scholarly journals Immunization with Pneumocystis Cross-Reactive Antigen 1 (Pca1) Protects Mice against Pneumocystis Pneumonia and Generates Antibody to Pneumocystis jirovecii

2016 ◽  
Vol 85 (4) ◽  
Author(s):  
Brenda L. Tesini ◽  
Terry W. Wright ◽  
Jane E. Malone ◽  
Constantine G. Haidaris ◽  
Martha Harber ◽  
...  
Keyword(s):  
Pneumocystis Carinii ◽  
Surface Protein ◽  
Pneumocystis Pneumonia ◽  
Negative Control ◽  
Cross Reactivity ◽  
Pneumocystis Jirovecii ◽  
Content Type ◽  
Life Threatening ◽  
Potential Vaccine ◽  
Preventive Methods

ABSTRACT Pneumocystis pneumonia (PcP) is a life-threatening infection that affects immunocompromised individuals. Nearly half of all PcP cases occur in those prescribed effective chemoprophylaxis, suggesting that additional preventive methods are needed. To this end, we have identified a unique mouse Pneumocystis surface protein, designated Pneumocystis cross-reactive antigen 1 (Pca1), as a potential vaccine candidate. Mice were immunized with a recombinant fusion protein containing Pca1. Subsequently, CD4+ T cells were depleted, and the mice were exposed to Pneumocystis murina. Pca1 immunization completely protected nearly all mice, similar to immunization with whole Pneumocystis organisms. In contrast, all immunized negative-control mice developed PcP. Unexpectedly, Pca1 immunization generated cross-reactive antibody that recognized Pneumocystis jirovecii and Pneumocystis carinii. Potential orthologs of Pca1 have been identified in P. jirovecii. Such cross-reactivity is rare, and our findings suggest that Pca1 is a conserved antigen and potential vaccine target. The evaluation of Pca1-elicited antibodies in the prevention of PcP in humans deserves further investigation.

scholarly journals Immunization with Pneumocystis carinii A121–85 antigen activates immune function against P. carinii

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Tong Tong ◽  
Zhongxin Wang ◽  
Yuanhong Xu ◽  
Jilu Shen
Keyword(s):  
Flow Cytometry ◽  
Vaccine Candidate ◽  
Pneumocystis Carinii ◽  
Surface Protein ◽  
Inflammatory Factors ◽  
Qrt Pcr ◽  
Serum Titer ◽  
Life Threatening ◽  
Potential Vaccine ◽  
Preventive Methods

Abstract Background Pneumocystis pneumonia (PcP), which is caused by Pneumocystis carinii, is a life-threatening infection that affects immunocompromised individuals. Unfortunately, chemoprophylaxis and dapsone are only effective for half of the patients with PcP, indicating that additional preventive methods are needed. We predicated the pneumocystis surface protein A12 sequence 1–85 by DNAStar software and BepiPred, and identified it as a potential vaccine candidate by bioresearch. Methods We used recombinant A121–85 as antigen to immunized mice and detected serum titer of IgG, expression of inflammatory factors by EILSA, qRT-PCR and flow cytometry. Results Our results showed that immunization with recombinant A121–85 increased the serum titer of IgG, promoted the secretion of T lymphocytes, increased the expression of inflammatory factors, and elevated lung inflammatory injury in mice. Conclusions Our findings suggest that A121–85 is a potential vaccine target for preventing Pneumocystis carinii. The evaluation of A121–85-elicited antibodies in the prevention of PcP in humans deserves further investigation.

scholarly journals Development of an Anti-Elicitin Antibody-Based Immunohistochemical Assay for Diagnosis of Pythiosis

2015 ◽  
Vol 54 (1) ◽  
pp. 43-48 ◽  
Author(s):  
Ruchuros Inkomlue ◽  
Noppadol Larbcharoensub ◽  
Patcharee Karnsombut ◽  
Tassanee Lerksuthirat ◽  
Rangsima Aroonroch ◽  
...  
Keyword(s):  
Pathogenic Fungi ◽  
Negative Control ◽  
Cross Reactivity ◽  
Detection Sensitivity ◽  
Surgical Removal ◽  
Human Pathogens ◽  
Pythium Insidiosum ◽  
Content Type ◽  
Life Threatening ◽  
Detection Specificity

Pythiosis is an emerging and life-threatening infectious disease of humans and animals living in tropical and subtropical countries and is caused by the fungus-like organismPythium insidiosum. Antifungals are ineffective against this pathogen. Most patients undergo surgical removal of the infected organ, and many die from advanced infections. Early and accurate diagnosis leads to prompt management and promotes better prognosis for affected patients. Immunohistochemical assays (IHCs) have been developed using rabbit antibodies raised againstP. insidiosumcrude extract, i.e., culture filtrate antigen (CFA), for the histodiagnosis of pythiosis, but cross-reactivity with pathogenic fungi compromises the diagnostic performance of the IHC. Therefore, there is a need to improve detection specificity. Recently, the elicitin protein, ELI025, was identified inP. insidiosum, but it was not identified in other human pathogens, including true fungi. The ELI025-encoding gene was successfully cloned and expressed as a recombinant protein inEscherichia coli. This study aims to develop a new IHC using the rabbit anti-ELI025 antibody (anti-ELI) and to compare its performance with the previously reported anti-CFA-based IHC. Thirty-eightP. insidiosumhistological sections stained positive by anti-ELI-based and anti-CFA-based IHCs indicating 100% detection sensitivity for the two assays. The anti-ELI antibody stained negative for all 49 negative-control sections indicating 100% detection specificity. In contrast, the anti-CFA antibody stained positive for one of the 49 negative controls (a slide prepared fromFusarium-infected tissue) indicating 98% detection specificity. In conclusion, the anti-ELI based IHC is sensitive and specific for the histodiagnosis of pythiosis and is an improvement over the anti-CFA-based assay.

scholarly journals Identification and Immunological Characterization of Three Potential Vaccinogens against Cryptosporidium Species

2011 ◽  
Vol 18 (11) ◽  
pp. 1796-1802 ◽  
Author(s):  
Patricio A. Manque ◽  
Fernando Tenjo ◽  
Ute Woehlbier ◽  
Ana M. Lara ◽  
Myrna G. Serrano ◽  
...  
Keyword(s):  
The Novel ◽  
Cryptosporidium Hominis ◽  
Content Type ◽  
Vaccine Candidates ◽  
Novel Approach ◽  
Intellectual Abilities ◽  
Significant Impairment ◽  
Life Threatening ◽  
Potential Vaccine ◽  
Cellular Immune

ABSTRACTCryptosporidiosis is a ubiquitous infectious disease, caused by the protozoan parasitesCryptosporidium hominisandCryptosporidium parvum, leading to acute, persistent, and chronic diarrhea with life-threatening consequences in immunocompromised individuals. In developing countries, cryptosporidiosis in early childhood has been associated with subsequent significant impairment in growth, physical fitness, and intellectual abilities. Currently, vaccines are unavailable and chemotherapeutics are toxic and impractical, and agents for immunoprophylaxis or treatment of cryptosporidiosis are a high priority. Availability of the genome sequences forC. hominisandC. parvumprovides new opportunities to procure and examine novel vaccine candidates. Using the novel approach of “reverse vaccinology,” we identified several new potential vaccine candidates. Three of these antigens—Cp15, profilin, and aCryptosporidiumapyrase—were delivered in heterologous prime-boost regimens as fusions with cytolysin A (ClyA) in aSalmonellalive vaccine vector and as purified recombinant antigens, and they were found to induce specific and potent humoral and cellular immune responses, suggesting their potential as new vaccinogens againstCryptosporidiuminfection.

scholarly journals Comparative Genomics Suggests Primary Homothallism of Pneumocystis Species

mBio ◽  
2015 ◽  
Vol 6 (1) ◽  
Author(s):  
João M. G. C. F. Almeida ◽  
Ousmane H. Cissé ◽  
Álvaro Fonseca ◽  
Marco Pagni ◽  
Philippe M. Hauser
Keyword(s):  
Comparative Genomics ◽  
Sexual Reproduction ◽  
Mating Type ◽  
Fungal Pathogens ◽  
Pneumocystis Carinii ◽  
Severe Pneumonia ◽  
Genomic Region ◽  
Pneumocystis Jirovecii ◽  
Content Type

ABSTRACT   Pneumocystis species are fungal parasites of mammal lungs showing host specificity. Pneumocystis jirovecii colonizes humans and causes severe pneumonia in immunosuppressed individuals. In the absence of in vitro cultures, the life cycle of these fungi remains poorly known. Sexual reproduction probably occurs, but the system of this process and the mating type (MAT) genes involved are not characterized. In the present study, we used comparative genomics to investigate the issue in P. jirovecii and Pneumocystis carinii, the species infecting rats, as well as in their relative Taphrina deformans. We searched sex-related genes using 103 sequences from the relative Schizosaccharomyces pombe as queries. Genes homologous to several sex-related role categories were identified in all species investigated, further supporting sexuality in these organisms. Extensive in silico searches identified only three putative MAT genes in each species investigated (matMc, matMi, and matPi). In P. jirovecii, these genes clustered on the same contig, proving their contiguity in the genome. This organization seems compatible neither with heterothallism, because two different MAT loci on separate DNA molecules would have been detected, nor with secondary homothallism, because the latter involves generally more MAT genes. Consistently, we did not detect cis-acting sequences for mating type switching in secondary homothallism, and PCR revealed identical MAT genes in P. jirovecii isolates from six patients. A strong synteny of the genomic region surrounding the putative MAT genes exists between the two Pneumocystis species. Our results suggest the hypothesis that primary homothallism is the system of reproduction of Pneumocystis species and T. deformans. IMPORTANCE   Sexual reproduction among fungi can involve a single partner (homothallism) or two compatible partners (heterothallism). We investigated the issue in three pathogenic fungal relatives: Pneumocystis jirovecii, which causes severe pneumonia in immunocompromised humans; Pneumocystis carinii, which infects rats; and the plant pathogen Taphrina deformans. The nature, the number, and the organization within the genome of the genes involved in sexual reproduction were determined. The three species appeared to harbor a single genomic region gathering only three genes involved in sexual differentiation, an organization which is compatible with sexual reproduction involving a single partner. These findings illuminate the strategy adopted by fungal pathogens to infect their hosts.

scholarly journals Evaluation of RevA, a Fibronectin-Binding Protein of Borrelia burgdorferi, as a Potential Vaccine Candidate for Lyme Disease

2013 ◽  
Vol 20 (6) ◽  
pp. 892-899 ◽  
Author(s):  
Angela M. Floden ◽  
Tammy Gonzalez ◽  
Robert A. Gaultney ◽  
Catherine A. Brissette
Keyword(s):  
Lyme Disease ◽  
Borrelia Burgdorferi ◽  
Passive Immunization ◽  
Surface Protein ◽  
Surface Expression ◽  
Content Type ◽  
Good Target ◽  
Potential Vaccine ◽  
Mammalian Infection

ABSTRACTPrevious studies indicated that the Lyme disease spirocheteBorrelia burgdorferiexpresses the RevA outer surface protein during mammalian infection. As an adhesin that promotes bacterial interaction with fibronectin, RevA appears to be a good target for preventive therapies. RevA proteins are highly conserved across all Lyme borreliae, and antibodies against RevA protein are cross-reactive among RevA proteins from diverse strains. Mice infected withB. burgdorferimounted a rapid IgM response to RevA, followed by a strong IgG response that generally remained elevated for more than 12 months, suggesting continued exposure of RevA protein to the immune system. RevA antibodies were bactericidalin vitro. To evaluate the RevA antigen as a potential vaccine, mice were vaccinated with recombinant RevA and challenged withB. burgdorferiby inoculation with a needle or by a tick bite. Cultured tissues from all treatment groups were positive forB. burgdorferi. Vaccinated animals also appeared to have similar levels ofB. burgdorferiDNA compared to nonvaccinated controls. Despite its antigenicity, surface expression, and the production of bactericidal antibodies against it, RevA does not protect againstBorrelia burgdorferiinfection in a mouse model. However, passive immunization with anti-RevA antibodies did prevent infection, suggesting the possible utility of RevA-based immunotherapeutics or vaccine.

scholarly journals Conjugation of PspA4Pro with Capsular Streptococcus pneumoniae Polysaccharide Serotype 14 Does Not Reduce the Induction of Cross-Reactive Antibodies

2017 ◽  
Vol 24 (8) ◽  
Author(s):  
Míriam A. da Silva ◽  
Thiago R. Converso ◽  
Viviane M. Gonçalves ◽  
Luciana C. C. Leite ◽  
Martha M. Tanizaki ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Capsular Polysaccharide ◽  
Vaccine Coverage ◽  
Protein A ◽  
Surface Protein ◽  
Cross Reactivity ◽  
Carrier Protein ◽  
Content Type ◽  
Clade 1 ◽  
The Impact

ABSTRACT Current pneumococcal vaccines are composed of bacterial polysaccharides as antigens, plain or conjugated to carrier proteins. While efficacious against vaccine serotypes, epidemiologic data show an increasing incidence of infections caused by nonvaccine serotypes of Streptococcus pneumoniae. The use of pneumococcal surface protein A (PspA) as a carrier protein in a conjugate vaccine could help prevent serotype replacement by increasing vaccine coverage and reducing selective pressure of S. pneumoniae serotypes. PspA is present in all pneumococcal strains, is highly immunogenic, and is known to induce protective antibodies. Based on its sequence, PspA has been classified into three families and six clades. A PspA fragment derived from family 2, clade 4 (PspA4Pro), was shown to generate antibodies with a broad range of cross-reactivity, across clades and families. Here, PspA4Pro was modified and conjugated to capsular polysaccharide serotype 14 (PS14). We investigated the impact of conjugation on the immune response induced to PspA4Pro and PS14. Mice immunized with the PS14-mPspA4Pro conjugate produced higher titers of anti-PS14 antibodies than the animals that received coadministered antigens. The conjugate induced antibodies with opsonophagocytic activity against PS14-carrying strains, as well as against a panel of strains bearing PspAs from five clades (encompassing families 1 and 2) bearing a non-PS14 serotype. Furthermore, mice immunized with PS14-mPspA4Pro were protected against nasal colonization with a nonrelated S. pneumoniae strain bearing PspA from clade 1, serotype 6B. These results demonstrate that the cross-reactivity mediated by PspA4Pro is retained following conjugation, supporting the use of PspA4 as a carrier protein in order to enhance pneumococcal vaccine coverage and encourage its further investigation as a candidate in future vaccine designs.

scholarly journals Development of a Droplet Digital Polymerase Chain Reaction for Sensitive Detection of Pneumocystis jirovecii in Respiratory Tract Specimens

2021 ◽  
Vol 8 ◽  
Author(s):  
Jie Yi ◽  
Nan Wang ◽  
Jie Wu ◽  
Yueming Tang ◽  
Jingjia Zhang ◽  
...  
Keyword(s):  
Respiratory Tract ◽  
Digital Pcr ◽  
Absolute Quantification ◽  
Pneumocystis Pneumonia ◽  
Pneumocystis Jirovecii ◽  
Immunocompromised Patients ◽  
Balf Sample ◽  
Bronchoalveolar Fluid ◽  
Life Threatening ◽  
Digital Polymerase Chain Reaction

Background:Pneumocystis jirovecii is a human-specific opportunistic fungus that causes Pneumocystis pneumonia (PCP), a life-threatening opportunistic lung infection that affects immunocompromised patients. P. jirovecii colonization may be linked to the transmission of the infection. The detection of P. jirovecii in immunocompromised patients is thus especially important. The low fungal load and the presence of PCR inhibitors limit the usefulness of quantitative PCR (qPCR) for accurate absolute quantification of P. jirovecii in specimens. Droplet digital PCR (ddPCR), however, presents a methodology that allows higher sensitivity and accuracy. Here, we developed a ddPCR method for detecting P. jirovecii DNA in respiratory specimens, and evaluated its sensitivity against qPCR.Materials and Methods: One bronchoalveolar fluid (BALF) sample each was collected from 82 patients with potential PCP to test the presence of P. jirovecii DNA using both ddPCR and qPCR, and samples with inconsistent results between the two methods were further tested by metagenomic next generation sequencing (mNGS). In addition, 37 sputum samples from 16 patients diagnosed with PCP, as well as continuous respiratory tract specimens from nine patients with PCP and treated with sulfonamides, were also collected for P. jirovecii DNA testing using both ddPCR and qPCR.Results: ddPCR and qPCR gave the same results for 95.12% (78/82) of the BALF samples. The remaining four specimens tested positive using ddPCR but negative using qPCR, and they were found to be positive by mNGS. Detection results of 78.37% (29/37) sputum samples were consistent between ddPCR and qPCR, while the other eight samples tested positive using ddPCR but negative using qPCR. The P. jirovecii load of patients with PCP decreased to undetectable levels after treatment according to qPCR, but P. jirovecii was still detectable using ddPCR.Conclusions: ddPCR was more sensitive than qPCR, especially at detecting low-pathogen-load P. jirovecii. Thus, ddPCR represents a useful, viable, and reliable alternative to qPCR in P. jirovecii testing in patients with immunodeficiency.

scholarly journals High Prevalence of Pneumocystis jirovecii Dihydropteroate Synthase Gene Mutations in Patients with a First Episode of Pneumocystis Pneumonia in Santiago, Chile, and Clinical Response to Trimethoprim-Sulfamethoxazole Therapy

2016 ◽  
Vol 61 (2) ◽  
Author(s):  
Carolina A. Ponce ◽  
Magali Chabé ◽  
Claudio George ◽  
Alejandra Cárdenas ◽  
Luisa Durán ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Latin American ◽  
Clinical History ◽  
Pneumocystis Pneumonia ◽  
Pneumocystis Jirovecii ◽  
First Episode ◽  
Sulfa Drugs ◽  
Content Type ◽  
Dihydropteroate Synthase ◽  
High Prevalence

ABSTRACT Mutations in the dihydropteroate synthase (DHPS) gene of Pneumocystis jirovecii are associated with the failure of sulfa prophylaxis. They can develop by selection in patients receiving sulfa drugs or be acquired via person-to-person transmission. DHPS mutations raise concern about the decreasing efficacy of sulfa drugs, the main available therapeutic tool for Pneumocystis pneumonia (PCP). The prevalence of Pneumocystis DHPS mutations was examined in Pneumocystis isolates from 56 sulfa-prophylaxis-naive adults with a first episode of PCP from 2002 to 2010 in Santiago, Chile. Their clinical history was reviewed to analyze the effect of these mutations on response to trimethoprim-sulfamethoxazole (TMP-SMX) therapy and outcome. Mutant genotypes occurred in 22 (48%) of 46 HIV-infected patients and in 5 (50%) of 10 HIV-uninfected patients. Compared to patients with a wild-type genotype, those with mutant genotypes were more likely to experience sulfa treatment-limiting adverse reactions and to have a twice-longer duration of mechanical ventilation if mechanically ventilated. Specific genotypes did not associate with death, which occurred in none of the HIV-infected patients and in 50% of the non-HIV-infected patients. Chile has a high prevalence of DHPS mutations, which were presumably acquired through interhuman transmission because patients were not on sulfa prophylaxis. These results contrast with the low prevalence observed in other Latin American countries with similar usage of sulfa drugs, suggesting that additional sources of resistant genotypes may be possible. The twice-longer duration of mechanical ventilation in patients with mutant DHPS genotypes suggests a decreased efficacy of TMP-SMX and warrants collaborative studies to assess the relevance of DHPS mutations and further research to increase therapeutic options for PCP.

scholarly journals Detection of Pneumocystis jirovecii by Quantitative PCR To Differentiate Colonization and Pneumonia in Immunocompromised HIV-Positive and HIV-Negative Patients

2016 ◽  
Vol 54 (6) ◽  
pp. 1487-1495 ◽  
Author(s):  
T. Fauchier ◽  
L. Hasseine ◽  
M. Gari-Toussaint ◽  
V. Casanova ◽  
P. M. Marty ◽  
...  
Keyword(s):  
Hiv Infection ◽  
Quantitative Pcr ◽  
Pneumocystis Jirovecii ◽  
Hiv Positive ◽  
Immunocompromised Patients ◽  
Infection Status ◽  
Content Type ◽  
Fungal Burden ◽  
Life Threatening ◽  
Hiv Negative

Pneumocystisjiroveciipneumonia (PCP) is an acute and life-threatening lung disease caused by the fungusPneumocystis jirovecii. The presentation of PCP in HIV-positive patients is well-known and consists of a triad of dyspnea, fever, and cough, whereas the presentation of PCP in HIV-negative patients is atypical and consists of a sudden outbreak, O2desaturation, and a rapid lethal outcome without therapy. Despite the availability of direct and indirect identification methods, the diagnosis of PCP remains difficult. The cycle threshold (CT) values obtained by quantitative PCR (qPCR) allow estimation of the fungal burden. The more elevated that the fungal burden is, the higher the probability that the diagnosis is pneumonia. The purposes of the present study were to evaluate theCTvalues to differentiate colonization and pneumonia in a population of immunocompromised patients overall and patients stratified on the basis of their HIV infection status. Testing of bronchoalveolar lavage (BAL) fluid samples from the whole population of qPCR-positive patients showed a meanCTvalue for patients with PCP of 28 (95% confidence interval [CI], 26 to 30) and a meanCTvalue for colonized patients of 35 (95% CI, 34 to 36) (P< 10−3). For the subgroup of HIV-positive patients, we demonstrated that aCTvalue below 27 excluded colonization and aCTvalue above 30 excluded PCP with a specificity of 100% and a sensitivity of 80%, respectively. In the subgroup of HIV-negative patients, we demonstrated that aCTvalue below 31 excluded colonization and aCTvalue above 35 excluded PCP with a specificity of 80% and a sensitivity of 80%, respectively. Thus, qPCR of BAL fluid samples is an important tool for the differentiation of colonization and pneumonia inP. jirovecii-infected immunocompromised patients and patients stratified on the basis of HIV infection status with differentCTvalues.

scholarly journals Malaria Immunoepidemiology in Low Transmission: Correlation of Infecting Genotype and Immune Response to Domains of Plasmodium falciparum Merozoite Surface Protein 3

2011 ◽  
Vol 79 (5) ◽  
pp. 2070-2078 ◽  
Author(s):  
Stephen J. Jordan ◽  
Ana L. Oliveira ◽  
Jean N. Hernandez ◽  
Robert A. Oster ◽  
Debasish Chattopadhyay ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Effective Vaccine ◽  
Serum Samples ◽  
Content Type ◽  
Low Transmission ◽  
Rational Development ◽  
Time Of Infection ◽  
Potential Vaccine

ABSTRACTMalaria caused byPlasmodium falciparumis a major cause of global infant mortality, and no effective vaccine currently exists. Multiple potential vaccine targets have been identified, and immunoepidemiology studies have played a major part in assessing those candidates. When such studies are carried out in high-transmission settings, individuals are often superinfected with complex mixtures of genetically distinctP. falciparumtypes, making it impossible to directly correlate the genotype of the infecting antigen with the antibody response. In contrast, in regions of low transmissionP. falciparuminfections are often genetically simple, and direct comparison of infecting genotype and antigen-specific immune responses is possible. As a test of the utility of this approach, responses against several domains and allelic variants of the vaccine candidateP. falciparummerozoite surface protein 3 (PfMSP3) were tested in serum samples collected near Iquitos, Peru. Antibodies recognizing both the conserved C-terminal and the more variable N-terminal domain were identified, but anti-N-terminal responses were more prevalent, of higher titers, and primarily of cytophilic subclasses. Comparing antibody responses to different PfMSP3 variants with thePfMSP3genotype present at the time of infection showed that anti-N-terminal responses were largely allele class specific, but there was some evidence for responses that cross-reacted across allele classes. Evidence for cross-reactive responses was much stronger when variants within one allele class were tested, which has implications for the rational development of genotype-transcending PfMSP3-based vaccines.

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