Spatiotemporal Dynamic of the RTS,S/AS01 Malaria Vaccine Target Antigens in Senegal

2021 ◽  
Author(s):  
Mamadou Alpha Diallo ◽  
Coralie L’Ollivier ◽  
Khadim Diongue ◽  
Aida Sadikh Badiane ◽  
Aly Kodio ◽  
...  
Keyword(s):  
Immune Responses ◽  
Malaria Vaccine ◽  
Haplotype Frequency ◽  
Circumsporozoite Protein ◽  
Repeat Region ◽  
Genome Database ◽  
Exact Test ◽  
Vaccine Target ◽  
Significant Difference ◽  
Study Sites

The RTS,S/AS01 malaria vaccine confers only moderate protection against malaria. Evidence suggests that the effectiveness of the RTS,S/AS01 vaccine depends upon the parasite population genetics, specifically regarding the circumsporozoite protein haplotypes in the population. We investigated Plasmodium falciparum circumsporozoite protein (PfCSP) gene sequences from two endemic sites in 2018 in Senegal. The PfCSP sequences were compared with those retrieved from the Pf3k genome database. In the central repeat region of PfCSP, the distribution of haplotypes differed significantly between the two study sites (Fisher’s exact test, P < 0.001). No 3D7 vaccine strain haplotype was observed in this locus. In the C-terminal region, there was no significant difference in haplotypes distribution between Kedougou and Diourbel (Fischer’s exact test, P = 0.122). The 3D7 haplotype frequency was 8.4% in early samples (2001–2011), but then it contracted in the subsequent years. The extensive plasticity of the P. falciparum genes coding the RTS,S/AS01 vaccine target antigens may influence the immune responses to circulating alleles. Monitoring the genetic diversity baseline and its dynamics over time and space would be instrumental in rationally improving the malaria RTS,S/AS01 vaccine and/or its implementation schedule.

scholarly journals Antibody feedback limits the expansion of cognate memory B cells but drives the diversification of vaccine-induced antibody responses

2019 ◽  
Author(s):  
Hayley A. McNamara ◽  
Azza H. Idris ◽  
Henry J. Sutton ◽  
Barbara J. Flynn ◽  
Yeping Cai ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Plasmodium Falciparum ◽  
B Cells ◽  
Immune Responses ◽  
Memory B Cells ◽  
Antibody Responses ◽  
Circumsporozoite Protein ◽  
Repeat Region ◽  
Antibody Titres

AbstractGenerating sufficient antibody to block infection is a key challenge for vaccines against malaria. Here we show that antibody titres to a key target, the repeat region of the Plasmodium falciparum circumsporozoite protein (PfCSP), plateaued after two immunizations in a clinical trial of the radiation-attenuated sporozoite vaccine. To understand the mechanisms limiting vaccine responsiveness, we developed Ig-knockin mice with elevated numbers of PfCSP-binding B cells. We determined that recall responses were inhibited by antibody feedback via epitope masking of the immunodominant PfCSP repeat region. Importantly, the amount of antibody that prevents boosting is below the amount of antibody required for protection. Finally, while antibody feedback limited responses to the PfCSP-repeat region in vaccinated volunteers, potentially protective subdominant responses to C-terminal regions did expand with subsequent boosts. These data suggest that antibody feedback drives the diversification of immune responses and that vaccination for malaria will require the targeting of multiple antigens.

scholarly journals Minimal Role for the Circumsporozoite Protein in the Induction of Sterile Immunity by Vaccination with Live Rodent Malaria Sporozoites

2010 ◽  
Vol 78 (5) ◽  
pp. 2182-2188 ◽  
Author(s):  
Marjorie Mauduit ◽  
Rita Tewari ◽  
Nadya Depinay ◽  
Michèle Kayibanda ◽  
Eliette Lallemand ◽  
...  
Keyword(s):  
Immune Responses ◽  
Malaria Vaccine ◽  
Vaccine Candidate ◽  
Parasite Load ◽  
Circumsporozoite Protein ◽  
Rodent Malaria ◽  
Malaria Vaccine Candidate ◽  
Malaria Species ◽  
Full Protection

ABSTRACT Immunization with live Plasmodium sporozoites under chloroquine prophylaxis (Spz plus CQ) induces sterile immunity against sporozoite challenge in rodents and, more importantly, in humans. Full protection is obtained with substantially fewer parasites than with the classic immunization with radiation-attenuated sporozoites. The sterile protection observed comprised a massive reduction in the hepatic parasite load and an additional effect at the blood stage level. Differences in the immune responses induced by the two protocols occur but are as yet little characterized. We have previously demonstrated that in mice immunized with irradiated sporozoites, immune responses against the circumsporozoite protein (CSP), the major component of the sporozoite's surface and the leading malaria vaccine candidate, were not essential for sterile protection. Here, we have employed transgenic P lasmodium berghei parasites in which the endogenous CSP was replaced by that of P lasmodium yoelii, another rodent malaria species, to assess the role of CSP in the sterile protection induced by the Spz-plus-CQ protocol. The data demonstrated that this role was minor because sterile immunity was obtained irrespective of the origin of CSP expressed by the parasites in this model of protection. The immunity was obtained through a single transient exposure of the host to the immunizing parasites (preerythrocytic and erythrocytic), a dose much smaller than that required for immunization with radiation-attenuated sporozoites.

scholarly journals Breadth of humoral immune responses to the C-terminus of the circumsporozoite protein is associated with protective efficacy induced by the RTS,S malaria vaccine

2020 ◽  
Author(s):  
Sidhartha Chaudhury ◽  
Randall S. MacGill ◽  
Angela M. Early ◽  
Jessica S. Bolton ◽  
C. Richter King ◽  
...  
Keyword(s):  
Immune Responses ◽  
Malaria Vaccine ◽  
Protective Efficacy ◽  
Cross Reactivity ◽  
Antibody Responses ◽  
Circumsporozoite Protein ◽  
Humoral Immune ◽  
Humoral Immune Responses ◽  
C Terminus ◽  
Fold Reduction

AbstractThe circumsporozoite protein (CSP) is the main surface antigen of malaria sporozoites and a prime vaccine target. Responses induced by the CSP-based RTS,S vaccine towards the polymorphic C-terminal region of P.falciparum-CSP raise concerns that vaccines using single alleles may have lower efficacy against genotypic variants. We characterized the extent of C-terminal cross-reactivity of antibodies induced by RTS,S (based on the 3D7 allele) with variants representing seven circulating field isolates through a novel HTS-multiplex assay for screening closely related peptides. Reactivity to variants showed approximately 30-fold reduction in recognition relative to 3D7. The degree of reduced cross-reactivity,ranging from 21 to 69-fold, directly correlated with the number of polymorphisms between variants and 3D7. Surprisingly, protection assessed by challenge with 3D7 parasites was strongly associated with higher C-terminal antibody breadth suggesting that C-terminal specific avidity or fine-specificity may play a role in RTS,S/AS01B-mediated protection and that breadth of C-terminal CSP-specific antibody responses may be a marker of protection.

scholarly journals The repeat region of the circumsporozoite protein is an elastic linear spring with a functional role in Plasmodium sporozoite motility

2021 ◽  
Author(s):  
Amanda Balaban ◽  
Sachie Kanatani ◽  
Jaba Mitra ◽  
Jason Gregory ◽  
Natasha Vartak ◽  
...  
Keyword(s):  
Single Molecule ◽  
Functional Role ◽  
Malaria Vaccine ◽  
Circumsporozoite Protein ◽  
Site Formation ◽  
Repeat Region ◽  
Biophysical Properties ◽  
Adhesion Sites ◽  
Linear Spring ◽  
Adhesion Site

The circumsporozoite protein (CSP) forms a dense coat on the surface of the sporozoite, the infective stage of the malaria parasite. The central repeat region of CSP is a critical component of the only licensed malaria vaccine yet little is known about its structure or function. We found that sporozoite mutants with severely truncated or scrambled repeats have impaired motility due to altered adhesion site formation and dynamics, suggesting that the CSP repeats provide a cohesive environment in which adhesion sites can form. We hypothesized that biophysical properties of the repeats are important in this role and interrogated this using single-molecule fluorescence-force spectroscopy. We show that the repeats are a stiff, linear spring with elastic properties, dependent upon length and lost when the repeats are scrambled. These data are the first evidence that the CSP repeat region serves a functional role during infection and motility, likely mediated through its biophysical properties.

Success Rate of Obturation of Root Canals by Different Techniques in Primary Molars: A Comparative Clinical Study

2020 ◽  
Vol 2 (1) ◽  
pp. 36-44
Author(s):  
Satyawan G. Damle ◽  
Ritika Bansal ◽  
Dhanashree D. Sakhare
Keyword(s):  
Success Rate ◽  
Study Groups ◽  
Primary Molars ◽  
Control Group ◽  
Second Primary ◽  
Chi Square ◽  
Exact Test ◽  
Root Canals ◽  
Significant Difference ◽  
Comparative Clinical Study

Objective: To compare the success rate of different obturation procedures in primary mandibular second molars clinically and also by digital radiovisiography. Methods: A total of 40 children aged between 4-8 years with deeply carious mandibular second primary molars indicated for single session pulpectomy were selected. Canals were obturated with Metapex. The 3 study groups (Endodontic plugger, Handheld lentulospiral, Navi Tip syringe) were compared with the control group (reamer) both clinically and radiovisiographically. The data collected were statistically analyzed using Pearson’s Chi-square and Fisher’s exact test. Results: The use of Navi tip syringe led to the least number of voids followed by Endodontic plugger and Reamer and the highest number of voids was reported with Lentulospiral. Navitip presented maximum number of optimally filled cases followed by Endodontic plugger and Lentulospiral and least number of optimally filled cases with reamer. However, there was no statistically significant difference (p>0.05) in any of the groups with clinical (pain and tenderness to percussion) and radiographic parameters (presence or absence of voids and length of obturation). Conclusion: Within the limitations of the present study, though the clinical outcome was statistically insignificant, Navitip syringe exhibited encouraging results and is a promising option for obturation in primary teeth.

scholarly journals An epitope-based malaria vaccine targeting the junctional region of circumsporozoite protein

npj Vaccines ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Lucie Jelínková ◽  
Hugo Jhun ◽  
Allison Eaton ◽  
Nikolai Petrovsky ◽  
Fidel Zavala ◽  
...  
Keyword(s):  
Mouse Model ◽  
Malaria Vaccine ◽  
High Titer ◽  
Circumsporozoite Protein ◽  
Infection Model ◽  
Vaccine Platform ◽  
Junctional Region ◽  
Mouse Infection Model ◽  
Virus Like Particle ◽  
Major Surface

AbstractA malaria vaccine that elicits long-lasting protection and is suitable for use in endemic areas remains urgently needed. Here, we assessed the immunogenicity and prophylactic efficacy of a vaccine targeting a recently described epitope on the major surface antigen on Plasmodium falciparum sporozoites, circumsporozoite protein (CSP). Using a virus-like particle (VLP)-based vaccine platform technology, we developed a vaccine that targets the junctional region between the N-terminal and central repeat regions of CSP. This region is recognized by monoclonal antibodies, including mAb CIS43, that have been shown to potently prevent liver invasion in animal models. We show that CIS43 VLPs elicit high-titer and long-lived anti-CSP antibody responses in mice and is immunogenic in non-human primates. In mice, vaccine immunogenicity was enhanced by using mixed adjuvant formulations. Immunization with CIS43 VLPs conferred partial protection from malaria infection in a mouse model, and passive transfer of serum from immunized macaques also inhibited parasite liver invasion in the mouse infection model. Our findings demonstrate that a Qβ VLP-based vaccine targeting the CIS43 epitope combined with various adjuvants is highly immunogenic in mice and macaques, elicits long-lasting anti-CSP antibodies, and inhibits parasite infection in a mouse model. Thus, the CIS43 VLP vaccine is a promising pre-erythrocytic malaria vaccine candidate.

scholarly journals COVD-26. TELEPHONE CONSULTATIONS IN NEURO-ONCOLOGY DURING THE COVID-19 PANDEMIC: LEVELS OF PATIENT SATISFACTION AND COMPARISON WITH TRADITIONAL FACE-TO-FACE CONSULTATIONS

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii26-ii26
Author(s):  
Emma Toman ◽  
Claire Goddard ◽  
Frederick Berki ◽  
William Garratt ◽  
Teresa Scott ◽  
...  
Keyword(s):  
Patient Satisfaction ◽  
University Hospitals ◽  
Health Crisis ◽  
Patient Satisfaction Questionnaire ◽  
Telephone Consultation ◽  
Exact Test ◽  
Face To Face ◽  
Significant Difference ◽  
The Face ◽  
The University

Abstract INTRODUCTION Controversy exists as to whether telephone clinics are appropriate in neurosurgical-oncology. The COVID-19 pandemic forced neuro-oncology services worldwide to re-design and at the University Hospitals Birmingham UK, telephone clinics were quickly implemented in select patients to limit numbers of patients attending hospital. It was important to determine how these changes were perceived by patients. METHODS A 20-question patient satisfaction questionnaire was distributed to patients who attended neuro-oncology clinic in person (“face-to-face”), or via the telephone. Fisher’s exact test was used to determine significance, which was set at p&lt; 0.05. RESULTS Eighty questionnaires were distributed between June 2020 and August 2020. Overall, 50% (n=40) of patients returned the questionnaire, 50% (n=23) of face-to-face and 50% (n=17) telephone patients. Of those who received telephone consultations, 88% (n=15) felt the consultation was convenient, 88% (n=15) were satisfied with their consultation and 18% (n=3) felt they would have preferred to have a face-to-face appointment. Of those who attended clinic in person, 96% (n=22) felt their consultation was convenient, 100% (n=23) were satisfied with their consultation and 13% (n=3) would have preferred a telephone consultation. Within the face-to-face clinic attendees, only 13% (n=3) were concerned regarding the COVID risk associated with attending hospital. There was no significant difference in patient convenience or satisfaction (p=0.565 and p=0.174 respectively) between face-to-face and telephone clinics. There was no significant difference in whether patients would’ve preferred the alternative method of consultation (p &gt; 0.999). CONCLUSION Our study suggests that careful patient selection for neuro-oncology telephone clinic is not inferior to face-to-face clinic. Telephone clinic during COVID-19 pandemic proved to be convenient, safe and effective. This global health crisis has transformed telephone neuro-oncology consultations from an experimental innovation into established practice and should be continued beyond the pandemic in select cases.

scholarly journals AB0009 ASSOCIATION OF STAT4 RS7574865, RUNX1 RS9979383, IL6 RS1800795, IL6R RS2228145, IL6R RS4845618 WITH SYSTEMIC LUPUS ERYTHEMATOSUS SUSCEPTIBILITY AND SOME LUPUS MANIFESTATIONS IN BELARUSIAN POPULATION

2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 1039.2-1040
Author(s):  
N. Dostanko ◽  
V. Yagur ◽  
R. Goncharova ◽  
E. Siniauskaya ◽  
T. Zybalova
Keyword(s):  
Systemic Lupus Erythematosus ◽  
Lupus Erythematosus ◽  
Diagnostic Odds Ratio ◽  
Protective Role ◽  
Fisher Exact Test ◽  
Systemic Lupus ◽  
Exact Test ◽  
American College Of Rheumatology ◽  
Healthy Donors ◽  
Significant Difference

Background:Systemic lupus erythematosus (SLE) has a significant genetic predisposition. Many genetic variants of susceptibility to SLE have been published and analyzed, but the clinical and functional significance of the various genotypes has not yet been clearly defined [1].Objectives:To estimate the association between some of non-HLA gene polymorphisms such as STAT4 rs7574865, RUNX1 rs9979383, IL6 rs1800795, IL6R rs2228145, IL6R rs4845618 and susceptibility to SLE in Belarusian population as well as some disease manifestations.Methods:We examined 383 healthy blood donors and 54 SLE patients (18-72 years old, median age 35) classified according to the 1997 American College of Rheumatology (ACR) revised classification criteria [2]. Deoxyribonucleic acid was extracted from peripheral blood samples by phenol-chloroform method. Genotyping was performed by real-time PCR with fluorescent probes. Differences of distribution of all the single nucleotide polymorphism (SNP) genotypes and their associations with secondary antiphospholipid syndrom (APS) and lupus arthritis were analyzed using Pearson χ2 (χ2) and two-way Fisher exact test (F, p2-t). Diagnostic odds ratio (dOR), likelihood ratio of positive (LR +) and negative (LR –) tests and corresponding 95% confidence intervals (CI) were also calculated.Results:We revealed significant difference in STAT4 rs7574865 genotypes in SLE patients and healthy donors (χ2=8,27, р=0,016) with significant increase of ТТ genotype frequency in SLE patients vs healthy donors (χ2=6.83 p=0.009; p2-t =0.020; dOR=3.78 (CI95% 1.36-10.55); LR+ =3.44 (CI95% 1.35-8.71); LR– =0.91 (CI95% 0.83-0.98)). Lupus arthritis was more common in risk TT-genotype SLE carriers than in other SLE patients (χ2=5.902 p=0.015; p2-t =0.027).We revealed significant increase of СТ genotype (RUNX1 rs9979383) in healthy donors vs SLE patients (χ2=4.14; p=0.042; dOR=0.53 (CI95% 0.29-0.98); LR+ =0.69 (CI95% 0.45-0.99); LR– =1.3 (CI95% 1.01-1,56)). Lupus arthritis was more common in SLE СТ-genotype carriers than in other SLE patients (χ2=4.66 p=0.031; p2-t =0.058).Significant differences in IL6 rs1800795, IL6R rs2228145 and IL6R rs4845618 genotypes distribution between studied groups were not found (χ2, p=0.427, p=0.559 and p=0.407, correspondingly) but GG-genotype (IL6 rs1800795) carriership in SLE patients was associated with increased APS frequency (χ2=4.45, p=0.035; dOR=0.19 (CI95% 0.04-0.9); LR+ =0.28 (CI95% 0.07-0.93); LR– =1.41 (CI95% 1.03-1.64).Conclusion:Our data suggest the susceptibility to SLE in ТТ genotype of STAT4 rs7574865 polymorphism, protective role of СТ genotype of RUNX1 rs9979383 for SLE and association between GG-genotype of IL6 rs1800795 and APS in SLE patients in Belarusian population. Lupus arthritis was associated with ТТ genotype of STAT4 rs7574865 and СТ genotype of RUNX1 rs9979383.References:[1]Chen L, Morris DL, Vyse TJ. Genetic advances in systemic lupus erythematosus: an update. Curr Opin Rheumatol 2017;29:423–33.[2]Hochberg MC. Updating the American College of Rheumatology Revised Criteria for the classification of Systemic Lupus Erythematosus. Arthritis Rheum 1997;40:1725.Disclosure of Interests:None declared

scholarly journals Detection of AZF microdeletions and reproductive hormonal profile analysis of infertile sudanese men pursuing assisted reproductive approaches

BMC Urology ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Hassan Osman Alhassan Elsaid ◽  
Tarteel Gadkareim ◽  
Tagwa Abobakr ◽  
Eiman Mubarak ◽  
Mehad A. Abdelrhem ◽  
...  
Keyword(s):  
Y Chromosome ◽  
Klinefelter Syndrome ◽  
Semen Analysis ◽  
Control Group ◽  
Male Factor ◽  
Exact Test ◽  
Fisher's Exact Test ◽  
Infertile Men ◽  
Significant Difference ◽  
Fisher’S Exact Test

Abstract Background Male factor is the major contributor in roughly half of infertility cases. Genetic factors account for 10–15% of male infertility. Microdeletions of azoospermia factors (AZF) on the Yq region are the second most frequent spermatogenesis disorder among infertile men after Klinefelter syndrome. We detected in our previous study a frequency of 37.5% AZF microdeletions which investigated mainly the AZFb and AZFc. We attempted in this study for the first time to evaluate the frequencies of all AZF sub-regions microdeletions and to analyze reproductive hormonal profiles in idiopathic cases of azoospermic and oligozoospermic men from Sudan. Methods A group of 51 medically fit infertile men were subjected to semen analysis. Four couples have participated in this study as a control group. Semen analysis was performed according to WHO criteria by professionals at Elsir Abu-Elhassan Fertility Centre where samples have been collected. We detected 12 STSs markers of Y chromosome AZF microdeletions using a multiplex polymerase chain reaction. Analysis of reproductive hormone levels including Follicle Stimulating, Luteinizing, and Prolactin hormones was performed using ELISA. Comparisons between outcome groups were performed using Student’s t-test Chi-square test or Fisher’s exact test. Results AZF microdeletion was identified in 16 out of 25 Azoospermic and 14 out of 26 of the Oligozoospermic. Microdeletion in the AZFa region was the most frequent among the 30 patients (N = 11) followed by AZFc, AZFd (N = 4 for each) and AZFb (N = 3). Among the Oligozoospermic participants, the most frequent deletions detected were in the AZFa region (N = 10 out of 14) and was significantly associated with Oligozoospermic phenotype, Fisher's Exact Test (2-sided) p = 0.009. Among the Azoospermic patients, the deletion of the AZFc region was the most frequent (N = 9 out of 16) and was significantly associated with Azoospermia phenotype Fisher's Exact Test p = 0.026. There was a significant difference in Y chromosome microdeletion frequency between the two groups. The hormonal analysis showed that the mean levels of PRL, LH, and FSH in Azoospermic patients were slightly higher than those in oligozoospermic. A weak negative correlation between prolactin higher level and Azoospermic patients was detected. (AZFa r = 0.665 and 0.602, p = 0.000 and 0.0004, AZFb r = 0.636 and 0.409, p = 0.000 and 0.025, and AZFd r = 0.398 and 0.442, p = 0.029 and 0.015). The correlation was positive for AZFa and negative for AZFb and AZFd. Conclusions We concluded in this study that the incidences of microdeletions of the Y chromosome confined to AZF a, b, c and d regions is 58.8% in infertile subjects with 31.4% were Azoospermic and 27.5% were Oligozoospermic. This might provide a piece of evidence that these specified regions of the Y chromosome are essential for controlling spermatogenesis. These findings will be useful for genetic counseling within infertility clinics in Sudan and to adopt appropriate methods for assisted reproduction.

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