scholarly journals The role ofPlasmodium falciparumvariant surface antigens in protective immunity and vaccine development

2010 ◽  
Vol 6 (1) ◽  
pp. 84-89 ◽  
Author(s):  
Lars Hviid
Keyword(s):  
Protective Immunity ◽  
Vaccine Development ◽  
Surface Antigens

scholarly journals Mucosal Vaccine Development Based on Liposome Technology

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Valentina Bernasconi ◽  
Karin Norling ◽  
Marta Bally ◽  
Fredrik Höök ◽  
Nils Y. Lycke
Keyword(s):  
Immune Responses ◽  
Protective Immunity ◽  
Recent Progress ◽  
Vaccine Development ◽  
Mucosal Vaccine ◽  
Limiting Factor ◽  
Successful Development ◽  
Mucosal Vaccines ◽  
Increasing Demand ◽  
Portal Of Entry

Immune protection against infectious diseases is most effective if located at the portal of entry of the pathogen. Hence, there is an increasing demand for vaccine formulations that can induce strong protective immunity following oral, respiratory, or genital tract administration. At present, only few mucosal vaccines are found on the market, but recent technological advancements and a better understanding of the principles that govern priming of mucosal immune responses have contributed to a more optimistic view on the future of mucosal vaccines. Compared to live attenuated vaccines, subcomponent vaccines, most often protein-based, are considered safer, more stable, and less complicated to manufacture, but they require the addition of nontoxic and clinically safe adjuvants to be effective. In addition, another limiting factor is the large antigen dose that usually is required for mucosal vaccines. Therefore, the combination of mucosal adjuvants with the recent progress in nanoparticle technology provides an attractive solution to these problems. In particular, the liposome technology is ideal for combining protein antigen and adjuvant into an effective mucosal vaccine. Here, we describe and discuss recent progress in nanoparticle formulations using various types of liposomes that convey strong promise for the successful development of the next generation of mucosal vaccines.

scholarly journals Mycobacterium bovis BCG Surface Antigens Expressed under the Granuloma-Like Conditions as Potential Inducers of the Protective Immunity

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Yingyu Chen ◽  
Lia Danelishvili ◽  
Sasha J. Rose ◽  
Luiz E. Bermudez
Keyword(s):  
Mycobacterium Bovis ◽  
Recombinant Proteins ◽  
Protective Immunity ◽  
Bacterial Load ◽  
Surface Antigens ◽  
Surface Proteins ◽  
Host Cells ◽  
Biologically Relevant ◽  
Mucosal Cells ◽  
Potential Reservoir

Bovine tuberculosis (bTB) is a highly transmissible infection and remains of great concern as a zoonosis. The worldwide incidence of bTB is in rise, creating potential reservoir and increased infection risk for humans and animals. In attempts to identify novel surface antigens of Mycobacterium bovis as a proof-of-concept for potential inducers of protective immunity, we investigated surface proteome of M. bovis BCG strain that was cultured under the granuloma-like condition. We also demonstrated that the pathogen exposed to the biologically relevant environment has greater binding and invasion abilities to host cells than those of bacteria incubated under regular laboratory conditions. A total of 957 surface-exposed proteins were identified for BCG cultured under laboratory condition, whereas 1,097 proteins were expressed under the granuloma-like condition. The overexpression of Mb1524, Mb01_03198, Mb1595_p3681 (PhoU1 same as phoY1_1), and Mb1595_p0530 (HbhA) surface proteins in Mycobacterium smegmatis leads to increased binding and invasion to mucosal cells. We also examined the immunogenicity of purified recombinant proteins and tested M. smegmatis overexpressing these surface antigens for the induction of protective immunity in mice. Significantly high levels of specific IgA and IgG antibodies were observed in recombinant protein immunized groups by both inhalation and intraperitoneal (IP) routes, but only IP delivery induced high total IgA and IgG levels. We did not detect major differences in antibody levels in the M. smegmatis group that overexpressed surface antigens. In addition, the bacterial load was significantly reduced in the lungs of mice immunized with the combination of inhaled recombinant proteins. Our findings suggest that the activation of the mucosal immunity can lead to increased ability to confer protection upon M. bovis BCG infection.

scholarly journals Assessment of avidity related to IgG subclasses in SARS-CoV-2 Brazilian infected patients

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Andrew D. Moura ◽  
Hernan H. M. da Costa ◽  
Victor A. Correa ◽  
Ana K. de S. Lima ◽  
José A. L. Lindoso ◽  
...  
Keyword(s):  
Protective Immunity ◽  
Vaccine Development ◽  
Immunological Response ◽  
Hospitalized Patients ◽  
Igg Antibody ◽  
Antibody Avidity ◽  
Mild Disease ◽  
Life Threatening ◽  
Antibody Levels

AbstractSARS-CoV-2 is considered a global emergency, resulting in an exacerbated crisis in the health public in the world. Although there are advances in vaccine development, it is still limited for many countries. On the other hand, an immunological response that mediates protective immunity or indicates that predict disease outcome in SARS-CoV-2 infection remains undefined. This work aimed to assess the antibody levels, avidity, and subclasses of IgG to RBD protein, in symptomatic patients with severe and mild forms of COVID-19 in Brazil using an adapted in-house RBD-IgG ELISA. The RBD IgG-ELISA showed 100% of specificity and 94.3% of sensibility on detecting antibodies in the sera of hospitalized patients. Patients who presented severe COVID-19 had higher anti-RBD IgG levels compared to patients with mild disease. Additionally, most patients analyzed displayed low antibody avidity, with 64.4% of the samples of patients who recovered from the disease and 84.6% of those who died in this avidity range. Our data also reveals an increase of IgG1 and IgG3 levels since the 8th day after symptoms onset, while IgG4 levels maintained less detectable during the study period. Surprisingly, patients who died during 8–14 and 15–21 days also showed higher anti-RBD IgG4 levels in comparison with the recovered (P < 0.05), suggesting that some life-threatening patients can elicit IgG4 to RBD antibody response in the first weeks of symptoms onset. Our findings constitute the effort to clarify IgG antibodies' kinetics, avidity, and subclasses against SARS-CoV-2 RBD in symptomatic patients with COVID-19 in Brazil, highlighting the importance of IgG antibody avidity in association with IgG4 detection as tool laboratory in the follow-up of hospitalized patients with more significant potential for life-threatening.

scholarly journals Role of Opsonophagocytosis in Immune Protection against Malaria

Vaccines ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 264
Author(s):  
Wolfgang W. Leitner ◽  
Megan Haraway ◽  
Tony Pierson ◽  
Elke S. Bergmann-Leitner
Keyword(s):  
Protective Immunity ◽  
Defense Mechanisms ◽  
Vaccine Development ◽  
Immune Defense ◽  
Complement Components ◽  
Correlates Of Protection ◽  
Immune Correlates ◽  
Antibody Titers ◽  
Simple Measurement ◽  
Humoral Responses

The quest for immune correlates of protection continues to slow vaccine development. To date, only vaccine-induced antibodies have been confirmed as direct immune correlates of protection against a plethora of pathogens. Vaccine immunologists, however, have learned through extensive characterizations of humoral responses that the quantitative assessment of antibody responses alone often fails to correlate with protective immunity or vaccine efficacy. Despite these limitations, the simple measurement of post-vaccination antibody titers remains the most widely used approaches for vaccine evaluation. Developing and performing functional assays to assess the biological activity of pathogen-specific responses continues to gain momentum; integrating serological assessments with functional data will ultimately result in the identification of mechanisms that contribute to protective immunity and will guide vaccine development. One of these functional readouts is phagocytosis of antigenic material tagged by immune molecules such as antibodies and/or complement components. This review summarizes our current understanding of how phagocytosis contributes to immune defense against pathogens, the pathways involved, and defense mechanisms that pathogens have evolved to deal with the threat of phagocytic removal and destruction of pathogens.

Lipopolysaccharide: a tool and target in enterobacterial vaccine development

2008 ◽  
Vol 389 (5) ◽  
Author(s):  
Gábor Nagy ◽  
Tibor Pál
Keyword(s):  
Immune Response ◽  
Protective Immunity ◽  
Vaccine Development ◽  
The Other ◽  
Live Vaccine Strain ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Vaccination Strategies ◽  
Optimal Balance ◽  
Alternative Approaches

AbstractLipopolysaccharide (LPS) is an essential component of Gram-negative bacteria. While mutants exhibiting truncated LPS molecules are usually over-attenuated, alternative approaches that affect the extent or timing of LPS expression, as well as its modification may establish the optimal balance for a live vaccine strain of sufficient attenuation and retained immunogenicity. On the other hand, a specific immune response to LPS molecules in itself is capable of conferring protective immunity to certain enterobacterial pathogens. Therefore, purified LPS derivatives could be used as parenteral vaccines. This review summarizes various LPS-based vaccination strategies, as well as approaches that utilize LPS mutants as whole-cell vaccines.

scholarly journals Multiparameter Selection of Helicobacter pylori Antigens Identifies Two Novel Antigens with High Protective Efficacy

2002 ◽  
Vol 70 (11) ◽  
pp. 6499-6503 ◽  
Author(s):  
N. Sabarth ◽  
R. Hurwitz ◽  
T. F. Meyer ◽  
D. Bumann
Keyword(s):  
Helicobacter Pylori ◽  
Protective Immunity ◽  
Vaccine Development ◽  
Protective Efficacy ◽  
Infection Model ◽  
Protective Antigens ◽  
High Yields ◽  
Selection Of

ABSTRACT A multiparameter selection of Helicobacter pylori antigens for vaccine development identified 15 candidates, 6 of which are known protective antigens. Two novel antigens with low homology to other organisms (HP0231 and HP0410) were overexpressed and purified with high yields. Both confer protective immunity in the mouse Helicobacter infection model.

scholarly journals Characterization of an Antibody Depletion Assay for Analysis of Bactericidal Antibody Specificity

2009 ◽  
Vol 16 (12) ◽  
pp. 1789-1795 ◽  
Author(s):  
Wendell D. Zollinger ◽  
Elizabeth E. Moran ◽  
Deborah H. Schmiel
Keyword(s):  
Protective Immunity ◽  
Vaccine Development ◽  
Solid Phase ◽  
Soluble Antigen ◽  
Inhibition Assay ◽  
Direct Inhibition ◽  
Test Mixture ◽  
Bactericidal Antibody ◽  
Soluble Immune Complexes

ABSTRACT Serum bactericidal antibodies are important for protection against systemic Neisseria meningitidis infections. Consequently, identifying the specific targets of bactericidal antibodies is important for understanding protective immunity to meningococcal disease and for vaccine development and evaluation. We have developed a new assay that can be used to investigate the specificity of serum bactericidal antibodies. Prior to testing for bactericidal activity, antibodies specific for a given antigen or group of antigens are depleted from a serum sample by incubation with the antigen(s) bound to the wells of a 96-well microplate. A dilution series of the antigen is bound to the plate to assess the effectiveness of the antigen in removing the bactericidal antibodies. Removal of antibodies with solid-phase antigen prior to bactericidal testing avoids depletion of complement by soluble immune complexes that can form when soluble antigen is present in the bactericidal test mixture (direct inhibition). The parameters associated with this assay are investigated and compared with those associated with a direct-inhibition assay. The bactericidal depletion assay can be an effective tool for studying the specificity of serum bactericidal antibodies.

scholarly journals Composition of the Surface Proteome of Anaplasma marginale and Its Role in Protective Immunity Induced by Outer Membrane Immunization

2008 ◽  
Vol 76 (5) ◽  
pp. 2219-2226 ◽  
Author(s):  
Susan M. Noh ◽  
Kelly A. Brayton ◽  
Wendy C. Brown ◽  
Junzo Norimine ◽  
Gerhard R. Munske ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Protective Immunity ◽  
Vaccine Development ◽  
Bacterial Pathogen ◽  
Protein Composition ◽  
Anaplasma Marginale ◽  
Surface Proteins ◽  
Mammalian Host ◽  
Surface Complexes ◽  
Surface Proteome

ABSTRACT Surface proteins of tick-borne, intracellular bacterial pathogens mediate functions essential for invasion and colonization. Consequently, the surface proteome of these organisms is specifically relevant from two biological perspectives, induction of protective immunity in the mammalian host and understanding the transition from the mammalian host to the tick vector. In this study, the surface proteome of Anaplasma marginale, a tick-transmitted bacterial pathogen, was targeted by using surface-specific cross-linking to form intermolecular bonds between adjacent proteins. Liquid chromatography and tandem mass spectroscopy were then employed to characterize the specific protein composition of the resulting complexes. The surface complexes of A. marginale isolated from erythrocytes of the mammalian host were composed of multiple membrane proteins, most of which belong to a protein family, pfam01617, which is conserved among bacteria in the genus Anaplasma and the closely related genus Ehrlichia. In contrast, the surface proteome of A. marginale isolated from tick cells was much less complex and contained a novel protein, AM778, not identified within the surface proteome of organisms from the mammalian host. Immunization using the cross-linked surface complex induced protection against high-level bacteremia and anemia upon A. marginale challenge of cattle and effectively recapitulated the protection induced by immunization with whole outer membranes. These results indicate that a surface protein subset of the outer membrane is capable of inducing protective immunity and serves to direct vaccine development. Furthermore, the data support that remodeling of the surface proteome accompanies the transition between mammalian and arthropod hosts and identify novel targets for blocking transmission.

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