Characterization of Anopheles gambiae D7 salivary proteins as markers of human–mosquito bite contact

Abstract Background Malaria is transmitted when infected Anopheles mosquitoes take a blood meal. During this process, the mosquitoes inject a cocktail of bioactive proteins that elicit antibody responses in humans and could be used as biomarkers of exposure to mosquito bites. This study evaluated the utility of IgG responses to members of the Anopheles gambiae D7 protein family as serological markers of human–vector contact. Methods The D7L2, D7r1, D7r2, D7r3, D7r4 and SG6 salivary proteins from An. gambiae were expressed as recombinant antigens in Escherichia coli. Antibody responses to the salivary proteins were compared in Europeans with no prior exposure to malaria and lifelong residents of Junju in Kenya and Kitgum in Uganda where the intensity of malaria transmission is moderate and high, respectively. In addition, to evaluate the feasibility of using anti-D7 IgG responses as a tool to evaluate the impact of vector control interventions, we compared responses between individuals using insecticide-treated bednets to those who did not in Junju, Kenya where bednet data were available. Results We show that both the long and short forms of the D7 salivary gland antigens elicit a strong antibody response in humans. IgG responses against the D7 antigens reflected the transmission intensities of the three study areas, with the highest to lowest responses observed in Kitgum (northern Uganda), Junju (Kenya) and malaria-naïve Europeans, respectively. Specifically, the long form D7L2 induced an IgG antibody response that increased with age and that was lower in individuals who slept under a bednet, indicating its potential as a serological tool for estimating human–vector contact and monitoring the effectiveness of vector control interventions. Conclusions This study reveals that D7L2 salivary antigen has great potential as a biomarker of exposure to mosquito bites and as a tool for assessing the efficacy of vector control strategies such as bednet use. Graphical abstract

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Impact of Treatment Regimens on Antibody Response to the SARS-CoV-2 Coronavirus

Frontiers in Immunology ◽

10.3389/fimmu.2021.580147 ◽

2021 ◽

Vol 12 ◽

Author(s):

Yufeng Shang ◽

Tao Liu ◽

Jingfeng Li ◽

Natasha Mupeta Kaweme ◽

Xinghuan Wang ◽

...

Keyword(s):

Critical Illness ◽

Antibody Response ◽

Multivariable Analysis ◽

Antibody Test ◽

Antibody Responses ◽

Systematic Evaluation ◽

Igg Antibody ◽

Treatment Regimens ◽

Asymptomatic Patients ◽

The Impact

The coronavirus disease 2019 (COVID-19) is widely spread and remains a global pandemic. Limited evidence on the systematic evaluation of the impact of treatment regimens on antibody responses exists. Our study aimed to analyze the role of antibody response on prognosis and determine factors influencing the IgG antibodies’ seroconversion. A total of 1,111 patients with mild to moderate COVID-19 symptoms admitted to Leishenshan Hospital in Wuhan were retrospectively analyzed. A serologic SARS-CoV-2 IgM/IgG antibody test was performed on all the patients 21 days after the onset of symptoms. Patient clinical characteristics were compared. In the study, 42 patients progressed to critical illness, with 6 mortalities reported while 1,069 patients reported mild to moderate disease. Advanced age (P = 0.028), gasping (P < 0.001), dyspnea (P = 0.024), and IgG negativity (P = 0.006) were associated with progression to critical illness. The mortality rate in critically ill patients with IgG antibody was 6.45% (95% CI 1.12–22.84%) and 36.36% (95% CI 12.36–68.38%) in patients with no IgG antibody (P = 0.003). Symptomatic patients were more likely to develop IgG antibody responses than asymptomatic patients. Using univariable analysis, fever (P < 0.001), gasping (P = 0.048), cancer (P < 0.001), cephalosporin (P = 0.015), and chloroquine/hydroxychloroquine (P = 0.021) were associated with IgG response. In the multivariable analysis, fever, cancer, cephalosporins, and chloroquine/hydroxychloroquine correlated independently with IgG response. We determined that the absence of SARS-CoV-2 antibody IgG in the convalescent stage had a specific predictive role in critical illness progression. Importantly, risk factors affecting seropositivity were identified, and the effect of antimalarial drugs on antibody response was determined.

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Generation of Antibody Responses to Pneumococcal Capsular Polysaccharides Is Independent of CD1 Expression in Mice

Infection and Immunity ◽

10.1128/iai.01091-08 ◽

2009 ◽

Vol 77 (5) ◽

pp. 1976-1980 ◽

Cited By ~ 4

Author(s):

Leen Moens ◽

Axel Jeurissen ◽

Stefan Nierkens ◽

Louis Boon ◽

Luc Van Kaer ◽

...

Keyword(s):

Antibody Response ◽

The Elderly ◽

Immunoglobulin M ◽

Antibody Responses ◽

Capsular Polysaccharides ◽

Wild Type ◽

Igg Antibody ◽

Antibody Treatment ◽

Serious Infection ◽

Protection Against Infection

ABSTRACT Streptococcus pneumoniae is a bacterial microorganism that frequently causes serious infection, particularly in children and the elderly. Protection against infection with S. pneumoniae is based mainly on the generation of antibodies to the pneumococcal capsular polysaccharides (caps-PS), but the mechanisms responsible for the generation of anticapsular antibodies remain incompletely understood. The aim of the present study was to evaluate the role of CD1-restricted T cells in the antibody response to caps-PS. When immunized with Pneumo23, wild-type mice and CD1 knockout mice on BALB/c and C57BL/6 backgrounds generated immunoglobulin M (IgM) and IgG antibody responses to soluble caps-PS that were comparable. Similar results were obtained after immunization with heat-inactivated S. pneumoniae. The IgM and IgG antibody response of wild-type mice to Pneumo23 was not affected by an antagonizing monoclonal anti-CD1 antibody treatment. In summary, our data provide evidence that the antibody response to caps-PS is generated independently of CD1 expression.

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Linking individual phenotype to density-dependent population growth: the influence of body size on the population dynamics of malaria vectors

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2011.0153 ◽

2011 ◽

Vol 278 (1721) ◽

pp. 3142-3151 ◽

Cited By ~ 37

Author(s):

Tanya L. Russell ◽

Dickson W. Lwetoijera ◽

Bart G. J. Knols ◽

Willem Takken ◽

Gerry F. Killeen ◽

...

Keyword(s):

Population Dynamics ◽

Body Size ◽

Population Growth ◽

Vector Control ◽

Anopheles Gambiae ◽

Phenotypic Expression ◽

Phenotypic Traits ◽

Density Dependent ◽

Individual Fitness ◽

The Impact

Understanding the endogenous factors that drive the population dynamics of malaria mosquitoes will facilitate more accurate predictions about vector control effectiveness and our ability to destabilize the growth of either low- or high-density insect populations. We assessed whether variation in phenotypic traits predict the dynamics of Anopheles gambiae sensu lato mosquitoes, the most important vectors of human malaria. Anopheles gambiae dynamics were monitored over a six-month period of seasonal growth and decline. The population exhibited density-dependent feedback, with the carrying capacity being modified by rainfall (97% w AIC c support). The individual phenotypic expression of the maternal ( p = 0.0001) and current ( p = 0.040) body size positively influenced population growth. Our field-based evidence uniquely demonstrates that individual fitness can have population-level impacts and, furthermore, can mitigate the impact of exogenous drivers (e.g. rainfall) in species whose reproduction depends upon it. Once frontline interventions have suppressed mosquito densities, attempts to eliminate malaria with supplementary vector control tools may be attenuated by increased population growth and individual fitness.

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Insecticide resistance in Bemisia tabaci Gennadius (Homoptera: Aleyrodidae) and Anopheles gambiae Giles (Diptera: Culicidae) could compromise the sustainability of malaria vector control strategies in West Africa

Acta Tropica ◽

10.1016/j.actatropica.2013.06.004 ◽

2013 ◽

Vol 128 (1) ◽

pp. 7-17 ◽

Cited By ~ 22

Author(s):

Olivier Gnankiné ◽

Imael H.N. Bassolé ◽

Fabrice Chandre ◽

Isabelle Glitho ◽

Martin Akogbeto ◽

...

Keyword(s):

West Africa ◽

Insecticide Resistance ◽

Vector Control ◽

Anopheles Gambiae ◽

Bemisia Tabaci ◽

Malaria Vector ◽

Control Strategies ◽

Malaria Vector Control ◽

Anopheles Gambiae Giles

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Modelling the impact of vector control interventions on Anopheles gambiae population dynamics

Parasites & Vectors ◽

10.1186/1756-3305-4-153 ◽

2011 ◽

Vol 4 (1) ◽

Cited By ~ 112

Author(s):

Michael T White ◽

Jamie T Griffin ◽

Thomas S Churcher ◽

Neil M Ferguson ◽

María-Gloria Basáñez ◽

...

Keyword(s):

Population Dynamics ◽

Vector Control ◽

Anopheles Gambiae ◽

Gambiae Population ◽

The Impact

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Reduced human-biting preferences of the African malaria vectors Anopheles arabiensis and Anopheles gambiae in an urban context: controlled, competitive host-preference experiments in Tanzania

10.21203/rs.3.rs-64353/v3 ◽

2020 ◽

Author(s):

Yeromin P Mlacha ◽

Prosper P. Chaki ◽

Athuman Muhili ◽

Dennis J. Massue ◽

Marcel Tanner ◽

...

Keyword(s):

Vector Control ◽

Anopheles Gambiae ◽

Anopheles Arabiensis ◽

Host Preference ◽

Urban Setting ◽

Sub Saharan Africa ◽

Rural Setting ◽

Malaria Vectors ◽

Baited Traps ◽

The Impact

Abstract BackgroundHost preference is a critical determinant of human exposure to vector-borne infections and the impact of vector control interventions. Widespread use of long-lasting insecticide-treated nets (LLINs) and indoor residual spraying (IRS) across sub-Saharan Africa, which protect humans against mosquitoes, may select for altered host preference traits of malaria vectors over the long term. Here, the host preferences of Anopheles arabiensis and Anopheles gambiae sensu stricto (s.s.) were experimentally assessed in the field, using direct host-preference assays in two distinct ecological settings in Tanzania.MethodsEight Ifakara Tent Trap (ITT), four baited with humans and four with bovine calves, were simultaneously used to catch malaria vectors in open field sites in urban and rural Tanzania. The numbers of mosquitoes collected in human-baited traps versus calf-baited traps were used to estimate human feeding preference for each site's vector species. ResultsThe estimated proportion [95% confidence interval (CI)] of mosquitoes attacking humans rather than cattle was 0.60 [0.40, 0.77] for An. arabiensis in the rural setting and 0.61 [0.32, 0.85] for An. gambiae s.s. in the urban setting, indicating no preference for either host in both cases (P=0.32 and 0.46, respectively) and no difference in preference between the two (Odds Ratio (OR) [95%] = 0.95 [0.30, 3.01], P=0.924). However, only a quarter of An. arabiensis in the urban setting attacked humans (0.25 [0.09, 0.53]), indicating a preference for cattle that approached significance (P=0.08). Indeed, urban An. arabiensis were less likely to attack humans rather than cattle when compared to the same species in the rural setting (OR [95%] = 0.21 [0.05, 0.91], P =0.037). ConclusionUrban An. arabiensis had a stronger preference for cattle than the rural population and urban An. gambiae s.s. showed no clear preference for either humans or cattle. In the urban setting, both species exhibited stronger tendencies to attack cattle than previous studies of the same species in rural contexts. Cattle keeping may, therefore, particularly limit the impact of human-targeted vector control interventions in Dar es Salaam and perhaps in other African towns and cities.

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Significantly Low Levels of IgG Antibodies Against Oncogenic Merkel Cell Polyomavirus in Sera From Females Affected by Spontaneous Abortion

Frontiers in Microbiology ◽

10.3389/fmicb.2021.789991 ◽

2021 ◽

Vol 12 ◽

Author(s):

Chiara Mazziotta ◽

Giulia Pellielo ◽

Mauro Tognon ◽

Fernanda Martini ◽

John Charles Rotondo

Keyword(s):

Antibody Response ◽

Spontaneous Abortion ◽

Viral Infections ◽

Merkel Cell Polyomavirus ◽

Enzyme Linked Immunosorbent Assay ◽

Merkel Cell ◽

Igg Antibodies ◽

Igg Antibody ◽

The Impact

Merkel cell polyomavirus (MCPyV) is a small DNA tumor virus ubiquitous in humans. MCPyV establishes a clinically asymptomatic lifelong infection in healthy immunocompetent individuals. Viral infections are considered to be risk factors for spontaneous abortion (SA), which is the most common adverse complication of pregnancy. The role of MCPyV in SA remains undetermined. Herein, the impact of MCPyV infection in females affected by SA was investigated. Specifically, an indirect enzyme-linked immunosorbent assay (ELISA) method with two linear synthetic peptides/mimotopes mimicking MCPyV antigens was used to investigate immunoglobulin G (IgG) antibodies against MCPyV in sera from 94 females affected by SA [mean ± standard deviation (SD) age 35 ± (6) years] and from 96 healthy females undergoing voluntary pregnancy interruption [VI, mean (±SD) age 32 ± (7) years]. MCPyV seroprevalence and serological profiles were analyzed. The overall prevalence of serum IgG antibodies against MCPyV was 35.1% (33/94) and 37.5% (36/96) in SA and VI females, respectively (p > 0.05). Notably, serological profile analyses indicated lower optical densities (ODs) in females with SA compared to those undergoing VI (p < 0.05), thus indicating a reduced IgG antibody response in SA females. Circulating IgGs were identified in sera from SA and VI females. Our immunological findings indicate that a relatively reduced fraction of pregnant females carry serum anti-MCPyV IgG antibodies, while SA females presented a more pronounced decrease in IgG antibody response to MCPyV. Although yet to be determined, this immunological decrease might prompt an increase in MCPyV multiplication events in females experiencing abortive events. The role of MCPyV in SA, if present, remains to be determined.

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SELECTIVE ROLES OF THYMUS-DERIVED LYMPHOCYTES IN THE ANTIBODY RESPONSE

Journal of Experimental Medicine ◽

10.1084/jem.140.1.239 ◽

1974 ◽

Vol 140 (1) ◽

pp. 239-252 ◽

Cited By ~ 67

Author(s):

Tomio Tada ◽

Toshitada Takemori

Keyword(s):

T Cells ◽

B Cells ◽

Antibody Response ◽

Suppressive Effect ◽

Antibody Responses ◽

Cell Transfer ◽

Spleen Cells ◽

Igg Antibody ◽

Igm Antibody

Passively transferred thymocytes and spleen cells from donors primed with keyhole limpet hemocyanin (KLH) exerted differential suppressive effect on IgM and IgG antibody responses of syngeneic recipients immunized with DNP-KLH depending primarily on the time when KLH-primed cells were transferred. This was demonstrated by the decrease in the numbers of DNP-specific direct and indirect PFC in the spleen of the recipients given KLH-primed cells at different times during primary and secondary immunization. Whereas the cell transfer simultaneously with or 2 days after the primary immunization produced only slight suppression of the peak IgM antibody response, it caused profound suppression of late IgM and IgG antibody responses. By contrast, the cell transfer 3 days after the immunization produced immediate suppression of the ongoing IgM antibody response resulting in its earlier termination, while being unable to prevent the induction of IgG antibody response. KLH-primed cells could moderately suppress the secondary anti-DNP antibody response, in which IgG antibody response was found to be slightly more sensitive than IgM antibody response to the suppressive influence of KLH-primed cells. The suppressive effect of the KLH-primed spleen cells was completely eliminated by the in vitro treatment of the cells with anti-θ and C before cell transfer, indicating that cells responsible for the suppression are, in fact, T cells. The suppression of DNP-specific antibody response by KLH-primed T cells was achieved only if the recipients were immunized with DNP-KLH but not with DNP-heterologous carrier, suggesting that direct interaction between T and B cells is necessary for the suppression of the antibody response. It is concluded that susceptibility of B cells to the specific suppressive influence of T cells is inherently different depending on the differentiation stage of B cells and on the immunoglobulin class they are destined to produce.

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Patterns of epidemiology and control of onchocerciasis in West Africa

Journal of Helminthology ◽

10.1017/s0022149x00015741 ◽

1997 ◽

Vol 71 (2) ◽

pp. 91-101 ◽

Cited By ~ 36

Author(s):

B. Boatin ◽

D.H. Molyneux ◽

J.M. Hougard ◽

O.W. Christensen ◽

E.S. Alley ◽

...

Keyword(s):

West Africa ◽

Vector Control ◽

Control Strategies ◽

Control Programme ◽

Transmission Potential ◽

The Public ◽

And Control ◽

Combined Impact ◽

The Impact ◽

Onchocerciasis Control

AbstractThis paper summarizes the work of the Onchocerciasis Control Programme (OCP) in West Africa, a programme which over a 22 year history has reduced the public health problems of blinding onchocerciasis in eleven countries of West Africa through vector control and, more recently, ivermectin distribution. The paper emphasizes the different approaches to control the programme has developed in the different parts of the programme area which have been determined by the epidemiology of the disease (savanna/forest form), the migratory characteristics of the vectors, intensity of the disease before commencement of treatment, the combined impact of vector control and ivermectin and the likelihood of infiltration of infective blackflies from outside the programme area. The programme has constantly monitored the impact of operations on the trends in prevalence, incidence, annual transmission potential, ocular morbidity and species of fly populations, and as a result, has identified areas where special interventions are required until the programme comes to an end in 2002. The paper illustrates the changes in intensity of infection as measured by community microfilarial load and annual transmission potential over the duration of the programme control activities. The paper also defines and justifies the control strategies in different areas and identifies areas for special interventions.

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