Multi-antigen Vaccine Research Articles

Construction and evaluation of a novel multi-antigenic Mycobacterium tuberculosis subunit vaccine candidate BfrB-GrpE/DPC

Tuberculosis poses a significant threat to human health due to the lack of an effective vaccine. Although promising progress has been made in the development of tuberculosis vaccines, new vaccines that broaden the antigenic repertoire need to be developed to eradicate this illness. In this study, we used Mycobacterium tuberculosis ferritin BfrB and heat-shock protein GrpE to construct a novel multi-antigenic fusion protein, BfrB-GrpE (BG). BG protein was stably overexpressed in the soluble form in Escherichia coli at a high yield and purified via sequential salt fractionation and hydrophobic chromatography. Purified BG was emulsified in an adjuvant containing N, N'-dimethyl-N, N'-dioctadecylammonium bromide, polyinosinic-polycytidylic acid, and cholesterol (DPC) to construct the BG/DPC vaccine, which stimulated strong cellular and humoral immune responses in mice. Moreover, combination of BG with our previously developed vaccine, Mtb10.4-HspX (MH), containing antigens from both the proliferating and dormant stages, significantly reduced the bacterial counts in the lungs and spleens of M. tuberculosis-infected mice. Importantly, mice that received BG + MH/DPC after M. tuberculosis H37Rv infection survived slightly better (100% survival) than those that received the BCG vaccine (80% survival), although the difference was not statistically significant. Our findings can aid in the selection of antigens and optimization of vaccination regimens to improve the efficacy of tuberculosis vaccines.

A T cell-targeted multi-antigen vaccine generates robust cellular and humoral immunity against SARS-CoV-2 infection

SARS-CoV-2, the etiological agent behind the coronavirus disease 2019 (COVID-19) pandemic, has continued to mutate and create new variants with increased resistance against the WHO-approved spike-based vaccines. With a significant portion of the worldwide population still unvaccinated and with waning immunity against newly emerging variants, there is a pressing need to develop novel vaccines that provide broader and longer-lasting protection. To generate broader protective immunity against COVID-19, we developed our second-generation vaccinia virus-based COVID-19 vaccine, TOH-VAC-2, encoded with modified versions of the spike (S)and nucleocapsid (N)proteins as well as a unique poly-epitope antigen that contains immunodominant Tcell epitopes from seven different SARS-CoV-2 proteins. We show that the poly-epitope antigen restimulates Tcells from the PBMCs of individuals formerly infected with SARS-CoV-2. In mice, TOH-VAC-2 vaccination produces high titers of S- and N-specific antibodies and generates robust Tcell immunity against S, N, and poly-epitope antigens. The immunity generated from TOH-VAC-2 is also capable of protecting mice from heterologous challenge with recombinant VSV viruses that express the same SARS-CoV-2 antigens. Altogether, these findings demonstrate the effectiveness of our versatile vaccine platform as an alternative or complementary approach to current vaccines.

An mRNA-based broad-spectrum vaccine candidate confers cross-protection against heterosubtypic influenza A viruses

ABSTRACT Influenza virus is a prominent cause of respiratory illness in humans. Current influenza vaccines offer strain-specific immunity, while provide limited protection against drifted strains. Broad-spectrum influenza vaccines can induce broad and long-term immunity, and thus are regarded as a future direction for the development of next-generation influenza vaccines. In this study, we have conceptualized a novel mRNA-based multi-antigen influenza vaccine consisting of three conserved antigens of influenza A virus, including the ectodomain of the M2 ion channel (M2e), the long alpha helix of haemagglutinin stalk region (LAH), and nucleoprotein (NP). The vaccine design aims to enhance its potency and promote the development of a future broad-spectrum influenza vaccine. Our mRNA-based vaccine demonstrated potent humoral and cellular responses throughout the time points of the murine model, inducing viral neutralizing antibodies, antibody-dependent cell cytotoxicity effect mediating antibodies and cross-reactive CD8+ T cell immune responses. The vaccine conferred broad protection against H1N1, H3N2, and H9N2 viruses. Moreover, the single-cell transcriptional profiling of T cells in the spleens of vaccinated mice revealed that the mRNA-based vaccine significantly promoted CD8+ T cells and memory T cells by prime-boost immunization. Our results suggest that the mRNA-based influenza vaccine encoding conserved proteins is a promising approach for eliciting broadly protective humoral and cellular immunity against various influenza viruses.

A new vaccination regimen using adenovirus-vectored vaccine confers effective protection against African swine fever virus in swine

ABSTRACT African swine fever (ASF) is an acute and highly contagious lethal infectious disease in swine that severely threatens the global pig industry. At present, a safe and efficacious vaccine is urgently required to prevent and control the disease. In this study, we evaluated the safety and immunogenicity of replication-incompetent type-2 adenoviruses carrying African swine fever virus (ASFV) antigens, namely CP204L (p30), E183L (p54), EP402R (CD2v), B646L (p72), and B602L (p72 chaperone). A vaccine cocktail delivered by simultaneous intramuscular (IM) and intranasal (IN) administration robustly elicited both systemic and mucosal immune responses against AFSV in mice and swine and provided highly effective protection against the circulating ASFV strain in farmed pigs. This multi-antigen cocktail vaccine was well tolerated in the vaccinated animals. No significant interference among antigens was observed. The combined IM and IN vaccination using this adenovirus-vectored antigen cocktail vaccine warrants further evaluation for providing safe and effective protection against ASFV infection and transmission.

Function-guided selection of salivary antigens from Ornithodoros erraticus argasid ticks and assessment of their protective efficacy in rabbits

The identification of new protective antigens for the development of tick vaccines may be approached by selecting antigen candidates that have key biological functions. Bioactive proteins playing key functions for tick feeding and pathogen transmission are secreted into the host via tick saliva. Adult argasid ticks must resynthesise and replace these proteins after each feeding to be able to repeat new trophogonic cycles. Therefore, these proteins are considered interesting antigen targets for tick vaccine development. In this study, the salivary gland transcriptome and saliva proteome of Ornithodoros erraticus females were inspected to select and test new vaccine candidate antigens. For this, we focused on transcripts overexpressed after feeding that encoded secretory proteins predicted to be immunogenic and annotated with functions related to blood ingestion and modulation of the host defensive response. Completeness of the transcript sequence, as well as a high expression level and a high fold-change after feeding were also scored resulting in the selection of four candidates, an acid tail salivary protein (OeATSP), a multiple coagulation factor deficiency protein 2 homolog (OeMCFD2), a Cu/Zn-superoxide dismutase (OeSOD) and a sulfotransferase (OeSULT), which were later produced as recombinant proteins. Vaccination of rabbits with each individual recombinant antigen induced strong humoral responses that reduced blood feeding and female reproduction, providing, respectively, 46.8%, 45.7%, 54.3% and 31.9% protection against O. erraticus infestations and 0.7%, 3.9%, 3.1% and 8.7% cross-protection against infestations by the African tick, Ornithodoros moubata. The joint protective efficacy of these antigens was tested in a second vaccine trial reaching 58.3% protection against O. erraticus and 18.6% cross-protection against O. moubata. These results (i) provide four new protective salivary antigens from argasid ticks that might be included in multi-antigenic vaccines designed for the control of multiple tick species; (ii) reveal four functional protein families never tested before as a source of protective antigens in ticks; and (iii) show that multi-antigenic vaccines increase vaccine efficacy compared with individual antigens. Finally, our data add value to the salivary glands as a protective antigen source in argasids for the control of tick infestations.

Universal Tick Vaccines: Candidates and Remaining Challenges.

Recent advancements in molecular biology, particularly regarding massively parallel sequencing technologies, have enabled scientists to gain more insight into the physiology of ticks. While there has been progress in identifying tick proteins and the pathways they are involved in, the specificities of tick-host interaction at the molecular level are not yet fully understood. Indeed, the development of effective commercial tick vaccines has been slower than expected. While omics studies have pointed to some potential vaccine immunogens, selecting suitable antigens for a multi-antigenic vaccine is very complex due to the participation of redundant molecules in biological pathways. The expansion of ticks and their pathogens into new territories and exposure to new hosts makes it necessary to evaluate vaccine efficacy in unusual and non-domestic host species. This situation makes ticks and tick-borne diseases an increasing threat to animal and human health globally, demanding an urgent availability of vaccines against multiple tick species and their pathogens. This review discusses the challenges and advancements in the search for universal tick vaccines, including promising new antigen candidates, and indicates future directions in this crucial research field.

Mpox multi-antigen mRNA vaccine candidates by a simplified manufacturing strategy afford efficient protection against lethal orthopoxvirus challenge

ABSTRACT Current unprecedented mpox outbreaks in non-endemic regions represent a global public health concern. Although two live-attenuated vaccinia virus (VACV)-based vaccines have been urgently approved for people at high risk for mpox, a safer and more effective vaccine that can be available for the general public is desperately needed. By utilizing a simplified manufacturing strategy of mixing DNA plasmids before transcription, we developed two multi-antigen mRNA vaccine candidates, which encode four (M1, A29, B6, A35, termed as Rmix4) or six (M1, H3, A29, E8, B6, A35, termed as Rmix6) mpox virus antigens. We demonstrated that those mpox multi-antigen mRNA vaccine candidates elicited similar potent cross-neutralizing immune responses against VACV, and compared to Rmix4, Rmix6 elicited significantly stronger cellular immune responses. Moreover, immunization with both vaccine candidates protected mice from the lethal VACV challenge. Investigation of B-cell receptor (BCR) repertoire elicited by mpox individual antigen demonstrated that the M1 antigen efficiently induced neutralizing antibody responses, and all neutralizing antibodies among the top 20 frequent antibodies appeared to target the same conformational epitope as 7D11, revealing potential vulnerability to viral immune evasion. Our findings suggest that Rmix4 and Rmix6 from a simplified manufacturing process are promising candidates to combat mpox.

Abstract 5112: Immune biomarkers of clinical response after NSAID treatment in combination with vaccination targeting EGFR-COX2-CDC25B in the APC(Min/+) mouse model

Abstract Studies from our group have shown that administration of NSAIDs in mouse models of Familial Adenomatous Polyposis (FAP) results in a decrease in the development in small intestinal polyps with a significant increase in CD8 tumor infiltrating lymphocytes (TIL) and downregulation of PD-L1 on tumors. Furthermore, we have demonstrated that NSAIDs could be used in combination with vaccination to even further reduce the development of intestinal polyps. We questioned what tissue specific biomarkers could define the efficacy of response with the combination treatment. APC(Min/+) male and female mice (4-6 weeks old) were immunized with a multi-antigen (EGFR, COX2, CDC25B) peptide vaccine with CFA/IFA as an adjuvant. Control mice received immune adjuvant alone. Regular chow or chow containing 400 ppm naproxen was provided intermittently (3 weeks on, 3 weeks off for 3 cycles) or continuously (18 weeks on) at the initiation of the vaccine regimen. Animals were euthanized at 22 weeks and tumors quantified. TIL were evaluated by flow cytometry. Since intermittent naproxen treatment was just as effective at inhibiting tumor development as continuous naproxen treatment, with or without vaccine, we did not differentiate between NSAID regimens. We observed an increase in CD8+ (83%; p<0.0001), Tbet+CD4+ (94%; p<0.001), effector memory (EM) CD4+ (76%; p<0.0001) and EM CD8+ (94%; p<0.0001) TIL in the tumors that did develop in the mice treated with the combination NSAID and vaccination as compared to control. There was increased CD8+ (Pearson correlation coefficient: −0.506, p<0001), Tbet+CD4+ (Pearson correlation coefficient: -0.6222, p<0.001), EM CD4+ (Pearson correlation coefficient: 0.-6074, p<0.001) and EM CD8+ (Pearson correlation coefficient: -0.7155, p<0.001) in mice with greater tumor inhibition than those with less protection. Receiver operator curves revealed that CD8+ (AUC: 0.7623; p=0.002), Tbet+CD4+ (AUC 0.7273; p=0.008), EM CD4+ (AUC 0.6782; p=0.04) and EM CD8 (AUC 0.7897; p<0.001) TIL can differentiate mice receiving the combination of NSAID and vaccination as compared to either monotherapy alone. These data define potential biomarkers of response that can guide human clinical trials of NSAIDs +/- vaccination in patients with FAP. Citation Format: Denise L. Cecil, Ying Liu, Lauren Corulli, Mary L. Disis. Immune biomarkers of clinical response after NSAID treatment in combination with vaccination targeting EGFR-COX2-CDC25B in the APC(Min/+) mouse model. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5112.

Immunogenicity of the Non-toxic Form of Staphylococcus Aureus α-Hemolysin Using a Chimeric Fusion in Mice.

Staphylococcus aureus is an opportunistic pathogen responsible for various infections with diverse clinical presentation and severity. The α-hemolysin is a major virulence factor in the pathogenesis of S. aureus infections. To produce a chimeric fusion protein for hemolytic detection of the S. aureus isolates and as a component of a multi-antigen vaccine. The fused strategy employed a flexible linker to incorporate the possible B cell and T cell determinants into one chimera (HlaD). The humoral and cellular response to the HlaD in mice was assessed to reveal a non-significant difference compared with the full-length α-hemolysin mutant (Hla H35L). The results of the protective effect, the mimetic lung cell injury, and bacterial clearness demonstrated that the mice vaccinated with the HlaD alleviated the severity of the infection of the S. aureus, and the HlaD could similarly function with Hla H35L. The chimeric fusion (HlaD) provided a diagnostic antigen for hemolysis of the S. aureus strains and a potential vaccine component.

Co-Immunization Efficacy of Recombinant Antigens against Rhipicephalus microplus and Hyalomma anatolicumTick Infestations.

The immunoprophylactic management of ticks is the most effective option to control tick infestations and counter spread the acaricide resistance problem worldwide. Several researchers reported an inconsistent efficacy of the single antigen-based immunization of hosts against different tick species. In the present study, to develop a multi-target immunization protocol, proteins from Rhipicephalus microplus BM86 and Hyalomma anatolicum subolesin (SUB) and tropomyosin (TPM) were targeted to evaluate the cross-protective potential. The sequence identities of the BM86, SUB, and TPM coding genes amongst Indian tick isolates of targeted species were 95.6-99.8%, 98.7-99.6%, and 98.9-99.9%, respectively, while at the predicted amino acid level, the identities were 93.2 to 99.5, 97.6 to 99.4, and 98.2 to 99.3%. The targeted genes were expressed in the eukaryotic expression system, pKLAC2-Kluyveromyces lactis, and 100 µg each of purified recombinant protein (Bm86-89 kDa, SUB-21 kDa, and TPM-36 kDa) mixed with adjuvant was injected individually through the intramuscular route at different sites of the body on days 0, 30, and 60 to immunize cross-bred cattle. Post-immunization, a statistically significant (p < 0.001) antibody response (IgG, IgG1, and IgG2) in comparison to the control, starting from 15 to 140 days, against each antigen was recorded. Following multi-antigen immunization, the animals were challenged twice with the larvae of R. microplus and H. anatolicum and theadults of H. anatolicum, and a significant vaccine efficacy of 87.2% and 86.2% against H. anatolicum larvae and adults, respectively, and 86.7% against R. microplus was obtained. The current study provides significant support to develop a multi-antigen vaccine against cattle tick species.

Coimmunization with Preerythrocytic Antigens alongside Circumsporozoite Protein Can Enhance Sterile Protection against Plasmodium Sporozoite Infection.

Malaria-causing Plasmodium parasites have a complex life cycle and present numerous antigen targets that may contribute to protective immune responses. The currently recommended vaccine-RTS,S-functions by targeting the Plasmodium falciparum circumsporozoite protein (CSP), which is the most abundant surface protein of the sporozoite form responsible for initiating infection of the human host. Despite showing only moderate efficacy, RTS,S has established a strong foundation for the development of next-generation subunit vaccines. Our previous work characterizing the sporozoite surface proteome identified additional non-CSP antigens that may be useful as immunogens individually or in combination with CSP. In this study, we examined eight such antigens using the rodent malaria parasite Plasmodium yoelii as a model system. We demonstrate that despite conferring weak protection individually, coimmunizing each of several of these antigens alongside CSP could significantly enhance the sterile protection achieved by CSP immunization alone. Thus, our work provides compelling evidence that a multiantigen preerythrocytic vaccine approach may enhance protection compared to CSP-only vaccines. This lays the groundwork for further studies aimed at testing the identified antigen combinations in human vaccination trials that assess efficacy with controlled human malaria infection. IMPORTANCE The currently approved malaria vaccine targets a single parasite protein (CSP) and results in only partial protection. We tested several additional vaccine targets in combination with CSP to identify those that could enhance protection from infection upon challenge in the mouse malaria model. In identifying several such enhancing vaccine targets, our work indicates that a multiprotein immunization approach may be a promising avenue to achieving higher levels of protection from infection. Our work identified several candidate leads for follow-up in the models relevant for human malaria and provides an experimental framework for efficiently carrying out such screens for other combinations of vaccine targets.

Evaluation of an equine multi-antigen rabies combination vaccine in pregnant mares

Mares are commonly vaccinated during pregnancy, especially in the late third trimester, with multiple vaccine products containing a variety of antigens. Currently, a new core antigens vaccine containing rabies virus, tetanus toxoid, eastern equine encephalomyelitis virus, western equine encephalomyelitis virus, and West Nile virus with and without the inclusion of Venezuelan equine encephalomyelitis virus is used in later term mares. Use of this vaccine has not been evaluated for safety in pregnant broodmares. We determined the safety of this vaccine in pregnant mares as it pertains to live foaling rate and per cycle pregnancy rate. Findings indicated that the use of a new multi-antigen rabies combination vaccine had no impact on live foaling rate nor per cycle pregnancy rates.

Multi-antigen spherical nucleic acid cancer vaccines.

Cancer vaccines must activate multiple immune cell types to be effective against aggressive tumours. Here we report the impact of the structural presentation of two antigenic peptides on immune responses at the transcriptomic, cellular and organismal levels. We used spherical nucleic acid (SNA) nanoparticles to investigate how the spatial distribution and placement of two antigen classes affect antigen processing, cytokine production and the induction of memory. Compared with single-antigen SNAs, a single dual-antigen SNA elicited a 30% increase in antigen-specific T cell activation and a two-fold increase in T cell proliferation. Antigen placement within dual-antigen SNAs altered the gene expression of T cells and tumour growth. Specifically, dual-antigen SNAs encapsulating antigens targeting helper T cells and with externally conjugated antigens targeting cytotoxic T cells elevated antitumour genetic pathways, stalling lymphoma tumours in mice. Additionally, when combined with the checkpoint inhibitor anti-programmed-cell-death protein-1 in a mouse model of melanoma, a specific antigen arrangement within dual-antigen SNAs suppressed tumour growth and increased the levels of circulating memory T cells. The structural design of multi-antigen vaccines substantially impacts their efficacy.

Rational vaccinology maximizes the efficacy of multi-antigen vaccines.

Rational vaccinology maximizes the efficacy of multi-antigen vaccines.

Plasmodium vivax vaccine: What is the best way to go?

Malaria is one of the most devastating human infectious diseases caused by Plasmodium spp. parasites. A search for an effective and safe vaccine is the main challenge for its eradication. Plasmodium vivax is the second most prevalent Plasmodium species and the most geographically distributed parasite and has been neglected for decades. This has a massive gap in knowledge and consequently in the development of vaccines. The most significant difficulties in obtaining a vaccine against P. vivax are the high genetic diversity and the extremely complex life cycle. Due to its complexity, studies have evaluated P. vivax antigens from different stages as potential targets for an effective vaccine. Therefore, the main vaccine candidates are grouped into preerythrocytic stage vaccines, blood-stage vaccines, and transmission-blocking vaccines. This review aims to support future investigations by presenting the main findings of vivax malaria vaccines to date. There are only a few P. vivax vaccines in clinical trials, and thus far, the best protective efficacy was a vaccine formulated with synthetic peptide from a circumsporozoite protein and Montanide ISA-51 as an adjuvant with 54.5% efficacy in a phase IIa study. In addition, the majority of P. vivax antigen candidates are polymorphic, induce strain-specific and heterogeneous immunity and provide only partial protection. Nevertheless, immunization with recombinant proteins and multiantigen vaccines have shown promising results and have emerged as excellent strategies. However, more studies are necessary to assess the ideal vaccine combination and test it in clinical trials. Developing a safe and effective vaccine against vivax malaria is essential for controlling and eliminating the disease. Therefore, it is necessary to determine what is already known to propose and identify new candidates.

Abstract IA016: Vaccine approach for the interception of colon cancer

Abstract This year, in the US, an estimated 150,000 people will be diagnosed with colon cancer and ~52,000 will die of the disease. A vaccine approach is well suited to colon cancer prevention. First, a limited number of immunizations can be given over a short period of time to achieve a desired immune response. If immunologic memory develops, antigen specific T-cells will persist in the body for years, ready to be deployed when aberrant cells are detected. Finally, there are several well-defined high-risk populations that would be suitable for testing a preventative colon cancer vaccine including individuals (1) with a hereditary genetic syndrome such as familial adenomatous polyposis, (2) with a history of inflammatory bowel disease such as Crohn’s disease or ulcerative colitis, and (3) those with a history of hyperplastic colonic polyps. Vaccines targeting virally mediated cancers are effective, in part, because T-cells are primed to proteins involved in oncogenesis. The most common type of colon adenoma and invasive cancer associated antigens are non-mutated growth-related proteins that become markedly overexpressed in the disease state. Genes which are aberrantly up-regulated and conserved from adenoma to invasive colon carcinoma may encode overexpressed proteins that are associated with colon cancer initiation. Evaluating gene expression data derived from over 600 colorectal cancers, matched normal tissues, and colon adenomas we identified 160 genes overexpressed in the majority of adenomas and early-stage colon cancers, but not in normal tissues. Using siRNA screening we demonstrated 35 of those genes, when silenced, resulted in apoptosis or inhibition of growth of colon cancer cells and an adenoma cell line but not a non-neoplastic colon cell line. Of those genes, 16 have been shown to encode proteins that are overexpressed in both adenomas and colon cancer and are associated with disease progression and over a third of these proteins are immunogenic. These proteins could serve as potential candidate antigens for inclusion in a multi-antigen vaccine. Recently, we have identified epitopes within the natural sequences of non-mutated tumor antigens that only generate Th1 (Th1 selective) antigen specific T-cells. This discovery and the development of high throughput methods to both identify and screen putative Class II binding peptides for Th selective function has allowed us to develop antigen specific Th1 selective vaccines. A vaccine targeting CDC25B, COX2, and EGFR can inhibit intestinal tumor formation in both APCmin mice and mice with tumor induced by AOM. Concomitant use of NSAIDs potentiates the immune response generated with vaccination. The anti-tumor response observed after vaccination is significantly correlated with elevated CD8 T-cells found in the lesions and induced by immunization as well as high magnitude antigen specific T-cells identified in the spleen. These data validate a genomic approach to antigen discovery and anti-tumor efficacy of Th1 selective vaccines for colon cancer prevention. Citation Format: Mary Disis, Ying Liu, Lauren Corulli, Erin Rodmaker, Denise Cecil. Vaccine approach for the interception of colon cancer. [abstract]. In: Proceedings of the AACR Special Conference: Precision Prevention, Early Detection, and Interception of Cancer; 2022 Nov 17-19; Austin, TX. Philadelphia (PA): AACR; Can Prev Res 2023;16(1 Suppl): Abstract nr IA016.

Listeria-vectored multi-antigenic tuberculosis vaccine protects C57BL/6 and BALB/c mice and guinea pigs against Mycobacterium tuberculosis challenge

Mycobacterium tuberculosis (Mtb) infects one-third of the world’s population and is a leading cause of death from a single infectious agent. New TB vaccines are urgently needed to augment immunity conferred by the current modestly protective BCG vaccine. We have developed live attenuated recombinant Listeria monocytogenes (rLm)-vectored TB vaccines expressing five [Mpt64/23.5-EsxH/TB10.4-EsxA/ESAT6-EsxB/CFP10-Ag85B/r30] (rLmMtb5Ag) or nine (additionally EsxN-PPE68-EspA-TB8.4) immunoprotective Mtb antigens (rLmMtb9Ag) and evaluated them for safety, immunogenicity and efficacy as standalone vaccines in two mouse models and an outbred guinea pig model. In immunogenicity studies, rLmMtb5Ag administered subcutaneously induces significantly enhanced antigen-specific CD4+ and CD8+ T-cell responses in C57BL/6 and BALB/c mice, and rLmMtb9Ag induces antigen-specific CD4+ and CD8+ T-cell proliferation in guinea pigs. In efficacy studies, both rLmMtb5Ag and rLmMtb9Ag are safe and protect C57BL/6 and BALB/c mice and guinea pigs against aerosol challenge with highly virulent Mtb. Hence, multi-antigenic rLm vaccines hold promise as new vaccines against TB.

Abstract PR007: Candidate antigens for a ductal carcinoma in situ vaccine, essential for breast cancer cell survival across multiple subtypes, are immunogenic in DCIS and IBC

Abstract Vaccine therapy may to destroy the current ductal carcinoma in situ (DCIS), prevent recurrence, and have little risk of long-term complications. One of the limitations for a DCIS vaccine is identifying appropriate antigens which, when targeted, may be able to treat DCIS and prevent development of IBC. In this study, we identified proteins that were overexpressed in both DCIS and IBC tumors across fifteen human Geo and Array Express data sets. From the 68 candidate proteins, twelve proteins expression was necessary for cancer cell survival across breast cancer subtypes using a high throughput siRNA screen. We chose candidates that increased apoptosis and decreased cell survival in human HER2 positive (HER2), triple negative (TN), and hormone receptor positive HER2 negative (HR) human breast cancer cell lines with decreased expression of the target protein. Twelve proteins (AURKA, KIF11, NDC80, RRM2, SDC1, UBE2C, HJURP, CENPA, CENPF, HIST2H2AA3, KRT8, and TOP2A) were the twelve antigens developed for the vaccine. All twelve targets were immunogenic in women with DCIS and IBC as compared to age matched control women. For example, autoantibodies to four of the antigens (AURKA, NDC80, KRT8, and RRM2) predicted women with DCIS with AUC 0.69 (p=0.005 95% CI 0.56 to 0.80) and IBC with AUC 0.79 (p&amp;lt;0.001 95% CI 0.66 to 0.90) as compared to age matched control women in a discovery set of 59 DCIS patients, 37 IBC patients, and 43 control women. In an independent validation set of serum samples of 50 DCIS, 60 IBC, and 50 control patients, autoantibodies to the four candidate antigens could predict women with DCIS with AUC 0.62 (p=0.04, 95% CI 0.51 to 0.73) and IBC with AUC 0.69 (p&amp;lt;0.001, 95% CI 0.60 to 0.79). Autoantibodies to the four DCIS antigens could identify each subtype of breast cancer subtype as compared to control, HR+(n=20 patients) with AUC 0.69 (p=0.01, 95% CI 0.55 to 0.83), HER2+ (n=20 patients) with AUC 0.70 (p=0.01, 95% CI 0.55 to 0.84), and TN (n=20 patients) with AUC 0.74 (p=0.002, 95% CI 0.61 to 0.87). All these were IgG autoantibodies suggest pre-existing T cells that recognize the candidate antigens because Ig class switching from IgM to IgG requires antigen-specific T cells. These twelve candidate antigens, overexpressed in human breast cancer, are also overexpressed in the TgMMTV-neu and C3(1)Tag transgenic mouse mammary tumor models of breast cancer. Vaccination with human MHC Class II predicted epitopes from KRT8, conserved between mouse and human, inhibited tumor growth in TgMMTV-neu mice by 47% and C3(1)Tag by 62%. The KRT8- specific IFN-g immune response developed was associated with lower tumor volume with mice vaccinated with the human MHC Class II Th1 KRT8 epitopes with the KRT8-specific IFN-g immune response associated with smaller tumors in TgMMTV-neu mice (R2= 0.64, p=0.02). We plan to develop these antigens in a multi-antigen DCIS vaccine that may be able to destroy DCIS and prevent breast cancer across all breast cancer subtypes. Citation Format: Sasha E. Stanton, Jason Schlumbohm, Mary L. Disis. Candidate antigens for a ductal carcinoma in situ vaccine, essential for breast cancer cell survival across multiple subtypes, are immunogenic in DCIS and IBC [abstract]. In: Proceedings of the AACR Special Conference on Rethinking DCIS: An Opportunity for Prevention?; 2022 Sep 8-11; Philadelphia, PA. Philadelphia (PA): AACR; Can Prev Res 2022;15(12 Suppl_1): Abstract nr PR007.

Immunological evaluation of a novel multi-antigenic DNA vaccine encoding SAG1, SAG3, MIC4, GRA5, GRA7, AMA1and BAG1 against Toxoplasma gondii in BALB/c mice

Many recent studies have been conducted to find new DNA vaccines based on Toxoplasma gondii antigens. DNA vaccines encoding complex of different antigens showed better immune responses compared to single antigen vaccine. In this study, we constructed a DNA vaccine encoding SAG1, SAG3, MIC4, GRA5, GRA7, AMA1 and BAG1 against T. gondii, and evaluated the immune response it induced in BALB/c mice. For this purposes, thirty BALB/c mice were randomly divided into three groups containing tenmice each. There were two negative control groups (PBSand pVAX1 vector) and one vaccination group (pVAX1-MAF, Multantigenic Fragment). On days 0, 14 and 28, the mice were immunized intramuscularly, and 5 weeks later they were challenged with T. gondii RH strain. The immune responses were evaluated using lymphocyte proliferation assay, T-cell subsets detection, and measurement of antibody and cytokine levels. The results showed that mice immunized with pVAX1-MAF developed high levels of IL-2, IL-12, IgG and IFN- γ as well as CD3+CD4+ T cells. In addition, the survival time of mice immunized by pVAX1-MAF was longer than that control mice. In conclusion, our results show that the multiple DNA vaccine encodingSAG1, SAG3, mic4, GRA5, GRA7, AMA and BAG1effectively enhanced humoral and cellular immune responses, and prolonged the survival time. Together this would suggest that further investigation may result in a promising candidate vaccine to treat toxoplasmosis.

Optimal sequence-based design for multi-antigen HIV-1 vaccines using minimally distant antigens.

The immense global diversity of HIV-1 is a significant obstacle to developing a safe and effective vaccine. We recently showed that infections established with multiple founder variants are associated with the development of neutralization breadth years later. We propose a novel vaccine design strategy that integrates the variability observed in acute HIV-1 infections with multiple founder variants. We developed a probabilistic model to simulate this variability, yielding a set of sequences that present the minimal diversity seen in an infection with multiple founders. We applied this model to a subtype C consensus sequence for the Envelope (Env) (used as input) and showed that the simulated Env sequences mimic the mutational landscape of an infection with multiple founder variants, including diversity at antibody epitopes. The derived set of multi-founder-variant-like, minimally distant antigens is designed to be used as a vaccine cocktail specific to a HIV-1 subtype or circulating recombinant form and is expected to promote the development of broadly neutralizing antibodies.