RESUMO
Investigating whether high-risk human papillomavirus (HR-HPV) types tend to become grouped in a particular way and whether factors are associated with such grouping is important for measuring the real impact of vaccination. In total, 219 women proving positive for HPV as detected by real-time PCR were included in the study. Each sample was analysed for detecting and quantifying six viral types and the hydroxymethylbilane synthase gene. Multiple correspondence analysis led to determining grouping patterns for six HR-HPV types and simultaneous association with multiple variables and whether viral load was related to the coexistence of other viral types. Two grouping profiles were identified: the first included HPV-16 and HPV-45 and the second profile was represented by HPV-31, HPV-33 and HPV-58. Variables such as origin, contraceptive method, births and pregnancies, educational level, healthcare affiliation regime, atypical squamous cells of undetermined significance and viral load were associated with these grouping profiles. Different socio-demographic characteristics were found when coinfection occurred by phylogenetically related HPV types and when coinfection was due to non-related types. Biological characteristics, the number of viral copies, temporality regarding acquiring infection and competition between viral types could influence the configuration of grouping patterns. Characteristics related to women and HPV, influence such interactions between coexisting HPV types reflecting the importance of their evaluation.
Assuntos
Alphapapillomavirus/genética , Coinfecção/epidemiologia , Genótipo , Infecções por Papillomavirus/epidemiologia , Adulto , Coinfecção/virologia , Colômbia/epidemiologia , Estudos Transversais , Feminino , Humanos , Pessoa de Meia-Idade , Infecções por Papillomavirus/virologia , Prevalência , Fatores de Risco , Adulto JovemRESUMO
The specific function of putative cut2 protein (or CFP25), encoded by the Rv2301 gene from Mycobacterium tuberculosis H37Rv, has not been identified yet. The aim of this study was to assess some of CFP25 characteristics and its possible biological role in Mycobacterium tuberculosis H37Rv invasion process to target cells. Molecular assays indicated that the gene encoding Rv2301 is present and transcribed in M. tuberculosis complex strains. The presence of Rv2301 protein over the bacilli surface was confirmed by Western blot and immunoelectron microscopy analyses, using goats sera inoculated with synthetic peptides derived from Rv2301 protein. Receptor-ligand binding assays with carcinomic human alveolar basal epithelial cells (A549) and macrophages derived from human histolytic lymphoma monocytes (U937) allowed us to identify five high activity binding peptides (HABPs) in both cell lines, and two additional HABPs only in A549 cells. U937 HABPs binding interactions were characterized by saturation assays, finding dissociation constants (Kd) within the nanomolar range and positive cooperativity (nH>1). Inhibition assays were performed to assess the possible biological role of Rv2301 identified HABPs, finding that some of them were able to inhibit invasion at a 5 µM concentration, compared with the cytochalasin control. On the other hand, HABPs, and especially HABP 36507 located at the N-terminus of the protein, facilitated the internalization of fluorescent latex beads into A549 cells. These findings are of vital importance for the rational selection of Rv2301 HABPs, to be included as components of an antituberculosis vaccine.
Assuntos
Antígenos de Bactérias/química , Proteínas de Bactérias/química , Células Epiteliais/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Mycobacterium tuberculosis/química , Peptídeos/metabolismo , Sequência de Aminoácidos , Antígenos de Bactérias/genética , Proteínas de Bactérias/genética , Sítios de Ligação , Western Blotting , Linhagem Celular Tumoral , Citocalasinas/farmacologia , Células Epiteliais/metabolismo , Células Epiteliais/microbiologia , Humanos , Cinética , Macrófagos/metabolismo , Macrófagos/microbiologia , Microscopia Imunoeletrônica , Dados de Sequência Molecular , Mycobacterium tuberculosis/patogenicidade , Mycobacterium tuberculosis/fisiologia , Especificidade de Órgãos , Peptídeos/síntese química , Peptídeos/farmacologia , Ligação Proteica , Tuberculose Pulmonar/microbiologiaRESUMO
Our ongoing search for a fully-effective vaccine against the Plasmodium falciparum parasite (causing the most lethal form of human malaria) has been focused on identifying and characterising proteins' amino acid sequences (high activity binding peptides or HABPs) involved in parasite invasion of red blood cells (RBC) by the merozoite and hepatocytes by the sporozoite. Many such merozoite HABPs have been recognised and molecularly and structurally characterised; however, native HABPs are immunologically silent since they do not induce any immune response or protection against P. falciparum malaria infection and they have to be structurally modified to allow them to fit perfectly into immune system molecules. A deeply structural analysis of these conserved merozoite HABPs and their modified analogues has led to rules or principles becoming recognised for constructing a logical and rational methodology for a minimal subunit-based, multi-epitope, multi-stage, chemically-synthesised vaccine. The same in-depth analysis of the most relevant sporozoite proteins involved in sporozoite cell-traversal and hepatocyte invasion as well as the hepatic stage is shown here. Specifically modifying these HABPs has resulted in a new set of potential pre-erythrocyte targets which are able to induce high, longlasting antibody titres in Aotus monkeys, against their corresponding recombinant proteins and the complete parasite native molecules. This review shows how these rules may be applied against the first stage of parasite invasion (i.e. the sporozoite) to mount the first line of defence against the malarial parasite, which may indeed be the most effective one. Our results strongly support including some of these modified sporozoite HABPs in combination with the previously-described modified merozoite HABPs for obtaining the aforementioned fully-protective, multiepitope, multi-stage, minimal subunit-based, chemically-synthesized, antimalarial vaccine.
Assuntos
Vacinas Antimaláricas/química , Vacinas Antimaláricas/imunologia , Malária/prevenção & controle , Peptídeos/química , Peptídeos/imunologia , Plasmodium/crescimento & desenvolvimento , Sequência de Aminoácidos , Animais , Antimaláricos , Humanos , Malária/imunologia , Vacinas Antimaláricas/uso terapêutico , Modelos Moleculares , Dados de Sequência Molecular , Peptídeos/uso terapêutico , Plasmodium/imunologia , Proteínas de Protozoários/química , Proteínas de Protozoários/imunologiaRESUMO
The development of an adequate immune response against pathogens is mediated by molecular interactions between different cell types. Among them, binding of antigenic peptides to the Major Histocompatibility Complex (MHC) molecule expressed on the membrane of antigen presenting cells (APCs), and their subsequent recognition by the T cell receptor have been demonstrated to be crucial for developing an adequate immune response. The present review compiles computational quantum chemistry studies about the electrostatic potential variations induced on the MHC binding region by peptide's amino acids, carried out with the aim of describing MHC-peptide binding interactions. The global idea is that the electrostatic potential can be represented in terms of a series expansion (charge, dipole, quadrupole, hexadecapole, etc.) whose three first terms provide a good local approximation to the molecular electrostatic 'landscape' and to the variations induced on such landscape by targeted modifications on the residues of the antigenic peptide. Studies carried out in four MHC class II human allele molecules, which are the most representative alleles of their corresponding haplotypes, showed that each of these molecules have conserved as well as specific electrostatic characteristics, which can be correlated at a good extent with the peptide binding profiles reported experimentally for these molecules. The information provided by such characteristics would help increase our knowledge about antigen binding and presentation, and could ultimately contribute to developing a logical and rational methodology for designing chemically synthesized, multi-antigenic, subunit-based vaccines, through the application of quantum chemistry methods.
Assuntos
Antígenos de Histocompatibilidade/química , Peptídeos/química , Vacinas/química , Antígenos HLA/química , Humanos , Peptídeos/imunologia , Ligação Proteica , Teoria Quântica , Eletricidade Estática , Vacinas/imunologiaRESUMO
The prevalence of human papillomavirus (HPV) infections in 2109 females inhabiting five cities of Colombia was determined. Of the 49.2% with an HPV infection, 59.8% were infected with more than one viral type. Species 7 (of the the genus Alphapapillomavirus) was associated with multiple infections. Analysis of the socio-demographic data revealed a statistically significant protective effect associated with the status of civil union (civil recognition of cohabitation without marriage), and indigenous ethnicity proved to be a risk factor for HPV infection. This is the first study comparing HPV infection among women from geographical regions of Colombia with different socio-cultural structures.
Assuntos
Alphapapillomavirus/genética , Infecções por Papillomavirus/epidemiologia , Adulto , Alphapapillomavirus/isolamento & purificação , Colômbia , Feminino , Humanos , Modelos Logísticos , Infecções por Papillomavirus/virologia , Prevalência , Fatores de Risco , Inquéritos e Questionários , Neoplasias do Colo do Útero/prevenção & controleRESUMO
An anti-malarial vaccine against the extremely lethal Plasmodium falciparum is desperately needed. Peptides from this parasite's proteins involved in invasion and having high red blood cell-binding ability were identified; these conserved peptides were not immunogenic or protection-inducing when used for immunizing Aotus monkeys. Modifying some critical binding residues in these high-activiy binding peptides' (HABPs') attachment to red blood cells (RBC) allowed them to induce immunogenicity and protection against experimental challenge and acquire the ability to bind to specific HLA-DRp1* alleles. These modified HABPs adopted certain characteristic structural configurations as determined by circular dichroism (CD) and 1H nuclear magnetic resonance (NMR) associated with certain HLA-DRbeta1* haplotype binding activities and characteristics, such as a 2-angstroms-distance difference between amino acids fitting into HLA-DRp1 Pockets 1 to 9, residues participating in binding to HLA-DR pockets and residues making contact with the TCR, suggesting haplotype and allele-conscious TCR. This has been demonstrated in HLA-DR-like genotyped monkeys and provides the basis for designing high effective, subunit-based, multi-antigen, multi-stage, synthetic vaccines, for immediate human use, malaria being one of them.
Assuntos
Epitopos/imunologia , Vacinas Antimaláricas/síntese química , Plasmodium falciparum/imunologia , Vacinas de Subunidades Antigênicas/síntese química , Vacinas Sintéticas/imunologia , Animais , Epitopos/genética , Epitopos/metabolismo , Antígenos HLA-DR/química , Antígenos HLA-DR/genética , Antígenos HLA-DR/imunologia , Humanos , Malária/genética , Malária/imunologia , Vacinas Antimaláricas/genética , Vacinas Antimaláricas/imunologia , Modelos Biológicos , Plasmodium falciparum/patogenicidade , Vacinas de Subunidades Antigênicas/química , Vacinas de Subunidades Antigênicas/imunologia , Vacinas Sintéticas/genética , Vacinas Sintéticas/metabolismoRESUMO
As microbes use many mechanisms for avoiding immunological pressure, new strategies must be developed to bypass the immunological code of silence of conserved, functionally-important amino acid sequences, such as those involved in high activity binding peptides' (HABPs) attaching to their host cells. Hundreds of experiments in large numbers of Aotus monkeys revealed that this immunological code of silence could be broken by shifting the polarity of some critical host cell binding residues in these HABPs by substituting F for R and vice versa, Y<-->W, L<-->H, I<-->N, P<-->D, M<-->K or E, C<-->T, V<-->N or S; there are special rules for A, G and S. (1)H-nuclear magnetic resonance of these modified, immunogenic, protection-inducing HABPs and molecular modelling revealed that such modifications induced appropriate fitting into specific HLA-DRbeta1 Pockets, suggesting the presence of new pockets and a haplotype- and allele-specific conscious TCR. A highly immunogenic and protection-inducing anti-malarial vaccine can thus be produced.
Assuntos
Antígeno HLA-DR1/química , Peptídeos/química , Motivos de Aminoácidos , Sequência de Aminoácidos , Animais , Aotidae , Sequência Conservada , Vacinas Antimaláricas/imunologia , Malária Falciparum/imunologia , Malária Falciparum/prevenção & controle , Modelos Moleculares , Dados de Sequência Molecular , Peptídeos/imunologia , Plasmodium falciparum/imunologia , Ligação Proteica , Receptores de Antígenos de Linfócitos T/química , Relação Estrutura-Atividade , Vacinas de Subunidades Antigênicas/imunologiaRESUMO
The K1 peptide is an HLA-A*0201-restricted cytotoxic epitope derived from the Trypanosoma cruzi KMP-11 protein, this being the etiological agent of Chagas' disease. This work describes the K1 peptide's secondary structure and its recognition by sera from chagasic patients. Circular dichroism and NMR spectroscopy analysis revealed that the K1 peptide adopts an alpha-helical conformation. Fifty-six percent of individuals had anti-K1 and 86% anti-KMP-11 antibodies by ELISA in the chronic Chagas' group and 28 and 68% in the indeterminate Chagas' group, respectively. By contrast, no reactivity was observed in sera from healthy individuals and tuberculosis patients. Antibody response subclass specificity to the K1 peptide was IgG1 and IgG3. Taken together these results support the idea that the K1 peptide acts as a B-cell-inducer epitope during Chagas' disease.
Assuntos
Antígenos de Protozoários/química , Proteínas de Protozoários/química , Proteínas de Protozoários/imunologia , Trypanosoma cruzi/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários/genética , Doença de Chagas/imunologia , Epitopos/química , Epitopos/genética , Humanos , Imunoglobulina G/sangue , Isotipos de Imunoglobulinas/sangue , Modelos Moleculares , Estrutura Secundária de Proteína , Proteínas de Protozoários/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Trypanosoma cruzi/genéticaRESUMO
A vaccine against malaria is desperately needed, and Aotus monkeys are highly susceptible to experimental infection with malarial parasites. A thorough analysis of this monkey's immune system molecules was thus undertaken in our institute. Cloning and sequencing, followed by three-dimensional analysis, has revealed high homology with some HLA-DRB1 molecules in terms of their peptide binding region pockets. Molecules such as HLA-DRB1*03, 11, 08, and HLA-DRB1*04 are so similar to Aotus MHC-DRB molecules that peptides identified as binding to these molecules and inducing protective immunity in these monkeys could be used in humans without further refinement, while small modifications seem to be needed for those binding to HLA-DRB1*07, HLA-DRB1*15, 16, and HLA-DRB1*10-like molecules, making this New World monkey an excellent model for tailor-made vaccine development, especially against malaria.
Assuntos
Desenho de Fármacos , Antígenos HLA-DR/química , Antígenos de Histocompatibilidade Classe II/química , Vacinas Antimaláricas/química , Platirrinos/imunologia , Sequência de Aminoácidos , Sítios de Ligação , Antígenos HLA-DR/genética , Antígenos HLA-DR/imunologia , Cadeias HLA-DRB1 , Antígenos de Histocompatibilidade Classe II/genética , Antígenos de Histocompatibilidade Classe II/imunologia , Humanos , Vacinas Antimaláricas/genética , Dados de Sequência Molecular , Peptídeos/química , Peptídeos/genética , Conformação Proteica , Alinhamento de SequênciaRESUMO
Plasmodium falciparum apical membrane antigen 1 (AMA-1) is expressed during both the sporozoite and merozoite stage of the parasite's life cycle. The role placed by AMA-1 during sporozoite invasion of hepatocytes has not been made sufficiently clear to date. Identifying the sequences involved in binding to hepatocytes is an important step towards understanding the structural basis for sporozoite-hepatocyte interaction. Binding assays between P. falciparum AMA-1 peptides and HepG2 cell were performed in this study to identify possible AMA-1 functional regions. Four AMA-1 high activity binding peptides (HABPs) bound specifically to hepatocytes: 4310 ((74)QHAYPIDHEGAEPAPQEQNL(93)), 4316 ((194)TLDEMRHFYKDNKYVKNLDE(213)), 4321 ((294)VVDNWEKVCPRKNLQNAKFGY(313)) and 4332 ((514)AEVTSNNEVVVKEEYKDEYA(533)). Their binding to these cells became saturable and resistant to treatment with neuraminidase. Most of these peptides were located in AMA-1 domains I and III, these being target regions for protective antibody responses. These peptides interacted with 36 and 58 kDa proteins on the erythrocyte surface. Some of the peptides were found in exposed regions of the AMA-1 protein, thereby facilitating their interaction with host cells. It is thus probable that AMA-1 regions defined by the four peptides mentioned above are involved in sporozoite-hepatocyte interaction.