of in vitro fertilization failure, the impact of opportunistic infections remains underestimated.&#x0D; AIMS: retrospective assessment of the dependence of the number of successful in vitro fertilization attempts on the intensity of immunity to opportunistic infections.&#x0D; MATERIALS AND METHODS: On the basis of the Clinic of the Kuban State Medical University, from January 2020 to March 2021, 865 women aged 26 to 48 years with infertility, included in the assisted reproductive technology program, were observed. Before the in vitro fertilization procedure, all patients were examined by enzyme immunoassay (ELISA) and polymerase chain reaction for the presence of herpesvirus infections (herpes infection, cytomegalovirus infection) and toxoplasmosis. The study included 79 people with unexplained infertility with a history of one to four in vitro fertilization cycles and positive antibody titers [IgG (+), IgM ()] to herpes simplex virus, cytomegalovirus, and toxoplasmosis. During the study, groups were formed depending on the presence of opportunistic infections and the number of unsuccessful in vitro fertilization attempts.&#x0D; RESULTS: During the study, a dependense was established between the number of in vitro fertilization attempts and the level of the initial (before pregnancy) IgG to toxoplasma. A negative prognosis for the effectiveness of in vitro fertilization is most likely in the presence of high titers of IgG to toxoplasma (370.057.0 U/ml). In the case of herpes infection, there was a tendency to increase the number of necessary in vitro fertilization attempts to 34 in the group with higher herpes simplex virus IgG levels. The baseline IgG cytomegalovirus level was not directly related to the effectiveness of the in vitro fertilization procedure.&#x0D; CONCLUSION: The study demonstrates the importance of determining the intensity of immunity to toxoplasma and herpes infection in preparation for in vitro fertilization, especially if there is a history of unsuccessful in vitro fertilization attempts or spontaneous abortion.

Cross-Reactivity of IgG Antibodies and Virus Neutralization in mRNA-Vaccinated People Against Wild-Type SARS-CoV-2 and the Five Most Common SARS-CoV-2 Variants of Concern.

The rapid development, approval, and production of vaccines against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in less than 1 year after the first reports of a new infectious disease was a real game changer, providing 80%–90% efficacy in preventing severe etiopathologies of the coronavirus disease 2019 (COVID-19). These vaccines induce an immune response against the SARS-CoV-2 spike (S) protein located on the surface of the virus particle. Antibodies (Abs) recognizing the S-protein can inhibit binding of the virus via the S-protein to the angiotensin-converting enzyme-2 (ACE-2) receptor expressed on different human cells, especially when these Abs bind to the interaction site, the so-called receptor-binding domain (RBD). We have expressed the RBDs of wild-type SARS-CoV-2 and five variants of concern (VOCs) to test the immune response in people before vaccination with mRNA vaccines BNT162b2 and mRNA-1273 and after up to three vaccinations using in-house ELISA and inhibition assays. The methods of both assays are provided. Both vaccines initiated similarly high IgG titers after two vaccinations against the wild-type and even two VOC-RBDs (alpha and delta) and strongly inhibited the corresponding RBD-ACE-2 binding. The IgG titers and inhibition of ACE-2 binding were lower for beta and gamma RBDs and much lower for omicron RBD. The third vaccination after 6 months strongly increased both the IgG titers and the neutralizing effect against all variants, especially for omicron, leading to 63% ± 13% neutralization potential. Importantly, neutralization linearly increased with the IgG titers.

Показники клітинної ланки імунітету у серопозитивних та серонегативних котів за токсоплазмозу

The article presents the data of immunogram studies in seropositive and seronegative for Toxoplasma gondii cats and the dependence of the absolute number of immunocompetent cells on their housing conditions. The blood from domestic and stray cats aged 3 to 5 years in which IgG to T. gondii was detected during a serological study was used in the study. During analyzes of the average values of seropositive (SP) cats it was detected that 10 animals (22%) had sufficiently high IgG titers of 3.24±0.835 (P≤0.05) and only 5 cats (11%) can be considered as animals that did not come into contact with the causative agent of toxoplasmosis. Neutrophils, as immunoregulatory cells, are among the first to encounter and become infected with Toxoplasma after the parasite crosses the intestinal epithelium. Determination of phagocytic activity of neutrophils showed that in the SP stray cats this indicator is 2 times lower than in the SP domestic cats and more than 4.0 times in the seronegative (SN) domestic cats. Analysis of the absolute content of lymphocytes and their T-subpopulation in the blood of different cats’ groups showed that in the SP stray cats, these indicators were lower. It is a proven fact that in order to control the adequate immune response in animals, it is extremely important not only the quantitative value of the immunoregulatory cells’ population, but also the ratio between them. The obtained results indicate that among homeless animals the seropositivity for toxoplasmosis is twice that of domestic cats. It was found that the SP domestic cats have a higher rate of T-suppressors and due to this IРI is 2.38±0.175. While the SP homeless cats have a larger T-helper subpopulation of lymphocytes and IРI is 4.13±0.506. In the SP domestic cats, the absolute content of B-lymphocytes was 0.616±0.038 and this indicator is the highest compared to other groups. There are also differences in the blood content of NK cells, namely in the homeless SP animals, it is higher than in the domestic cats. From this it should be noted that stray cats infected with T. gondii are mainly responsible for the widespread and constant pressure of infection in the region.

Chimeric Virus-like Particle-Based COVID-19 Vaccine Confers Strong Protection against SARS-CoV-2 Viremia in K18-hACE2 Mice.

Virus-like particles (VLPs) are highly immunogenic and versatile subunit vaccines composed of multimeric viral proteins that mimic the whole virus but lack genetic material. Due to the lack of infectivity, VLPs are being developed as safe and effective vaccines against various infectious diseases. In this study, we generated a chimeric VLP-based COVID-19 vaccine stably produced by HEK293T cells. The chimeric VLPs contain the influenza virus A matrix (M1) proteins and the SARS-CoV-2 Wuhan strain spike (S) proteins with a deletion of the polybasic furin cleavage motif and a replacement of the transmembrane and cytoplasmic tail with that of the influenza virus hemagglutinin (HA). These resulting chimeric S-M1 VLPs, displaying S and M1, were observed to be enveloped particles that are heterogeneous in shape and size. The intramuscular vaccination of BALB/c mice in a prime-boost regimen elicited high titers of S-specific IgG and neutralizing antibodies. After immunization and a challenge with SARS-CoV-2 in K18-hACE2 mice, the S-M1 VLP vaccination resulted in a drastic reduction in viremia, as well as a decreased viral load in the lungs and improved survival rates compared to the control mice. Balanced Th1 and Th2 responses of activated S-specific T-cells were observed. Moderate degrees of inflammation and viral RNA in the lungs and brains were observed in the vaccinated group; however, brain lesion scores were less than in the PBS control. Overall, we demonstrate the immunogenicity of a chimeric VLP-based COVID-19 vaccine which confers strong protection against SARS-CoV-2 viremia in mice.

Anti-spike IgG antibody kinetics following the second and third doses of BNT162b2 vaccine in nursing home residents.

BackgroundDuration of post‐vaccination protection against COVID‐19 in nursing home (NH) residents is a critical issue. The objective of this study was to estimate the duration of the IgG(S) response to the mRNA BNT162b2 vaccine in NH residents with (COV‐Yes) or without (COV‐No) history of SARS‐CoV‐2 infection.MethodsA 574 COV‐Yes and COV‐No NH residents were included in 2 cohorts: Main (n = 115, median age 87 years) or Confirmatory (n = 459, median age 89 years). IgG(S) quantification was carried out at three different time points following the BNT162b2 vaccine: three (1st) and seven (2nd) months after the 2nd dose, and 1 month after the 3rd dose (3rd quantification) in the Main cohort, and twice (2nd and 3rd) in the Confirmatory cohort. The seroneutralization capacity according to COVID‐19 history was also measured in a subgroup of patients.ResultsNeutralization capacity was strongly correlated with IgG(S) levels (R 2:76%) without any difference between COV‐Yes and COV‐No groups for the same levels of IgG(S). After the 2nd dose, duration of the assumed robust protection (IgG(S) >264 BAU/ml) was two‐fold higher in the COV‐Yes vs. COV‐No group: 12.60 (10.69–14.44) versus 5.76 (3.91–8.64) months, with this advantage mainly due to the higher IgG(S) titers after the 2nd dose and secondary to a slower decay over time. After the 3rd dose, duration of robust protection was estimated at 11.87 (9.88–14.87) (COV‐Yes) and 8.95 (6.85–11.04) (COV‐No) months. These results were similar in both cohorts.Conclusions and RelevanceIn old subjects living in NH, history of SARS‐CoV‐2 infection provides a clear advantage in the magnitude and duration of high IgG(S) titers following the 2nd dose. Importantly, the 3rd dose induces a much more pronounced IgG(S) response than the 2nd dose in COV‐No subjects, the effect of which should be able to ensure a prolonged protection against severe forms of COVID‐19 in these subjects.

A neutralizing antibody target in early HIV-1 infection was recapitulated in rhesus macaques immunized with the transmitted/founder envelope sequence.

Transmitted/founder (T/F) HIV-1 envelope proteins (Envs) from infected individuals that developed neutralization breadth are likely to possess inherent features desirable for vaccine immunogen design. To explore this premise, we conducted an immunization study in rhesus macaques (RM) using T/F Env sequences from two human subjects, one of whom developed potent and broad neutralizing antibodies (Z1800M) while the other developed little to no neutralizing antibody responses (R66M) during HIV-1 infection. Using a DNA/MVA/protein immunization protocol, 10 RM were immunized with each T/F Env. Within each T/F Env group, the protein boosts were administered as either monomeric gp120 or stabilized trimeric gp140 protein. All vaccination regimens elicited high titers of antigen-specific IgG, and two animals that received monomeric Z1800M Env gp120 developed autologous neutralizing activity. Using early Env escape variants isolated from subject Z1800M as guides, the serum neutralizing activity of the two immunized RM was found to be dependent on the gp120 V5 region. Interestingly, the exact same residues of V5 were also targeted by a neutralizing monoclonal antibody (nmAb) isolated from the subject Z1800M early in infection. Glycan profiling and computational modeling of the Z1800M Env gp120 immunogen provided further evidence that the V5 loop is exposed in this T/F Env and was a dominant feature that drove neutralizing antibody targeting during infection and immunization. An expanded B cell clonotype was isolated from one of the neutralization-positive RM and nmAbs corresponding to this group demonstrated V5-dependent neutralization similar to both the RM serum and the human Z1800M nmAb. The results demonstrate that neutralizing antibody responses elicited by the Z1800M T/F Env in RM converged with those in the HIV-1 infected human subject, illustrating the potential of using immunogens based on this or other T/F Envs with well-defined immunogenicity as a starting point to drive breadth.

Investigating the role of interleukin-4 in anti-opioid vaccine efficacy

Abstract Vaccination against opioids is a novel therapeutic strategy to combat opioid use disorder (OUD) which can be used alone or in combination with currently available pharmacotherapies. Vaccination with opioid-carrier conjugates stimulates the production of opioid-specific antibodies that sequester the target drug in the serum and prevent distribution into the brain, attenuating the opioid’s pharmacological effects including analgesia, respiratory depression, and it’s reinforcing effects. An anti-oxycodone vaccine has shown promising preclinical efficacy, selectivity, and safety, and is now being tested in a Phase I clinical trial. Clinical trials for conjugate vaccines against cocaine and nicotine have shown that clinical efficacy is met in vaccinated subjects displaying high concentration of high affinity IgG titers. To increase anti-opioid vaccine clinical efficacy, we sought to elucidate their underlying immunobiology and identify predictive biomarkers of vaccine efficacy. Previously, our lab has found that the depletion of the cytokine interleukin-4 (IL-4) during anti-oxycodone immunization increases antibody titers, enhances class-switching from IgG1 to IgG2a, and leads to improved vaccine efficacy after oxycodone challenge in mice. Here, we investigated the association between increased IgG2a and improved vaccine efficacy by directly testing the role of this subclass during immune response after vaccination and during drug challenge. Furthermore, pre-immunization levels of IL-4 are explored as a predictive biomarker of vaccine efficacy in mice. Results from these studies will inform next generation vaccine design and biomarker identification in human clinical trial participants. Supported by grants from NIH (R01DA041730, T32DA007097, F31DA054760, HHSN272201800048C, U01DA051658)

Heterologous Production of Human Papillomavirus L1 Capsid Protein: Systematic Review and Meta-analysis

The coverage of HPV vaccination in Indonesia remains low due to the high-cost vaccination. The vaccine prices were affected by the production rate of L1, the active substance of HPV vaccines. L1 has been produced using various organisms with varying L1 production rates and immunogenicity. A systematic review and meta-analysis were conducted to determine the organism producing L1 with the highest production, treatments affecting the L1 expression rate, and immunogenicity (represented by anti-L1 IgG titer in mice). The data of L1 titer, induction period, and IgG titer were extracted from 19 articles that have passed the articles screening. The L1 titer and induction period data were used to calculate the L1 production rate, while the IgG titer was used in the immunogenicity analysis. On a 95% confidence level, the meta-analysis revealed weak evidence that E. coli produced L1 at the highest rate. The highest IgG titer was induced using L1 expressed in Saccharomyces cerevisiae, albeit insufficient evidence on 95% confidence level. Pearson’s correlation analysis showed that the concentration of glucose, IPTG, NH4+, K+, Ca2+, Mn2+, Fe2+, Zn2+, B4O72−, H2PO4−, HPO42−, Mo7O246−, and citric acid had a positive correlation with L1 production rate in E. coli. The treatment injection doses positively correlated with IgG titer in S. cerevisiae. This study reveals the mineral salts as the potential treatments to increase L1 production rates.

Convalescent plasma in COVID-19: renewed focus on the timing and effectiveness of an old therapy.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the coronavirus disease 2019 (COVID-19) pandemic that has strained health care systems worldwide and resulted in high mortality. The current COVID-19 treatment is based on supportive and symptomatic care. Therefore, convalescent plasma (CP), which provides passive immunization against many infectious diseases, has been studied for COVID-19 management. To date, a large number of randomized and non-randomized clinical trials as well as many systematic reviews have revealed conflicting results. This article summarizes the basic principles of passive immunization, particularly addressing CP in COVID-19. It also evaluates the effectiveness of CP as a therapy in patients with COVID-19, clinical trial reports and systematic reviews, regulatory considerations and different protocols that are authorized in different countries to use it safely and effectively. An advanced search was carried out in major databases (PubMed, Cochrane Library, and MEDLINE) and Google Scholar using the following key words: SARS-CoV-2, COVID-19, convalescent plasma, and the applied query was “convalescent plasma” AND “COVID-19 OR SARS-CoV-2”. The results were filtered and duplicate data were removed. Collective evidence indicates that two cardinal players determine the effectiveness of CP use, time of infusion, and quality of CP. Early administration of CP with high neutralizing anti-spike IgG titer is hypothesized to be effective in improving clinical outcome, prevent progression, decrease the length of hospital stay, and reduce mortality. However, more reliable, high quality, well-controlled, double-blinded, randomized, international and multicenter collaborative trials are still needed.

Chimeric virus-like particles presenting tumour-associated MUC1 epitope result in high titers of specific IgG antibodies in the presence of squalene oil-in-water adjuvant: towards safe cancer immunotherapy

BackgroundImmunotherapy is emerging as a powerful treatment approach for several types of cancers. Modulating the immune system to specifically target cancer cells while sparing healthy cells, is a very promising approach for safer therapies and increased survival of cancer patients. Tumour-associated antigens are favorable targets for cancer immunotherapy, as they are exclusively expressed by the cancer cells, minimizing the risk of an autoimmune reaction. The ability to initiate the activation of the immune system can be achieved by virus-like particles (VLPs) which are safe and potent delivery tools. VLP‐based vaccines have evolved dramatically over the last few decades and showed great potential in preventing infectious diseases. Immunogenic potency of engineered VLPs as a platform for the development of effective therapeutic cancer vaccines has been studied extensively. This study involves recombinant VLPs presenting multiple copies of tumour-specific mucin 1 (MUC1) epitope as a potentially powerful tool for future immunotherapy.ResultsIn this report VLPs based on the structural protein of Norovirus (NoV VP1) were genetically modified to present multiple copies of tumour-specific MUC1 epitope on their surface. Chimeric MUC1 particles were produced in the eukaryotic Leishmania tarentolae expression system and used in combination with squalene oil-in-water emulsion MF59 adjuvant to immunize BALB/c mice. Sera from vaccinated mice demonstrated high titers of IgG and IgM antibodies which were specifically recognizing MUC1 antigen.ConclusionsThe obtained results show that immunization with recombinant chimeric NoV VP1- MUC1 VLPs result in high titers of MUC1 specific IgG antibodies and show great therapeutic potential as a platform to present tumour-associated antigens.Graphical

In silico designed Staphylococcus aureus B-cell multi-epitope vaccine did not elicit antibodies against target antigens suggesting multi-domain approach

The vaccine development strategies have evolved from using an entire organism as an immunogen to a single antigen and further towards an epitope. Since an epitope is a relatively tiny and immunologically relevant part of an antigen, it has the potential to stimulate more robust and specific immune responses while causing minimal adverse effects. As a result, the recent focus of vaccine development has been to develop multi-epitope vaccines that can target multiple virulence mechanisms. Accordingly, we designed multi-epitope vaccine candidates B (multi-B-cell epitope immunogen) and CTB-B (an adjuvant – cholera toxin subunit B (CTB) – attached to immunogen B) against S. aureus by employing immunoinformatics approaches. The designed vaccines are composed of B-cell epitope segments (20-mer) of the eight well-characterized S. aureus virulence factors, namely ClfB, FnbpA, Hla, IsdA, IsdB, LukE, SdrD, and SdrE connected in series. The designed vaccines were expressed, purified, and administered to C57BL/6 mice with Freund adjuvant to evaluate the immunogenicity and protective efficacy. The results revealed that the immunized mice showed high IgG titers for the immunogen, and the antibody titers increased significantly following the second immunization. However, the generated antibodies did not protect the mice from infection. The interaction of anti-B antibodies with source virulence factors showed that the generated antibodies have no binding affinity with any of the corresponding virulence factors. Our results demonstrate the limitation of the in silico designed B-cell multi-epitope vaccine and suggest that a protein domain carrying both linear and conformational B-cell epitopes might be a better choice for developing an effective multi-epitope vaccine against S. aureus.