Phase 1 first-in-human dose-escalation study of ANV419 in patients with relapsed/refractory advanced solid tumors.

Patients with advanced cancer, previously treated with immune checkpoint blockade therapy, may retain residual treatment when undergoing the initial infusion of experimental monotherapy in phase 1 clinical trials. ANV419, an antibody-cytokine fusion protein, combines interleukin-2 (IL-2) with an anti-IL-2 monoclonal antibody, aiming to stimulate the expansion of CD8 T and natural killer lymphocytes while restricting regulatory T lymphocytes. In the recent publication of the phase 1 dose escalation study of ANV419, a notable gap exists in detailed information regarding patients' prior antitumoral treatments, specifically programmed death-1/programmed death-ligand 1 (PD-1/PD-L1) targeted monoclonal antibodies. Some patients likely retained residual anti-PD-1/PD-L1 monoclonal antibodies, potentially influencing the outcomes of ANV419. In a separate clinical cohort, we retrospectively measured the residual concentration of nivolumab and pembrolizumab, revealing persistent serum concentrations of anti-PD-1/PD-L1 antibodies even months after treatment cessation. This underscores the importance of comprehensively documenting prior immunotherapy details in clinical trials. Such information is crucial for understanding potential interactions that may impact both immunological and clinical effects.

Significant elevation of serum CA19-9 and CA242 levels induced by dulaglutide.

The use of dulaglutide, a common medication for managing type 2 diabetes, rarely causes elevated pancreatic tumour markers. Here, we report the case of a woman in her mid-60s with diabetes for over 10 years. The patient presented with markedly elevated serum CA19-9 and CA242 levels revealed during a routine health examination despite being asymptomatic. She had been receiving dulaglutide injections for 16 months. Imaging and interventional assessments did not reveal any hepatobiliary, gastrointestinal or pancreatic neoplasm. After excluding alternate diagnoses, the patient was determined to exhibit an adverse reaction to dulaglutide use. Management involved the discontinuation of dulaglutide, which resulted in normalisation of serum CA19-9 and CA242 levels within 6 weeks. This case underscores the importance of discontinuing dulaglutide and monitoring changes in the biomarker levels in asymptomatic patients receiving dulaglutide, rather than immediately resorting to imaging and endoscopic examinations.

[Pharmacoeconomic analysis of anti-angiogenic drugs for diabetic macular edema]. / Farmakoekonomicheskii analiz primeneniya antiangiogennykh preparatov pri diabeticheskom makulyarnom oteke.

Diabetic macular edema (DME) is a degenerative disease of the macular area in diabetes mellitus and can lead to vision loss, disability, and significantly reduced quality of life. Faricimab is the only bispecific antibody for DME therapy that targets two pathogenic pathways (Ang-2 and VEGF-A). PURPOSE: This study comparatively evaluates the clinical and economic feasibility of faricimab and other angiogenesis inhibitors in patients with DME. MATERIAL AND METHODS: This article analyzed literature on the efficacy and safety of intravitreal injections (IVI) of ranibizumab 0.5 mg, aflibercept 2 mg, and faricimab 6 mg. A model of medical care was developed for patients with DME receiving anti-angiogenic therapy. Pharmacoeconomic analysis was performed using cost minimization and budget impact analysis (BIA) methods. Modeling time horizon was 2 years. The research was performed from the perspective of the healthcare system of the Russian Federation. RESULTS: The efficacy and safety of faricimab in a personalized regimen (up to one IVI in 16 weeks) are comparable to those of aflibercept and ranibizumab, administered in various regimens. The use of faricimab is associated with the lowest number of IVIs. Over 2 years, the maximum costs of drug therapy were associated with the use of ranibizumab (about 914 thousand rubles), while the minimum costs were associated with the use of faricimab (614 thousand rubles). The reduction in inpatient care costs with faricimab therapy was 36% compared to aflibercept (216 and 201 thousand rubles in inpatient and day hospitals, respectively) and 82% compared to ranibizumab (486 and 451 thousand rubles in inpatient and day hospitals, respectively). BIA demonstrated that the use of faricimab will reduce the economic burden on the healthcare system by 11.3 billion rubles (9.8%) over 2 years. CONCLUSION: The use of faricimab is a cost-effective approach to treatment of adult patients with DME in Russia.

Tebentafusp in the treatment of metastatic uveal melanoma - the first patient treated in the Czech Republic.

BACKGROUND: Uveal melanoma is a rare cancer, in which metastases occur in approximately one half of cases. In metastatic disease, the prognosis is unfavorable and the median of survival does not exceed 6 months. Effective treatment options were very limited up to date. Tebentafusp is a bispecific fusion protein, which as the first drug proved efficacy in uveal melanoma. CASE: The patient was referred for suspected uveal melanoma of the left eye. She was treated for Hodgkin's disease in the past. Primarily, the tumor was treated by radiosurgery with radiotherapy of a small lesion of the vertebral body. However, later the patient had to undergo bulbus enucleation with confirmation of a large tumor category pT4b. PET/CT revealed metastases of the bones and the liver; simultaneously, haplotype A*02: 01 was confirmed. The patient underwent radiotherapy of the sternum and later, after confirmation of payment from the health insurance company, she started treatment with tebentafusp. The first three doses were administered during admission to the hospital, with a need to treat cytokine release syndrome by corticosteroids. Later, the administration was performed in an out-patient regimen, without complications, except for a transient elevation of transaminases. The first CT restaging confirmed stable disease; however, the second restaging confirmed a new osteolytic lesion in the processus of Th11. Because of progression, the treatment with tebentafusp was withdrawn after 6 months. Unfortunately, the lesion could not be treated by radiotherapy. Two months later, the patient was urgently admitted to the hospital because of right-sided hemiplegia; MRI revealed bleeding metastatic lesion in the brain stem. CONCLUSION: In this case report, we present the case of the first patient treated with this drug in the Czech Republic.

Fusion of histone variants to Cas9 suppresses non-homologous end joining.

As a versatile genome editing tool, the CRISPR-Cas9 system induces DNA double-strand breaks at targeted sites to activate mainly two DNA repair pathways: HDR which allows precise editing via recombination with a homologous template DNA, and NHEJ which connects two ends of the broken DNA, which is often accompanied by random insertions and deletions. Therefore, how to enhance HDR while suppressing NHEJ is a key to successful applications that require precise genome editing. Histones are small proteins with a lot of basic amino acids that generate electrostatic affinity to DNA. Since H2A.X is involved in DNA repair processes, we fused H2A.X to Cas9 and found that this fusion protein could improve the HDR/NHEJ ratio by suppressing NHEJ. As various post-translational modifications of H2A.X play roles in the regulation of DNA repair, we also fused H2A.X mimicry variants to replicate these post-translational modifications including phosphorylation, methylation, and acetylation. However, none of them were effective to improve the HDR/NHEJ ratio. We further fused other histone variants to Cas9 and found that H2A.1 suppressed NHEJ better than H2A.X. Thus, the fusion of histone variants to Cas9 is a promising option to enhance precise genome editing.

CRISPR/Cas9 genome editing of CCR5 combined with C46 HIV-1 fusion inhibitor for cellular resistant to R5 and X4 tropic HIV-1.

Hematopoietic stem-cell (HSC) transplantation using a donor with a homozygous mutation in the HIV co-receptor CCR5 (CCR5Δ32/Δ32) holds great promise as a cure for HIV-1. Previously, there were three patients that had been reported to be completely cured from HIV infection by this approach. However, finding a naturally suitable Human Leukocyte Antigen (HLA)-matched homozygous CCR5Δ32 donor is very difficult. The prevalence of this allele is only 1% in the Caucasian population. Therefore, additional sources of CCR5Δ32/Δ32 HSCs are required. The Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR-associated (Cas) system is one method to mediate CCR5 knockout in HSCs that has been successfully employed as a gene editing tool in clinical trials. Additional anti-HIV-1 strategies are still required for broad-spectrum inhibition of HIV-1 replication. Here in this study, we combined an additional anti-HIV-1 therapy, which is C46, a cell membrane-anchored HIV-1 fusion inhibitor with the CRISPR/Cas9 mediated knockout CCR5. The combined HIV-1 therapeutic genes were investigated for the potential prevention of both CCR5 (R5)- and CXCR4 (X4)-tropic HIV-1 infections in the MT4CCR5 cell line. The combinatorial CRISPR/Cas9 therapies were superior compared to single method therapy for achieving the HIV-1 cure strategy and shows potential for future applications.

Efficacy and safety of onasemnogene abeparvovec for the treatment of patients with spinal muscular atrophy type 1: A systematic review with meta-analysis.

BACKGROUND: Onasemnogene abeparvovec has been approved for the treatment of spinal muscular atrophy 5q type 1 in several countries, which calls for an independent assessment of the evidence regarding efficacy and safety. OBJECTIVE: Conduct a meta-analysis to assess the efficacy and safety of onasemnogene abeparvovec in patients diagnosed with SMA type 1, based on the available evidence. METHODS: This article results from searches conducted on databases up to November 2022. Outcomes of interest were global survival and event-free survival, improvement in motor function and treatment-related adverse events. Risk of bias assessment and certainty of evidence were performed for each outcome. Proportional meta-analysis models were performed when applicable. RESULTS: Four reports of three open-label, non-comparative clinical trials covering 67 patients were included. Meta-analyses of data available in a 12-month follow-up estimate a global survival of 97.56% (95%CI: 92.55 to 99.86, I2 = 0%, n = 67), an event-free survival of 96.5% (95%CI: 90.76 to 99.54, I2 = 32%, n = 66) and a CHOP-INTEND score ≥ 40 points proportion of 87.28% (95%CI: 69.81 to 97.83, I2 = 69%, n = 67). Proportion of 52.64% (95%CI: 27.11 to 77.45, I2 = 78%, n = 67) of treatment-related adverse events was estimated. CONCLUSION: The results indicate a potential change in the natural history of type 1 SMA, but the methodological limitations of the studies make the real extent of the technology's long-term benefits uncertain.

Efficient production of human interleukin-3 from Escherichia coli using protein disulfide isomerase b'a' domain.

Human interleukin-3 (IL3) is a multifunctional cytokine essential for both clinical and biomedical research endeavors. However, its production in Escherichia coli has historically been challenging due to its aggregation into inclusion bodies, requiring intricate solubilization and refolding procedures. This study introduces an innovative approach employing two chaperone proteins, maltose binding protein (MBP) and protein disulfide isomerase b'a' domain (PDIb'a'), as N-terminal fusion tags. Histidine tag (H) was added at the beginning of each chaperone protein gene for easy purification. This fusion of chaperone proteins significantly improved IL3 solubility across various E. coli strains and temperature conditions, eliminating the need for laborious refolding procedures. Following expression optimization, H-PDIb'a'-IL3 was purified using two chromatographic methods, and the subsequent removal of the H-PDIb'a' tag yielded high-purity IL3. The identity of the purified protein was confirmed through liquid chromatography coupled with tandem mass spectrometry analysis. Biological activity assays using human erythroleukemia TF-1 cells revealed a unique two-step stimulation pattern for both purified IL3 and the H-PDIb'a'-IL3 fusion protein, underscoring the protein's functional integrity and revealing novel insights into its cellular interactions. This study advances the understanding of IL3 expression and activity while introducing novel considerations for protein fusion strategies.

CYP116B5-SOX: An artificial peroxygenase for drug metabolites production and bioremediation.

CYP116B5 is a class VII P450 in which the heme domain is linked to a FMN and 2Fe2S-binding reductase. Our laboratory has proved that the CYP116B5 heme domain (CYP116B5-hd) is capable of catalyzing the oxidation of substrates using H2O2. Recently, the Molecular Lego approach was applied to join the heme domain of CYP116B5 to sarcosine oxidase (SOX), which provides H2O2 in-situ by the sarcosine oxidation. In this work, the chimeric self-sufficient fusion enzyme CYP116B5-SOX was heterologously expressed, purified, and characterized for its functionality by absorbance and fluorescence spectroscopy. Differential scanning calorimetry (DSC) experiments revealed a TM of 48.4 ± 0.04 and 58.3 ± 0.02°C and a enthalpy value of 175,500 ± 1850 and 120,500 ± 1350 cal mol-1 for the CYP116B5 and SOX domains respectively. The fusion enzyme showed an outstanding chemical stability in presence of up to 200 mM sarcosine or 5 mM H2O2 (4.4 ± 0.8 and 11.0 ± 2.6% heme leakage respectively). Thanks to the in-situ H2O2 generation, an improved kcat/KM for the p-nitrophenol conversion was observed (kcat of 20.1 ± 0.6 min-1 and KM of 0.23 ± 0.03 mM), corresponding to 4 times the kcat/KM of the CYP116B5-hd. The aim of this work is the development of an engineered biocatalyst to be exploited in bioremediation. In order to tackle this challenge, an E. coli strain expressing CYP116B5-SOX was employed to exploit this biocatalyst for the oxidation of the wastewater contaminating-drug tamoxifen. Data show a 12-fold increase in tamoxifen N-oxide production-herein detected for the first time as CYP116B5 metabolite-compared to the direct H2O2 supply, equal to the 25% of the total drug conversion.

Application of SUMO fusion technology for the enhancement of stability and activity of lysophospholipase from Pyrococcus abyssi.

Heterologous production of proteins in Escherichia coli has raised several challenges including soluble production of target proteins, high levels of expression and purification. Fusion tags can serve as the important tools to overcome these challenges. SUMO (small ubiquitin-related modifier) is one of these tags whose fusion to native protein sequence can enhance its solubility and stability. In current research, a simple, efficient and cost-effective method is being discussed for the construction of pET28a-SUMO vector. In order to improve the stability and activity of lysophospholipase from Pyrococcus abyssi (Pa-LPL), a 6xHis-SUMO tag was fused to N-terminal of Pa-LPL by using pET28a-SUMO vector. Recombinant SUMO-fused enzyme (6 H-S-PaLPL) works optimally at 35 °C and pH 6.5 with remarkable thermostability at 35-95 °C. Thermo-inactivation kinetics of 6 H-S-PaLPL were also studied at 35-95 °C with first order rate constant (kIN) of 5.58 × 10- 2 h-1 and half-life of 12 ± 0 h at 95 °C. Km and Vmax for the hydrolysis of 4-nitrophenyl butyrate were calculated to be 2 ± 0.015 mM and 3882 ± 22.368 U/mg, respectively. 2.4-fold increase in Vmax of Pa-LPL was observed after fusion of 6xHis-SUMO tag to its N-terminal. It is the first report on the utilization of SUMO fusion tag to enhance the overall stability and activity of Pa-LPL. Fusion of 6xHis-SUMO tag not only aided in the purification process but also played a crucial role in increasing the thermostability and activity of the enzyme. SUMO-fused enzyme, thus generated, can serve as an important candidate for degumming of vegetable oils at industrial scale.

An Elastin-like Polypeptide-fusion peptide targeting capsid-tegument interface as an antiviral against cytomegalovirus infection.

The tegument protein pp150 of Human Cytomegalovirus (HCMV) is known to be essential for the final stages of virus maturation and mediates its functions by interacting with capsid proteins. Our laboratory has previously identified the critical regions in pp150 important for pp150-capsid interactions and designed peptides similar in sequence to these regions, with a goal to competitively inhibit capsid maturation. Treatment with a specific peptide (PepCR2 or P10) targeted to pp150 conserved region 2 led to a significant reduction in murine CMV (MCMV) growth in cell culture, paving the way for in vivo testing in a mouse model of CMV infection. However, the general pharmacokinetic parameters of peptides, including rapid degradation and limited tissue and cell membrane permeability, pose a challenge to their successful use in vivo. Therefore, we designed a biopolymer-stabilized elastin-like polypeptide (ELP) fusion construct (ELP-P10) to enhance the bioavailability of P10. Antiviral efficacy and cytotoxic effects of ELP-P10 were studied in cell culture, and pharmacokinetics, biodistribution, and antiviral efficacy were studied in a mouse model of CMV infection. ELP-P10 maintained significant antiviral activity in cell culture, and this conjugation significantly enhanced P10 bioavailability in mouse tissues. The fluorescently labeled ELP-P10 accumulated to higher levels in mouse liver and kidneys as compared to the unconjugated P10. Moreover, viral titers from vital organs of MCMV-infected mice indicated a significant reduction of virus load upon ELP-P10 treatment. Therefore, ELP-P10 has the potential to be developed into an effective antiviral against CMV infection.

Synthetic intrinsically disordered protein fusion tags that enhance protein solubility.

We report the de novo design of small (<20 kDa) and highly soluble synthetic intrinsically disordered proteins (SynIDPs) that confer solubility to a fusion partner with minimal effect on the activity of the fused protein. To identify highly soluble SynIDPs, we create a pooled gene-library utilizing a one-pot gene synthesis technology to create a large library of repetitive genes that encode SynIDPs. We identify three small (<20 kDa) and highly soluble SynIDPs from this gene library that lack secondary structure and have high solvation. Recombinant fusion of these SynIDPs to three known inclusion body forming proteins rescue their soluble expression and do not impede the activity of the fusion partner, thereby eliminating the need for removal of the SynIDP tag. These findings highlight the utility of SynIDPs as solubility tags, as they promote the soluble expression of proteins in E. coli and are small, unstructured proteins that minimally interfere with the biological activity of the fused protein.

Affinity Purification of a 6X-His-Tagged Protein using a Fast Protein Liquid Chromatography System.

Functional characterization of proteins requires them to be expressed and purified in substantial amounts with high purity to perform biochemical assays. The Fast Protein Liquid Chromatography (FPLC) system allows high-resolution separation of complex protein mixtures. By adjusting various parameters in FPLC, such as selecting the appropriate purification matrix, regulating the protein sample's temperature, and managing the sample's flow rate onto the matrix and the elution rate, it is possible to ensure the protein's stability and functionality. In this protocol, we will demonstrate the versatility of the FPLC system to purify 6X-His-tagged flap endonuclease 1 (FEN1) protein, produced in bacterial cultures. To improve protein purification efficiency, we will focus on multiple considerations, including proper column packing and preparation, sample injection using a sample loop, flow rate of sample application to the column, and sample elution parameters. Finally, the chromatogram will be analyzed to identify fractions containing high yields of protein and considerations for proper recombinant protein long-term storage. Optimizing protein purification methods is crucial for improving the precision and reliability of protein analysis.

[Application of optical coherence tomography in the assessment of the posterior lens capsule during anti-angiogenic therapy]. / Primenenie opticheskoi kogerentnoi tomografii v otsenke zadnei kapsuly khrustalika na fone provedeniya antiangiogennoi terapii.

Intravitreal injection (IVI) of anti-angiogenic drugs is one of the most common therapeutic procedures in ophthalmology. In recent years, a new non-contact study method has been developed - anterior segment optical coherence tomography (AS-OCT), which allows the formation of three-dimensional images of the lens and provides more detailed information about its structure and morphology. PURPOSE: This study uses optical coherence tomography method to analyze the risks of developing changes in the posterior lens capsule in patients after IVI of an anti-angiogenic drug. MATERIAL AND METHODS: The study involved 100 people (14 men and 86 women) with a natural lens and neovascular age-related macular degeneration (nAMD). The average age was 70.57±7.98 years. During the study (12 months), all patients underwent IVI of an anti-angiogenic drug aflibercept in the treat-and-extend (T&E) mode. All subjects were divided into 2 groups: with a total number of IVI less than 10 - group 1 (50 patients), and more than 10 IVI - group 2 (50 patients, of which 49 were included in the study). All patients underwent OCT using the Optopol REVO NX device (Poland) with the Anterior B-scan Wide protocol before inclusion in the study, as well as after 3, 6 and 12 months. RESULTS: It was found that the risk of developing a posterior lens capsule rupture, visualized using OCT, depends on the total number of IVI (correlation coefficient 0.473 p=0.001): the more IVI, the higher the probability that damage to the posterior capsule will occur after the next IVI, and after the 15th injection the risk of developing damage to the posterior capsule increases sharply. CONCLUSION: The astudy analyzed the risk factors for the development of posterior lens capsule damage that can be detected using OCT, and presented three risk groups for the development of rupture (or damage) of the posterior lens capsule depending on the number of intravitreal injections performed.

Effects of Antithymocyte Globulin, Basiliximab, and Induction-Free Treatment in Living Donor Kidney Transplant Recipients on Tacrolimus-Based Immunosuppression.

OBJECTIVES: Induction treatment in renal transplant is associated with better graft survival. However, intensified immunosuppression is known to cause unwanted side effects such as infection and malignancy. Furthermore, the effects of the routine use of immunosuppressants in low-risk kidney transplant recipients are still not clear. In this study, we assessed the first-year safety and efficacy of induction treatment. MATERIALS AND METHODS: We examined first living donor kidney transplant patients who were on tacrolimus based immunosuppression therapy. We formed 3 groups according to the induction status: antithymocyte globulin induction, basiliximab induction, and no induction. We collected outcome data on delayed graft function, graft loss, creatinine levels, estimated glomerular filtration rates, acute rejection episodes, hospitalization episodes, and infection episodes, including cytomegalovirus infection and bacterial infections. RESULTS: We examined a total of 126 patients (age 35 ± 12 years; 65% male). Of them, 25 received antithymocyte globulin, 52 received basiliximab, and 49 did notreceive any induction treatment. We did not observe any statistically significant difference among the 3 groups in terms of acute rejection episodes, delayed graft function, and first-year graft loss. The estimated glomerular filtration rates were similar among the groups. Overall bacterial infectious complications and cytomegalovirus infection showed similar prevalence among all groups. Hospitalization was less common in the induction-free group. CONCLUSIONS: In low-risk patients, induction-free regimens could be associated with a better safety profile without compromising graft survival. Therefore, induction treatment may be disregarded in first living donor transplant patients who receive tacrolimusbased triple immunosuppression treatment.

Estudo testa proteínas quiméricas para avaliar cura da doença de Chagas após tratamento

O declínio dos títulos de anticorpos específicos para o Trypanosoma cruzi, em pacientes com diagnóstico de doença de Chagas crônica após o tratamento, foi avaliado em estudo, utilizando proteínas quiméricas. A pesquisa, de coorte transversal prospectiva envolveu participantes com diagnóstico positivo para T. cruzi, da região de Añatuya, na Argentina, e que foram tratados com benznidazol.

Preclinical Evaluation of HER2-Targeting DARPin G3: Impact of Albumin-Binding Domain (ABD) Fusion.

Designed ankyrin repeat protein (DARPin) G3 is an engineered scaffold protein. This small (14.5 kDa) targeting protein binds with high affinity to human epidermal growth factor receptor 2 (HER2). HER2 is overexpressed in several cancers. The use of the DARPin G3 for radionuclide therapy is complicated by its high renal reabsorption after clearance via the glomeruli. We tested the hypothesis that a fusion of the DARPin G3 with an albumin-binding domain (ABD) would prevent rapid renal excretion and high renal reabsorption resulting in better tumour targeting. Two fusion proteins were produced, one with the ABD at the C-terminus (G3-ABD) and another at the N-terminus (ABD-G3). Both variants were labelled with 177Lu. The binding properties of the novel constructs were evaluated in vitro and their biodistribution was compared in mice with implanted human HER2-expressing tumours. Fusion with the ABD increased the retention time of both constructs in blood compared with the non-ABD-fused control. The effect of fusion with the ABD depended strongly on the order of the domains in the constructs, resulting in appreciably better targeting properties of [177Lu]Lu-G3-ABD. Our data suggest that the order of domains is critical for the design of targeting constructs based on scaffold proteins.

Von-Hippel Lindau protein amyloid formation. The role of GST-tag.

In the last decade, much attention was given to the study of physiological amyloid fibrils. These structures include A-bodies, which are the nucleolar fibrillar formations that appear in the response to acidosis and heat shock, and disassemble after the end of stress. One of the proteins involved in the biogenesis of A-bodies, regardless of the type of stress, is Von-Hippel Lindau protein (VHL). Known also as a tumor suppressor, VHL is capable to form amyloid fibrils both in vitro and in vivo in response to the environment acidification. As with most amyloidogenic proteins fusion with various tags is used to increase the solubility of VHL. Here, we first performed AFM-study of fibrils formed by VHL protein and by VHL fused with GST-tag (GST-VHL) at acidic conditions. It was shown that formed by full-length VHL fibrils are short heterogenic structures with persistent length of 2400 nm and average contour length of 409 nm. GST-tag catalyzes VHL amyloid fibril formation, superimpose chirality, increases length and level of hierarchy, but decreases rigidity of amyloid fibrils. The obtained data indicate that tagging can significantly affect the fibrillogenesis of the target protein.

Feasibility of using a combination of staphylococcal superantigen-like proteins 3, 7 and 11 in a fusion vaccine for Staphylococcus aureus.

Staphylococcus aureus is a significant bacterial pathogen in both community and hospital settings, and the escalation of antimicrobial-resistant strains is of immense global concern. Vaccination is an inviting long-term strategy to curb staphylococcal disease, but identification of an effective vaccine has proved to be challenging. Three well-characterized, ubiquitous, secreted immune evasion factors from the staphylococcal superantigen-like (SSL) protein family were selected for the development of a vaccine. Wild-type SSL3, 7 and 11, which inhibit signaling through Toll-like receptor 2, cleavage of complement component 5 and neutrophil function, respectively, were successfully combined into a stable, active fusion protein (PolySSL7311). Vaccination of mice with an attenuated form of the PolySSL7311 protein stimulated significantly elevated specific immunoglobulin G and splenocyte proliferation responses to each component relative to adjuvant-only controls. Vaccination with PolySSL7311, but not a mixture of the individual proteins, led to a > 102 reduction in S. aureus tissue burden compared with controls after peritoneal challenge. Comparable antibody responses were elicited after coadministration of the vaccine in either AddaVax (an analog of MF59) or an Alum-based adjuvant; but only AddaVax conferred a significant reduction in bacterial load, aligning with other studies that suggest both cellular and humoral immune responses are necessary for protective immunity to S. aureus. Anti-sera from mice immunized with PolySSL7311, but not individual proteins, partially neutralized the functional activities of SSL7. This study confirms the importance of these SSLs for the survival of S. aureus in vivo and suggests that PolySSL7311 is a promising vaccine candidate.