Opsono-Adherence Assay to Evaluate Functional Antibodies in Vaccine Development Against Bacillus anthracis and Other Encapsulated Pathogens

Author(s):  
Jennifer Chua ◽  
Donald J. Chabot ◽  
Tammy Putmon-Taylor ◽  
Arthur M. Friedlander
2016 ◽  
Vol 66 (6) ◽  
pp. 645 ◽  
Author(s):  
Anshul Varshney ◽  
Nidhi Puranik ◽  
M. Kumar ◽  
A.K. Goel

Anthrax, caused by Bacillus anthracis is known to occur globally since antiquity. Besides being an important biothreat agent, it is an important public health importance pathogen also in countries like India. B. anthracis secretes three distinct toxins, namely protective antigen (PA), lethal factor (LF) and edema factor (EF). PA is the central moiety of the anthrax toxin complex and therefore has been a molecule of choice for vaccine development. PA has four different domains with different functions. In this study, the major domains of PA were cloned and expressed in bacterial system. The purified recombinant proteins were used to determine the humoral immune response by ELISA using 43 human cutaneous anthrax serum samples. The maximum immunoreactivity was observed with the whole PA protein followed by domain 2, 4 and 1. The study corroborated that in addition to full PA, individual domain 2 and 4 can also be good target for vaccine development as well as for serodiagnostic assays for cutaneous anthrax


2020 ◽  
Vol 12 (529) ◽  
pp. eaba9014
Author(s):  
Michelle Boyle

Vaccination with a Bordetella pertussis live attenuated vaccine induces a beneficial TH1 cell bias and broadly targeting functional antibodies in humans.


2006 ◽  
Vol 74 (7) ◽  
pp. 3987-4001 ◽  
Author(s):  
Orit Gat ◽  
Haim Grosfeld ◽  
Naomi Ariel ◽  
Itzhak Inbar ◽  
Galia Zaide ◽  
...  

ABSTRACTBacillus anthracisproteins that possess antigenic properties and are able to evoke an immune response were identified by a reductive genomic-serologic screen of a set of in silico-preselected open reading frames (ORFs). The screen included in vitro expression of the selected ORFs by coupled transcription and translation of linear PCR-generated DNA fragments, followed by immunoprecipitation with antisera fromB. anthracis-infected animals. Of the 197 selected ORFs, 161 were chromosomal and 36 were on plasmids pXO1 and pXO2, and 138 of the 197 ORFs had putative functional annotations (known ORFs) and 59 had no assigned functions (unknown ORFs). A total of 129 of the known ORFs (93%) could be expressed, whereas only 38 (64%) of the unknown ORFs were successfully expressed. All 167 expressed polypeptides were subjected to immunoprecipitation with the anti-B. anthracisantisera, which revealed 52 seroreactive immunogens, only 1 of which was encoded by an unknown ORF. The high percentage of seroreactive ORFs among the functionally annotated ORFs (37%; 51/129) attests to the predictive value of the bioinformatic strategy used for vaccine candidate selection. Furthermore, the experimental findings suggest that surface-anchored proteins and adhesins or transporters, such as cell wall hydrolases, proteins involved in iron acquisition, and amino acid and oligopeptide transporters, have great potential to be immunogenic. Most of the seroreactive ORFs that were tested as DNA vaccines indeed appeared to induce a humoral response in mice. We list more than 30 novelB. anthracisimmunoreactive virulence-related proteins which could be useful in diagnosis, pathogenesis studies, and future anthrax vaccine development.


PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0258317
Author(s):  
Tuvshinzaya Zorigt ◽  
Yoshikazu Furuta ◽  
Manyando Simbotwe ◽  
Akihiro Ochi ◽  
Mai Tsujinouchi ◽  
...  

Anthrax is a zoonotic disease caused by the gram-positive spore-forming bacterium Bacillus anthracis. Detecting naturally acquired antibodies against anthrax sublethal exposure in animals is essential for anthrax surveillance and effective control measures. Serological assays based on protective antigen (PA) of B. anthracis are mainly used for anthrax surveillance and vaccine evaluation. Although the assay is reliable, it is challenging to distinguish the naturally acquired antibodies from vaccine-induced immunity in animals because PA is cross-reactive to both antibodies. Although additional data on the vaccination history of animals could bypass this problem, such data are not readily accessible in many cases. In this study, we established a new enzyme-linked immunosorbent assay (ELISA) specific to antibodies against capsule biosynthesis protein CapA antigen of B. anthracis, which is non-cross-reactive to vaccine-induced antibodies in horses. Using in silico analyses, we screened coding sequences encoded on pXO2 plasmid, which is absent in the veterinary vaccine strain Sterne 34F2 but present in virulent strains of B. anthracis. Among the 8 selected antigen candidates, capsule biosynthesis protein CapA (GBAA_RS28240) and peptide ABC transporter substrate-binding protein (GBAA_RS28340) were detected by antibodies in infected horse sera. Of these, CapA has not yet been identified as immunoreactive in other studies to the best of our knowledge. Considering the protein solubility and specificity of B. anthracis, we prepared the C-terminus region of CapA, named CapA322, and developed CapA322-ELISA based on a horse model. Comparative analysis of the CapA322-ELISA and PAD1-ELISA (ELISA uses domain one of the PA) showed that CapA322-ELISA could detect anti-CapA antibodies in sera from infected horses but was non-reactive to sera from vaccinated horses. The CapA322-ELISA could contribute to the anthrax surveillance in endemic areas, and two immunoreactive proteins identified in this study could be additives to the improvement of current or future vaccine development.


2007 ◽  
Vol 75 (6) ◽  
pp. 2841-2852 ◽  
Author(s):  
Theodor Chitlaru ◽  
Orit Gat ◽  
Haim Grosfeld ◽  
Itzhak Inbar ◽  
Yael Gozlan ◽  
...  

ABSTRACTIn a previous comparative proteomic study ofBacillus anthracisexamining the influence of the virulence plasmids and of various growth conditions on the composition of the bacterial secretome, we identified 64 abundantly expressed proteins (T. Chitlaru, O. Gat, Y. Gozlan, N. Ariel, and A. Shafferman, J. Bacteriol.188:3551-3571, 2006). Using a battery of sera fromB. anthracis-infected animals, in the present study we demonstrated that 49 of these proteins are immunogenic. Thirty-eightB. anthracisimmunogens are documented in this study for the first time. The relative immunogenicities of the 49 secreted proteins appear to span a >10,000-fold range. The proteins eliciting the highest humoral response in the course of infection include, in addition to the well-established immunogens protective antigen (PA), Sap, and EA1, GroEL (BA0267), AhpC (BA0345), MntA (BA3189), HtrA (BA3660), 2,3-cyclic nucleotide diesterase (BA4346), collagen adhesin (BAS5205), an alanine amidase (BA0898), and an endopeptidase (BA1952), as well as three proteins having unknown functions (BA0796, BA0799, and BA0307). Of these 14 highly potent secreted immunogens, 11 are known to be associated with virulence and pathogenicity inB. anthracisor in other bacterial pathogens. Combining the results reported here with the results of a similar study of the membranal proteome ofB. anthracis(T. Chitlaru, N. Ariel, A. Zvi, M. Lion, B. Velan, A. Shafferman, and E. Elhanany, Proteomics4:677-691, 2004) and the results obtained in a functional genomic search for immunogens (O. Gat, H. Grosfeld, N. Ariel, I. Inbar, G. Zaide, Y. Broder, A. Zvi, T. Chitlaru, Z. Altboum, D. Stein, S. Cohen, and A. Shafferman, Infect. Immun.74:3987-4001, 2006), we generated a list of 84 in vivo-expressed immunogens for future evaluation for vaccine development, diagnostics, and/or therapeutic intervention. In a preliminary study, the efficacies of eight immunogens following DNA immunization of guinea pigs were compared to the efficacy of a PA DNA vaccine. All eight immunogens induced specific high antibody titers comparable to the titers elicited by PA; however, unlike PA, none of them provided protection against a lethal challenge (50 50% lethal doses) of virulentB. anthracisstrain Vollum spores.


2007 ◽  
Vol 14 (9) ◽  
pp. 1223-1227 ◽  
Author(s):  
Gowrisankar Rajam ◽  
George M. Carlone ◽  
Sandra Romero-Steiner

ABSTRACT The 23-valent pneumococcal polysaccharide (Ps) vaccine offer protection against vaccine serotypes, but its cross-protection against vaccine-related serotypes is variable. We have demonstrated that the functional antibodies to serotype 15B are specific to the O-acetylated 15B-Ps and that they have low cross-reactivity with serotype 15C. Demonstration of functionally cross-reactive antibodies to vaccine-related serotypes is important for surveillance and vaccine development.


Author(s):  
E. Ryabchevskaya ◽  
E. Evtushenko ◽  
N. Nikitin ◽  
O. Kondakova ◽  
P. Ivanov ◽  
...  

A stable genetically modified recombinant anthrax antigen containing 3rd and 4th Bacillus anthracis protective antigen domains has been obtained. Complexes of this antigen with structurally modified plant virus particles are a perspective basis for a new generation anthrax vaccine development.


2010 ◽  
Vol 108 (1) ◽  
pp. 349-354 ◽  
Author(s):  
Mariette F. Ducatez ◽  
Justin Bahl ◽  
Yolanda Griffin ◽  
Evelyn Stigger-Rosser ◽  
John Franks ◽  
...  

Since the reemergence of highly pathogenic H5N1 influenza viruses in humans in 2003, these viruses have spread throughout avian species in Asia, Europe, and Africa. Their sustained circulation has resulted in the evolution of phylogenetically diverse lineages. Viruses from these lineages show considerable antigenic variation, which has confounded vaccine planning efforts. We reconstructed ancestral protein sequences at several nodes of the hemagglutinin (HA) and neuraminidase (NA) gene phylogenies that represent ancestors to diverse H5N1 virus clades. By using the same methods that have been used to generate currently licensed inactivated H5N1 vaccines, we were able to produce a panel of replication competent influenza viruses containing synthesized HA and NA genes representing the reconstructed ancestral proteins. We identified two of these viruses that showed promising in vitro cross-reactivity with clade 1, 2.1, 2.2, 2.3.4, and 4 viruses. To confirm that vaccine antigens derived from these viruses were able to elicit functional antibodies following immunization, we created whole-virus vaccines and compared their protective efficacy versus that of antigens from positive control, naturally occurring, and broadly reactive H5N1 viruses. The ancestral viruses’ vaccines provided robust protection against morbidity and mortality in ferrets challenged with H5N1 strains from clades 1, 2.1, and 2.2 in a manner similar to those based on the control strains. These findings provide proof of principle that viable, computationally derived vaccine seed viruses can be constructed within the context of currently licensed vaccine platforms. Such technologies should be explored to enhance the cross reactivity and availability of H5N1 influenza vaccines.


2014 ◽  
Vol 21 (9) ◽  
pp. 1215-1223 ◽  
Author(s):  
Francis B. Ntumngia ◽  
Samantha J. Barnes ◽  
Amy M. McHenry ◽  
Miriam T. George ◽  
Jesse Schloegel ◽  
...  

ABSTRACTMolecules that play a role inPlasmodiummerozoite invasion of host red blood cells represent attractive targets for blood-stage vaccine development against malaria. InPlasmodium vivax, merozoite invasion of reticulocytes is mediated by the Duffy binding protein (DBP), which interacts with its cognate receptor, the Duffy antigen receptor for chemokines, on the surface of reticulocytes. The DBP ligand domain, known as region II (DBPII), contains the critical residues for receptor recognition, making it a prime target for vaccine development against blood-stage vivax malaria. In natural infections, DBP is weakly immunogenic and DBPII allelic variation is associated with strain-specific immunity, which may compromise vaccine efficacy. In a previous study, a synthetic vaccine termed DEKnull that lacked an immunodominant variant epitope in DBPII induced functional antibodies to shared neutralizing epitopes on the native Sal1 allele. Anti-DEKnull antibody titers were lower than anti-Sal1 titers but produced more consistent, strain-transcending anti-DBPII inhibitory responses. In this study, we further characterized the immunogenicity of DEKnull, finding that immunization with recombinant DEKnull produced an immune response comparable to that obtained with native recombinant DBP alleles. Further investigation of DEKnull is necessary to enhance its immunogenicity and broaden its specificity.


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