Immunostimulating Complexes Research Articles

Fractionation, characterization, and assessment of nutritional and immunostimulatory protein-rich polysaccharide-protein complexes isolated from Lentinula edodes mushroom

This study aimed to fractionate and characterize the protein-rich polysaccharide-protein (PSP) complexes from a well-known edible mushroom, Lentinula edodes, and assess their nutritional and immunostimulatory properties. Crude PSP isolated from the mushroom water extract was purified by anion exchange chromatography, yielding fractions PSP-F1 and PSP-F2 containing 66.1 % and 74.0 % protein, respectively. Both fractions exhibited primarily β-sheet and random-coil protein structures, though the crude PSP fraction exhibited an additional α-helix structure. On SDS-PAGE, PSP-F1 showed two molecular weight bands, one below 10 kDa and another at 34 kDa, and PSP-F2 showed several bands, one below 10 kDa and others between 34 and 95 kDa. The nutritional value of essential and non-essential amino acid profiles was in the order of PSP-F2 > PSP-F1 > crude PSP; the amino acid ratio coefficient values of the crude PSP, PSP-F1, and PSP-F2 were 63 %, 67 %, and 72 %, respectively. The combination of PS and PSP fractions exhibited stronger immunoactivity than PSP-F1 or PSP-F2 alone. PSP-F2 showed a higher immunostimulatory activity than PSP-F1 in RAW264.7 cell culture. PSP-F2 was also more abundant of easily absorbed high-quality proteins. The results provide useful references for dietary and medicinal uses of PSP fractions in L. edodes and other edible mushrooms.

Dual immunostimulatory CD73 antibody-polymeric cytotoxic drug complex for triple negative breast cancer therapy

Treatment of triple-negative breast cancer (TNBC) poses significant challenges due to its propensity for metastasis. A key impediment lies in the suppressive immune microenvironment, which fosters tumor progression. This study introduces an approach employing a dual immune-stimulatory CD73 antibody-polymeric cytotoxic drug complex (αCD73-PLG-MMAE). This complex is designed for targeted eradication of TNBC while modulating tumor immunity through mechanisms such as immunogenic cell death (ICD) and interference with the adenosine signaling pathway. By enhancing antitumor immune responses, this strategy offers a highly effective means of treating TNBC and mitigating metastasis. The complex is synthesized by combining αCD73 with poly(L-glutamic acid) (PLG) grafted Fc binding peptides (Fc-III-4C) and Val-Cit-PAB-monomethyl auristatin E (MMAE), exploiting the affinity between αCD73 and Fc-III-4C. αCD73 selectively targets CD73 molecules on both tumor and immune suppressive cells, thereby inhibiting the adenosine pathway. Meanwhile, Val-Cit-PAB-MMAE, activated by cathepsin B, triggers selective release of MMAE, inducing ICD in tumor cells. In a 4T1 tumor model, αCD73-PLG-MMAE significantly enhances drug accumulation in tumors by 4.13-fold compared to IgG-PLG-MMAE, leading to suppression of tumor growth and metastasis. Furthermore, it synergistically augments the antitumor effects of αPD-1, resulting in a tumor inhibition rate of 92% as compared to 21% with αPD-1 alone. This study thus presents a pioneering therapeutic strategy for TNBC, emphasizing the potential of targeted immunomodulation in cancer treatment. Statement of SignificanceAntibody-drug conjugate (ADC) therapy holds promise for treating triple-negative breast cancer (TNBC). However, the current ADC, sacituzumab govitecan, fails to overcome the crucial role of adenosine in the suppressive immune microenvironment characteristic of this "cold tumor". Here, we present a dual immune-stimulatory complex, αCD73-PLG-MMAE, which targets TNBC specifically and modulates tumor immunity through mechanisms such as immunogenic cell death (ICD) and interference with the adenosine signaling pathway. Thus, it kills tumor cells with cytotoxic drugs, comprehensively regulates immunosuppression, and restores a durable immune response. This study proposes an antibody-polymeric drug complex with immunomodulatory and immunoagonist roles, offering new insights into TNBC treatment.

The Use of Particulate Systems for Tuberculosis Prophylaxis and Treatment: Opportunities and Challenges.

The use of particles to develop vaccines and treatments for a wide variety of diseases has increased, and their success has been demonstrated in preclinical investigations. Accurately targeting cells and minimizing doses and adverse side effects, while inducing an adequate biological response, are important advantages that particulate systems offer. The most used particulate systems are liposomes and their derivatives, immunostimulatory complexes, virus-like particles, and organic or inorganic nano- and microparticles. Most of these systems have been proven using therapeutic or prophylactic approaches to control tuberculosis, one of the most important infectious diseases worldwide. This article reviews the progress and current state of the use of particles for the administration of TB vaccines and treatments in vitro and in vivo, with a special emphasis on polymeric particles. In addition, we discuss the challenges and benefits of using these particulate systems to provide researchers with an overview of the most promising strategies in current preclinical trials, offering a perspective on their progress to clinical trials.

Investigating antigenic features of the SARS-CoV-2 isolated in Russian Federation in 2021–2022 by hyperimmune mouse serum neutralisation

Introduction. The rapid spread of a new coronavirus infection among populations in many countries worldwide has contributed to the genetic evolution of the virus, resulting in the emergence of multiple genetic variants of the SARS-CoV-2 coronavirus. Mutations in the viral genome can affect the ability of the virus to bypass the immune system and complicate development of diagnostic and prophylactic drugs. Data on the neutralizing activity of the sera obtained against previously circulating genetic variants of the virus in relation to current SARS-CoV-2 strains may serve as a scientific basis for the selection of the antigens in vaccine development. The aim of this work was to study cross-reactivity of SARS-CoV-2 coronavirus strains belonging to different genetic variants, which were isolated in the territory of the Russian Federation during 20202022 in the neutralization reaction using mouse hyperimmune sera. Materials and methods. Ten strains of SARS-CoV-2 coronavirus belonging to different genetic variants were used (three non-VOC strains, alpha, beta, gamma, delta, delta+AY, omicron 1 and omicron 2). The hCoV-19/Australia/VIC01/2020 strain (Wuhan) was included in the study as a prototypical variant. BALBc mice were immunized with inactivated concentrated antigen mixed with a 1:1 adjuvant, which was a virus-like immunostimulatory complex based on Quillaja saponaria (Quillaja saponaria). The antibody titer was determined in the neutralization reaction. Results. Essential decrease of neutralizing ability of antibodies specific to non-vOC genetic variants of SARS-CoV-2 coronavirus was revealed against beta VOC and to a lesser degree against alpha and gamma VOC variants. The differences in the neutralizing activity level of antibodies for alpha and beta VOC variants are not significant among themselves, and with gamma VOC variants there are no significant differences. Neutralizing ability of antibodies specific to delta VOC against alpha and beta VOC variants decreased 4-fold. Neutralizing activity of sera obtained to omicron 1 and 2 variants in relation to the prototype coronavirus variant was reduced 18-fold, to the gamma variant 12-fold, to delta variants more than 30-fold; for other variants it was even lower. Conclusions. The results obtained testify to the presence of cross-reactivity between strains of coronavirus belonging to genetic lines Wuhan, alpha, beta, gamma; it is weaker for delta variants. Mutations in the genome of VOC omicron variants led to a significant decrease in antigenic cross-links with earlier genetic variants of the coronavirus. These findings explain the low efficacy of vaccines based on the Wuhan strain, synthetic immunogens, and recombinant proteins based on it against omicron VOC variants, which have caused a rise in morbidity since early 2022, as well as cases of re-infection of humans with new genetic variants of the coronavirus.

Small ruminant lentivirus capsid protein (SRLV-p25) antigenic structural prediction and immunogenicity to recombinant SRLV-rp25-coupled to immunostimulatory complexes based on glycyrrhizinic acid.

Small ruminant lentiviruses (SRLV) infect sheep and goats resulting in significant economic losses. This study evaluated for the first time the predicted conformational structure of the SRLV-capsid-protein 25 (SRLV-p25) and analyzed the antigenicity of recombinant protein (SRLV-rp25) in mice by coupling to an immunostimulatory complexes based on glycyrrhizinic acid liposomes (GAL) and tested plasma from goats and sheep naturally infected. Analysis in silico and conformational structure of SRLV-p25 (genotype B-FESC-752) showed similar characteristics to other lentiviral capsids. The efficient expression of SRLV-rp25 was confirmed by Western blot. The humoral immune responses in mice showed an increased level of antibodies from day 21 to 35 of the SRLV-rp25-GAL and SRLV-rp25-ISCOM® groups and the cellular immune response showed no significant difference in IL-10 levels (P>.05), however, a significant difference (P<.001) was observed when comparing SRLV-rp25-GAL with SRLV-rp25 groups. Immunoreactivity toward SRLV-rp25 revealed 61% of positive samples from naturally infected goats and sheep.

Virus-like immunostimulatory complexes based on plant saponins: preparation, quality control, adjuvant properties

Virus-like immunostimulatory complexes based on plant saponins: preparation, quality control, adjuvant properties

Efficacy and Immune Correlates of OMP-1B and VirB2-4 Vaccines for Protection of Dogs from Tick Transmission of Ehrlichia chaffeensis.

Ehrlichia chaffeensis, an obligatory intracellular bacterium, causes human monocytic ehrlichiosis, an emerging disease transmitted by the Lone Star tick, Amblyomma americanum. Here, we investigated the vaccine potential of OMP-1B and VirB2-4. Among the highly expressed and immunodominant E. chaffeensis porin P28s/OMP-1s, OMP-1B is predominantly expressed by E. chaffeensis in A. americanum ticks, whereas VirB2-4 is a pilus protein of the type IV secretion system essential for E. chaffeensis infection of host cells. Immunization with recombinant OMP-1B (rOMP-1B) or recombinant VirB2-4 (rVirB2-4) protected mice from E. chaffeensis infection as effectively as Entry-triggering protein of Ehrlichia immunization. Dogs vaccinated with a nanoparticle vaccine composed of rOMP-1B or rVirB2-4 and an immunostimulating complex developed high antibody titers against the respective antigen. Upon challenge with E. chaffeensis-infected A. americanum ticks, E. chaffeensis was undetectable in the blood of rOMP-1B or rVirB2-4 immunized dogs on day 3 or 6 post-tick attachment and for the duration of the experiment, whereas dogs sham-vaccinated with the complex alone were persistently infected for the duration of the experiment. E. chaffeensis exponentially replicates in blood-feeding ticks to facilitate transmission. Previously infected ticks removed from OMP-1B-immunized dogs showed significantly lower bacterial load relative to ticks removed from sham-immunized dogs, suggesting in-tick neutralization. Peripheral blood leukocytes from rVirB2-4-vaccinated dogs secreted significantly elevated amounts of interferon-γ soon after tick attachment by ELISpot assay and reverse transcription-quantitative PCR, suggesting interferon-γ-mediated Ehrlichia inhibition. Thus, Ehrlichia surface-exposed proteins OMP-1B and VirB2-4 represent new potential vaccine candidates for blocking tick-borne ehrlichial transmission. IMPORTANCE Ehrlichia are tick-borne pathogens that cause a potentially fatal illness-ehrlichiosis-in animals and humans worldwide. Currently, no vaccine is available for ehrlichiosis, and treatment options are limited. Ticks are biological vectors of Ehrlichia, i.e., Ehrlichia exponentially replicates in blood-sucking ticks before infecting animals. Ticks also inoculate immunomodulatory substances into animals. Thus, it is important to study effects of candidate vaccines on Ehrlichia infection in both animals and ticks and the immune responses of animals shortly after infected tick challenge. Here, we investigated the efficacy of vaccination with functionality-defined two surface-exposed outer membrane proteins of Ehrlichia chaffeensis, OMP-1B and VirB2-4, in a mouse infection model and then in a dog-tick transmission model. Our results begin to fill gaps in our understanding of Ehrlichia-derived protective antigens against tick-transmission and immune correlates and mechanisms that could help future development of vaccines for immunization of humans and animals to counter tick-transmitted ehrlichiosis.

ISCOM-Matrices Nanoformulation Using the Raw Aqueous Extract of Quillaja lancifolia (Q. brasiliensis)

Quillaja saponins have an intrinsic capacity to interact with membrane lipids that self-assembles in nanoparticles (immunostimulating complexes or ISCOM-matrices) with outstanding immunoadjuvant activity and low toxicity profile. However, the expensive and laborious purification processes applied to purify Quillaja saponins used to assemble ISCOM-matrices show an important drawback in the large-scale use of this vaccine adjuvant. Thus, in this study, we describe a protocol to appropriately formulate ISCOM-matrices using the raw aqueous extract (AE) of Quillaja lancifolia leaves. In the presence of lipids, AE was able to self-assemble in nanostructures that resembles immunostimulating complexes (ISCOM). These negatively charged nanoparticles of approximately 40 nm were characterized by transmission electron microscopy and dynamic light scattering. In addition, well-known saponins with remarkable immunoadjuvant activity, as QS-21, were detected into nanoparticles. Thus, the easier, robust, cheaper, and environmentally friendly method developed here may be an alternative to the classical methods for ISCOM-matrices production that use high-purified saponins.Graphical abstract

Final clinical results of pivotal trial of IL-15RαFc superagonist N-803 with BCG in BCG-unresponsive CIS and papillary nonmuscle-invasive bladder cancer (NMIBC).

4508 Background: Patients with NMIBC CIS unresponsive to BCG have limited treatment options. N-803 (Anktiva) is a mutant IL-15-based immunostimulatory fusion protein complex (IL15RaFc) that promotes proliferation and activation of natural killer (NK) cells and CD8+ T cells, but not regulatory T cells. Phase 1b data in BCG-naïve patients with NMIBC demonstrate that intravesical administration of N-803 with BCG induced complete response in all patients, without recurrences for the study duration of 24 months. Pembrolizumab was approved in 2020 with a 41% complete response (CR) rate in a single arm phase 2 trial of 96 patients. We report data on 160 subjects from an open-label, 3 cohort multicenter study (QUILT 3.032) of intravesical BCG plus N-803 in patients with BCG-unresponsive high-grade NMIBC (NCT03022825). Methods: All treated patients received intravesical N-803 plus BCG, consistent with the standard induction/maintenance treatment schedule. The primary endpoint for Cohort A (CIS) is incidence of CR of CIS at any time. The primary endpoint for Cohort B (Papillary) is disease-free rate (DFS) at 12 months. Results: To date, we enrolled 160 patients (83 CIS, 77 Papillary). In the overall population, median age is 72.3 years, 81% male, with mean number of prior TURBT = 4. Median number of prior BCG doses = 12. CIS patients have a CR rate of 71% (59/83), with a mediation duration of CR of 24.1 months in responders; 91% avoided cystectomy and 96% 24 month bladder cancer specific progression free survival (defined as progression to MIBC). Papillary patients have a 57% 12 month DFS rate, 48% 24 month DFS rate, and 95% avoided cystectomy. Median time to cystectomy in responders (N = 4) is 12.9 months versus 7.8 in non-responders (N = 8) for a 5.1 month delay in cystectomy. PK data shows no systemic levels of N-803; activity is confined to the bladder. Low grade treatment related AEs (grade 1-2) include dysuria (22%), pollakiurua (19%), hematuria (18%), fatigue (16%), and urgency (12%), all other AEs were seen at 7% or less. No treatment related grade 4 or 5 AE were seen. No SAE's were considered treatment related. No immune related SAE's have been seen. Conclusions: In 160 patients with BCG-unresponsive NMIBC, there is a 99% bladder cancer specific overall survival at 2 years. In CIS patients 71% CR rate with 24.1 months median duration of response, and 53% DFS rate at 18 months in Papillary disease. Cystectomy was avoided in over 90% of patients with 2 years of follow-up. The efficacy and safety profile of N-803+BCG exceeds that of other available intravesical and systemic options for BCG-unresponsive NMIBC. Clinical trial information: NCT03022825.

PLLBA-01 FINAL CLINICAL RESULTS OF PIVOTAL TRIAL OF IL-15RΑFC SUPERAGONIST N-803 WITH BCG IN BCG-UNRESPONSIVE NON-MUSCLE INVASIVE BLADDER CANCER (NMIBC) CIS AND PAPILLARY COHORTS

You have accessJournal of UrologyCME1 May 2022PLLBA-01 FINAL CLINICAL RESULTS OF PIVOTAL TRIAL OF IL-15RΑFC SUPERAGONIST N-803 WITH BCG IN BCG-UNRESPONSIVE NON-MUSCLE INVASIVE BLADDER CANCER (NMIBC) CIS AND PAPILLARY COHORTS Sam Chang, Karim Chamie, Mark Hidalgo, Eugene Kramolowsky, Wade Sexton, Sandeep Reddy, and Patrick Soon-Shiong Sam ChangSam Chang More articles by this author , Karim ChamieKarim Chamie More articles by this author , Mark HidalgoMark Hidalgo More articles by this author , Eugene KramolowskyEugene Kramolowsky More articles by this author , Wade SextonWade Sexton More articles by this author , Sandeep ReddySandeep Reddy More articles by this author , and Patrick Soon-ShiongPatrick Soon-Shiong More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002671.01AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Patients with NMIBC CIS unresponsive to BCG have limited treatment options. N-803 (Anktiva) is a mutant IL-15-based immunostimulatory fusion protein complex (IL15RaFc) that promotes proliferation and activation of natural killer (NK) cells and CD8+ T cells, but not regulatory T cells. Phase 1b data in BCG-naïve patients with NMIBC demonstrate that intravesical N-803 with BCG induced complete response in all patients, without recurrences for the study duration of 24 months. An open-label, 3 cohort multicenter study (QUILT 3.032) of intravesical BCG plus N-803 in patients with BCG-unresponsive high-grade NMIBC (NCT03022825) was opened. We report data on 160 subjects. METHODS: All treated patients received intravesical N-803 plus BCG, consistent with the standard induction/maintenance treatment schedule. The primary endpoint for Cohort A (CIS) is incidence of complete response (CR) of CIS at any time. The primary endpoint for Cohort B (Papillary) is disease-free rate (DFS) at 12 months. RESULTS: To date, 83 patients have enrolled in cohort A, 77 in Cohort B. In the overall population, median age is 72.3 years, 81% male, with mean number of prior TURBT=4. Median number of prior BCG doses = 12. CIS patients have a CR rate of 71% (59/83), with a mediation duration of CR of 24.1 months in responders; 91% avoided cystectomy and 96% 24 month bladder cancer specific progression free survival (defined as progression to MIBC). Papillary patients have a 57% 12 month DFS rate, 48% 24 month DFS rate, and 95% avoided cystectomy. Median time to cystectomy in responders (N=4) is 12.9 months versus 7.8 in non-responders (N=8) for a 5.1 month delay in cystectomy. PK data shows no systemic levels of N-803; thus activity is confined to the bladder. Low grade treatment related AEs (grade 1-2) include dysuria (22%), pollakiurua (19%), hematuria (18%), fatigue (16%), and urgency (12%), all other AEs were seen at 7% or less. No treatment related grade 4 or 5 AE were seen. No treatment emergent SAE's were considered treatment related. No immune related SAE's have been seen. Final data will be presented at AUA. CONCLUSIONS: In 160 patients with BCG-unresponsive NMIBC, there is a 99% bladder cancer specific overall survival at 2 years. In CIS patients 71% CR rate with 24.1 months median duration of response and 96% absence of progression to MIBC at 24 months. 53% DFS rate at 18 months in Papillary disease, N-803+BCG efficacy and safety profile exceeds other available intravesical and systemic options. Source of Funding: ImmunityBio © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e1047 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Sam Chang More articles by this author Karim Chamie More articles by this author Mark Hidalgo More articles by this author Eugene Kramolowsky More articles by this author Wade Sexton More articles by this author Sandeep Reddy More articles by this author Patrick Soon-Shiong More articles by this author Expand All Advertisement PDF DownloadLoading ...

Formulation of IMXQB: Nanoparticles Based on Quillaja brasiliensis Saponins to be Used as Vaccine Adjuvants.

Adjuvants are essential components of subunit, recombinant, nonreplicating and killed vaccines, as they are substances that boost, shape, and/or enhance the immune response triggered by vaccination. Saponins obtained from the Chilean Q. saponaria tree are used as vaccine adjuvants in commercial vaccines, although they are scarce and difficult to obtain. In addition, tree felling is needed during its extraction, which has ecological impact. Q. brasiliensis leaf-extracted saponins arise as a more sustainable alternative, although its use is still limited to preclinical studies. Despite the remarkable immunostimulating properties of saponins, they are toxic to mammalian cells, due to their intrinsic characteristics. For these reasons they are mostly used in veterinary vaccines, although recently the Q. saponaria purified saponin QS-21 has been included in adjuvant systems for human vaccines, such as Mosquirix and Shingrix (GSK). In order to abrogate the toxicity of the saponins fractions, they can be formulated as immunostimulating complexes (ISCOMs). ISCOM-matrices are cage-like nanoparticles of approximately 40nm, formulated combining saponins and lipids, without antigen, and are great adjuvants able to promote Th1-biased immune responses in a safe manner. Herein we describe how to formulate ISCOM-matrices nanoparticles using Q. brasiliensis purified saponin fractions (IMXQB) by the dialysis method. In addition, we indicate how to verify the appropriate size and homogeneity of the formulated nanoparticles.

PD09-05 PHASE 2/3 CLINICAL RESULTS OF IL-15RΑFC SUPERAGONIST N-803 WITH BCG IN BCG-UNRESPONSIVE NON-MUSCLE INVASIVE BLADDER CANCER (NMIBC) CARCINOMA IN-SITU (CIS) PATIENTS.

You have accessJournal of UrologyBladder Cancer: Non-invasive I (PD09)1 Sep 2021PD09-05 PHASE 2/3 CLINICAL RESULTS OF IL-15RΑFC SUPERAGONIST N-803 WITH BCG IN BCG-UNRESPONSIVE NON-MUSCLE INVASIVE BLADDER CANCER (NMIBC) CARCINOMA IN-SITU (CIS) PATIENTS. Karim Chamie, Sam Chang, Mark Gonzalgo, Eugene Kramolowski, Sandeep Reddy, Paul Bhar, Patrick Soon-Shiong, and Chad Garner Karim ChamieKarim Chamie More articles by this author , Sam ChangSam Chang More articles by this author , Mark GonzalgoMark Gonzalgo More articles by this author , Eugene KramolowskiEugene Kramolowski More articles by this author , Sandeep ReddySandeep Reddy More articles by this author , Paul BharPaul Bhar More articles by this author , Patrick Soon-ShiongPatrick Soon-Shiong More articles by this author , and Chad GarnerChad Garner More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000001977.05AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Patients with NMIBC CIS unresponsive to BCG have limited treatment options. N-803 (Anktiva) is an mutant IL-15-based immunostimulatory fusion protein complex (IL-15RαFc) that promotes proliferation and activation of natural killer (NK) cells and CD8+ T cells, but not regulatory T cells. Phase 1b data in BCG-naïve patients with NMIBC demonstrate that intravesical administration of N-803 with BCG induced complete response in all patients, without recurrences for the study duration of 24 months. An open-label, 3 cohort multicenter Phase 2/3 study (QUILT 3.032) of intravesical BCG plus N-803 in patients with BCG-unresponsive high-grade NMIBC (NCT03022825) was opened. We report here the interim analysis of Cohort A, BCG-unresponsive (CIS) [with or without Ta or T1 disease], as of December 2020 data cutoff. METHODS: All treated patients received intravesical N-803 plus BCG, consistent with the standard induction/maintenance treatment schedule. The primary endpoint for Cohort A of this phase 2/3 study is incidence of complete response (CR) of CIS at any time. RESULTS: To date, 80 patients have enrolled in cohort A of this phase 2/3 trial. Evaluable analysis at this time shows CR rate at any time of 72% (N=51/71); for patients achieving CR, the probability of maintaining a CR for 12 months is 59%, with a median duration of complete response of 19.2 (7.6, 26.4) months. Low grade treatment related AEs include dysuria, hematuria, and pollakiurua (all 16%), urgency (14%), and bladder spasm (8%), all other AEs were seen at 6% or less. A total of 9 subjects experienced at least 1 treatment emergent SAE (Severe Adverse event), the SAE rate is 1% for any given AE. No treatment emergent SAE’s were considered treatment related. No immune related SAE’s have been seen. To date, 10/80 (12.5%) patients proceeded to cystectomy in this BCG unresponsive population. Updated data on all 80 subjects will be presented at AUA. CONCLUSIONS: With a CR rate of 72%, N-803 has met its primary endpoint with 59% probability of CR patients maintaining CR for at least 12 months. With the observed strong efficacy and an SAE rate of 1%, N-803 represents a novel treatment option for BCG unresponsive CIS with a favorable benefit:risk ratio, in a therapeutically challenging disease. Source of Funding: ImmunityBio © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e120-e121 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Karim Chamie More articles by this author Sam Chang More articles by this author Mark Gonzalgo More articles by this author Eugene Kramolowski More articles by this author Sandeep Reddy More articles by this author Paul Bhar More articles by this author Patrick Soon-Shiong More articles by this author Chad Garner More articles by this author Expand All Advertisement Loading ...

Phase II/III clinical results of IL-15RαFc superagonist N-803 with BCG in BCG-unresponsive non-muscle invasive bladder cancer (NMIBC) carcinoma in situ (CIS) patients.

510 Background: Patients with NMIBC CIS unresponsive to BCG have limited treatment options. N-803 (Anktiva) is a mutant IL-15-based immunostimulatory fusion protein complex (IL-15RαFc) that promotes proliferation and activation of natural killer (NK) cells and CD8+ T cells, but not regulatory T cells. Phase Ib data in BCG-naive patients with NMIBC demonstrate that intravesical administration of N-803 with BCG induced complete response in all patients, without recurrences for the study duration of 24 months. An open-label, 3 cohort multicenter phase II/III study (QUILT 3.032) of intravesical BCG plus N-803 in patients with BCG-unresponsive high-grade NMIBC (NCT03022825) was opened. We report here the interim analysis of Cohort A, BCG-unresponsive (CIS) [with or without Ta or T1 disease], as of December 2020 data cutoff. Methods: All treated patients received intravesical N-803 plus BCG, consistent with the standard induction/maintenance treatment schedule. The primary endpoint for Cohort A of this phase II/III study is incidence of complete response (CR) of CIS at any time. Results: To date, 80 patients have enrolled in cohort A of this phase II/III trial. Evaluable analysis at this time shows CR rate at any time of 72% (N=51/71); for patients achieving CR, the probability of maintaining a CR for 12 months is 59%, with a median duration of complete response of 19.2 (7.6, 26.4) months. Low-grade treatment related AEs include dysuria, hematuria, and pollakiurua (all 16%), urgency (14%), and bladder spasm (8%), all other AEs were seen at 6% or less. A total of 9 subjects experienced at least 1 treatment emergent SAE (Severe Adverse event), the SAE rate is 1% for any given AE. No treatment emergent SAE’s were considered treatment related. No immune related SAE’s have been seen. To date, 10/80 (12.5%) patients proceeded to cystectomy in this BCG unresponsive population. Conclusions:With a CR rate of 72%, N-803 has met its primary endpoint with 59% probability of CR patients maintaining CR for at least 12 months. With the observed strong efficacy and an SAE rate of 1%, N-803 represents a novel treatment option for BCG unresponsive CIS with a favorable benefit:risk ratio, in a therapeutically challenging disease. Clinical trial information: NCT03022825.

Assessment of Immunostimulating effect of Carica papaya-based Immunostimulatory Complexes Against Streptococcus pneumoniae Infections

Objectives: Streptococcus pneumoniae infection is a bacterial infection responsible for one-fifth of child mortality in Africa. The aim of this study was to formulate and evaluate Carica papaya-based Immunostimulatory complexes against Streptococcus pneumoniae infections. Methods: Leaves of the plant were harvested, air-dried, pulverized and the saponin content extracted using distilled water and but anole in a Soxhlet’s apparatus. The formulation of Immunostimulatory complexes was prepared using the ethanol injection method. Acute toxicity test and Immunological assays, namely: neutrophil adhesion, carbon clearance, hem agglutinating antibody titer were conducted using healthy laboratory mice. The results were compared to standard drug (levamisole). Results: The aqueous extract and butanol fraction yielded 7.45% and 0.38% saponin. At 5000mg/ kg body weight of administered immunostimulatory complexes, no death or behavioral changes were recorded. Neutrophil adhesion showed no significant increase (20.82±4.34) as against the levamisole (20.74±3.31). The increased phagocytic index (0.089± 0.017) showed better stimulation of reticuloendothelial system when compared to both controls (distilled water = 0.032 ± 0.001; levamisole = 0.071 ± 0.001).The lower Hemagglutination antibody titre value indicates the potency of the formulated ISCOM to elicit an immune response. The ISCOM dose (250 mg/kg body weight) significantly elevated hemagglutination antibody titre (7.81±1.60). Conclusion: It can be inferred from this study that Carica papaya leaves has immunomodulatory capacity and has significant saponin yield which could potentially serve as a component of Immunostimulatory complexes formulation. Carica papaya-based Immunostimulatory complexes exhibit improved immunogenicity against Streptococcus pneumoniae infections.

Preliminary phase 2 clinical results of IL-15RαFc superagonist N-803 with BCG in BCG-unresponsive non-muscle invasive bladder cancer (NMIBC) patients.

4561 Background: Patients with non-muscle-invasive bladder cancer (NMIBC) unresponsive to BCG therapy have limited treatment options. N-803 (also known as ALT-803) is an IL-15-based immunostimulatory protein complex (IL-15RαFc) that promotes proliferation and activation of natural killer (NK) cells and CD8+ T cells, but not regulatory T cells. Phase Ib data in BCG-naïve patients with NMIBC demonstrate that intravesical administration of N-803 with BCG induced complete response in all patients, without recurrences for the study duration of 24 months. Methods: An open-label, single-arm multicenter Phase 2 study of intravesical BCG plus N-803 in patients with BCG-unresponsive high-grade NMIBC (NCT03022825) was opened. The study has two cohorts: Cohort A, patients with BCG-unresponsive carcinoma in situ (CIS) [with or without Ta or T1 disease] and Cohort B, patients with BCG-unresponsive high-grade Ta/T1 disease. All treated patients receive intravesical N-803 plus BCG, similar to a standard induction and maintenance treatment schedule. The primary endpoint for Cohort A is incidence of complete response (CR) of CIS at any time, and the primary endpoint for Cohort B is disease-free rate at 12 months. Results: To date, forty-six patients have enrolled in this phase 2 trial (Cohort A (CIS), n = 23, Cohort B (Papillary), n = 23). Of eleven evaluable patients in Cohort A, nine patients (82%) have a reported CR. In addition, seven out of nine (78%) patients in Cohort A demonstrated CR at their 6-month response assessment. Of thirteen evaluable patients in Cohort B, ten patients (77%) showed no evidence of recurrence at their 3-month response assessment; of these, none (0/8) evaluated past 3 months have had disease recurrence. Three serious adverse events (AEs) have been reported (E coli infection, anemia, and bacteremia), with no immune-related AEs. Conclusions: Nine out of eleven (82%) patients with BCG-unresponsive CIS of the bladder demonstrated a complete response. Ten out of thirteen patients with BCG-unresponsive papillary NMIBC show no evidence of disease at first assessment. Intravesical N-803 plus BCG was well-tolerated and no patients experienced immune-related AEs. Clinical trial information: NCT03022825.

Adjuvant activity of multimolecular complexes based on Glycyrrhiza glabra saponins, lipids, and influenza virus glycoproteins.

Numerous studies have shown that immunostimulatory complexes containing Quil-A saponin and various antigens are effective in stimulating the immune response and can be used as vaccine preparations for animals and humans. However, Quil-A saponin possesses toxicity and haemolytic activity. In the present work, a saponin-containing preparation named "Glabilox" was isolated from the roots of a Glycyrrhiza glabra L. plant by high-performance liquid chromatography (HPLC). The results showed that Glabilox has no toxicity or haemolytic activity and can form stable immunostimulatory complexes. Subcutaneous immunization of mice with an immunostimulating complex containing Glabilox and H7N1 influenza virus antigens stimulated high levels of humoral and cellular immunity. Vaccination of chickens with the same immunostimulating complex protected 100% of the animals after experimental infection with a homologous virus. Comparative studies showed that the immunogenic and protective activity of immunostimulatory complexes containing Quil-A and immunostimulatory complexes containing Glabilox are comparable to each other. The results of these studies indicated that Glycyrrhiza glabra saponins show great promise as safe and effective adjuvants.

Saponins from Quillaja saponaria and Quillaja brasiliensis: Particular Chemical Characteristics and Biological Activities.

Quillaja saponaria Molina represents the main source of saponins for industrial applications. Q. saponaria triterpenoids have been studied for more than four decades and their relevance is due to their biological activities, especially as a vaccine adjuvant and immunostimulant, which have led to important research in the field of vaccine development. These saponins, alone or incorporated into immunostimulating complexes (ISCOMs), are able to modulate immunity by increasing antigen uptake, stimulating cytotoxic T lymphocyte production (Th1) and cytokines (Th2) in response to different antigens. Furthermore, antiviral, antifungal, antibacterial, antiparasitic, and antitumor activities are also reported as important biological properties of Quillaja triterpenoids. Recently, other saponins from Q. brasiliensis (A. St.-Hill. & Tul.) Mart. were successfully tested and showed similar chemical and biological properties to those of Q. saponaria barks. The aim of this manuscript is to summarize the current advances in phytochemical and pharmacological knowledge of saponins from Quillaja plants, including the particular chemical characteristics of these triterpenoids. The potential applications of Quillaja saponins to stimulate further drug discovery research will be provided.

Immunogenicity and Protective Activity of a Chimeric Protein Based on the Domain III of the Tick-Borne Encephalitis Virus E Protein and the OmpF Porin of Yersinia pseudotuberculosis Incorporated into the TI-Complex

Tick-borne encephalitis (TBE) is a widespread, dangerous infection. Unfortunately, all attempts to create safe anti-TBE subunit vaccines are still unsuccessful due to their low immunogenicity. The goal of the present work was to investigate the immunogenicity of a recombinant chimeric protein created by the fusion of the EIII protein, comprising domain III and a stem region of the tick-borne encephalitis virus (TBEV) E protein, and the OmpF porin of Yersinia pseudotuberculosis (OmpF-EIII). Adjuvanted antigen delivery systems, the tubular immunostimulating complexes (TI-complexes) based on the monogalactosyldiacylglycerol from different marine macrophytes, were used to enhance the immunogenicity of OmpF-EIII. Also, the chimeric protein incorporated into the most effective TI-complex was used to study its protective activity. The content of anti-OmpF-EIII antibodies was estimated in mice blood serum by enzyme-linked immunosorbent assay (ELISA). To study protective activity, previously immunized mice were infected with TBEV strain Dal’negorsk (GenBank ID: FJ402886). The animal survival was monitored daily for 21 days. OmpF-EIII incorporated into the TI-complexes induced about a 30–60- and 5–10-fold increase in the production of anti-OmpF-EIII and anti-EIII antibodies, respectively, in comparison with the effect of an individual OmpF-EIII. The most effective vaccine construction provided 60% protection. Despite the dramatic effect on the specific antibody titer, the studied TI-complex did not provide a statistically significant increase in the protection of OmpF-EIII protein. However, our results provide the basis of the future search for approaches to design and optimize the anti-TBEV vaccine based on the OmpF-EIII protein.

Quillaja brasiliensis saponin-based nanoparticulate adjuvants are capable of triggering early immune responses

Commercially available saponins are extracted from Quillaja saponaria barks, being Quil A® the most widely used. Nanoparticulate immunostimulating complexes (ISCOMs or ISCOMATRIX) formulated with these, are able to stimulate strong humoral and cellular immune responses. Recently, we formulated novel ISCOMs replacing QuilA® by QB-90 (IQB-90), a Quillaja brasiliensis leaf-extracted saponin fraction, and reported that IQB-90 improved antigen uptake, and induced systemic and mucosal antibody production, and T-cell responses. However, its mechanism of action remains unclear. In this study we provide a deeper insight into the immune stimulatory properties of QB-90 and ISCOMATRIX-like based on this fraction (IMXQB-90). We show herein that, when used as a viral vaccine adjuvant, QB-90 promotes an “immunocompetent environment”. In addition, QB-90 and IMXQB-90 induce immune-cells recruitment at draining-lymph nodes and spleen. Subsequently, we prove that QB-90 or IMXQB-90 stimulated dendritic cells secret IL-1β by mechanisms involving Caspase-1/11 and MyD88 pathways, implying canonical inflammasome activation. Finally, both formulations induce a change in the expression of cytokines and chemokines coding genes, many of which are up-regulated. Findings reported here provide important insights into the molecular and cellular mechanisms underlying the adjuvant activity of Q. brasiliensis leaf-saponins and its respective nanoparticles.

Effectivity of nanovaccine against tick-borne encephalitis

The tubular immunostimulating complex (Tl-complex) is a new nanoparticulate antigen delivery system, which was developed to enhance immunogenicity of different subunit antigens within anti-infectious vaccines and increase their economic efficacy and safety. TI-complexes are self-organized from mixture of triterpene glycosides from Cucumaria japonica, cholesterol and monogalactosyldiacylglycerol (MGDG) from marine macrophytes. MGDG plays role of lipid matrix for subunit protein antigen interrupted in TI-complexes. Microviscosity of MGDG was shown to influence the conformation and immunogenicity of protein antigen. Present work was aimed to study adjuvant effect of Tl-complexes on immunogenicity of chimeric protein antigen based on E protein domain III of tick-borne encephalitis (TBE) virus and OmpF porin of Yersinia pseudotuberculosis depending on MGDGs isolated from different marine algae and seagrass. It was shown that TI-complex including MGDG from Ulva lactuca was most effective. Immunization by chimeric antigen incorporated in TI-complexes provided a high level of animal protection in experimental infection with TBE. Thus, the proposed construction is promising for the development of vaccines against TBE.