Phase I Study and Preliminary Pharmacology of the Novel Innate Immune Modulator rBBX-01 in Gynecologic Cancers

The roles and clinical applications of interleukins in endometrial carcinoma

As a common malignant tumor of the female reproductive system, endometrial carcinoma (EC) seriously endangers women's health with an increasing incidence. The oncogenesis and progression of cancer are closely linked with immune microenvironment, of which interleukins are the important components. In order to illustrate the roles and clinical applications of interleukins in EC, literature of interleukins and EC were reviewed. Based on the present studies, interleukins play crucial roles in the oncogenesis and development of EC via regulating the proliferation, migration, invasion, angiogenesis, apoptosis, pyroptosis and autophagy of EC as well as the immune function against EC. And some of the interleukins seems to have prospective clinical applications in EC, such as evaluating the risk of tumorigenesis, discriminating the malignancy from benign disorders or normal condition, indicating cancer aggressiveness, predicting the prognosis of patients and serving as the novel therapy. However, there is still a long way to go before the clinical applications of interleukins in EC come into reality. Nevertheless, it is certain that the exploration of interleukins will definitely be of great benefit to the screening, diagnosis and treatment of EC in the future.

Antitumour metastasis and the antiangiogenic and antitumour effects of a Eimeria stiedae soluble protein

Some protozoa (Plasmodium falciparum, Toxoplasma gondii, etc) are used to treat cancer because they can improve tumour-induced immunosuppression. This study aims to evaluate the antitumour effect of Eimeria stiedae oocyst soluble protein (ESSP). ESSP was extracted, and mice were injected with 5 × 10⁵ CT26 cells in the right axilla, and then, 50 μg of ESSP was intraperitoneally injected for 5 continuous days. The effect of ESSP on tumour immunity was detected by flow cytometry 25 days after the CT26 inoculation. The results showed that ESSP can inhibit the growth of CT26 subcutaneous tumours; significantly increase the expression of MHC I, MHC II, CD80 and CD86 on the surface of splenic dendritic cells; and enhance the level of IL-12 secretion. ESSP induced an increase in the number of NK cells in the mouse spleen, and the levels of IFN-γ and CD107 were upregulated in the NK cells and CD8⁺ T cells. The number of metastatic nodules in the lung tumours in the mice was significantly reduced, and the number of tubes, area of the loops and total length of the tubes were significantly reduced. ESSP enhances the antitumour immune response and inhibits tumour growth, metastasis and angiogenesis.

Immune disorder in endometrial cancer: Immunosuppressive microenvironment, mechanisms of immune evasion and immunotherapy

Immunotherapy is an emerging clinical approach that has gained traction over the past decade as a novel treatment option for lung cancer and melanoma. Notably, researchers have made marked improvements in the treatment of endometrial cancer (EC), and potential immune responses have been identified in patients with EC, thereby offering the possibility of exploring immunotherapy for EC. Nevertheless, various needs remain unmet, and immunotherapy applications in EC have yielded limited success, as only a minority of patients exhibited a clinical response. Therefore, further understanding of immune dysfunction associated with EC is still required. The present review describes recent findings regarding the immunosuppressive microenvironment of EC, with emphasis on immune evasion mechanisms and immunotherapy in EC.

Strengthened tumor antigen immune recognition by inclusion of a recombinant Eimeria antigen in therapeutic cancer vaccination

The need for novel, effective adjuvants that are capable of eliciting stronger cellular and humoral adaptive immune responses to antigenic targets is well understood in the vaccine development field. Unfortunately, many adjuvants investigated thus far are either too toxic for human application or too weak to induce a substantial response against difficult antigens, such as tumor-associated antigens (TAAs). In spite of this trend, clinical investigations of recombinant Eimeria antigen (rEA) have revealed this protein to be a non-toxic immunogenic agent with the ability to trigger a Th1-predominant response in both murine and human subjects. Our past studies have shown that the injection of a rEA-encoding adenovirus (rAd5-rEA) alongside an HIV antigen-encoding adenovirus greatly improves the adaptive immune response against this pathogen-derived transgene. In this report, we investigated whether rAd5-rEA could promote and/or alter cytotoxic memory responses toward carcinoembryonic antigen (CEA), a colorectal cancer-related TAA. We found that the addition of rAd5-rEA to an Ad-based CEA vaccine induced a dose-dependent increase in several anti-CEA T and B cell responses. Moreover, inclusion of rAd5-rEA increased the number of CEA-derived antigenic epitopes that elicited significant cell-mediated and IgG-mediated recognition. These enhanced anti-CEA immune responses also translated into superior CEA-targeted cell killing, as evaluated by an in vivo cytotoxic T lymphocyte assay. Overall, these results suggest that co-administration of rAd5-rEA with a tumor antigen vaccine can substantially boost and broaden the TAA-specific adaptive memory response, thereby validating the potential of rAd5-rEA to be a beneficial adjuvant during therapeutic cancer vaccination.

TRIF is a critical negative regulator of TLR agonist mediated activation of dendritic cells in vivo

Despite recent advances in developing and licensing adjuvants, there is a great need for more potent formulations to enhance immunogenicity of vaccines. An Eimeria tenella derived antigen (rEA) augments immune responses against several pathogens in animal models and recently was confirmed to be safe for human use. In this study, we have analyzed the molecular mechanisms underlying rEA activity in mice, and confirmed that rEA activates multiple immune cell types, including DCs, macrophages, NK, B, and T cells. The rEA adjuvant also elicits the induction of pleiotropic pro-inflammatory cytokines, responses that completely depend upon the presence of the TLR adaptor protein MyD88. Surprisingly, we also found that the TRIF adaptor protein acts as a potent negative regulator of TLR agonist-triggered immune responses. For example, IL12 production and the induction of co-stimulatory molecule expression by DCs and IFNγ production by NK cells in vivo were significantly increased in rEA-treated TRIF-KO mice. Importantly, however, TRIF suppressive effects were not restricted to rEA-mediated responses, but were apparent in LPS- or ODN2006-activated DCs as well. Taken together, our findings confirm that rEA is a potent adjuvant, triggering robust activation of the innate immune system, in a manner that is augmented by MyD88 and inhibited by TRIF; thereby unveiling the potential complexities of modulating TLR activity to augment vaccine efficacy.

A new adenovirus based vaccine vector expressing an Eimeria tenella derived TLR agonist improves cellular immune responses to an antigenic target

BACKGROUND

Adenoviral based vectors remain promising vaccine platforms for use against numerous pathogens, including HIV. Recent vaccine trials utilizing Adenovirus based vaccines expressing HIV antigens confirmed induction of cellular immune responses, but these responses failed to prevent HIV infections in vaccinees. This illustrates the need to develop vaccine formulations capable of generating more potent T-cell responses to HIV antigens, such as HIV-Gag, since robust immune responses to this antigen correlate with improved outcomes in long-term non-progressor HIV infected individuals.

METHODOLOGY/PRINCIPAL FINDINGS

In this study we designed a novel vaccine strategy utilizing an Ad-based vector expressing a potent TLR agonist derived from Eimeria tenella as an adjuvant to improve immune responses from a [E1-]Ad-based HIV-Gag vaccine. Our results confirm that expression of rEA elicits significantly increased TLR mediated innate immune responses as measured by the influx of plasma cytokines and chemokines, and activation of innate immune responding cells. Furthermore, our data show that the quantity and quality of HIV-Gag specific CD8(+) and CD8(-) T-cell responses were significantly improved when coupled with rEA expression. These responses also correlated with a significantly increased number of HIV-Gag derived epitopes being recognized by host T cells. Finally, functional assays confirmed that rEA expression significantly improved antigen specific CTL responses, in vivo. Moreover, we show that these improved responses were dependent upon improved TLR pathway interactions.

CONCLUSION/SIGNIFICANCE

The data presented in this study illustrate the potential utility of Ad-based vectors expressing TLR agonists to improve clinical outcomes dependent upon induction of robust, antigen specific immune responses.

Immunoprophylaxis of Punta Toro virus (Phlebovirus, Bunyaviridae) infection in hamsters with recombinant Eimeria profilin-like antigen

Recombinant Eimeria antigen (rEA) has been shown to have potent anticancer and antiviral activity in respective mouse disease models, presumably through robust immune stimulation that occurs via TLR11, a pattern recognition receptor that recognizes profilin-like proteins expressed on apicomplexan protozoans. Comparable immunostimulatory activity in other species has yet to be demonstrated. Since rEA is known to be highly effective in treating Punta Toro virus (PTV) infection in mice, its ability to elicit protective immunity in the hamster PTV infection model was investigated. rEA was given alone, or in combination with IL-18 or IL-2, and virally challenged hamsters were observed for mortality. Cytokine transcript profiles for IL-12p40, IL-21, IFN-gamma and TNF-alpha were assessed to evaluate the induction of these inflammatory mediators known to be induced in mice following exposure to rEA. A dose of 100 microg of rEA, given once 4 h prior to viral challenge, and a second time on day 3 of the infection, was found to be the most effective prophylactic therapy protecting 60% of treated hamsters from mortality, compared to only 5-10% observed in animals receiving placebo. Increased expression of IFN-gamma and IL-12p40 was evident following treatment with rEA. The data suggest that rEA does induce host antiviral responses in hamsters that result in significant protection from death, although determining the most appropriate dose for intervention in other species, including humans, will likely be challenging.