Cellular Mediated Immune Response Research Articles

Immunohistochemistry analyses of the abomasal mucosa show differences in cellular-mediated immune responses to Haemonchus contortus infection in resistant and susceptible young lambs

Haemonchus contortus is known for its high pathogenicity in sheep, and the uncontrolled use of anthelmintics resulted in the emergence of multiple drug-resistant populations. Breeding sheep for gastrointestinal nematode resistance is a sustainable alternative to reduce dependence of anthelmintic drugs, and differences in the degree of resistance between breeds have been reported. Here we compare two sheep breeds (Santa Ines and Ile de France), concerning the differences in innate and adaptive immune response involved in the resistance against H. contortus infection. Immunohistochemical analyses of the abomasum were conducted in naïve Santa Ines (n = 14) and Ile de France (n = 12) lambs randomized into four groups: infected Santa Ines (n = 8), non-infected control Santa Ines (n = 6), infected Ile de France (n = 8), and non-infected control Ile de France (n = 4). The infected lambs were initially infected with H. contortus infective larvae at 14 days of age, and multiple infections were conducted every second day until they reached 66 days of age. There was a significant effect (P < 0.001) of the infection with increase in numbers of CD3+ T; CD79α+ B; GATA3+ Th2/ILC2; POU2F3+ tuft cells; FOXP3+ T reg; and IgE + cells in the fundus of the abomasal mucosa in both Santa Ines and Ile de France lambs. Nevertheless, the infected Santa Ines lambs presented the highest averages for CD79α+ B; GATA3+ Th2/ILC; IgE + cells; and POU2F3+ tuft cells and there was a significant association of the breed and infection status with regards to POU2F3+ tuft cells, with the highest mean in the infected Santa Ines group. The infected Santa Ines group had three lambs with high degree of resistance and five lambs that showed a moderate infection. Our results suggest a mechanism of synergistic coordination between different immune-cell types in promoting resistance of suckling lambs under H. contortus infection.

Pathogenicity and escape to pre-existing immunity of a new genotype of swine influenza H1N2 virus that emerged in France in 2020

In 2020, a new genotype of swine H1N2 influenza virus (H1avN2–HA 1C.2.4) was identified in France. It rapidly spread within the pig population and supplanted the previously predominant H1avN1-HA 1C.2.1 virus. To characterize this new genotype which is genetically and antigenically distant from the other H1avNx viruses detected in France, an experimental study was conducted to compare the outcomes of H1avN2 and H1avN1 infections in pigs and evaluate the protection conferred by the only inactivated vaccine currently licensed in Europe containing an HA 1C (clade 1C.2.2) antigen. Infection with H1avN2 induced stronger clinical signs and earlier shedding than H1avN1. The neutralizing antibodies produced following H1avN2 infection were unable to neutralize H1avN1, and vice versa, whereas the cellular-mediated immunity cross-reacted. Vaccination slightly altered the impact of H1avN2 infection at the clinical level, but did not prevent shedding of infectious virus particles. It induced a cellular-mediated immune response towards H1avN2, but did not produce neutralizing antibodies against this virus. As in vaccinated animals, animals previously infected by H1avN1 developed a cross-reacting cellular immune response but no neutralizing antibodies against H1avN2. However, H1avN1 pre-infection induced a better protection against the H1avN2 infection than vaccination, probably due to higher levels of non-neutralizing antibodies and a mucosal immunity. Altogether, these results showed that the new H1avN2 genotype induced a severe respiratory infection and that the actual vaccine was less effective against this H1avN2-HA 1C.2.4 than against H1avN1-HA 1C.2.1, which may have contributed to the H1avN2 epizootic and dissemination in pig farms in France.

Factors Affecting Antibody-Mediated Immune Response and Cellular-Mediated Immune Response in Weaned Brahman Calves

Selecting high-immune-responding cattle benefits the individual animal and the herd. To assess factors that have a role in determining the immune status of cattle, this study used 55 weaned bull and 57 weaned heifer Brahman calves. Antibody-mediated immune response (AMIR) was determined by using a vaccine-specific IgG, enzyme-linked immunosorbent assay (ELISA) in response to cattle receiving the Salmonella Newport Extract vaccine. Cell-mediated immune response (CMIR) was determined by using a subcutaneous (neck) sensitization dose of Candida albicans (CA) with Quil-A adjuvant on Day 0. On Day 14, caudal skinfold thickness (SFT) was measured using Harpenden calipers prior to the intradermal injection of CA into the skinfold, and on Day 15, the injection site SFT was measured again. The response was determined by using the difference in SFT from Day 15 (post-injection) and Day 14 (pre-injection). In weaned Brahman calves, AMIR was not influenced by sex; however, there was sexual dimorphism associated with CMIR, in that bull calves had a greater response than heifers (p &lt; 0.05). Our studies demonstrate that weaned Brahman calves can be separated into AMIR and CMIR classes and that AMIR and CMIR should be investigated further as selection tools in beef cattle production.

The association of Sirtuin1 (SIRT1) polymorphism and downregulation of STAT4 gene expression with increased susceptibility to COVID-19 infection

ABSTRACT Sirtuin1 (SIRT1) is an epigenetic modulator that belongs to sirtuins family and participates in many physiologic reactions, as genomic stabilization, apoptosis, proliferation, and inflammation. STAT4 (signal transducer and activator of transcription 4) gene is a component of JAK-STAT signaling pathway, which plays key role in activating cellular-mediated immune responses. The present study aimed to investigate the association between SIRT1 rs12778366 SNP, expression level of STAT4 gene and susceptibility to COVID-19 infections as well as their correlation to clinicopathological data. The present study included 100 ICU patients with severe COVID-19 infection and 100 age- and sex-matched healthy controls. DNA was extracted. Genotyping of SNP in SIRT1 (rs12778366) was performed, Total RNA was extracted from PBMCs. Reverse transcription was done. STAT4 gene expression levels were evaluated with GAPDH as internal control using real-time PCR. We found a significantly higher frequency of ‘C’ allele and C/T genotype in case vs. control. The association was of low strength (φ = 0.105 for alleles, and 0.154 for genotypes). This was associated with higher expression of STAT4 gene (P < 0.001) and increased tendency for lower respiratory complications. Median STAT4 (FC) (Median = 0.18, 95% CI = 0.15–0.27) was lower than normal control value of 1.0. This difference was statistically significant (Hodges-Lehmann location estimator = 0.217, P < 0.001). SIRT1 polymorphism and decreased expression of STAT4 gene are associated with increased susceptibility to COVID-19 infection and correlate to its phenotypic manifestations.

Effect of Nitrogen Arc Discharge Plasma Treatment on Physicochemical Properties and Biocompatibility of PLA-Based Scaffolds.

The effect of low-temperature arc discharge plasma treatment in a nitrogen atmosphere on the modification of the physicochemical properties of PLA-based scaffolds was studied. In addition, the cellular-mediated immune response when macrophages of three donors interact with the modified surfaces of PLA-based scaffolds was investigated. PLA surface carbonization, accompanied by a carbon atomic concentration increase, was revealed to occur because of plasma treatment. Nitrogen plasma significantly influenced the PLA wettability characteristics, namely, the hydrophilicity and lipophilicity were improved, as well as the surface energy being raised. The viability of cells in the presence of the plasma-modified PLA scaffolds was evaluated to be higher than that of the initial cells.

Validation of Multi-epitope Peptides Encapsulated in PLGA Nanoparticles Against Influenza A Virus.

Influenza is a highly contagious respiratory disease which poses a serious threat to public health globally, causing severe diseases in 3-5 million humans and resulting in 650,000 deaths annually. The current licensed seasonal influenza vaccines lacked cross-reactivity against novel emerging influenza strains as they conferred limited neutralising capabilities. To address the issue, we designed a multi-epitope peptide-based vaccine delivered by the self-adjuvanting PLGA nanoparticles against influenza infections. A total of six conserved peptides representing B- and T-cell epitopes of Influenza A were identified and they were formulated in either incomplete Freund's adjuvant containing CpG ODN 1826 or being encapsulated in PLGA nanoparticles for the evaluation of immunogenicity in BALB/c mice. The self-adjuvanting PLGA nanoparticles encapsulating the six conserved peptides were capable of eliciting the highest levels of IgG and IFN- γ producing cells. In addition, the immunogenicity of the six peptides encapsulated in PLGA nanoparticles showed greater humoral and cellular mediated immune responses elicited by the mixture of six naked peptides formulated in incomplete Freund's adjuvant containing CpG ODN 1826 in the immunized mice. Peptide 3 from the mixture of six peptides was found to exert necrotic effect on CD3+ T-cells and this finding indicated that peptide 3 should be removed from the nanovaccine formulation. The study demonstrated the self-adjuvanting properties of the PLGA nanoparticles as a delivery system without the need for incorporation of toxic and costly conventional adjuvants in multi-epitope peptide-based vaccines.

Severe and mild-moderate SARS-CoV-2 vaccinated patients show different frequencies of IFNγ-releasing cells: An exploratory study.

Despite an apparent effective vaccination, some patients are admitted to the hospital after SARS-CoV-2 infection. The role of adaptive immunity in COVID-19 is growing; nonetheless, differences in the spike-specific immune responses between patients requiring or not hospitalization for SARS-CoV-2 infection remains to be evaluated. In this study, we aim to evaluate the spike-specific immune response in patients with mild-moderate or severeSARS-CoV-2 infection, after breakthrough infection following two doses of BNT162b2 mRNA vaccine. We included three cohorts of 15 cases which received the two BNT162b2 vaccine doses in previous 4 to 7 months: 1) patients with severe COVID-19; 2) patients with mild-moderate COVID-19 and 3) vaccinated individuals with a negative SARS-CoV-2 molecular pharyngeal swab (healthy subjects). Anti-S1 and anti-S2 specific SARS-CoV-2 IgM and IgG titers were measured through a chemiluminescence immunoassay technology. In addition, the frequencies of IFNγ-releasing cells were measured by ELISpot. The spike-specific IFNγ-releasing cells were significantly lower in severe patients (8 [0; 26] s.f.c.×106), as compared to mild-moderate patients (135 [64; 159] s.f.c.×106; p<0.001) and healthy subjects (103 [50; 188] s.f.c.×106; p<0.001). The anti-Spike protein IgG levels were similar among the three cohorts of cases (p = 0.098). All cases had an IgM titer below the analytic sensitivity of the test. The Receiver Operating Curve analysis indicated the rate of spike-specific IFNγ-releasing cells can discriminate correctly severe COVID-19 and mild-moderate patients (AUC: 0.9289; 95%CI: 0.8376-1.000; p< 0.0001), with a diagnostic specificity of 100% for s.f.c. > 81.2 x 106. 2-doses vaccinated patients requiring hospitalization for severe COVID-19 show a cellular-mediated immune response lower than mild-moderate or healthy subjects, despite similar antibody titers.

Humoral and T-Cell Mediated Response after the Third Dose of mRNA Vaccines in Patients with Systemic Lupus Erythematosus on Belimumab.

To evaluate humoral and T-cell cellular-mediated immune response after three doses of SARS-CoV-2 mRNA vaccines in patients with systemic lupus erythematosus (SLE) under Belimumab. 12 patients on Belimumab and 13 age-matched healthy volunteers were recruited. Patients were in remission or in low disease activity, and they were taking no corticosteroids or only low doses. None of the patients and controls had detectable anti-SARS-CoV-2 antibodies due to previous exposure to the virus. All the patients received three doses of mRNA anti-SARS-CoV-2 vaccines and the humoral and cellular-mediated response were tested 4 weeks after the second dose (T0), 6 months after the second dose (T1) and 4 weeks after the third dose (T2). Comparison with the control group was performed at time T0 (i.e., 4 weeks after the second dose). Total anti-SARS-CoV-2 RBD antibodies were analyzed using a diagnostic assay, while cellular-mediated response was evaluated using the interferon-gamma release assay (IGRA). A humoral response was documented in all the patients at T0 (median 459; IQR 225.25-758.5), but the antibody titer significantly declined from T0 to T1 (median 44.7; IQR: 30.3-202; p = 0.0066). At T2, the antibody titer significantly increased from T1 (median 2500; IQR: 2500-2500), and it was not different from T0 (respectively p < 0.0001, p = 0.66). Cellular-mediated response significantly declined from T0 to T1 (p = 0.003) but not from T0 to T2 (p = 0.3). No differences were found between patients and controls at T0 as regards both humoral and cellular responses (p = 1.0 and p = 0.09 for humoral and cellular responses, respectively). The third dose of mRNA COVID-19 vaccine can restore both humoral and cellular immune response in SLE patients on Belimumab.

Prevalence of Depression in Patients with Oral Lichen Planus Referred to Isfahan Dental School

Introduction: Oral lichen planus is a relatively common chronic autoimmune and inflammatory disease in which altered cellular mediated immune response plays a major role in its pathogenesis. Among the possible factors influencing development of oral lichen planus, the role of mental disorders, especially depression and anxiety, has been discussed in pathogenesis of this disease. Therefore, the aim of this study was to investigate the prevalence of depression in patients with oral lichen planus referred to the dental clinic of Isfahan University in year 2018-2019.&#x0D; Materials &amp; Methods: In the present case-control study, 40 patients with oral lichen planus referred to the dental clinic of Isfahan University in 2018-2019 (case group) and 40 subjects without oral lichen planus (control group) were investigated. Next, the Beck Depression Inventory (BDI) was completed by all subjects. Finally, the obtained data were analyzed using statistical software.&#x0D; Results: The obtained results indicated that the average age in case group (43.53 years) was lower than the control group (44.68 years). In addition, the mean for depression in case group (12.78) was higher than control group (9.5), however, this difference was not statistically significant (p value &gt; 0.05).&#x0D; Conclusion: In general, this study indicated the role of depression in the pathogenesis of oral lichen planus. It was noted that high levels of depression can be an initiation point for various autoimmune reactions and oral lichen planus.

EPCO-05. DIFFERENTIAL MOLECULAR PROFILING OF IDH WILD TYPE GLIOBLASTOMA SURVIVORS REVEALS THE ASSOCIATION OF NEOANTIGEN QUALITY WITH EXCEPTIONAL LONG SURVIVAL

Abstract Glioblastoma multiforme (GBM) is the most common and malignant type of primary brain tumor. Despite intensive multimodal treatment, the prognosis of GBM patients is poor with the median overall survival under 15 months. Defining the genetic profiles of rare long-term GBM survivors may provide insights into the molecular basis of GBM progression. IDH mutations have been identified as a favorable prognostic factors, and define a clinically and molecularly distinct group of GBM. Additional molecular mechanisms underlying the prolonged survival in IDHwt GBM patients remained unclear. Therefore, we explored the molecular profiles of 71 IDHwt GBM homogeneously treated patients exhibiting disproportionate survival. The cohort included 36 short-term survivors that deceased within 1 year after diagnosis (median survival of 7 months) and 35 long-term survivors exhibiting an exceptional survival above 4 years (median survival of 88 months). The differential genetic landscape of short- and long-term IDHwt GBM survivors outlined similar mutation load and few differences in the frequency of recurrent alterations, including chromosomes 19 and 20 duplication significantly overrepresented in long-term survivors. To assess the potential impact of T lymphocyte neoantigen-mediated activation towards extended GBM survival, we inferred the restricted HLA binding affinity of the somatic mutations and applied the immune fitness model to accurately predict high-quality neoantigens. Although the general neoantigen burden remained unvaried between short- and long-term survivors, we found that the immune quality of the predicted neoantigens is significantly higher in the patients with exceptional long survival. Moreover, the immune deconvolution of the tumor microenvironment from the gene expression data indicated the presence of CD8+ T lymphocytes and pro-inflammatory macrophages in samples harboring high-quality neoantigens from long-term survivors. This study identified the neoantigen quality as a main distinctive feature of exceptionally long-term survivors supporting the key role of cellular-mediated immune response to restrict tumor progression in IDHwt GBM.

Construction and protective efficacy of a novel Streptococcus pneumoniae fusion protein vaccine NanAT1-TufT1-PlyD4.

During the past decades, with the implementation of pneumococcal polysaccharide vaccine (PPV) and pneumococcal conjugate vaccines (PCVs), a dramatic reduction in vaccine type diseases and transmissions has occurred. However, it is necessary to develop a less expensive, serotype-independent pneumococcal vaccine due to the emergence of nonvaccine-type pneumococcal diseases and the limited effect of vaccines on colonization. As next-generation vaccines, conserved proteins, such as neuraminidase A (NanA), elongation factor Tu (Tuf), and pneumolysin (Ply), are promising targets against pneumococcal infections. Here, we designed and constructed a novel fusion protein, NanAT1-TufT1-PlyD4, using the structural and functional domains of full-length NanA, Tuf and Ply proteins with suitable linkers based on bioinformatics analysis and molecular cloning technology. Then, we tested whether the protein protected against focal and lethal pneumococcal infections and examined its potential protective mechanisms. The fusion protein NanAT1-TufT1-PlyD4 consists of 627 amino acids, which exhibits a relatively high level of thermostability, high stability, solubility and a high antigenic index without allergenicity. The purified fusion protein was used to subcutaneously immunize C57BL/6 mice, and NanAT1-TufT1-PlyD4 induced a strong and significant humoral immune response. The anti-NanAT1-TufT1-PlyD4 specific IgG antibody assays increased after the first immunization and reached the highest value at the 35th day. The results from in vitro experiments showed that anti-NanAT1-TufT1-PlyD4 antisera could inhibit the adhesion of Streptococcus pneumoniae (S. pneumoniae) to A549 cells. In addition, immunization with NanAT1-TufT1-PlyD4 significantly reduced S. pneumoniae colonization in the lung and decreased the damage to the lung tissues induced by S. pneumoniae infection. After challenge with a lethal dose of serotype 3 (NC_WCSUH32403), a better protection effect was observed with NanAT1-TufT1-PlyD4-immunized mice than with the separate full-length proteins and the adjuvant control; the survival rate was 50%, which met the standard of the marketed vaccine. Moreover, we showed that the humoral immune response and the Th1, Th2 and Th17-cellular immune pathways are involved in the immune protection of NanAT1-TufT1-PlyD4 to the host. Collectively, our results support that the novel fusion protein NanAT1-TufT1-PlyD4 exhibits extensive immune stimulation and is effective against pneumococcal challenges, and these properties are partially attributed to humoral and cellular-mediated immune responses.

Low-Temperature Barrier Discharge Plasma Modification of Scaffolds Based on Polylactic Acid.

We have explored the effect of low-temperature barrier discharge plasma treatment in oxygen, nitrogen, and argon on modification of the physicochemical properties of polylactic acid (PLA)-based scaffolds. The cellular-mediated immune response to the interaction of macrophages of three donors with the modified surface of PLA-based scaffolds was also investigated. Carbonization of the PLA surface accompanied by a carbon atomic concentration increase is shown to occur following plasma treatment. Argon plasma significantly affects the wettability characteristics of PLA; the hydrophilicity and lipophilicity are improved, and the surface energy is increased. The viability of cells in the presence of plasma-modified PLA scaffolds is lower than that for unmodified PLA but remains greater than that for the negative control. We find that PLA scaffolds do not cause increased expression of the proinflammatory (TNFα, IL-6, IL-1β) cytokines after 6 days of cell cultivation. At the same time, PLA scaffolds do not affect the increased production of anti-inflammatory cytokines (IL-10).

Adjunctive Thymosin Beta-4 Treatment Influences PMN Effector Cell Function during Pseudomonas aeruginosa-Induced Corneal Infection.

Previous work examining the therapeutic efficacy of adjunct thymosin beta 4 (Tβ4) to ciprofloxacin for ocular infectious disease has revealed markedly reduced inflammation (inflammatory mediators and innate immune cells) with increased activation of wound healing pathways. Understanding the therapeutic mechanisms of action have further revealed a synergistic effect with ciprofloxacin to enhance bacterial killing along with a regulatory influence over macrophage effector cell function. As a natural extension of the aforementioned work, the current study uses an experimental model of P. aeruginosa-induced keratitis to examine the influence of Tβ4 regarding polymorphonuclear leukocyte (PMN/neutrophil) cellular function, contributing to improved disease response. Flow cytometry was utilized to phenotypically profile infiltrating PMNs after infection. The generation of reactive oxygen species (ROS), neutrophil extracellular traps (NETs), and PMN apoptosis were investigated to assess the functional activities of PMNs in response to Tβ4 therapy. In vitro work using peritoneal-derived PMNs was similarly carried out to verify and extend our in vivo findings. The results indicate that the numbers of infiltrated PMNs into infected corneas were significantly reduced with adjunctive Tβ4 treatment. This was paired with the downregulated expression of proinflammatory markers on these cells, as well. Data generated from PMN functional studies suggested that the corneas of adjunctive Tβ4 treated B6 mice exhibit a well-regulated production of ROS, NETs, and limited PMN apoptosis. In addition to confirming the in vivo results, the in vitro findings also demonstrated that neutrophil elastase (NE) was unnecessary for NETosis. Collectively, these data provide additional evidence that adjunctive Tβ4 + ciprofloxacin treatment is a promising option for bacterial keratitis that addresses both the infectious pathogen and cellular-mediated immune response, as revealed by the current study.

A Case Report on Post COVID -19 Vaccine Associated Guillain–Barré Syndrome

Guillain–Barré syndrome (GBS) is an autoimmune demyelinating illness in which a patient’s immune system attacks and cause deterioration of peripheral nervous system leading to progressive paralysis and polyneuropathy. The exact cause of the GBS is unclear but the main mechanism of behindis the demyelination of nerves especially the motor, sensory, and autonomic nerves which can be triggered by any immunologic or infectious agent. The infectious agent elicits the humoral and cellular mediated immune response due to their molecular mimicry in which the antibodies created against the infection matches with the proteins on the nerve. The characteristic features of Guillain–Barré syndrome are ascending flaccid paralysis, paresthesia, impairment of muscle reflexes, respiratory failureetc. The GBS is diagnosed via nerve conduction studies, lumbar puncture (Cerebrospinal fluid analysis), electromyography, Brighton criteria. Treatments like intravenous immunoglobulin therapy, plasma exchange can ease the symptoms and reduce the duration of the illness. This case report focusing on a 43-year-old female patient admitted seeking ventilatory support for respiratory distress caused by Guillain–Barré Syndrome in a tertiary hospital. Patient had developed limb weakness with ascending paralysis along with facial weakness within a couple of weeks after receiving the COVID -19 vaccination (COVISHIELD)one month back. Patient underwent nerve conduction study and routine monitoring of vital parameters. After conservative management with physiotherapy, ventilation, intravenous immunoglobulins and prophylaxis for pain and DVT patient gradually started improving the muscle power and was discharged to continue the rehabilitation care at home.

Literature review of cancer stem cells in oral lichen planus: a premalignant lesion.

As there is no review study about cancer stem cells (CSCs) involved in the pathogenesis of oral lichen planus (OLP), for the first time we review the role of these cells in OLP and this hypothesis may be a clue for the evaluation of the premalignancy of OLP. Cellular mediated immune responses are the main etiopathogenesis in OLP and it is a potentially premalignant lesion. One of the factors proposed in the pathogenesis of OLP and the comparable trend of this autoimmune disease to squamous cell carcinoma (SCC) are CSCs. CSCs have been detected in several solid tumors including head and neck cancers, and have special characteristics including metastasis and resistance to chemotherapy. Related keywords were searched and risk of bias assessment was done for each study. Among all of the studies reviewed in this article, all markers had increased expression in OLP compared to controls that are consistent with SCC. Only CD44 was in contradiction to other papers, in which different expression of CD44 strains was measured in different samples such as saliva and tissue. Based on the results of this review and more studies in the future by investigating the levels of these markers in OLP, it may be possible to determine the prognosis and course of the disease for each patient individually.

Adaptive Immune System in Fish

The immune system of all jawed vertebrates is composed of two major subsystems, the innate (non-specific) and adaptive (specific) immune system. The innate immune system is the first to respond to infectious agents; however, it does not provide longlasting protection. The adaptive immune system is activated later and responds to pathogens with specificity and memory. The main components of the adaptive immune system, including T cell receptors (TCRs), major histocompatibility complex (MHC), immunoglobulins (Igs), and recombination-activating gene (RAG) arose in the first jawed fish (cartilaginous and teleost fish). This review explores and discusses components of the adaptive immune system in teleost fish and recent developments in comparative immunology. Similar to mammals, the adaptive immune system in teleost fish is divided into two components: cellular-mediated responses and humoralmediated responses. T cells, the principal elements of cellular-mediated adaptive immune responses, differentiate into effector helper T (Th) cells or effector cytotoxic T cells (CTLs). The central elements involved in the differentiation of Th subsets in mammals, cytokines and master transcription factors, have also been identified in teleost fish. In addition, each subset of Th cells, defined with a particular cytokine to control the immune responses, has been described in teleost fish. Similarly, to mammals, CTLs contribute to cellular cytotoxicity in teleost fish. B cells act as a central player in humoral-mediated adaptive immunity by producing opsonizing, neutralizing and complement-binding antibodies and inducing antibody-dependent cellular cytotoxicity (ADCC). Three classes of antibodies named IgM, IgD, and IgT/Z have been characterized in teleost fish. The presence of an adaptive immune system and consequent immune memory in teleost fish allows vaccination, the most appropriate method for disease control in aquaculture. Immunological studies in fish provide a comprehensive assessment of the fish immune system, which is crucial for understanding the evolution of the mammalian immune system.

ISCOM-like Nanoparticles Formulated with Quillaja brasiliensis Saponins Are Promising Adjuvants for Seasonal Influenza Vaccines.

Vaccination is the most effective public health intervention to prevent influenza infections, which are responsible for an important burden of respiratory illnesses and deaths each year. Currently, licensed influenza vaccines are mostly split inactivated, although in order to achieve higher efficacy rates, some influenza vaccines contain adjuvants. Although split-inactivated vaccines induce mostly humoral responses, tailoring mucosal and cellular immune responses is crucial for preventing influenza infections. Quillaja brasiliensis saponin-based adjuvants, including ISCOM-like nanoparticles formulated with the QB-90 saponin fraction (IQB90), have been studied in preclinical models for more than a decade and have been demonstrated to induce strong humoral and cellular immune responses towards several viral antigens. Herein, we demonstrate that a split-inactivated IQB90 adjuvanted influenza vaccine triggered a protective immune response, stronger than that induced by a commercial unadjuvanted vaccine, when applied either by the subcutaneous or the intranasal route. Moreover, we reveal that this novel adjuvant confers up to a ten-fold dose-sparing effect, which could be crucial for pandemic preparedness. Last but not least, we assessed the role of caspase-1/11 in the generation of the immune response triggered by the IQB90 adjuvanted influenza vaccine in a mouse model and found that the cellular-mediated immune response triggered by the IQB90-Flu relies, at least in part, on a mechanism involving the casp-1/11 pathway but not the humoral response elicited by this formulation.

Safety and efficiency modifications of SIV-based integrase-defective lentiviral vectors for immunization

Integrase-defective lentiviral vectors (IDLVs) represent an attractive platform for vaccine development as a result of the ability to induce persistent humoral- and cellular-mediated immune responses against the encoded transgene. Compared with the parental integrating vector, the main advantages for using IDLV are the reduced hazard of insertional mutagenesis and the decreased risk for vector mobilization by wild-type viruses. Here we report on the development and use in the mouse immunogenicity model of simian immunodeficiency virus (SIV)-based IDLV containing a long deletion in the U3 region and with the 3′ polypurine tract (PPT) removed from the transfer vector for improving safety and/or efficacy. Results show that a safer extended deletion of U3 sequences did not modify integrase-mediated or -independent integration efficiency. Interestingly, 3′ PPT deletion impaired integrase-mediated integration but did not reduce illegitimate, integrase-independent integration efficiency, contrary to what was previously reported in the HIV system. Importantly, although the extended deletion in the U3 did not affect expression or immunogenicity from IDLV, deletion of 3′ PPT considerably reduced both expression and immunogenicity of IDLV.

Effectiveness of a proteoliposome-based vaccine against salmonid rickettsial septicaemia in Oncorhynchus mykiss

Salmonid rickettsial septicaemia (SRS) is a contagious disease caused by Piscirickettsia salmonis, an intracellular bacterium. SRS causes an estimated economic loss of $700 million USD to the Chilean industry annually. Vaccination and antibiotic therapy are the primary prophylactic and control measures used against SRS. Unfortunately, commercially available SRS vaccines have not been shown to have a significant effect on reducing mortality. Most vaccines contain whole inactivated bacteria which results in decreased efficacy due to the limited ability of the vaccine to evoke a cellular mediated immune response that can eliminate the pathogen or infected cells. In addition, SRS vaccine efficacy has been evaluated primarily with Salmo salar (Atlantic salmon). Vaccine studies using Oncorhynchus mykiss (rainbow trout) are scarce, despite SRS being the leading cause of infectious death for this species. In this study, we evaluate an injectable vaccine based on P. salmonis proteoliposome; describing the vaccine security profile, capacity to induce specific anti-P. salmonis IgM and gene expression of immune markers related to T CD8 cell-mediated immunity. Efficacy was determined by experimental challenge with P. salmonis intraperitoneally. Our findings indicate that a P. salmonis proteoliposome-based vaccine is able to protect O. mykiss against challenge with a P. salmonis Chilean isolate and causes a specific antibody response. The transcriptional profile suggests that the vaccine is capable of inducing cellular immunity. This study provides new insights into O. mykiss protection and the immune response induced by a P. salmonis proteoliposome-based vaccine.

The Analysis of Live-Attenuated Piscirickettsia salmonis Vaccine Reveals the Short-Term Upregulation of Innate and Adaptive Immune Genes in Atlantic Salmon (Salmo salar): An In Situ Open-Sea Cages Study.

Piscirickettsia salmonis, the etiological agent of the Salmon Rickettsial Septicemia (SRS), is one the most serious health problems for the Chilean salmon industry. Typical antimicrobial strategies used against P. salmonis include antibiotics and vaccines, but these applications have largely failed. A few years ago, the first attenuated-live vaccine against SRS (ALPHA JECT LiVac® SRS vaccine) was released to the market. However, there is no data about the agents involved in the activation of the immune response induced under field conditions. Therefore, in this study we evaluated the expression profile of a set of gene markers related to innate and adaptive immunity in the context of a cellular response in Atlantic salmon (Salmo salar) reared under productive farm conditions and immunized with a live-attenuated vaccine against P. salmonis. We analyzed the expression at zero, 5-, 15- and 45-days post-vaccination (dpv). Our results reveal that the administration of the attenuated live SRS LiVac vaccine induces a short-term upregulation of the cellular-mediated immune response at 5 dpv modulated by the upregulation of ifnα, ifnγ, and the cd4 and cd8α T cell surface markers. In addition, we also registered the upregulation of il-10 and tgfβ. Altogether, the results suggest that a balanced activation of the immune response took place only at early times post-vaccination (5 dpv). The scope of this short-term upregulation of the cellular-mediated immune response against a natural outbreak in fish subjected to productive farm conditions deserves further research.