scholarly journals Characterization of Naturally Acquired Immunity to a Panel of Antigens Expressed in Mature P. falciparum Gametocytes

2021 ◽  
Vol 11 ◽  
Author(s):  
Michelle K. Muthui ◽  
Eizo Takashima ◽  
Brian R. Omondi ◽  
Christine Kinya ◽  
William I. Muasya ◽  
...  
Keyword(s):  
Antibody Responses ◽  
Acquired Immunity ◽  
Linear Regression Models ◽  
Transmission Blocking ◽  
Study Population ◽  
The Mean ◽  
Acquired Immune Responses ◽  
Antibody Levels ◽  
Variant Antigen

IntroductionNaturally acquired immune responses against antigens expressed on the surface of mature gametocytes develop in individuals living in malaria-endemic areas. Evidence suggests that such anti-gametocyte immunity can block the development of the parasite in the mosquito, thus playing a role in interrupting transmission. A better comprehension of naturally acquired immunity to these gametocyte antigens can aid the development of transmission-blocking vaccines and improve our understanding of the human infectious reservoir.MethodsAntigens expressed on the surface of mature gametocytes that had not previously been widely studied for evidence of naturally acquired immunity were identified for protein expression alongside Pfs230-C using either the mammalian HEK293E or the wheat germ cell-free expression systems. Where there was sequence variation in the candidate antigens (3D7 vs a clinical isolate PfKE04), both variants were expressed. ELISA was used to assess antibody responses against these antigens, as well as against crude stage V gametocyte extract (GE) and AMA1 using archived plasma samples from individuals recruited to participate in malaria cohort studies. We analyzed antibody levels (estimated from optical density units using a standardized ELISA) and seroprevalence (defined as antibody levels greater than three standard deviations above the mean levels of a pool of malaria naïve sera). We described the dynamics of antibody responses to these antigens by identifying factors predictive of antibody levels using linear regression models.ResultsOf the 25 antigens selected, seven antigens were produced successfully as recombinant proteins, with one variant antigen, giving a total of eight proteins for evaluation. Antibodies to the candidate antigens were detectable in the study population (N = 216), with seroprevalence ranging from 37.0% (95% CI: 30.6%, 43.9%) for PSOP1 to 77.8% (95% CI: 71.6%, 83.1%) for G377 (3D7 variant). Responses to AMA1 and GE were more prevalent than those to the gametocyte proteins at 87.9% (95% CI: 82.8%, 91.9%) and 88.3% (95% CI: 83.1%, 92.4%), respectively. Additionally, both antibody levels and breadth of antibody responses were associated with age and concurrent parasitaemia.ConclusionAge and concurrent parasitaemia remain important determinants of naturally acquired immunity to gametocyte antigens. Furthermore, we identify novel candidates for transmission-blocking activity evaluation.

scholarly journals Previous COVID-19 Infection and Antibody Levels After Vaccination

2021 ◽  
Vol 9 ◽  
Author(s):  
Hamad Ali ◽  
Barrak Alahmad ◽  
Abdullah A. Al-Shammari ◽  
Abdulmohsen Alterki ◽  
Maha Hammad ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Individual Characteristics ◽  
Linear Regression Models ◽  
Health Authorities ◽  
Previous Infection ◽  
Public Health Authorities ◽  
The Mean ◽  
Vaccine Shortages ◽  
Antibody Levels ◽  
Ig G

Background: The emergence of new COVID-19 variants of concern coupled with a global inequity in vaccine access and distribution has prompted many public health authorities to circumvent the vaccine shortages by altering vaccination protocols and prioritizing persons at high risk. Individuals with previous COVID-19 infection may not have been prioritized due to existing humoral immunity.Objective: We aimed to study the association between previous COVID-19 infection and antibody levels after COVID-19 vaccination.Methods: A serological analysis to measure SARS-CoV-2 immunoglobulin (Ig)G, IgA, and neutralizing antibodies was performed on individuals who received one or two doses of either BNT162b2 or ChAdOx1 vaccines in Kuwait. A Student t-test was performed and followed by generalized linear regression models adjusted for individual characteristics and comorbidities were fitted to compare the average levels of IgG and neutralizing antibodies between vaccinated individuals with and without previous COVID-19 infection.Results: A total of 1,025 individuals were recruited. The mean levels of IgG, IgA, and neutralizing antibodies were higher in vaccinated subjects with previous COVID-19 infections than in those without previous infection. Regression analysis showed a steeper slope of decline for IgG and neutralizing antibodies in vaccinated individuals without previous COVID-19 infection compared to those with previous COVID-19 infection.Conclusion: Previous COVID-19 infection appeared to elicit robust and sustained levels of SARS-CoV-2 antibodies in vaccinated individuals. Given the inconsistent supply of COVID-19 vaccines in many countries due to inequities in global distribution, our results suggest that even greater efforts should be made to vaccinate more people, especially individuals without previous COVID-19 infection.

scholarly journals Systemic Antibiotics Influence Periodontal Parameters and Oral Microbiota, But Not Serological Markers

2021 ◽  
Vol 11 ◽  
Author(s):  
Elisa Kopra ◽  
Laura Lahdentausta ◽  
Milla Pietiäinen ◽  
Kåre Buhlin ◽  
Päivi Mäntylä ◽  
...  
Keyword(s):  
Alveolar Bone ◽  
Serum Antibody ◽  
Oral Microbiota ◽  
Microbiota Composition ◽  
Periodontal Pathogens ◽  
Linear Regression Models ◽  
Periodontal Inflammation ◽  
The Mean ◽  
Antibody Levels ◽  
Systemic Antibiotics

The use of systemic antibiotics may influence the oral microbiota composition. Our aim was to investigate in this retrospective study whether the use of prescribed antibiotics associate with periodontal status, oral microbiota, and antibodies against the periodontal pathogens. The Social Insurance Institution of Finland Data provided the data on the use of systemic antibiotics by record linkage to purchased medications and entitled reimbursements up to 1 year before the oral examination and sampling. Six different classes of antibiotics were considered. The Parogene cohort included 505 subjects undergoing coronary angiography with the mean (SD) age of 63.4 (9.2) years and 65% of males. Subgingival plaque samples were analysed using the checkerboard DNA-DNA hybridisation. Serum and saliva antibody levels to periodontal pathogens were analysed with immunoassays and lipopolysaccharide (LPS) activity with the LAL assay. Systemic antibiotics were prescribed for 261 (51.7%) patients during the preceding year. The mean number of prescriptions among them was 2.13 (range 1–12), and 29.4% of the prescriptions were cephalosporins, 25.7% penicillins, 14.3% quinolones, 12.7% macrolides or lincomycin, 12.0% tetracycline, and 5.8% trimethoprim or sulphonamides. In linear regression models adjusted for age, sex, current smoking, and diabetes, number of antibiotic courses associated significantly with low periodontal inflammation burden index (PIBI, p < 0.001), bleeding on probing (BOP, p = 0.006), and alveolar bone loss (ABL, p = 0.042). Cephalosporins associated with all the parameters. The phyla mainly affected by the antibiotics were Bacteroidetes and Spirochaetes. Their levels were inversely associated with the number of prescriptions (p = 0.010 and p < 0.001) and directly associated with the time since the last prescription (p = 0.019 and p < 0.001). Significant inverse associations were observed between the number of prescriptions and saliva concentrations of Prevotella intermedia, Tannerella forsythia, and Treponema denticola and subgingival bacterial amounts of Porphyromonas gingivalis, P. intermedia, T. forsythia, and T. denticola. Saliva or serum antibody levels did not present an association with the use of antibiotics. Both serum (p = 0.031) and saliva (p = 0.032) LPS activity was lower in patients having any antibiotic course less than 1 month before sampling. Systemic antibiotics have effects on periodontal inflammation and oral microbiota composition, whereas the effects on host immune responses against the periodontal biomarker species seem unchanged.

scholarly journals Epitope-Specific Humoral Immunity to Plasmodium vivax Duffy Binding Protein

2003 ◽  
Vol 71 (5) ◽  
pp. 2508-2515 ◽  
Author(s):  
Jia Xainli ◽  
Jennifer L. Cole-Tobian ◽  
Moses Baisor ◽  
Will Kastens ◽  
Moses Bockarie ◽  
...  
Keyword(s):  
Plasmodium Vivax ◽  
Binding Protein ◽  
Antibody Responses ◽  
Acquired Immunity ◽  
Duffy Binding Protein ◽  
Erythrocyte Invasion ◽  
Repeated Infection ◽  
Linear Epitopes ◽  
Critical Binding ◽  
Antibody Levels

ABSTRACT Erythrocyte invasion by Plasmodium vivax is completely dependent on binding to the Duffy blood group antigen by the parasite Duffy binding protein (DBP). The receptor-binding domain of this protein lies within a cysteine-rich region referred to as region II (DBPII). To examine whether antibody responses to DBP correlate with age-acquired immunity to P. vivax, antibodies to recombinant DBP (rDBP) were measured in 551 individuals residing in a village endemic for P. vivax in Papua New Guinea, and linear epitopes mapped in the critical binding region of DBPII. Antibody levels to rDBPII increased with age. Four dominant linear epitopes were identified, and the number of linear epitopes recognized by semiimmune individuals increased with age, suggesting greater recognition with repeated infection. Some individuals had antibodies to rDBPII but not to the linear epitopes, indicating the presence of conformational epitopes. This occurred in younger individuals or subjects acutely infected for the first time with P. vivax, indicating that repeated infection is required for recognition of linear epitopes. All four dominant B-cell epitopes contained polymorphic residues, three of which showed variant-specific serologic responses in over 10% of subjects examined. In conclusion, these results demonstrate age-dependent and variant-specific antibody responses to DBPII and implicate this molecule in partial acquired immunity to P. vivax in populations in endemic areas.

scholarly journals Profiling the Quality and Quantity of Naturally Induced Antibody Responses Against Pfs230 and Pfs48/45 Among Non-Febrile Children Living in Southern Ghana: A Longitudinal Study

2021 ◽  
Vol 11 ◽  
Author(s):  
Fermin K. Broni ◽  
Festus K. Acquah ◽  
Dorcas Obiri-Yeboah ◽  
Evans K. Obboh ◽  
Esther Sarpong ◽  
...  
Keyword(s):  
Longitudinal Study ◽  
Venous Blood ◽  
Dry Season ◽  
Antibody Responses ◽  
Clear Understanding ◽  
Older Children ◽  
Igg Antibody ◽  
Transmission Blocking ◽  
Antibody Levels ◽  
Transmission Blocking Vaccine

A clear understanding of the properties of naturally induced antibody responses against transmission-blocking vaccine candidates can accelerate the understanding of the development of transmission-blocking immunity. This study characterized the naturally induced IgG responses against two leading transmission-blocking vaccine antigens, Pfs230 and Pfs48/45, in non-febrile children living in Simiw, Ghana. Consecutive sampling was used to recruit 84 non-febrile children aged from 6 to 12 years old into the 6-month (November 2017 until May 2018) longitudinal study. Venous blood (1 ml) was collected once every 2 months and used to determine hemoglobin levels, P. falciparum prevalence using microscopy and polymerase chain reaction, and the levels and relative avidity of IgG responses against Pfs230 and Pfs48/45 using indirect ELISA. IgG levels against Pfs230 and Pfs48/45 decreased from the start (November) to the middle (January) and end (March) of the dry season respectively, then they began to increase. Participants, especially older children (10–12 years old) with active infections generally had lower antibody levels against both antigens. The relative avidities of IgG against both antigens followed the trend of IgG levels until the middle of the dry season, after which the relative avidities of both antigens correlated inversely with the antibody levels. In conclusion, although IgG antibody levels against both Pfs48/45 and Pfs230 began to increase by the early rainy season, they were inversely correlated to their respective relative avidities.

scholarly journals Previous COVID-19 infection and antibody levels after vaccination

2021 ◽  
Author(s):  
Hamad Ali ◽  
Barrak Alahmad ◽  
Abdullah A. Al-Shammari ◽  
Abdelmohsen Al-Terki ◽  
Maha Hammad ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Regression Models ◽  
Individual Characteristics ◽  
Linear Regression Models ◽  
Serological Analysis ◽  
Health Authorities ◽  
Public Health Authorities ◽  
The Mean ◽  
Vaccine Shortages ◽  
Antibody Levels

AbstractBackgroundThe emergence of new COVID-19 variants of concern coupled with a global inequity in vaccine access and distribution, prompted many public health authorities to circumvent the vaccine shortages by altering vaccination protocols and prioritizing high-risk individuals. Those with previous COVID-19 infection may have not been prioritized due to existing humoral immunity.ObjectiveWe aim to study the association between previous COVID-19 infection and antibody levels after COVID-19 vaccination.MethodsA serological analysis to measure SARS-CoV-2 IgG, IgA and neutralizing antibodies was performed on individuals who received one or two doses of either BNT162b2 or ChAdOx1 vaccines in Kuwait. Generalized linear regression models adjusted for individual characteristics and comorbidities were fitted to study the average levels of IgG and neutralizing antibodies in vaccinated individuals based who had previous COVID-19 infection compared to those who had not.ResultsA total of 1025 individuals were recruited. The mean levels of IgG, IgA and neutralizing antibodies were higher in vaccinated subjects with previous COVID-19 infection when compared with those vaccinated without previous COVID-19 infection. Regression analysis showed a steeper slope of decline for IgG in vaccinated individuals without previous COVID-19 infection in comparison with vaccinated individuals with previous COVID-19 infection.ConclusionPrevious COVID-19 infection appears to elicit robust and sustained levels of SARS-CoV-2 antibodies in vaccinated individuals. Given the inconsistent supply of COVID-19 vaccines in many countries due to the global inequity, our results point towards wider vaccination plans to especially cover individuals without previous COVID-19 infection.

Efficacy model for mosquito stage transmission blocking vaccines for malaria

Parasitology ◽  
2008 ◽  
Vol 135 (13) ◽  
pp. 1497-1506 ◽  
Author(s):  
A. SAUL
Keyword(s):  
Herd Immunity ◽  
Field Trials ◽  
Host Population ◽  
Antibody Responses ◽  
Human Populations ◽  
Transmission Blocking ◽  
Antibody Levels ◽  
The Relationship ◽  
Transmission Blocking Vaccines ◽  
Field Setting

SUMMARYVaccines that target antigens found on the mosquito stages of Plasmodium falciparum and Plasmodium vivax parasites are under development as transmission blocking vaccines. Antisera from vaccinated animals and humans are able to block oocyst development in artificially fed mosquitoes but it is not clear from these data what level of antibody response would be required for a useful vaccine in a field setting. This paper describes a mathematical model that takes into account the relationship between antibody levels and blocking of oocyst levels in artificial feeds, the distribution of antibody responses seen in human populations and the distribution of oocyst densities in infected mosquitoes in the field to calculate the levels of antibody in the host population that would be required to achieve a level of herd immunity in a vaccinated human population that would give an operationally useful level of transmission blocking. The model predicts that current formulations of Pfs25 are likely to achieve useful reductions in transmission when tested in human field trials.

scholarly journals Characterization of Thermal and Mechanical Indices from Serial Ultrasound Exams and Associations with Neonatal Anthropometry: The NICHD Fetal Growth Studies

2017 ◽  
Vol 35 (07) ◽  
pp. 632-642 ◽  
Author(s):  
Germaine Louis ◽  
Paul Albert ◽  
Sungduk Kim ◽  
Karin Fuchs ◽  
Jagteshwar Grewal ◽  
...  
Keyword(s):  
Regression Models ◽  
Anthropometric Measurements ◽  
Linear Regression Models ◽  
Negatively Associated ◽  
Skinfold Measurements ◽  
The Mean ◽  
Race Ethnicity ◽  
Index Weight ◽  
Multiple Linear Regression Models

Objective This article aims to determine if the number of maternal ultrasound scans where the highest thermal (TI) or mechanical (MI) indices recorded during obstetrical ultrasound exceed 1.0 were associated with neonatal anthropometric measurements. Study Design A prospective cohort of 2,334 nonobese low-risk pregnant women from 12 U.S. clinical sites underwent a total of six ultrasound scans, for which the highest TI and MI values were recorded. Neonatal anthropometric measurements were obtained within 12 to 24 hours of delivery. Multiple linear regression models adjusted for maternal race/ethnicity, body mass index, weight gain, and gestational age were used to examine associations between the number of maternal ultrasounds during gestation with a TI or MI exceeding 1.0 and the mean change in neonatal anthropometry. Results Ultrasounds with TI or MI >1.0 were not associated with birth weight, neonatal length, nor head, chest, and abdominal circumferences. TI >1.0 was negatively associated with neonatal mid-upper arm and mid-upper thigh circumferences. MI >1.0 was negatively associated with neonatal skinfold measurements of the anterior thigh and triceps, and neonatal circumferences of the mid-upper thigh and umbilicus. Conclusion Prenatal ultrasound examinations in which TI or MI intermittently exceeded 1.0 did not identify a pattern of alterations of birth size.

scholarly journals Serum IgG levels in children 6 months after SARS-CoV-2 infection and comparison with adults

2021 ◽  
Author(s):  
Silvia Bloise ◽  
Alessia Marcellino ◽  
Alessia Testa ◽  
Anna Dilillo ◽  
Saverio Mallardo ◽  
...  
Keyword(s):  
Antibody Response ◽  
Clinical Manifestations ◽  
Antibody Responses ◽  
Serological Tests ◽  
Gene Characterization ◽  
Children And Parents ◽  
Antibody Levels ◽  
Serum Igg Levels

AbstractSince the outbreak of SARS-CoV-2 among the population has occurred quite recently, there is a lack of evidence on the long-term duration of antibody response, especially in children. It is therefore crucial to clarify this aspect, considering its implications in the development of successful surveillance strategies, therapies, and vaccinations. The aim of this study was to assess the antibody response in a children group after SARS-CoV-2 infection, and to compare it with that of their parents affected by SARS-CoV-2 infection. We enrolled 12 children and their parents, both groups being affected by COVID-19 in April 2020. In the children’s group, we collected real-time RT-PCR cycle threshold (Ct) values and gene characterization of first nasal-throat swab at the time of diagnosis (T0); 30 days after the diagnosis (T30), we performed blood tests to detect anti-SARS-CoV-2 IgM and IgG. Finally, 180 days after the diagnosis (T180), we measured anti-SARS-CoV-2 IgG in both children and parents. In children, antibody levels declined significantly at 180 days (T180) after first measurement (T30). There were no significant differences in IgG level related to age, sex, and clinical manifestations. We found a significant correlation between IgG titers at T30 and Ct value of gene N. Children showed a lower level of antibodies against SARS-CoV-2 at T180 compared to their parents.Conclusion: Antibody responses in children waned 180 days after SARS-CoV-2 infection, and at the same time, their parents showed a different antibody response to the virus. These results highlight that serological tests should be used with caution in surveillance strategies among the general population. What is known:• Currently is not known how long antibody response will be maintained or if it protects from reinfection.• Recent reports in adults suggest that antibodies to SARS-CoV-2 declined several months after infection, but data are missing in pediatric age. What is new:• We showed that antibody responses to SARS-CoV-2 wane several months after infection also in children with quantitative differences in antibody levels between children and adults.• In this context, serological tests should be used with caution in surveillance strategies.

Caracterização da Peneira Média em Clones de Coffea canephora

REVISTA FIMCA ◽  
2018 ◽  
Vol 5 (2) ◽  
pp. 28-31
Author(s):  
Darlan Darlan Sanches Barbosa Alves ◽  
Victor Mouzinho Spinelli ◽  
Marcos Santana Moraes ◽  
Carolina Augusto De Souza ◽  
Rodrigo da Silva Ribeiro ◽  
...  
Keyword(s):  
Genetic Improvement ◽  
Block Design ◽  
Coffea Canephora ◽  
Coffee Production ◽  
Randomized Block Design ◽  
Significant Difference ◽  
The Mean ◽  
Four Blocks ◽  
Selection Of

Introdução: O estado de Rondônia se destaca como tradicional produtor de café, sendo o segundo maior produtor brasileiro de C. canephora. No melhoramento genético de C. canephora, a seleção de plantas de elevada peneira média está associada à bebida de qualidade superior. Objetivos: O objetivo desse estudo foi avaliar a variabilidade genética de clones de C. canephora para o tamanho dos grãos, mensurado a partir da avaliação da peneira média (PM). Materiais e Métodos: Para isso, foi conduzido ao longo de dois anos agrícolas experimento no campo experimental da Embrapa no município de Ouro Preto do Oeste-RO, para a avaliação da peneira média de 130 genótipos (clones) com características das variedades botânicas Conilon, Robusta e híbridos intervarietais. O delineamento experimental utilizado foi de blocos ao acaso, com quatro repetições de quatro plantas por parcela. Resultados: Não houve resultados significativos para a interação clones X anos, indicando uma maior consistência no comportamento das plantas ao longo do tempo. Porém foram observadas diferenças significativas para o tamanho dos grãos entre os genótipos avaliados, possibilitando selecionar genótipos superiores. Conclusão: Os genótipos agruparam-se em cinco classes de acordo com o teste de média, subsidiando a caracterização de um gradiente de variabilidade da característica avaliada ABSTRACTIntroduction: Coffea canephora accounts for approximately 35% of the world's coffee production. The state of Rondônia stands out as a traditional coffee producer, being the second largest Brazilian producer of C. canephora. In the classical genetic improvement of C. anephora, the selection of plants of high average sieve is associated with a drink of superior quality. Objectives: The objective of this udy was to evaluate the genetic variability of Coffea canephora clones for the agronomic medium sieve (PM). Materials and Methods: The experiment was conducted in the experimental field of Embrapa, municipality of OuroPreto do Oeste-RO, located at coordinates 10º44'53 "S and 62º12'57". One hundred thirty genotypes (clones) of botanical characteristics Conilon, Robusta and intervarietal hybrids were evaluated in the agricultural years 2013-2014 and 2014-2015. The experimental design was a randomized block design with four blocks and four plants per plot, spacing 3.5 x 1.5 meters between plants. Results: Significant difference was found for the grain size. According to the F test, at 5% probability, the genotypes were grouped into five classes according to the mean test. Conclusion: The results obtained subsidized the characterization of a variability gradient of the evaluated trait.

scholarly journals Elimination of nasal obstruction improves pulmonary functions and oxygenation

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Eman Sobh ◽  
Fatma Elhussieny ◽  
Taghreed Ismail
Keyword(s):  
Nasal Obstruction ◽  
Blood Gases ◽  
Medical Problem ◽  
Forced Expiratory Volume ◽  
Nasal Packing ◽  
Nasal Pack ◽  
Arterial Blood ◽  
Study Population ◽  
The Mean ◽  
The Impact

Abstract Background Nasal obstruction is a significant medical problem. This study aimed to examine the effect of nasal obstruction and nasal packing on arterial blood gases and pulmonary function indices, and the impact of the elimination of nasal obstruction on preoperative values. Results The mean age of the study population was 26.6 ± 10.1 years, males represented 50.8%. Spirometric indices showed statistically significant improvement (preoperative forced expiratory volume in 1st second 66.9 ± 13.9 vs 79.6 ± 14.9 postoperative and preoperative forced vital capacity 65.5 ± 12.7 vs 80.4 ± 13.8 postoperative). Oxygen saturation was significantly lower during nasal packing (95.6 ± 1.6 preoperative vs 94.7 ± 2.8 with nasal pack), and significant improvement (97.2 ± 1.4) was observed after removal of the nasal pack. Nasal obstruction scores significantly improved. Conclusion The results of this study indicate that either simple nasal obstruction or nasal packing may cause hypoxemia and abnormalities in lung function tests. Hypoxemia was more evident with nasal packing.

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