scholarly journals Potential Usefulness of Streptococcus pneumoniae Extracellular Membrane Vesicles as Antibacterial Vaccines

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Chi-Won Choi ◽  
Edmond Changkyun Park ◽  
Sung Ho Yun ◽  
Sang-Yeop Lee ◽  
Seung Il Kim ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Immune Responses ◽  
Mammalian Cells ◽  
Membrane Vesicles ◽  
Focus Of Attention ◽  
Common Phenomenon ◽  
Highly Pathogenic ◽  
Vaccine Candidates ◽  
Homologous Strain ◽  
Host Cell Interactions

The secretion of extracellular membrane vesicles (EMVs) is a common phenomenon that occurs in archaea, bacteria, and mammalian cells. The EMVs of bacteria play important roles in their virulence, biogenesis mechanisms, and host cell interactions. Bacterial EMVs have recently become the focus of attention because of their potential as highly effective vaccines that cause few side effects. Here, we isolated the EMVs of Streptococcus pneumoniae and examined their potential as new vaccine candidates. Although the S. pneumoniae bacteria were highly pathogenic in a mouse model, the EMVs purified from these bacteria showed low pathological activity both in cell culture and in mice. When mice were injected intraperitoneally with S. pneumoniae EMVs and then challenged, they were protected from both the homologous strain and another pathogenic serotype of S. pneumoniae. We also identified a number of proteins that may have immunogenic activity and may be responsible for the immune responses by the hosts. These results suggest that S. pneumoniae EMVs or their individual immunogenic antigens may be useful as new vaccine agents.

scholarly journals Exploiting bacterial outer membrane vesicles as a cross-protective vaccine candidate against avian pathogenic Escherichia coli

2020 ◽  
Author(s):  
Rujiu Hu ◽  
Jing Li ◽  
Hua Lin ◽  
Liu Liang ◽  
Yuezhen Zhao ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Immune Responses ◽  
Outer Membrane ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Cross Protection ◽  
Avian Pathogenic Escherichia Coli ◽  
Vaccine Candidates ◽  
Pathogenic Escherichia Coli ◽  
Bacterial Outer Membrane

Abstract Background: The well-known fact that avian pathogenic Escherichia coli (APEC) is harder to prevent due to its numerous serogroups has promoted the development of biological immunostimulatory materials as new vaccine candidates in poultry farms. Bacterial outer membrane vesicles (OMVs), known as spherical nanovesicles enriched with various immunostimulants, are naturally secreted by Gram-negative bacteria, and have gained much attention for developing effective vaccine candidates. Here, a novel multi-serogroup OMVs (MOMVs) vaccine was developed to achieve cross-protection against APEC infection in broiler chickens.Results: In this study, OMVs produced by three APEC strains were isolated, purified and prepared into MOMVs by mixing these three OMVs. By using SDS-PAGE and LC-MS/MS, 159 proteins were identified in MOMVs and the subcellular location and biological functions of 20 most abundant proteins were analyzed. The immunogenicity of MOMVs was evaluated, and the results showed that MOMVs could elicit innate immune responses, including internalization by chicken macrophage and production of immunomodulatory cytokines. Vaccination with MOMVs induced specific broad-spectrum antibodies as well as Th1 and Th17 immune responses. The animal experiment has confirmed that immunization with an appropriate dose of MOMVs could not cause any adverse effect and was able to reduce bacteria loads and pro-inflammatory cytokines production, thus providing effective cross-protection against lethal infections induced by multi-serogroup APEC in chickens. Further experiments indicated that, although vesicular proteins were able to induce stronger protective efficiency than lipopolysaccharide, both vesicular proteins and lipopolysaccharide are crucial in MOMVs-mediated protection.Conclusions: The multi-serogroup nanovesicles produced by APEC strains will open up a new way for the development of next generation vaccines with low toxicity and broad protection in the treatment and control of APEC infection.

scholarly journals Exploiting bacterial outer membrane vesicles as a cross-protective vaccine candidate against avian pathogenic Escherichia coli (APEC)

2020 ◽  
Author(s):  
Rujiu Hu ◽  
Jing Li ◽  
Yuezhen Zhao ◽  
Hua Lin ◽  
Liu Liang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Immune Responses ◽  
Outer Membrane ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Cross Protection ◽  
Effective Vaccine ◽  
Protective Efficiency ◽  
Vaccine Candidates ◽  
Bacterial Outer Membrane

Abstract Background: The well-known fact that avian pathogenic Escherichia coli (APEC) is harder to prevent due to its numerous serogroups has promoted the development of biological immunostimulatory materials as new vaccine candidates in poultry farms. Bacterial outer membrane vesicles (OMVs), known as spherical nanovesicles enriched with various immunostimulants, are naturally secreted by Gram-negative bacteria, and have gained much attention for developing effective vaccine candidates. Recent report has demonstrated that OMVs of APEC O78 can induce protective immunity in chickens. Here, a novel multi-serogroup OMVs (MOMVs) vaccine was developed to achieve cross-protection against APEC infection in broiler chickens.Results: In this study, OMVs produced by three APEC strains were isolated, purified and prepared into MOMVs by mixing these three OMVs. By using SDS-PAGE and LC-MS/MS, 159 proteins were identified in MOMVs and the subcellular location and biological functions of 20 most abundant proteins were analyzed. The immunogenicity of MOMVs was evaluated, and the results showed that MOMVs could elicit innate immune responses, including internalization by chicken macrophage and production of immunomodulatory cytokines. Vaccination with MOMVs induced specific broad-spectrum antibodies as well as Th1 and Th17 immune responses. The animal experiment has confirmed that immunization with an appropriate dose of MOMVs could not cause any adverse effect and was able to reduce bacteria loads and pro-inflammatory cytokines production, thus providing effective cross-protection against lethal infections induced by multi-serogroup APEC strains in chickens. Further experiments indicated that, although vesicular proteins were able to induce stronger protective efficiency than lipopolysaccharide, both vesicular proteins and lipopolysaccharide are crucial in MOMVs-mediated protection. Conclusions: The multi-serogroup nanovesicles produced by APEC strains will open up a new way for the development of next generation vaccines with low toxicity and broad protection in the treatment and control of APEC infection.

scholarly journals RelCoVax®, a two antigen subunit protein vaccine candidate against SARS-CoV-2 induces strong immune responses in mice

2022 ◽  
Author(s):  
Abhishek Phatarphekar ◽  
GEC Vidyadhar Reddy ◽  
Abhiram Gokhale ◽  
Gopala Karanam ◽  
Pushpa Kuchroo ◽  
...  
Keyword(s):  
Immune Responses ◽  
Mammalian Cells ◽  
Neutralizing Antibodies ◽  
Vaccine Candidate ◽  
Protein Vaccine ◽  
Vaccine Candidates ◽  
N Protein ◽  
Subunit Protein ◽  
Boost Dose

The COVID-19 pandemic has spurred an unprecedented movement to develop safe and effective vaccines against the SARS-CoV-2 virus to immunize the global population. The first set of vaccine candidates that received emergency use authorization targeted the spike (S) glycoprotein of the SARS-CoV-2 virus that enables virus entry into cells via the receptor binding domain (RBD). Recently, multiple variants of SARS-CoV-2 have emerged with mutations in S protein and the ability to evade neutralizing antibodies in vaccinated individuals. We have developed a dual RBD and nucleocapsid (N) subunit protein vaccine candidate named RelCoVax® through heterologous expression in mammalian cells (RBD) and E. coli (N). The RelCoVax® formulation containing a combination of aluminum hydroxide (alum) and a synthetic CpG oligonucleotide as adjuvants elicited high antibody titers against RBD and N proteins in mice after a prime and boost dose regimen administered 2 weeks apart. The vaccine also stimulated cellular immune responses with a potential Th1 bias as evidenced by increased IFN-γ release by splenocytes from immunized mice upon antigen exposure particularly N protein. Finally, the serum of mice immunized with RelCoVax® demonstrated the ability to neutralize two different SARS-CoV-2 viral strains in vitro including the Delta strain that has become dominant in many regions of the world and can evade vaccine induced neutralizing antibodies. These results warrant further evaluation of RelCoVax® through advanced studies and contribute towards enhancing our understanding of multicomponent subunit vaccine candidates against SARS-CoV-2.

scholarly journals Bacterial Membrane Vesicles in Pneumonia: From Mediators of Virulence to Innovative Vaccine Candidates

2021 ◽  
Vol 22 (8) ◽  
pp. 3858
Author(s):  
Felix Behrens ◽  
Teresa C. Funk-Hilsdorf ◽  
Wolfgang M. Kuebler ◽  
Szandor Simmons
Keyword(s):  
Extracellular Vesicles ◽  
Inflammatory Responses ◽  
Significant Proportion ◽  
Treatment Strategies ◽  
Membrane Vesicles ◽  
Multidrug Resistant ◽  
Biochemical Properties ◽  
Outer Membrane Vesicles ◽  
Vaccine Candidates ◽  
Treatment Regimens

Pneumonia due to respiratory infection with most prominently bacteria, but also viruses, fungi, or parasites is the leading cause of death worldwide among all infectious disease in both adults and infants. The introduction of modern antibiotic treatment regimens and vaccine strategies has helped to lower the burden of bacterial pneumonia, yet due to the unavailability or refusal of vaccines and antimicrobials in parts of the global population, the rise of multidrug resistant pathogens, and high fatality rates even in patients treated with appropriate antibiotics pneumonia remains a global threat. As such, a better understanding of pathogen virulence on the one, and the development of innovative vaccine strategies on the other hand are once again in dire need in the perennial fight of men against microbes. Recent data show that the secretome of bacteria consists not only of soluble mediators of virulence but also to a significant proportion of extracellular vesicles—lipid bilayer-delimited particles that form integral mediators of intercellular communication. Extracellular vesicles are released from cells of all kinds of organisms, including both Gram-negative and Gram-positive bacteria in which case they are commonly termed outer membrane vesicles (OMVs) and membrane vesicles (MVs), respectively. (O)MVs can trigger inflammatory responses to specific pathogens including S. pneumonia, P. aeruginosa, and L. pneumophila and as such, mediate bacterial virulence in pneumonia by challenging the host respiratory epithelium and cellular and humoral immunity. In parallel, however, (O)MVs have recently emerged as auspicious vaccine candidates due to their natural antigenicity and favorable biochemical properties. First studies highlight the efficacy of such vaccines in animal models exposed to (O)MVs from B. pertussis, S. pneumoniae, A. baumannii, and K. pneumoniae. An advanced and balanced recognition of both the detrimental effects of (O)MVs and their immunogenic potential could pave the way to novel treatment strategies in pneumonia and effective preventive approaches.

scholarly journals Contrasting Adult and Infant Immune Responses to HIV Infection and Vaccination

2015 ◽  
Vol 23 (2) ◽  
pp. 84-94 ◽  
Author(s):  
David R. Martinez ◽  
Sallie R. Permar ◽  
Genevieve G. Fouda
Keyword(s):  
Immune Responses ◽  
Hiv Infection ◽  
Vaccine Efficacy ◽  
Neutralizing Antibody ◽  
Hiv Vaccine ◽  
Antibody Responses ◽  
Hiv Vaccines ◽  
Vaccine Candidates ◽  
Protective Antibodies ◽  
Pediatric Populations

ABSTRACTExtensive studies have demonstrated that infant immune responses are distinct from those of adults. Despite these differences, infant immunization can elicit protective immune responses at levels comparable to or, in some cases, higher than adult immune responses to many vaccines. To date, only a few HIV vaccine candidates have been tested in infant populations, and none of them evaluated vaccine efficacy. Recent exciting studies showing that HIV-infected infants can develop broad neutralizing antibody responses and that some HIV vaccine regimens can elicit high levels of potentially protective antibodies in infants provide support for the development and testing of HIV vaccines in pediatric populations. In this review, we discuss the differences in adult and infant immune responses in the setting of HIV infection and vaccination.

Cell surface interactions in conjugation: Tetrahymena ciliary membrane vesicles

1984 ◽  
Vol 4 (4) ◽  
pp. 681-687
Author(s):  
B Love ◽  
M B Rotheim
Keyword(s):  
Cell Surface ◽  
Mating Type ◽  
Mammalian Cells ◽  
Membrane Vesicles ◽  
Surface Interactions ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Ciliary Membrane ◽  
Adhesion Sites ◽  
Cell Surface Interactions

Tetrahymena ciliary membrane vesicles are shown to interact with preconjugant cells in a mating type-specific way. When cells are treated with vesicles of a different mating type before mixing for conjugation, cell pairing is enhanced, and the normal prepairing period is partially eliminated. This enhancement is mating type specific since it is not observed after pretreatment of cells with vesicles of their own mating type. In contrast, when vesicles are added at the time of mixing of two starved cultures, cell pairing is delayed in a concentration-dependent manner. By varying the conditions, we demonstrated enhancement or inhibition, or both. These results are interpreted in terms of two independent interactions of cells with vesicles. We suggest that first, vesicles substitute for another cell in cell-cell prepairing interaction and second, vesicles compete for adhesion sites produced during the prepairing period. Finally, the data presented are summarized within a speculative framework that calls attention to potential analogies with hormone-receptor signaling in mammalian cells.

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