Immune Complex Vaccine Research Articles

Effectiveness of the use of immune complex vaccine “Novamune” in the prevention of Gamboro's disease in egg poultry farming

In recent decades, the poultry industry has developed rapidly. Increased demand for higher volumes, better quality and competitive prices led to industrialization, intensification and concentration of production. All this has put significant pressure on animals with genetic potential to achieve higher profits and higher efficiency, which in turn increases the risk of infectious diseases. In addition to disease control, there is pressure on producers to reduce the use of antibiotics and other chemicals, on par with the elimination of pathogens, forcing producers to seek optimal disease control methods. In this context, the principles of biosecurity and vaccination have greatly improved efforts and become important tools for disease control. The vaccine market today is quite broad and includes many vaccines developed on the basis of the latest technologies, such as immune complex vaccines, as well as the largest range of recombinant vector vaccines for poultry. However, all of them have many disadvantages and negative points in practical application, namely: different possibilities of overcoming the level of maternal antibodies (MAT), the need to collect blood serum and conduct laboratory tests to determine the exact day of vaccination, some have a high degree of tissue depletion of the bursa of Fabricius (due to destruction of lymphocytes), low percentage of protection of the bird due to incorrect drinking of the vaccine, etc. Therefore, today specialists face key questions, such as effectiveness against variations of a specific microorganism distributed in different parts of the world; compatibility between vaccines; increasing the resistance or preventing (reducing) the isolation and spread of the pathogen in the environment, which are of crucial importance for reducing the risk of the persistence of the pathogen or preventing the spread of the disease; influence or intervention of passive immunity, advantages of using one category of vaccines over others, etc.

Functionalized chitosan-G-poly caprolactone vaccine delivery system fabricated to display antigen–antibody immune complexes of Mycobacterium tuberculosis elicits immune response in Ex-vivo model

BackgroundVaccine development against tuberculosis remains a global health imperative, necessitating robust immunogenicity and safety profiles. Nanoparticle-based delivery systems offer promising avenues to enhance vaccine efficacy while ensuring tolerability. This study explores the utilization of chitosan micelles as a delivery platform for immune complex vaccination against tuberculosis. Leveraging two key antigens of Mycobacterium tuberculosis, namely HspX and Mpt51, known for their relevance in latent tuberculosis and its co-infection with the human immunodeficiency virus, immune complexes were synthesized in vitro using antibodies raised against these antigens. The immune complexes were then conjugated onto chitosan micelles, characterized for their physicochemical properties, and evaluated for their biocompatibility and immunogenicity.ResultsChitosan nanoparticles conjugated with either antigen or its immune complexes were synthesized as micelles and physicochemical characterizations confirm the formation of micelles without altering the polymer composition. These immune complex-conjugated chitosan micelles were found to be safe, exhibiting no significant hemolytic and cytotoxic activity even at a higher concentration of 400 µg/ml. Peripheral blood mononuclear cells upon stimulation with immune complex-conjugated chitosan micelles showed enhanced cellular uptake and one to two-fold increased expression of key immune markers—interferon gamma and CD-86.ConclusionsThese findings underscore the potential of chitosan nanoparticles as a versatile delivery platform for immune complex vaccination against tuberculosis. While limitations exist, such as including only two markers of immune modulation, this study lays a foundation for future investigations into immune complex vaccine potential in animal models. In conclusion, chitosan micelles carrying immune complexes of HspX and Mpt51 tuberculosis antigens exhibit promising immunogenicity, highlighting their potential as a platform for multi-antigenic vaccine components warranting further in vivo studies.

The booster immunization using commercial vaccines effectively protect chickens against novel variants of infectious bursal disease virus (genotype A2dB1)

The novel variant IBDV (nVarIBDV, genotype A2dB1), characterized by bursal atrophy of fabricius and decreased lymphocytes, has been emerging on a large scale in Asia (including China) since late 2018. nVarIBDV is a new threat to the poultry industry, yet the currently licensed commercial vaccines, including the live viral vector vaccine, IBDV immune complex vaccine or VP2 subunit vaccine, are ineffective against nVarIBDV infection. In this study, specific-pathogen-free (SPF) chickens and broilers divided into three groups were vaccinated with the live viral vector vaccine, the VP2 subunit vaccine or the IBDV immune complex vaccine at 1 day old, respectively. The SPF chickens received a secondary vaccination with the live B87 strain vaccine at 11 days-old. The bursa/body weight ratio, histopathology lesion of the bursa, and the differentiation between infected and vaccinated animals (DIVA) by qRT-PCR confirmed that the live viral vector vaccine or immune complex vaccine plus live B87 strain booster could provide at least 80% protection against the FJ2019-01 strain of nVarIBDV in SPF chickens. The broilers also received a secondary vaccination using a live W2512 G-61 strain vaccine at 14 days-old, and analyses showed that the VP2 subunit vaccine or immune complex vaccine plus the live W2512 G-61 strain booster also provided more than 80% protection against the FJ2019-01 strain of nVarIBDV. Unfortunately, the live viral vector vaccine plus live W2512 G-61 strain booster provided poor to moderate protection against FJ2019-01 in broilers. These findings suggest that combining commercial vaccines with rational booster immunization can effectively protect chickens against an nVarIBDV challenge.

Persistent Circulation of Very virulent Infectious Bursal Disease virus (IBDV) in Egypt: Phylogenetic analysis, Pathogenicity and Immunogenicity of an immune-complex vaccine

Persistent Circulation of Very virulent Infectious Bursal Disease virus (IBDV) in Egypt: Phylogenetic analysis, Pathogenicity and Immunogenicity of an immune-complex vaccine

Cytokines, Serological, and Histopathological Assessment of Recombinant Vaccination Strategies for Combatting Infectious Bursal Disease in Broiler Chickens.

Infectious bursal disease (IBD) represents a greatly transmissible viral disease found worldwide, causing significant health and production challenges in young chickens. The aim of this research was to assess the immune reaction induced by different vaccines targeting IBD. These vaccines included recombinant (Vac1; HVT-IBD vector), immune complex (Vac2; Bursa-Plex®), and intermediate plus (Vac3; Bursine plus) IBD vaccines. Our assessment relied on serological and histopathological analyses, as well as the pattern of immune-related cytokine expression in the bursal tissue. The vaccinated groups, along with a control positive (CP) group, were subjected to a vvIBDV challenge on their 28th day of life, while the control negative (CN) group received a mock vaccination with PBS. Our study revealed that Vac1 resulted in the most favorable growth performance, as well as maintained normal liver and kidney function, mitigating the impact of IBDV infection. Serological analysis using VP2 ELISA kits indicated that Vac1 induced the strongest immunological response among all vaccines. Histopathological examination demonstrated that Vac1 caused minimal lymphoid depletion observed in the lymphoid organs, followed by Vac2. Analysis of cytokine expression profiles showed significant upregulation in all vaccinated groups, particularly Vac1, during the pre-challenge period. Following IBDV infection, Vac1 resulted in a noteworthy increase in the expression of IL2 and IFN-γ, Vac2 showed a significant upregulation in TNF-α and granzyme, and both Vac1 and Vac3 exhibited increased levels of IL1β and IL10. In conclusion, our study suggests that the various vaccines triggered immune responses against IBD through both humoral and cell-mediated immunity. However, recombinant followed by immune complex vaccines appeared to induce more robust immunity while also being safer for broiler chickens in contrast to the intermediate plus vaccine.

A self-binding immune complex vaccine elicits strong neutralizing responses against herpes simplex virus in mice.

It has been known for over half a century that mixing an antigen with its cognate antibody in an immune complex (IC) can enhance antigen immunogenicity. However, many ICs produce inconsistent immune responses, and the use of ICs in the development new vaccines has been limited despite the otherwise widespread success of antibody-based therapeutics. To address this problem, we designed a self-binding recombinant immune complex (RIC) vaccine which mimics the larger ICs generated during natural infection. In this study, we created two novel vaccine candidates: 1) a traditional IC targeting herpes simplex virus 2 (HSV-2) by mixing glycoprotein D (gD) with a neutralizing antibody (gD-IC); and 2) an RIC consisting of gD fused to an immunoglobulin heavy chain and then tagged with its own binding site, allowing self-binding (gD-RIC). We characterized the complex size and immune receptor binding characteristics in vitro for each preparation. Then, the in vivo immunogenicity and virus neutralization of each vaccine were compared in mice. gD-RIC formed larger complexes which enhanced C1q receptor binding 25-fold compared to gD-IC. After immunization of mice, gD-RIC elicited up to 1,000-fold higher gD-specific antibody titers compared to traditional IC, reaching endpoint titers of 1:500,000 after two doses without adjuvant. The RIC construct also elicited stronger virus-specific neutralization against HSV-2, as well as stronger cross-neutralization against HSV-1, although the proportion of neutralizing antibodies to total antibodies was somewhat reduced in the RIC group. This work demonstrates that the RIC system overcomes many of the pitfalls of traditional IC, providing potent immune responses against HSV-2 gD. Based on these findings, further improvements to the RIC system are discussed. RIC have now been shown to be capable of inducing potent immune responses to a variety of viral antigens, underscoring their broad potential as a vaccine platform.

EXPERIENCE OF USING THE IMMUNE-COMPLEX VACCINE PULVAK MAGNIPLEX IN THE PREVENTION OF INFECTIOUS BURSA DISEASE OF BROILERS

The article presents the results of serological control of the effectiveness of vaccination of broilers against infectious bursal disease (IBD) when the immune-complex vaccine Pulvak MagniPlex is used in the incubator.
 Immune-complex vaccines are vaccines of a new generation, the use of which completely eliminates post-vaccination complications in birds and interference phenomena. The vaccine includes a mixture of specific antibodies and the vaccine strain of the IBH virus. The main property of these vaccines is that when administered subcutaneously in day-old chicks or 18-day-old chicken embryos by the in ovo method, immunity is quickly created even in the presence of high maternal antibodies (MAB). Vaccination in the incubator using immune-complex vaccines is more accurate and provides protection to the whole bird, unlike live vaccines, the main method of which is administration with drinking water. Immuno-complex vaccines are effective even in the presence of high MAT in chickens. Due to this, they provide a much higher level of protection due to the high homogeneity of protective antibodies compared to live attenuated vaccines.
 We present the data of serological monitoring on the average titer of antibodies to the IBH virus in blood sera from 15 batches of broilers aged 45-50 days, which were immunized on the first day in the incubator with the immune-complex vaccine Pulvak MagniPlex. It was established that during a single vaccination in the incubator (15 batches), the Pulvak MagniPlex vaccine stimulates the formation of an active immune response to the IBH virus for the entire period of fattening of broilers. The average titers in the blood sera of broilers aged 45-50 days to the IBH virus ranged from 6,995 to 12,388 after a single vaccination in the incubator (15 batches). The percentage of protective antibodies to the IBH virus in 15 batches of broilers varied from 77.3 to 100, which indicates the intensity of immunity to IBH. A single application of the immune-complex vaccine Pulvak MagniPlex in the incubator stimulates the formation of an active immune response to the IBD virus for the entire period of broiler fattening and provides 100 % protection of 12 batches of broilers and 77.3 % of broilers of 3 batches to IBD. The use of Pulvak MagniPlex allows: to create stable immunity against IBD; to form immunity in each individual broiler, regardless of the level of maternal antibodies; to reduce the impact of stress (compared to mass vaccination in the poultry house by the drinking method. Constant control of the effectiveness of the Pulvak MagniPlex immune-complex vaccine by means of serological monitoring of blood sera in ELISA will allow, depending on the epizootic situation, to timely adjust the vaccination scheme of poultry against IBD.

Immunotherapeutic and immunomodulatory potentials of Antigen-Antibody complex vaccines

Immune system battles with deadly pathogens that mostly deteriorate health and cause morbidity and mortality. Antibodies are considered great players in the elimination of pathogens and hence, provide a shield against the future onset of various diseases. The immune complex, also known as an antigen–antibody (Ag-Ab) complex, exhibits the immunomodulatory potential leading to enhanced vaccine efficacy. A deeper understanding of Fc receptors (FcRs) and the interaction of the Fc part of an antibody with the different immune cells lead to in-depth knowledge of using this strategy for the development of immune complex vaccines. The concept of the Ag-Ab complex has been used in the prevention and therapy of various viral and bacterial diseases. Ag-Ab complex is gaining attention in COVID-19 vaccine development too, due to their greater immunoregulatory potential. The present literature highlights the importance of the Ag-Ab complex, the role of Fc receptors in immunomodulation, and their success as vaccines in viral and bacterial diseases of human and animal origin. Moreover, potential areas and lapses are explored to make better use of this prospect as a vaccine candidate. Studies revealed that the immunogenic and immunomodulatory potential of Ag-Ab complex can lead to greater protection. However, there is a dire need of establishing a link between laboratory and clinical findings to make it effective and safe tool for in vivo treatments.

Development of an Immune Complex Vaccine against Infectious Bursal Disease Virus and its Potential Response in Poultry Birds

Development of an Immune Complex Vaccine against Infectious Bursal Disease Virus and its Potential Response in Poultry Birds

Efficacy of live attenuated, vector and immune complex infectious bursal disease virus (IBDV) vaccines in preventing field strain bursa colonization: A European multicentric study.

Infectious bursal disease virus (IBDV) is among the most relevant and widespread immunosuppressive agents, which can severely damage poultry farming by causing direct losses, predisposing the host to secondary diseases and reducing the efficacy of vaccination protocols against other infections. IBDV has thus been the object of intense control activities, largely based on routine vaccination. However, the need for protecting animals from the infection in the first period of the production cycle, when the bursa susceptibility is higher, clashes with the blanketing effect of maternally derived antibodies. To overcome this issue, other strategies have been developed besides live attenuated vaccines, including vector vaccines and immune complex (icx) ones. The present study aims to investigate, in field conditions, the efficacy of these approaches in preventing IBDV infection in laying chickens vaccinated with either live attenuated, vector or immune complex (icx) vaccines. For this purpose, a multicentric study involving 481 farms located in 11 European countries was organized and IBDV infection diagnosis and strain characterization was performed at 6 weeks of age using a molecular approach. Vaccine strains were commonly detected in flocks vaccinated with live or icx vaccines. However, a significantly higher number of field strains (characterized as very virulent IBDVs) was detected in flocks vaccinated with vector vaccines, suggesting their lower capability of preventing bursal colonization. Different from vector vaccines, live and icx ones have a marked bursal tropism. It can thus be speculated that vaccine virus replication in these sites could limit vvIBDV replication by direct competition or because of a more effective activation of innate immunity. Although such different behavior doesn't necessarily affect clinical protection, further studies should be performed to evaluate if vvIBDV replication could still be associated with subclinical losses and/or for viral circulation in a “vaccinated environment” could drive viral evolution and favor the emergence of vaccine-escape variants.

FG comparative study between antigen-antibody complex vaccine and traditional vaccine of infectious bursal disease in commercial broiler

Infectious bursal disease (IBD) is a viral disease causes increased mortality and severe immunosuppressionin commercial chickens. The virus infects the bursa of Fabricius of particularly the actively dividing and differentiating lymphocytes of the B-cellslineage of young chickens, resultant in morbidity, mortality, and immunosuppression. Immunosuppression enhances the susceptibility of chickens to other infections and interferes with vaccination against other diseases. Immunization is the most important measure to control IBD; however, wild usage of live vaccines has resulted in the evolution of new strains. Although the immunosuppression caused by IBDV is more directed toward the B lymphocytes, the protective immunity in birds depends on inducement of both humeral and cell-mediated immune responses. Currently vaccination mainly used to control IBD. In this study, Group 1(n = 50) received the immune complex vaccine (Bursa-Plex®) s/c at 1 day of age. Group 2 (n = 50) received the GUMBORO (D78)(intervet)vaccine by drinking water and Group 3 (n = 50) were non IBD vaccinated birds. The aim of study: Evaluation between two types of IBD vaccines, immune-complex IBD vaccine (Bursaplex®) with the use of GUMBORO D78(intervet) vaccine. Depending on:At 7,14,21, 28th day P.V. • Serology (IBD ELISA (INFY)- cellular immunity).

Protective Efficacy of IBDV Winterfield H-2512 and SYZA-26 Immune-complex Vaccines against Recent Egyptian Very Virulent IBDV in Commercial Broiler Chickens

Protective Efficacy of IBDV Winterfield H-2512 and SYZA-26 Immune-complex Vaccines against Recent Egyptian Very Virulent IBDV in Commercial Broiler Chickens

A Comparative Study on Winterfield 2512-G61 and Winterfield-2512 IBDV Immune-complex Vaccines in Commercial Broiler Chickens

A Comparative Study on Winterfield 2512-G61 and Winterfield-2512 IBDV Immune-complex Vaccines in Commercial Broiler Chickens

Six decades of infectious bursal disease in poultry: The journey so far and challenges ahead


 
 
 Despite six decades of concerted efforts, Infectious bursal disease (IBD) still remains a major threat to the poultry industry worldwide. Most importantly, the emergence of variant and very virulent strains of infectious bursal disease virus (IBDV) has dramatically changed the epidemiology of the disease, thus resulting in the renewed efforts in the search for effective control measures. Currently, live attenuated, inactivated, and immune-complex vaccines are among the immune-therapeutic approaches employed for the control of IBD in the field alongside adequate biosecurity, albeit with various degrees of success and limitations. Progress in genetic engineering has allowed the generation of reverse genetic IBDV mutants, recombinant live viral vectors expressing the IBDV VP2 immunodominant protein, intra-serotypic recombinant IBDV viral-like particle co-expressing the outer capsid protein structures derived from 2 or more serotype 1 strains or the incorporation of either VP2 or VP2-4-3 polyprotein sequences alongside molecular adjuvants that can be used as IBD vaccine candidates to elicit an immune response. However, despite these advances, outbreaks are still reported even in flocks that have up to date vaccination records and somewhat excellent management practices. This paper reviews aspect of genetic characteristics of IBDV and reflects on the progress and future challenges in providing effective IBD vaccine to achieve effective control of both classical and very-virulent IBDV serotypes that constitute a major devastation to poultry production and health.
 
 

Comparison study between the efficacy of immune complex and conventionally live vaccine against Gumboro disease in broilers

This study aimed to evaluate the immune response and histological changes of two Gumboro disease vaccines. Two hundred, days old broilers were divided into 4 groups: group A was vaccinated with live attenuated infectious bursal disease (IBD) vaccine at 7 and 21 days of age, group B was vaccinated with Immune-Complex vaccine (Icx) at 1 day old, then all broilers of the groups A, B and C were vaccinated with ND vaccine at 10 and 24 days, while the group D was negative control. The blood was collected at 1, 7,14,21,28 and 35 days of age to obtain serum for ELISA. Samples of bursa from broilers of all groups at 14 and 28 days of age were submitted for histological examination. As a result of vaccination in group A the antibody titers are elevated after the 1st and 2nd dose of vaccination at 7 and 21 days. In group B this titer is increased from 21 day of age and reaches to peak at 35 day 7810±858 with significant difference, while in unvaccinated groups C and D the titer decreased gradually. The histological examination of bursal sections in group A and B varied at 14 and 28 days post vaccination and showed degeneration and necrosis of follicular lymphocytes compared with group and D. Thus we conclude that (Icx) vaccine improves the immune response after IBD and ND vaccination in comparison with live IBD vaccine.

Expression of an immunocomplex consisting of Fc fragment fused with a consensus dengue envelope domain III in Saccharomyces cerevisiae

ObjectivesTo explore Saccharomyces cerevisiae as an expression platform for dengue oral immune complex vaccine development.ResultsMolecular engineering was applied to create a fusion gene construct (scEDIII-PIGS) consisting of a yeast codon optimized sequence encoding for a synthetic consensus dengue envelope domain III (scEDIII) followed by a modified IgG Fc domain (PIGS). Northern blot showed transcription of the target gene, with a temporal expression pattern similar to those from previous work. Western blot showed assembly of various immune complexes from monomer to hexamer. Partial purification of scEDIII-PIGS was also attempted to demonstrate the feasibility of yeast system for immune complex vaccine development. Approximately 1 mg of scEDIII-PIGS can be produced from 1 l culture.ConclusionThis work demonstrated for the first time that various immunocomplex structures of our target protein could be efficiently produced in S. cerevisiae for future application in developing oral and injectable vaccines against various pathogens.

Monitoring serologic response to single in ovo vaccination with an immune complex vaccine against infectious bursal disease in broilers

The infectious bursal disease (IBD) virus is one of the most resistant and prevalent virus worldwide in the poultry industry, being vaccination the main tool to control the disease. For this reason, consistent and uniform immunization of broiler flocks against IBD is necessary to avoid the disease spreading. The aim of this study was to apply and assess an epidemiologic mapping tool focused on the immunization by in ovo single broiler vaccination using an immune complex IBD vaccine. With this regard, 7,576 serum samples were collected from 603 broiler flocks raised in 354 Spanish farms. To do so, blood samples were randomly collected from birds with ages between 35 to 51 d, and the serum was analyzed by ELISA. The results obtained from this study suggested a high uniform immunization against IBDV and a protective immunization between 35 and 51 d of age, with mean titer values ranging between 6,331 and 7,426. In addition, seroprevalence titer data of this large-scale monitoring study fitted a polynomial equation with a R2 value of 0.77, helping to explain and predict the humoral response to IBD vaccination. This seroprevalence map was applied to broiler production and was based on business intelligence tool that incorporates newly developed mapping tool to cover the need of having real-time information of humoral response to IBD vaccination and could be an effective tool for veterinary services to control and prevent IBD.

Evaluation of Serum Conversion Induced by Infectious Bursal Disease Vaccines Submitted to Official Quality Control in the Period 2013 to April 2014

The prophylaxis of many avian diseases is based on measures of biosecurity and active immunization using live vaccines. One of the most important tests for vaccine quality control is a serum conversion. Serum conversion is performed to check the production of certain virus, after immunization. The Avian Health Unit at LFDA-SP carries out the quality control of commercially available avian vaccines in Brazil. The aim of the study was to evaluate the results of serum conversion of live monovalent vaccines and complex Infectious Bursal Disease vaccines (IBDV) in the period of 2013 to April/2014. Twelve batches of live monovalent vaccines belonging to seven laboratories were tested and 16 batches of immune complex vaccines belonging to two laboratories.

Alteration of immunological parameters in infectious bronchitis vaccinated–specific pathogen-free broilers after the use of different infectious bursal disease vaccines

The vaccines currently available to control infectious bursal disease (IBD) include live-attenuated and inactivated vaccines, immune-complex vaccines, and vaccines consisting of viral constructs of herpesvirus of turkeys genetically engineered to express VP2 surface protein. To evaluate the impact of vaccines on the chicken immune system, 2 animal trials were performed in specific pathogen-free broiler chickens. In trial 1, birds were either vaccinated when they are one-day old with a dual recombinant herpes virus of turkey construct vaccine, expressing VP2 protein of (IBDV) and F protein of Newcastle disease virus, or an immune-complex IBDV vaccine or birds were not vaccinated. At 14, 28, and 35 D, the bursa of Fabricius was collected for bursa:body weight (B:BW) ratio calculation. In trial 2, birds were vaccinated when they were 1-day old according to the same protocol as trial 1, but at day 14, all groups also received a live infectious bronchitis (IB) vaccine. At 0, 7, 14, 21, and 28 days after IB vaccination, birds were tested by ELISA for IB serology and, soon after the last blood sampling, they were euthanized for collection of Harderian glands, trachea, and spleen and testing by flow cytometry for characterization of mononuclear cells. The immune-complex vaccine groups showed significantly lower B:BW ratio, lower IBV antibody titers, and higher mean percentage of CD8+ T cells in the spleen, trachea, and Harderian glands than those in the other experimental groups. The results of the in vivo trials coupled with a depth analysis of the repertoire of parameters involved in the immune response to IBD and IB vaccinations show one vaccine may influence the immune response of other vaccines included in the vaccination program.

Codelivery of improved immune complex and virus-like particle vaccines containing Zika virus envelope domain III synergistically enhances immunogenicity

Zika virus (ZIKV) reemergence poses a significant health threat especially due to its risks to fetal development, necessitating safe and effective vaccines that can protect pregnant women. Zika envelope domain III (ZE3) has been identified as a safe and effective vaccine candidate, however it is poorly immunogenic. We previously showed that plant-made recombinant immune complex (RIC) vaccines are a robust platform to improve the immunogenicity of weak antigens. In this study, we altered the antigen fusion site on the RIC platform to accommodate N-terminal fusion to the IgG heavy chain (N-RIC), and thus a wider range of antigens, with a resulting 40% improvement in RIC expression over the normal C-terminal fusion (C-RIC). Both types of RICs containing ZE3 were efficiently assembled in plants and purified to >95% homogeneity with a simple one-step purification. Both ZE3 RICs strongly bound complement receptor C1q and elicited strong ZE3-specific antibody titers that correlated with ZIKV neutralization. When either N-RIC or C-RIC was codelivered with plant-produced hepatitis B core (HBc) virus-like particles (VLP) displaying ZE3, the combination elicited 5-fold greater antibody titers (>1,000,000) and more strongly neutralized ZIKV than either RICs or VLPs alone, after only two doses without adjuvant. These findings demonstrate that antigens that require a free N-terminus for optimal antigen display can now be used with the RIC system, and that plant-made RICs and VLPs are highly effective vaccines targeting ZE3. Thus, the RIC platform can be more generally applied to a wider variety of antigens.