High Levels Of IgG Antibodies Research Articles

The immunogenicity of plant-based COE-GCN4pII protein in pigs against the highly virulent porcine epidemic diarrhea virus strain from genotype 2.

Porcine epidemic diarrhea virus (PEDV) is a serious infectious causative agent in swine, especially in neonatal piglets. PEDV genotype 2 (G2) strains, particularly G2a, were the primary causes of porcine epidemic diarrhea (PED) outbreaks in Vietnam. Here, we produced a plant-based CO-26K-equivalent epitope (COE) variant from a Vietnamese highly virulent PEDV strain belonging to genotype 2a (COE/G2a) and evaluated the protective efficacy of COE/G2a-GCN4pII protein (COE/G2a-pII) in piglets against the highly virulent PEDV G2a strain following passive immunity. The 5-day-old piglets had high levels of PEDV-specific IgG antibodies, COE-IgA specific antibodies, neutralizing antibodies, and IFN-γ responses. After virulent challenge experiments, all of these piglets survived and had normal clinical symptoms, no watery diarrhea in feces, and an increase in their body weight, while all of the negative control piglets died. These results suggest that the COE/G2a-pII protein produced in plants can be developed as a promising vaccine candidate to protect piglets against PEDV G2a infection in Vietnam.

Synthesis and immunological study of a glycosylated wall teichoic acid-based vaccine against Staphylococcus aureus

Staphylococcus aureus wall teichoic acids (WTAs) are attractive targets for antibacterial vaccine development. In this study, three core glycosylated WTA structure, including α-1,4-GlcNAc, β-1,4-GlcNAc and β-1,3-GlcNAc modified ribitol phosphates containing a linker are chemically synthesized and conjugated with tetanus toxin (TT) carrier protein as vaccine candidates. In vivo immunological studies demonstrate that the synthesized glycosylated WTAs display high immunogenicity and all conjugates provoke strong immune responses and elicit high levels of specific IgG antibodies against the GlcNAc-modified WTA. Furthermore, antibodies elicited by the vaccine candidates remain the capability to recognize S. aureus cells and display significant opsonophagocytic activity to clear S. aureus. This study demonstrates that the core structure of glycosylated WTAs are effective antigens for constructing anti-S. aureus vaccines to prevent and control S. aureus infections.

B cell memory responses induced by foot-and-mouth disease virus-like particles in BALB/c mice

A challenging but critical question is that new foot-and-mouth disease (FMD) vaccines should be to induce B cell memory to provide antibodies for long-term protection. The maintenance of B cell memory is dependent on long-lived plasma cells (LLPCs) and memory B cells. We developed a chimeric FMDV virus-like particles (FMDV-VLPs), fusing VP1-VP4 into HBcAg. In our study, we investigated if or how long B cell memory was induced by FMDV-VLPs in mice. The data showed that FMDV-VLPs can induce memory humoral responses with a high level of total IgG1, IgG2a, IgA, and FMDV-specific IgG antibodies in serum. The persistence of antibody levels in serum could depend on LLPCs. The proportion of LLPCs in CD19+ cells in bone marrow exhibited a dynamic trend with two peaks at 28 days post-immunization (dpi) and 72 dpi, respectively. Additionally, the proportion of memory B cells in CD19+ cells in the spleen increased significantly both at 7 days post primary immunization and at 7 days post -boost immunization. Of note, LLPCs together with memory B cells contribute to the production of FMDV-specific IgG and IgG1. The changes of LLPCs and memory B cells may be related to TNF-α, IL-6 and, CXCL12. Taken together, FMDV-VLPs could induce B cells memory responses. A further understanding of the mechanisms that FMDV-VLPs how we can manipulate the induction and maintenance of memory B cells and LLPCs will promote vaccine design and likely address several challenges to develop FMDV new vaccines in the future.

Abstract LB179: Patient-derived, vaccine-elicited, anti-MUC1 antibodies directly target tumor cells for elimination via multiple immune mechanisms

Abstract During premalignant and malignant transformation, cells undergo antigenic changes that can be recognized by the immune system, and this can be leveraged both for immune prevention and therapy. One such change occurs with MUC1, or Mucin-1, a large variable number tandem repeat (VNTR)-containing transmembrane protein that is overexpressed and hypoglycosylated on a majority of precancerous and adenocarcinoma cells, including those of the colon, lung, breast, pancreas and ovaries. This tumor form of MUC1 is recognized by both cellular and humoral immunity. Healthy individuals at high risk of developing colon cancer due to a history of colonic polyps were enrolled in a clinical trial testing the feasibility of prophylactic vaccination against the tumor form of MUC1, also expressed on polyps (Kimura et al., 2013). Half the participants generated high levels of anti-MUC1 IgG antibodies, some of which were cloned to further analyze their tumor specificity and to potentially develop them as therapeutics for patients with cancer (Lohmueller et al., 2016). As these fully human IgG1 monoclonal antibodies (mAbs) were selected and affinity matured in healthy individuals who experienced no negative side effects to the vaccine in >10 years, it increases the likelihood that as therapeutics they will be safe. To study anti-tumor efficacy and mechanism(s) of action of 12 of these mAbs, tumor cells were co-incubated with immune cells in the presence of the mAbs, and each mAb’s ability to mediate antibody-dependent cellular cytotoxicity (ADCC) by NK cells, antibody-dependent cellular phagocytosis (ADCP) by monocytes, antibody-dependent trogocytosis/trogoptosis (ADCT) by neutrophils, antibody-dependent cytokine release (ADCR) and complement dependent cytotoxicity (CDC) was assessed. Several MUC1 mAbs examined could mediate ADCC, ADCP, ADCT and ADCR, with some mechanisms being cell-line dependent. One mAb was selected for in vivo testing and found to delay breast cancer growth and prolong survival in immunocompromised mice lacking T cells, B cells and NK cells, pointing to ADCP and ADCT as important anti-tumor functions. Additionally, the relationship between epitope location and immune effector functions was explored by creating different MUC1 constructs that vary epitope distance from the cell surface, number of epitopes, etc, to test properties of the target antigen that may affect antibody efficacy. These latter experiments revealed an increased efficiency in phagocytosis and trogocytosis when the mAbs bound an epitope that was both proximal to and anchored to the membrane. Notably, unlike published studies of rituximab and alemtuzumab, the amount of MUC1 mAb binding did not always correlate with increased effector function. Our results may inform not only the development of these MUC1-based therapies but more broadly future therapeutic mAb design against a variety of targets. Citation Format: Michelle L. McKeague, Jason Lohmueller, Matthew T. Dracz, Najla Saadallah, Jia Xue, Eric D. Ricci, William Lu, Olivera J. Finn. Patient-derived, vaccine-elicited, anti-MUC1 antibodies directly target tumor cells for elimination via multiple immune mechanisms [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB179.

Seroprevalence of immunoglobulin G antibodies against SARS-CoV-2 in Cyprus.

Monitoring the levels of IgG antibodies against the SARS-CoV-2 is important during the coronavirus disease 2019 (COVID-19) pandemic, to plan an adequate and evidence-based public health response. After this study we report that the plasma levels of IgG antibodies against SARS-CoV-2 spike protein were higher in individuals with evidence of prior infection who received at least one dose of either an mRNA-based vaccine (Comirnaty BNT162b2/Pfizer-BioNTech or Spikevax mRNA-1273/Moderna) or an adenoviral-based vaccine (Vaxzervia ChAdOx1 nCoV-19 /Oxford-Astra Zeneca) (n = 39) compared to i) unvaccinated individuals with evidence of prior infection with SARS-CoV-2 (n = 109) and ii) individuals without evidence of prior infection with SARS-CoV-2 who received one or two doses of one of the aforementioned vaccines (n = 342). Our analysis also revealed that regardless of the vaccine technology (mRNA-based and adenoviral vector-based) two doses achieved high anti- SARS-CoV-2 IgG responses. Our results indicate that vaccine-induced responses lead to higher levels of IgG antibodies compared to those produced following infection with the virus. Additionally, in agreement with previous studies, our results suggest that among individuals previously infected with SARS-CoV-2, even a single dose of a vaccine is adequate to elicit high levels of antibody response.

Effects of Antibody Responses to Pre-Existing Coronaviruses on Disease Severity and Complement Activation in COVID-19 Patients

The severity of coronavirus disease 2019 (COVID-19) may be influenced by pre-existing immune responses against endemic coronaviruses, but conflicting data have been reported. We studied 148 patients who were hospitalised because of a confirmed diagnosis of COVID-19, classified mild in 58, moderate in 44, and severe in 46. The controls were 27 healthy subjects. At admission, blood samples were collected for the measurement of biomarkers of disease severity and levels of the IgG against the receptor-binding domain (RBD) of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and pre-existing coronaviruses OC43, HKU1, NL63 and 229E. Higher levels of IgG antibodies against the RBD of pre-existing coronavirus (with the highest significance for anti-HKU1 IgG, p = 0.01) were found in patients with mild disease, compared with those with moderate or severe disease. Multivariable logistic regression confirmed the association of high levels of antibodies to pre-existing coronavirus with mild disease and showed their associations with low levels of the complement activation marker SC5b-9 (p range = 0.007–0.05). High levels of anti-NL63 antibodies were associated with low levels of the coagulation activation marker D-dimer (p = 0.04), while high levels of IgG against 229E were associated with low levels of the endothelial activation marker von Willebrand factor (p = 0.05). Anti-SARS-CoV-2-neutralising activity of plasma positively correlated with anti-SARS-CoV-2 IgG (r = 0.53, p = 0.04) and with anti-HKU1 IgG (r = 0.51, p = 0.05). In hospitalised patients with COVID-19, high levels of antibodies to pre-existing coronaviruses are associated with mild disease, suggesting that their measurement could be useful in predicting the severity of the disease.

Evaluation of prime and prime-boost immunization strategies in BALB/c mice inoculated with Leishmania infantum transfected with toxic plasmids

The etiologic agents of visceral leishmaniasis are Leishmania infantum and Leishmania donovani. Despite the variety of drugs available to treat leishmaniasis, most lead to serious adverse effects, and resistance to these drugs has been reported. Currently, no leishmaniasis vaccine is available for humans. That is why the group developed transgenic L. infantum promastigote lines, which express toxic proteins after differentiation into amastigotes. That is why group developed the pFL-AMA plasmid and transfected it into L. Infantum promastigotes. This plasmid was expressed only in the amastigote form of the parasite. Sequences encoding toxic proteins (active bovine trypsin and egg avidin) were inserted in this plasmid, and the transfected parasites died after the differentiation process. In this study, two immunization protocols were performed in BALB/c mice: prime and prime-boost immunization prior to challenge with the wild-type L. infantum (WT). The parasite burdens in the spleen, liver, and bone marrow were evaluated to verify immunological protection. Histopathological analysis of the spleen and liver and the humoral immune response were also performed. The data showed that the parasite burden was reduced in prime-boosted mice in the spleen, liver, and bone marrow, indicating that mice immunized with two doses of the transfected parasites were satisfactorily protected. High levels of IgG, IgG1, and IgG2a antibodies were observed, as well as the presence of anti-inflammatory cytokine Interleukine-10 and pro-inflammatory cytokine Tumor Necrosis Factor-α (TNF-α) and Interferon-γ (IFN – γ) suggesting a Th1/Th2 mix response, in addition to the presence of multinucleated giant cells in the spleen and lymphocyte infiltration in the liver. Therefore, L. infantum transfected with a toxic plasmid is an excellent vaccine candidate against visceral leishmaniasis and the application of a boost before the challenge promotes greater protection against WT L. infantum infection.

MULTIPLE TROMBOSIS IN CHILD WITH POST COVID-19 INFECTION

Introduction: SARS CoV-2 infection can cause acute, as well as chronic damage to the cardiovascular system. Blood vessel dysfunction and clot formation, as suggested by elevated D-dimer levels, are thought to play a significant role in morbidity, as well as in mortality in Covid-19 patients, leading to clots causing pulmonary embolisms and ischemic events within the brain1. Aim: To confirm the correlation between SARS CoV-2 infection and possibility for vascular complication, including thrombotic brain lesion. Materials: Detailed patient’s history, physical examination particularly noting the neurological status and locomotor skills, as well as blood analysis with hemostasis and d-dimers, serology for SARS CoV-2 IgG antibodies and PCR swab were all part of the diagnostic process for this patient. Methods: Computed tomography and brain MRI with angiography were main imaging tools used in the diagnostic process. Results: Thrombosis of the left middle cerebral artery was confirmed on brain MRI with angiography in a patient recovered from SARS CoV-2 infection, noted with high levels of IgG antibodies to the particular virus and elevated D-dimer levels, presenting with symptomatic right sided hemiparesis. Conclusion: Some of the patients recovered from SARS CoV 2 infection can develop ischemic stroke. This link is confirmed by elevated levels of IgG antibodies in patient’s serum against SARS CoV-2. This kind of vascular post viral complication can cause different kind of disability, presented with neurological impairment and coagulation disorders. The prognose is improving with anticoagulant and physical therapy started early.2 Keywords: Thrombosis, SARS Cov-2, Brain, Hemiparesis

Intranasal administration of a recombinant RBD vaccine induces long-term immunity against Omicron-included SARS-CoV-2 variants

The outbreak of coronavirus disease 2019 (COVID-19) has posed great threats to global health and economy. Several effective vaccines are available now, but additional booster immunization is required to retain or increase the immune responses owing to waning immunity and the emergency of new variant strains. The deficiency of intramuscularly delivered vaccines to induce mucosal immunity urged the development of mucosal vaccines. Here, we developed an adjuvanted intranasal RBD vaccine and monitored its long-term immunogenicity against both wild-type and mutant strains of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), including Omicron variants, in mice. Three-dose intranasal immunization with this vaccine induced and maintained high levels of neutralizing IgG antibodies in the sera for at least 1 year. Strong mucosal immunity was also provoked, including mucosal secretory IgA and lung-resident memory T cells (TRM). We also demonstrated that the long-term persistence of lung TRM cells is a consequence of local T-cell proliferation, rather than T-cell migration from lymph nodes. Our data suggested that the adjuvanted intranasal RBD vaccine is a promising vaccine candidate to establish robust, long-lasting, and broad protective immunity against SARS-CoV-2 both systemically and locally.

Nucleocapsid protein of SARS-CoV-2 is a potential target for developing new generation of vaccine.

BackgroundSARS‐CoV‐2 has spread worldwide causing more than 400 million people with virus infections since early 2020. Currently, the existing vaccines targeting the spike glycoprotein (S protein) of SARS‐CoV‐2 are facing great challenge from the infection of SARS‐CoV‐2 virus and its multiple S protein variants. Thus, we need to develop a new generation of vaccines to prevent infection of the SARS‐CoV‐2 variants. Compared with the S protein, the nucleocapsid protein (N protein) of SARS‐CoV‐2 is more conservative and less mutations, which also plays a vital role in viral infection. Therefore, the N protein may have the great potential for developing new vaccines.MethodsThe N protein of SARS‐CoV‐2 was recombinantly expressed and purified in Escherichia coli. Western Blot and ELISA assays were used to demonstrate the immunoreactivity of the recombinant N protein with the serum of 22 COVID‐19 patients. We investigated further the response of the specific serum antibodies and cytokine production in BALB/c mice immunized with recombinant N protein by Western Blot and ELISA.ResultsThe N protein had good immunoreactivity and the production of IgG antibody against N protein in COVID‐19 patients was tightly correlated with disease severity. Furthermore, the N protein was used to immunize BALB/c mice to have elicited strong immune responses. Not only high levels of IgG antibody, but also cytokine‐IFN‐γ were produced in the N protein‐immunized mice. Importantly, the N protein immunization induced a high level of IgM antibody produced in the mice.ConclusionSARS‐CoV‐2 N protein shows a great big bundle of potentiality for developing a new generation of vaccines in fighting infection of SARS‐CoV‐2 and its variants.

A Sporothrix spp. enolase derived multi-epitope vaccine confers protective response in BALB/c mice challenged with Sporothrix brasiliensis

Sporotrichosis is a cosmopolitan mycosis caused by pathogenic species of Sporothrix genus, that in Brazil is often acquired by zoonotic transmission involved infected cats with S. brasiliensis. Previous studies showed that the Sporothrix spp. recombinant enolase (rSsEno), a multifunctional protein with immunogenic properties, could be a promising target for vaccination against sporotrichosis in cats. Nevertheless, the considerable sequence identity (62%) of SsEno with its feline counterpart is a great concern. Here, we report the identification in silico, chemical synthesis and biological validation of six peptides of SsEno with low sequence identity to its cat orthologue. All synthesized peptides exhibit B-cell epitopes on the molecular surface of SsEno and proved to be highly reactive with the serum of infected mice with S. brasiliensis and sera of cats with sporotrichosis. Interestingly, our study revealed that anti-peptide sera did not react with the recombinant enolase from Felis catus (cats, rFcEno), thus, may not trigger autoimmune response in these felines if used as a vaccine antigen. The immunization with peptide mixture (PeptMix) formulated with Freund adjuvant (FA), induced high levels of antigen-specific IgG, IgG1 and IgG2b antibodies that conferred protection upon passive transference in infected BALB/c mice with S. brasiliensis. We also observed, that the FA+PeptMix formulation induced a Th1/Th2/Th17 cytokine profile ex vivo, associated with protecting effect against the experimental sporotrichosis. Our results suggest that the six SsEno-derived peptides here evaluated, could be used as safe antigens for the development of vaccine strategies against feline sporotrichosis, whether prophylactic or therapeutic.

Structure Guided Design of Bacteriophage Qβ Mutants as Next Generation Carriers for Conjugate Vaccines.

Vaccines are critical tools to treat and prevent diseases. For an effective conjugate vaccine, the carrier is crucial, but few carriers are available for clinical applications. In addition, a drawback of current protein carriers is that high levels of antibodies against the carrier are induced by the conjugate vaccine, which are known to interfere with the immune responses against the target antigen. To overcome these challenges, we obtained the near atomic resolution crystal structure of an emerging protein carrier, i.e., the bacteriophage Qβ virus like particle. On the basis of the detailed structural information, novel mutants of bacteriophage Qβ (mQβ) have been designed, which upon conjugation with tumor associated carbohydrate antigens (TACAs), a class of important tumor antigens, elicited powerful anti-TACA IgG responses and yet produced lower levels of anticarrier antibodies as compared to those from the wild type Qβ-TACA conjugates. In a therapeutic model against an aggressive breast cancer in mice, 100% unimmunized mice succumbed to tumors in just 12 days even with chemotherapy. In contrast, 80% of mice immunized with the mQβ-TACA conjugate were completely free from tumors. Besides TACAs, to aid in the development of vaccines to protect against COVID-19, the mQβ based conjugate vaccine has been shown to induce high levels of IgG antibodies against peptide antigens from the SARS-CoV-2 virus, demonstrating its generality. Thus, mQβ is a promising next-generation carrier platform for conjugate vaccines, and structure-based rational design is a powerful strategy to develop new vaccine carriers.

Selection of new diagnostic markers for Dirofilaria repens infections with the use of phage display technology

Dirofilaria repens is a parasitic nematode causing vector-borne disease (dirofilariasis), considered an emerging problem in veterinary and human medicine. Although main hosts are carnivores, particularly dogs, D. repens shows high zoonotic potential. The disease spreads uncontrollably, affecting new areas. Since there is no vaccine against dirofilariasis, the only way to limit disease transmission is an early diagnosis. Currently, diagnosis depends on the detection of microfilariae in the host bloodstream using modified Knott's test or multiplex PCR. However, the efficacy of tests relying on microfilariae detection is limited by microfilariae periodic occurrence. Therefore, a new reliable diagnostic test is required. Our study aimed to select new diagnostic markers for dirofilariasis with potential application in diagnostics. We focused on single epitopes to ensure high specificity of diagnosis and avoid cross-reactivity with the other parasite infections common in dogs. Using phage display technology and 12-mer peptides library, we selected epitopes highly reactive with IgG from sera of infected dogs. Additionally, our study presents the possibility of detecting D. repens specific cell-free DNA in dogs with no microfilaria but high IgG and IgM antibody levels against parasite somatic antigen.

Immunogenicity and protective efficacy of an inactivated SFTS vaccine candidate in mice

Severe fever with thrombocytopenia syndrome (SFTS), caused by a novel identified bunyavirus SFTS virus (SFTSV), was an emerging viral infectious disease that was firstly reported in China. There are no licensed vaccines and therapeutics against SFTSV currently. B-Propiolactone (BPL) inactivated whole virions of SFTSV strain AH12 were prepared as experimental vaccine in different antigen dose with or without Al(OH)3 adjuvant. The experimental SFTS vaccine was a satisfying immunogen, which could efficiently trigger the development of high levels of SFTSV NP-specific IgG antibodies and neutralizing antibodies against SFTSV Strain HB29 in BALB/c and C57/BL6 mice, and could induce SFTS virus-specific cellular immune responses to a certain extent. A single dose of vaccine was immunogenically insufficient in BALB/c mice; the second and third dose resulted in significant boost in antibody response. The use of Al(OH)3 adjuvant resulted in higher antibody titers. The mediate-dose of vaccine could induce as high and equivalent level of antibody titer as that of high-dose. The experimental SFTS vaccine in mediate- and high antigen dose with adjuvant resulted in solid protection of C57/BL6 mice against wild-type SFTSV challenge with markedly accelerated virus clearance from blood and spleen compared with controls. The experimental SFTS vaccine prepared in this study could efficiently elicit virus specific humoral and cellular immune responses in both BALB/c and C57/BL6 mice, and could protect C57/BL6 mice against SFTS virus challenge. These results supplied evidence that inactivated vaccine was a promising vaccine candidate for the prevention of SFTSV infection.

Immunogenicity and protection against Glaesserella parasuis serotype 13 infection after vaccination with recombinant protein LolA in mice.

Glaesserella parasuis is a pathogen causing Glässer's disease characterized by fibrinous polyserositis, polyarthritis, and meningitis. Owing to the low cross-immunogenicity of different bacterial antigens in commercial vaccines, finding and identifying effective immunoprotective antigens will facilitate the development of novel subunit vaccines. In this study, LolA, identified by bioinformatics approaches, was cloned and successfully expressed as a recombinant protein in Escherichia coli, and its immunogenicity and protection were evaluated in a mouse model. The results showed that the recombinant protein LolA can stimulate mice to produce high levels of IgG antibodies and confer 50% protection against challenge with the highly virulent G. parasuis CY1201 strain (serotype 13). By testing the cytokine levels of interleukin 4 (IL-4), IL-10, and interferon-γ (IFN-γ), it was found that the recombinant protein LolA can induce both Th1 and Th2 immune responses in mice. These results suggest that the recombinant protein LolA has the potential to serve as an alternative antigen for a novel vaccine to prevent G. parasuis infection.

β-1,2-Mannan-based glycoconjugates as potential antifungal vaccines

Phosphorylated di-, tri- and tetra-saccharides of β-1,2-mannan antigen derived from Candida albicans (C. albicans) cell wall were synthesized and covalently conjugated with keyhole limpet hemocyanin (KLH) and human serum albumin (HSA) via a bifunctional linker under mild conditions. The semi-synthetic β-1,2-mannoside–KLH conjugates were evaluated for the immunization of BALB/c mice. The ELISA results revealed that all three conjugates could elicit high levels of specific IgG antibodies and the acquired antisera could effectively identify the β-1,2-mannan epitope. Furthermore, the immunofluorescence and flow cytometry assays also uncovered that the induced antibodies, especially that obtained from immunization with β-1,2-mannotriose–KLH conjugate (1b), could bind well to fungi cell. Eventually, the structure–immunogenicity relationship analysis of β-mannan showed that the length of oligo-β-mannoses had a big impact on their immunogenicity and β-1,2-mannotriose showed the strongest immunogenicity. The results suggested the great potential of β-1,2-mannotriose–KLH conjugate as an antifungal vaccine candidate.

Immune Responses in Pregnant Sows Induced by Recombinant Lactobacillus johnsonii Expressing the COE Protein of Porcine Epidemic Diarrhea Virus Provide Protection for Piglets against PEDV Infection.

Porcine epidemic diarrhea (PED) induced by porcine epidemic diarrhea virus (PEDV) is an intestinal infectious disease in pigs that causes serious economic losses to the pig industry. To develop an effective oral vaccine against PEDV infection, we used a swine-origin Lactobacillus johnsonii (L. johnsonii) as an antigen delivery carrier. A recombinant strain pPG-T7g10-COE/L. johnsonii (L. johnsonii-COE) expressing COE protein (a neutralizing epitope of the viral spike protein) was generated. The immunomodulatory effect on dendritic cell in vitro and immunogenicity in pregnant sows was evaluated following oral administration. L. johnsonii-COE could activate monocyte-derived dendritic cell (MoDC) maturation and triggered cell immune responses. After oral vaccination with L. johnsonii-COE, levels of anti-PEDV-specific serum IgG, IgA, and IgM antibodies as well as mucosal secretory immunoglobulin A (SIgA) antibody were induced in pregnant sows. High levels of PEDV-specific SIgA and IgG antibodies were detected in the maternal milk, which provide effective protection for the piglets against PEDV infection. In summary, oral L. johnsonii-COE was able to efficiently activate anti-PEDV humoral and cellular immune responses, demonstrating potential as a vaccine for use in sows to provide protection of their piglets against PEDV.

Seven-year kinetics of RTS, S/AS01-induced anti-CSP antibodies in young Kenyan children

BackgroundRTS,S/AS01, the leading malaria vaccine has been recommended by the WHO for widespread immunization of children at risk. RTS,S/AS01-induced anti-CSP IgG antibodies are associated with the vaccine efficacy. Here, the long-term kinetics of RTS,S/AS01-induced antibodies was investigated.Methods150 participants were randomly selected from the 447 children who participated in the RTS,S/AS01 phase IIb clinical trial in 2007 from Kilifi-Kenya. Cumulatively, the retrospective follow-up period was 93 months with annual plasma samples collection. The levels of anti-CSP IgM, total IgG, IgG1, IgG2, IgG3, and IgG4 antibodies were then determined using an enzyme-linked immunosorbent assay.ResultsRTS,S/AS01 induced high levels of anti-CSP IgG antibodies which exhibited a rapid waning over 6.5 months post-vaccination, followed by a slower decay over the subsequent years. RTS,S/AS01-induced anti-CSP IgG antibodies remained elevated above the control group levels throughout the 7 years follow-up period. The anti-CSP IgG antibodies were mostly IgG1, IgG3, IgG2, and to a lesser extent IgG4. IgG2 predominated in later timepoints. RTS,S/AS01 also induced high levels of anti-CSP IgM antibodies which increased above the control group levels by month 3. The controls exhibited increasing levels of the anti-CSP IgM antibodies which caught up with the RTS,S/AS01 vaccinees levels by month 21. In contrast, there were no measurable anti-CSP IgG antibodies among the controls.ConclusionRTS,S/AS01-induced anti-CSP IgG antibodies kinetics are consistent with long-lived but waning vaccine efficacy. Natural exposure induces anti-CSP IgM antibodies in children, which increases with age, but does not induce substantial levels of anti-CSP IgG antibodies.

Avascular Necrosis Bone Complication after Active COVID-19 Infection: Preliminary Results.

Background and objectives: The course of SARS-CoV-2 (COVID-19) is still under analysis. The majority of complications arising from the infection are related to the respiratory system. The adverse effect of the viral infection on bone and joint tissue has also been observed. Materials and Methods: We present a group of 10 patients with degeneration of large joints and adjacent epiphyses of long bones and the spine, with a background of bone infarctions and avascular necrosis (AVN) immediately after infection with the COVID-19 virus. In MR imaging, changes in the characteristics of AVN were documented. Results: Observation of this group showed a clear correlation among the history of COVID-19 disease in the patients, moderately severe symptoms, high levels of IgG antibodies, and the time of occurrence of joint changes. No other clinically significant complications were observed following COVID-19 infection in the study group. No other risk factors for AVN or autoimmune or degenerative diseases were found in the study group. The group of patients responded well to empirical treatment with steroids, which normalized acute inflammatory symptoms and pain in the joints. Conclusions: During coronavirus (COVID-19) infection, there are complications in the locomotor system, such as microembolism and the formation of AVN; hence, more research is needed.

Subcutaneous immunization with the fusion protein ΔA146Ply-SP0148 confers protection against Streptococcus pneumoniae infection

Pneumococcal SP0148 and pneumolysin (Ply) derivatives are important vaccine candidates. SP0148 is a conserved lipoprotein with high immunogenicity produced by Streptococcus pneumoniae. We have previously demonstrated that SP0148 can confer protection against fatal infections caused by S. pneumoniae. ΔA146Ply is a noncytotoxic mutant of Ply that retains the TLR4 agonistic effect and has mucosal and subcutaneous adjuvant activities suggested to induce protective immunity against S. pneumoniae infection. In this study, we constructed the fusion protein ΔA146Ply-SP0148, composed of ΔA146Ply and SP0148, and evaluated the immunoprotective effect of the fusion protein. When mice were subcutaneously immunized with the fusion protein ΔA146Ply-SP0148, high levels of anti-ΔA146Ply and anti-SP0148 IgG antibodies were induced in the serum. Specific antibodies can bind to a variety of different serotypes of S. pneumoniae. Compared with mice immunized with ΔA146Ply and SP0148 alone, mice immunized subcutaneously with the fusion protein ΔA146Ply-SP0148 with Al(OH)3 had a higher survival rate when challenged by a lethal dose of S. pneumoniae, and they also had significantly lower lung bacterial loads and milder lung inflammation. In addition, mice immunized subcutaneously with the fusion protein ΔA146Ply-SP0148 stimulated strong Th1, Th2, and Th17 cell responses. In summary, these results suggest that subcutaneous immunization with the ΔA146Ply-SP0148 fusion protein can protect mice against fatal pneumococcal infection and lung infection. The fusion protein ΔA146ply-SP0148 can be a new pneumococcal vaccine target.