Biology subjects

Ivanova, D. L.

Publications and source records attributed to Ivanova, D. L..

6 recordsLinked to original sources

bioRxiv2026

Atomic Layering Thermostable Antigen and Adjuvant (ALTA(R)) platform provides unique antigen delivery system through controlled release to improve immune response to vaccination

Prophylactic vaccines are commonly delivered using a multi-dose regimen with the goal of generating potent, durable protection against a specific pathogen. However, the requirement for multiple administrations can impede patient adherence and reduce overall protection. Designing a single-shot vaccine without compromising efficacy could significantly improve vaccine adherence and performance. Previously, it has been shown that atomic-layer deposition (ALD) of alumina (Al2O3) can be applied to spray dried, thermostabilized antigen-containing powders to produce alumina-coated vaccine particles that, when compared to a liquid control, elicit improved humoral immunity with response kinetics controlled by ALD-coat thickness. However, previous studies have not defined the particle release/antigen delivery profile of ALD-coated vaccines. The studies in this manuscript were designed to investigate how the kinetics of antigen release from ALD-coated vaccines impacts the timing and magnitude of the immune response relative to single- and multi-dose liquid vaccine regimens using two distinct antigens, Ovalbumin and the HIV-1 envelope trimer, N332-GT5 gp140. By combining longitudinal in vivo imaging and immunological readouts, we demonstrate that ALD-coated vaccines exhibit tunable, variable-rate release and deliver antigen in a unique, prolonged manner that results in an improved immune response to single-shot vaccination for difficult to target pathogens, such as HIV-1. Furthermore, using in vitro analytical methods, we confirmed the ability of our Atomic Layering and Thermostable Antigen and Adjuvant (ALTA(R)) platform to impart thermostability upon the N332-GT5 gp140 antigen, a clinically relevant HIV-1 immunogen, indicating the potential for ALTA(R) formulation to generate thermostable, single-dose vaccine products. Highlights- ALTA(R) microparticles provide sustained antigen delivery with variable release rates, which can be controlled by altering ALD-coat thickness - Sustained antigen release from thermostable, spray-dried ALTA(R) vaccine products impacts kinetics of humoral and cellular responses, and improves antigen-specific immunogenicity compared to single administration of liquid vaccine - ALTA(R) formulation imparts vaccine thermostability through spray-drying and ALD-coating to clinically relevant HIV-1 Env antigen, N332-GT5 gp140

immunology↗

bioRxiv2026

Subunit Vaccination Using Atomic Layering Thermostable Antigen and Adjuvant (ALTA(R)) Platform Elicits Enhanced Humoral and Cellular Immune Responses

AbstractCreating effective and thermostable vaccines is of significant relevance for public health. The Atomic Layering Thermostable Antigen and Adjuvant (ALTA(R)) platform combines spray drying to stabilize antigens in a sugar matrix followed by coating with atomic layer deposition (ALD) for temporal control over in vivo release. While these technologies have shown preliminary promise for different vaccine antigens, further characterizations of the immune response to ALTA(R) formulated antigens are still needed. Here, the immune response to ALTA(R) formulated antigens is described and compared to a set of adjuvanted liquid vaccine formulations that included Alhydrogel(R), AddaVax, and Alhydrogel(R)+CpG. The humoral and cell-mediated responses were measured by ELISA and flow cytometry. Increased and lasting antigen-specific antibody titers following administration of ALTA(R) containing ovalbumin (OVA) demonstrated robust and durable humoral response. Furthermore, ALTA(R) injected mice produced both IgG2c and IgG1 indicating a balanced Th1/Th2 response. Importantly, ALTA(R) OVA elicited robust humoral response at lower doses of aluminum than Alhydrogel(R). The most striking difference between ALTA(R) and the liquid vaccine formulations tested was a greater OVA-specific CD8+ T cell response observed at all antigen doses tested. Mechanistically, antigen encapsulation within ALTA(R) particles was critical for antibody production and CD8+ T cell responses as well as antigen capture by antigen-presenting cells (APCs) at the site of injection and draining lymph nodes. To test these concepts in a more physiological application, protein and polysaccharide vaccine antigens derived from a facultative intracellular bacterium Burkholderia pseudomallei, the causative agent of melioidosis, were formulated using the ALTA(R) platform. Compared to liquid vaccine formulations, ALTA(R) immunized mice showed enhanced antigen-specific antibody production and IFN-{gamma} secreting T cell responses using lower adjuvant doses of aluminum and CpG. Overall, ALTA(R) formulated protein and polysaccharide antigens elicited strong humoral and cell-mediated immunity suggesting potential broad applicability of the platform to vaccines against various diseases, including against cancer and infections from intracellular pathogens.

immunology↗

bioRxiv2024

IL-27 Stablizes Myc-Mediated Transcription In Memory-Fated, Vaccine-Elicited CD8+ T Cells

Protection from pathogens relies on both humoral (antibody-mediated) and cellular (T cell-mediated) responses. While infections robustly elicit both types of immunity, currently approved vaccine adjuvants largely fail to induce T cell responses on par with that instigated by infections. Our goal was to investigate the transcriptional programming that supports the formation of CD8+ T cells elicited by subunit vaccines compared to those elicited by infections. Our data show that vaccine-elicited T cells represent a transcriptionally unique subset of activated T cells with high proliferative capacity and a memory cell fate. This relies on IL-27 signaling, which stabilizes c-Myc and thereby supports the biomass acquisition necessary for clonal expansion. Collectively, our findings reveal that subunit vaccine-elicited T cells uniquely combine aspects of both memory and effector T cell subsets, and selectively utilize IL-27 signaling to sustain the clonal expansion of cells dedicated to a memory fate. One Sentence SummaryIn contrast to infection, subunit vaccines induce a distinct population of CD8+ T cells with memory fate characteristics which maintain their proliferative capacity during the expansion phase through IL-27 receptor signaling.

immunology↗

bioRxiv2019

NK cells negatively regulate CD8 T cells to promote immune exhaustion and chronic Toxoplasma gondii infection

NK cells regulate CD4+ and CD8+ T cells in acute viral infection, vaccination and the tumor microenvironment. NK cells also become exhausted in chronic activation settings. The mechanisms causing these ILC responses and their impact on adaptive immunity are unclear. CD8+ T cell exhaustion develops during chronic Toxoplasma gondii (T. gondii) infection resulting in parasite reactivation and death. How chronic T. gondii infection impacts the NK cell compartment is not known. We demonstrate that NK cells do not exhibit hallmarks of exhaustion. Their numbers are stable and they do not express high PD1 or LAG3. NK cell depletion with anti-NK1.1 is therapeutic and rescues chronic T. gondii infected mice from CD8+ T cell exhaustion dependent death, increases survival after lethal secondary challenge and reduces parasite reactivation. Anti-NK1.1 treatment increased polyfunctional CD8+ T cell responses in spleen and brain and reduced CD8+ T cell apoptosis. Chronic T. gondii infection promotes the development of a modified NK cell compartment, which does not exhibit normal NK cell behavior. This splenic CD49a-CD49b+NKp46+ NK cell population develops during the early chronic phase of infection and increases through the late chronic phase of infection. They are Ly49 and TRAIL negative and are enriched for expression of CD94/NKG2A and KLRG1. They do not produce IFN{gamma}, are IL-10 negative, do not increase PDL1 expression, but do increase CD107a on their surface. They are also absent from brain. Based on the NK cell receptor phenotype we observed NKp46 and CD94-NKG2A cognate ligands were measured. Activating NKp46 (NCR1-ligand) ligand increased and NKG2A ligand Qa-1b expression was reduced. Blockade of NKp46 also rescued the chronically infected mice from death. Immunization with a single dose non-persistent 100% protective T. gondii vaccination did not induce this cell population in the spleen, suggesting persistent infection is essential for their development. We hypothesize chronic T. gondii infection induces an NKp46 dependent modified NK cell population that reduces functional CD8+ T cells to promote persistent parasite infection in the brain. NK cell targeted therapies could enhance immunity in people with chronic infections, chronic inflammation and cancer.

immunology↗

bioRxiv2019

Anti-Asialo GM1 treatment during secondary Toxoplasma gondii infection is lethal and depletes T cells

Using vaccine challenge model of T. gondii infection, we found that treatments with two commonly used for NK cell depletion antibodies resulted in different survival outcomes during secondary infection. Anti-ASGM1 resulted in 100% death and greater parasite burden at the site of infection than anti-NK1.1. Anti-NK1.1 treatment resulted in increased parasite burdens, but animals did not die. Further we found that anti-ASGM1 treatment depleted T cells. CD8+ T cells were more susceptible that CD4+ T cells to the treatment. ASGM1 was expressed on a higher percentage of CD8+ T cells than CD4+ T cells and CD8+ T cells. In T. gondii-immunized animals ASGM1 was enriched on effector memory (Tem) and central memory (Tcm) CD8+ T cells. However, Tem were more susceptible to the treatment. After secondary infection, Tem, Tcm, effector (Tef) and naive (Tn) CD8+ T cells were positive for ASGM1. Anti-ASGM1 treatment during reinfection resulted in greater depletion of activated IFN{gamma}+, Granzyme B+, Tem and Tef than Tcm and Tn CD8+ T cells. Anti-ASGM1 also depleted IFN{gamma}+ CD4+ T cells. Recombinant IFN{gamma} supplementation prolonged survival of anti-ASGM1 treated mice, demonstrating that this antibody eliminated IFN{gamma}-producing T and NK cells important for control of the parasite. These results highlight that anti-ASGM1 antibody is not an optimal choice for targeting only NK cells and more precise approaches should be used. This study uncovers ASGM1 as a marker of activated effector T cells and the potential importance of changes in sialylation in lipid rafts for T cell activation during T. gondii infection.

immunology↗

bioRxiv2019

The IL-12 and IL-23-Dependent NK Cell Response is Essential For Protective Immunity Against Secondary Toxoplasma gondii Infection.

Natural Killer (NK) cells can develop memory-like features and contribute to long-term immunity in mice and humans. NK cells are critical for protection against acute T. gondii infection. However, whether they contribute to long-term immunity in response to this parasite is unknown. We used a vaccine challenge model of parasite infection to address this question and to define the mechanism by which NK cells are activated during secondary parasite infection. We found NK cells were required for control of secondary infection. NK cells increased in number at the infection site, became cytotoxic and produced IFN{gamma}. Adoptive transfer and NK-cell fate mapping revealed that T. gondii-experienced NK cells were not intrinsically different from naive NK cells with respect to their long-term persistence and ability to protect. Thus, they did not develop memory-like characteristics. Instead, a cell-extrinsic mechanism may control protective NK-cell responses during secondary infection. To test the involvement of a cell-extrinsic mechanism, we used anti-IL-12p70 and IL-12p35-/- mice and found that the secondary NK-cell response was not fully dependent on IL-12. IL-23 depletion with anti-IL-23p19 in vivo significantly reduced the secondary NK-cell response, suggesting that both IL-12 and IL-23 were involved. Anti-IL-12p40 treatment, which blocks both IL-12 and IL-23, eliminated the protective secondary NK-cell response, supporting this hypothesis. Our results define a previously unknown protective role for NK cells during secondary T. gondii infection that is dependent on IL-12 and IL-23.

immunology↗