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1.
Front Immunol ; 15: 1384193, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38694504

RESUMO

The common bed bug, Cimex lectularius, is an urban pest of global health significance, severely affecting the physical and mental health of humans. In contrast to most other blood-feeding arthropods, bed bugs are not major vectors of pathogens, but the underlying mechanisms for this phenomenon are largely unexplored. Here, we present the first transcriptomics study of bed bugs in response to immune challenges. To study transcriptional variations in bed bugs following ingestion of bacteria, we extracted and processed mRNA from body tissues of adult male bed bugs after ingestion of sterile blood or blood containing the Gram-positive (Gr+) bacterium Bacillus subtilis or the Gram-negative (Gr-) bacterium Escherichia coli. We analyzed mRNA from the bed bugs' midgut (the primary tissue involved in blood ingestion) and from the rest of their bodies (RoB; body minus head and midgut tissues). We show that the midgut exhibits a stronger immune response to ingestion of bacteria than the RoB, as indicated by the expression of genes encoding antimicrobial peptides (AMPs). Both the Toll and Imd signaling pathways, associated with immune responses, were highly activated by the ingestion of bacteria. Bacterial infection in bed bugs further provides evidence for metabolic reconfiguration and resource allocation in the bed bugs' midgut and RoB to promote production of AMPs. Our data suggest that infection with particular pathogens in bed bugs may be associated with altered metabolic pathways within the midgut and RoB that favors immune responses. We further show that multiple established cellular immune responses are preserved and are activated by the presence of specific pathogens. Our study provides a greater understanding of nuances in the immune responses of bed bugs towards pathogens that ultimately might contribute to novel bed bug control tactics.


Assuntos
Percevejos-de-Cama , Perfilação da Expressão Gênica , Transcriptoma , Animais , Percevejos-de-Cama/imunologia , Percevejos-de-Cama/genética , Masculino , Escherichia coli/imunologia , Bacillus subtilis/imunologia , Bacillus subtilis/genética , Transdução de Sinais/imunologia , Peptídeos Antimicrobianos/genética , Peptídeos Antimicrobianos/imunologia
2.
J Insect Physiol ; 135: 104322, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34644597

RESUMO

Unlike almost all hematophagous insects, common bed bugs, Cimex lectularius, are not known to transmit pathogens to humans. To help unravel the reasons for their lack of vector competence, we studied the time- and tissue-dependent expression of innate immune factors after blood feeding or immune activation through the intrathoracic injection of bacteria. We used minimum inhibitory concentration (MIC1) bioassays and the Kirby-Bauer protocol to evaluate antimicrobial peptide (AMP2) activity in tissue extracts from the midguts or 'rest of body' (RoB3) tissues (containing hemolymph and fat body AMPs) against Gram-positive and Gram-negative bacteria. We compared AMP activity between blood-fed female bed bugs and yellow fever mosquitoes, Aedes aegypti and determined how female and male bed bugs respond to immune challenges, and how long AMP gene expression remains elevated in bed bugs following a blood meal. Blood meal-induced AMP activity is 4-fold stronger in female bed bugs than in female mosquitoes. Male bed bugs have elevated AMP activity within 8 h of a blood meal or an intrathoracic injection with bacteria, with the strongest activity expressed in RoB tissue 24 h after the immune challenge. Female bed bugs have a stronger immune response than males within 24 h of a blood meal. The effects of blood meal-induced elevated AMP activity lasts longer against the Gram-positive bacterium, Bacillus subtilis, than against the Gram-negative bacterium Escherichia coli. Unravelling the specific immune pathways that are activated in the bed bugs' immune responses and identifying the bed bug-unique AMPs might help determine why these insects are not vectors of human parasites.


Assuntos
Peptídeos Antimicrobianos/imunologia , Percevejos-de-Cama , Aedes , Animais , Percevejos-de-Cama/imunologia , Percevejos-de-Cama/microbiologia , Corpo Adiposo/imunologia , Comportamento Alimentar , Feminino , Bactérias Gram-Negativas , Bactérias Gram-Positivas , Hemolinfa/imunologia , Masculino , Fatores de Tempo
3.
Parasite Immunol ; 42(12): e12764, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32516446

RESUMO

AIMS: To investigate the immunoglobulin (Ig) G response after being fed upon by Cimex lectularius L. METHODS AND RESULTS: Participants were fed upon by three male C lectularius insects weekly for a month. Blood was obtained before the feeding and at the last feeding, which was used for immunoblots against bed bug salivary gland extract, with antihuman Immunoglobulin G (IgG) secondary antibodies. No consistent IgG changes developed in 11 humans serially fed upon by C lectularius. Two participants had new IgG responses to proteins at molecular weights of approximately 12-13 kDa, and one had an IgG response to a protein at approximately 40 kDa. At the last study visit, more intense IgG bands to proteins at molecular weights of 12-13 kDa had developed in 55% of participants (6/11) and at molecular weights of ≈30, ≈40 and ≈70 kDa in 45% (5/11) compared with the first study visit. Nitrophorin and apyrase were the most common C lectularius proteins identified with liquid chromatography-tandem mass spectrometry in both crushed bed bug salivary gland extract and post-bed bug feeding extract. CONCLUSIONS: Human participants did not have consistent IgG responses to crushed C lectularius salivary gland extract.


Assuntos
Percevejos-de-Cama/imunologia , Imunoglobulina G/imunologia , Mordeduras e Picadas de Insetos/imunologia , Saliva/imunologia , Adolescente , Adulto , Animais , Feminino , Humanos , Imunoglobulina G/sangue , Mordeduras e Picadas de Insetos/sangue , Masculino , Pessoa de Meia-Idade , Saliva/química , Glândulas Salivares/química , Proteínas e Peptídeos Salivares/análise , Proteínas e Peptídeos Salivares/imunologia , Adulto Jovem
4.
J Insect Physiol ; 123: 104048, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32179035

RESUMO

Besides typical sexually transmitted microbes, even environmental, opportunistic microbes have been found in copulatory organs of insects and even humans. To date, only one study has experimentally investigated the sexual transmission of opportunistic microbes from male to female insects, whereas nothing is known about the transmission from females to males. Even if opportunistic microbes do not cause infection upon transmission, they might eventually become harmful if they multiply inside the female. While the immune system of females is often assumed to target sexually transmitted microbes, most studies ignore the role of mating-associated opportunistic microbes. Variation in immunity between populations has been linked to parasite or bacteria prevalence but no study has ever addressed between-population differences in immune responses to sexually transmitted opportunistic microbes. We here show that bacteria applied to the copulatory organs of common bedbugs, Cimex lectularius, are sexually transmitted to the opposite sex at a high rate, including the transmission from female to male. Bacterial growth in the female sperm-receiving organ was inhibited over the first hours after introduction, but after this initial inhibition bacterial numbers increased, suggesting a shift of investment from immune defence towards reproduction. However, 24 h after the injection of bacteria, male components, or saline as a control, the sperm-receiving organ showed lysozyme-like activity and inhibited the growth of Gram-negative and Gram-positive bacteria in vitro, potentially to mop up the remaining bacteria. Contrasting our prediction, neither bacterial growth nor immune responses differed between populations. Future studies should link transmission dynamics, immune responses and fitness effects in both sexes. Experimental manipulation of environmental bacteria could be used to investigate how transmission frequency and toxicity of sexually transmitted opportunistic microbes shapes bacteria clearance and immune responses across populations.


Assuntos
Acetobacteraceae/fisiologia , Percevejos-de-Cama/imunologia , Copulação , Imunidade Inata , Animais , Percevejos-de-Cama/microbiologia , Feminino , Genitália Feminina/microbiologia
5.
Parasite Immunol ; 39(3)2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28075502

RESUMO

Little is known about cimicosis, the resultant dermal reaction from feeding activity by the common bedbug, Cimex lectularius L. We fed C. lectularius on human study subjects four times over four weeks and measured serum cytokine and antibody levels, and subjects recorded any cimicosis. The average time for subjects to develop cimicosis decreased with each feeding from 8.4, to 2.1, 1.5 and 1.3 days, respectively. There were no significant changes in total IgG, IgG1, IgG2, IgG4 or IgE levels between the first and fourth bedbug feedings, but there was a significant decrease in total IgG3 levels (P<.001). IgG4 was not required for cimicosis. Higher IgG2 and IgG4 levels at study visit 4 were associated with an increased duration of cimicosis (P=.04) and lower pruritis (P=.03), respectively. There were no significant changes in serum TNF-α, IL-1ß, IL-4, IL-5, IL-6, IL-10, IFN-γ and IL-17A levels before and one hour after the C. lectularius feeding. Lower post-C. lectularius feeding IL-6 levels were associated with increased pruritis (P=.001) and the time to maximum pruritis (P=.04), respectively. Higher post-C. lectularius feeding IL-5 levels were associated with a longer duration of pruritis (P=.05).


Assuntos
Anticorpos/sangue , Percevejos-de-Cama/imunologia , Citocinas/sangue , Mordeduras e Picadas de Insetos/imunologia , Animais , Anticorpos/imunologia , Feminino , Humanos , Imunoglobulina G/sangue , Mordeduras e Picadas de Insetos/sangue , Masculino
6.
Int Arch Allergy Immunol ; 161(2): 127-30, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23343710

RESUMO

Bed bugs may cause mild to severe cutaneous reactions. We studied the ability of bed bug salivary extract (SGE) to induce inflammatory reactions responsible for cutaneous manifestations and found that SGE stimulated the production of several potent chemokines and cytokines from macrophages. Chemokines induced by SGE included those known to recruit eosinophils (eotaxin), attract neutrophils [interleukin (IL)-8] or induce their survival and proliferation (granulocyte colony-stimulating factor). Cytokines involved in cell-mediated immunity, including IL-7, IL-10 and IL-12, were also induced. Saliva of bed bugs contains protein and non-protein molecules that have pleotropic effects on macrophages, orchestrating the immune response in the skin after bed bug bites.


Assuntos
Percevejos-de-Cama/imunologia , Mediadores da Inflamação/imunologia , Mordeduras e Picadas de Insetos/imunologia , Macrófagos/imunologia , Monócitos/imunologia , Saliva/imunologia , Proteínas e Peptídeos Salivares/imunologia , Animais , Linhagem Celular , Humanos , Imunidade Celular/imunologia , Mediadores da Inflamação/análise , Camundongos , Camundongos Knockout , Saliva/química , Proteínas e Peptídeos Salivares/química
8.
Am Nat ; 174(2): 292-5, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19548839

RESUMO

The rapid evolution of ejaculate components is considered to be largely driven by sexual selection. Less attention has been paid to the fact that sperm and microorganisms frequently meet; we consequently predict selection for substances that protect a male's ejaculate. We report, for the first time, bacteriolytic activity (lysozyme-like immune activity [LLA]) in the ejaculate of an animal, the common bedbug Cimex lectularius. We also show that in almost half the males LLA in the seminal fluid exceeded LLA in the hemolymph. We detected no antimicrobial peptide activity in seminal fluid. Because lysozymes degrade only bacteria, our results suggest that sperm-microbe interactions are probably important in the evolution of ejaculate components and thereby provide a route for natural selection to account for some of the diversity of seminal components.


Assuntos
Anti-Infecciosos/metabolismo , Percevejos-de-Cama/imunologia , Muramidase/metabolismo , Sêmen/imunologia , Animais , Anti-Infecciosos/farmacologia , Percevejos-de-Cama/enzimologia , Percevejos-de-Cama/microbiologia , Hemolinfa/enzimologia , Masculino , Testes de Sensibilidade Microbiana , Micrococcus luteus/efeitos dos fármacos , Muramidase/farmacologia , Seleção Genética , Sêmen/enzimologia , Sêmen/microbiologia
9.
Parasitol Res ; 98(6): 550-6, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16425065

RESUMO

IgG and IgE against salivary gland proteins of bedbug (Cimex lectularius) were assessed in comparison with mosquito (Culex pipiens) and flea (Pulex irritans) antigens in the sera of papular urticaria patients (group I), siblings without papular urticaria (group IIa), patients' parents (group IIb), and healthy controls (group III) (Immunoblotting). Anti-C. lectularius IgG was significantly recognized at 66 and 10 kDa in 40% of group I, besides others ranging from 45 to 107 kDa. Group IIa significantly reacted with 70 kDa (57.1%). Group IIb reacted with 21 and 8.5 kDa (26.7%). Sixty percent of group IIb and 100% of group III significantly identified a band of 12.5 kDa. IgG against C. pipiens was significantly recognized at a range of 18-105 kDa in group I, IIb (115, 7 kDa), and III (58, 50 kDa). Anti-P. irritans IgG was significantly recognized by group I (100, 70 kDa) and group IIa (60, 35 kDa). IgE response was confined to C. pipiens at 115 and 54 kDa in groups I and III, respectively, besides 68 and 58 kDa in group IIa. It is concluded that IgG is present against C. lectularius, C. pipiens, and P. irritans in papular urticaria and may contribute to its pathogenesis.


Assuntos
Anticorpos/sangue , Percevejos-de-Cama/imunologia , Ectoparasitoses/complicações , Ectoparasitoses/imunologia , Urticária/imunologia , Adulto , Animais , Antígenos/imunologia , Western Blotting , Criança , Pré-Escolar , Culex/imunologia , Feminino , Humanos , Imunoglobulina E/sangue , Imunoglobulina G/sangue , Lactente , Masculino , Peso Molecular , Proteínas e Peptídeos Salivares/imunologia , Sifonápteros/imunologia
10.
Proc Biol Sci ; 270(1531): 2371-5, 2003 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-14667353

RESUMO

The frequent wounding of female bedbugs (Cimex lectularius: Cimicidae) during copulation has been shown to decrease their fitness, but how females have responded to this cost in evolutionary terms is unclear. The evolution of a unique anatomical structure found in female bedbugs, the spermalege, into which the male's intromittent organ passes during traumatic insemination, is a possible counteradaptation to harmful male traits. Several functions have been proposed for this organ, and we test two hypotheses related to its role in sexual conflict. We examine the hypotheses that the spermalege functions to (i) defend against pathogens introduced during traumatic insemination; and (ii) reduce the costs of wound healing during traumatic insemination. Our results support the 'defence against pathogens' hypothesis, suggesting that the evolution of this unique cimicid organ resulted, at least partly, from selection to reduce the costs of mating-associated infection. We found no evidence that the spermalege reduces the costs of wound healing.


Assuntos
Estruturas Animais/fisiologia , Percevejos-de-Cama/anatomia & histologia , Percevejos-de-Cama/fisiologia , Comportamento Sexual Animal/fisiologia , Estruturas Animais/anatomia & histologia , Animais , Percevejos-de-Cama/imunologia , Feminino , Fertilidade , Longevidade
11.
J Egypt Soc Parasitol ; 21(3): 735-46, 1991 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-1765685

RESUMO

In bronchial asthma, house dust is one of the important precipitating factor. Cimex lectularius or bedbug is a well known house insect and share in the constitution of house dust. 54 asthmatic patients and 11 control individuals were skin tested using the common environmental inhalant antigens as well as Cimex extracts (Head and thorax, 1st antigen and abdomen, 2nd antigen). Also precipitin test using both Cimex extracts were used. The percentage of positive skin reactions to 1st Cimex antigen was 37.1 as compared to 9.1 in controls The percentage of positivity to Cimex 2nd antigen was 50.1 as compared to 18.2 in controls. On the other hand, the asthmatic patients showed different percentages of positivity to the common environmental inhalant antigens. The whole results were discussed. Of interest was the significant relation between the positivity in asthmatic patients to the antigens of Cimex abdominal extract and cotton dust extract. On the other hand, the precipitin tests gave negative results in both the asthmatic and control group.


Assuntos
Antígenos/efeitos adversos , Asma/etiologia , Percevejos-de-Cama/imunologia , Poeira/efeitos adversos , Adolescente , Adulto , Animais , Criança , Egito , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes de Precipitina , Testes Cutâneos
12.
J Egypt Public Health Assoc ; 65(3-4): 229-36, 1990.
Artigo em Inglês | MEDLINE | ID: mdl-2133897

RESUMO

Bedbug (Cimex lectularius) samples adult and nymphs either engorged or starved from Central Security Forces sleeping wards, laboratory animal house and control samples from laboratory reared colonies were ground and subjected to ELISA test of hepatitis B surface antigen together with 276 serum samples from the recruits slept in those wards. In the camp 7 out of 30 samples of engorged adult bedbugs were positive to HBSAg and 5 out of 30 samples of starved bedbugs were positive. Regarding nymphs 4 out of 30 engorged samples showed positive results. One of five samples of engorged adult bedbugs from the laboratory animal farm was positive. The control samples were negative. Serum samples of 276 recruits showed 3.6% positive results of HBSAg.


Assuntos
Percevejos-de-Cama/microbiologia , Antígenos de Superfície da Hepatite B/análise , Vírus da Hepatite B/imunologia , Hepatite B/transmissão , Insetos Vetores , Animais , Percevejos-de-Cama/imunologia , Ensaio de Imunoadsorção Enzimática , Humanos
15.
J Infect Dis ; 140(3): 411-4, 1979 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-501152

RESUMO

The fate of hepatitis B virus in the bedbug was investigated to assess this insect's potential as a vector. Colony-reared Cimex hemipterus (Fabr.) were fed once on blood positive for hepatitis B surface antigen (HBsAg). The insects were sampled at intervals thereafter and tested for HBsAg by radioimmunoassay. HBsAg persisted for up to six weeks in the bedbug's body after a single HBsAg-positive meal, during which time several further HBsAg-negative blood meals were taken. This result explains the high rates of field infection in bedbugs and further supports the hypothesis that bedbugs may play a role in transmission of hepatitis B virus.


Assuntos
Percevejos-de-Cama/imunologia , Antígenos de Superfície da Hepatite B/análise , Animais , Percevejos-de-Cama/microbiologia , Vírus da Hepatite B/crescimento & desenvolvimento , Fatores de Tempo
16.
S Afr Med J ; 56(2): 54-7, 1979 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-573506

RESUMO

Hepatitis B surface antigen (HBsAg)-positive blood meals were fed to a colony of the common bedbug (Cimex lectularius L) in a series of 5 experiments. Antigen persisted in the bugs for at least 7 1/2 weeks, but was undetectable after 18 weeks. Trans-stadial transmission was demonstrated through one moult only, and transovarial transmission did not occur. Antigen was successfully transmitted by adult bugs into 3 out of 35 canisters of HBsAg-negative blood. Antibody of HBsAg was detected in the serum from a rabbit on which HBsAg-positive adult bugs had fed as well as in the serum of 2 out of 10 guinea-pigs on which HBsAg-positive 4th and 5th nymphal instars had fed. The results as a whole indicate that biological multiplication and biological transmission do not occur in C. lectularius, but mechanical transmission has been demonstrated. This is probably an important means of hepatitis B virus transmission among humans in South Africa.


Assuntos
Percevejos-de-Cama/imunologia , Antígenos de Superfície da Hepatite B , Animais , Animais de Laboratório , Comportamento Alimentar , Feminino , Cobaias , Hepatite B/transmissão , Antígenos de Superfície da Hepatite B/análise , Insetos Vetores , Ninfa/imunologia , Óvulo/imunologia , Coelhos
17.
Gastroenterology ; 69(4): 982-7, 1975 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-240757

RESUMO

The fate of ingested hepatitis B antigen (HBsAg) in two mosquito species and two Hemiptera species was compared with the rate of blood meal digestion by these insects. In both mosquito species HBsAg was detected by radioimmunoassay for only a few hours after ingestion, disappearing well before the time of blood meal digestion. Production of a protease by the mosquito midgut may have been responsible for destruction of the antigen. In contrast, in the bedbug HBsAg remained detectable throughout a 5-week testing period. Moreover, titers rose during the last week, when blood meal digestion was complete, suggesting possible replication of the antigen. At no time was antigen detected in eggs or feces of any species tested, but juvenile bedbugs fed HBsAg when in the fourth or fifth instar stage still contained antigen after molting. These studies suggest that bedbugs may potentially be a more dangerous source of hepatitis B transmission than mosquitoes.


Assuntos
Percevejos-de-Cama/imunologia , Culicidae/imunologia , Hepatite A/transmissão , Antígenos da Hepatite B/metabolismo , Animais , Percevejos-de-Cama/metabolismo , Culicidae/metabolismo , Insetos Vetores/imunologia
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