Preclinical assessment of an anti-HTLV-1 heterologous DNA/MVA vaccine protocol expressing a multiepitope HBZ protein.

BACKGROUND: Human T-lymphotropic virus 1 (HTLV-1) is associated with the development of several pathologies and chronic infection in humans. The inefficiency of the available treatments and the challenge in developing a protective vaccine highlight the need to produce effective immunotherapeutic tools. The HTLV-1 basic leucine zipper (bZIP) factor (HBZ) plays an important role in the HTLV-1 persistence, conferring a survival advantage to infected cells by reducing the HTLV-1 proteins expression, allowing infected cells to evade immune surveillance, and enhancing cell proliferation leading to increased proviral load. METHODS: We have generated a recombinant Modified Virus Vaccinia Ankara (MVA-HBZ) and a plasmid DNA (pcDNA3.1(+)-HBZ) expressing a multiepitope protein based on peptides of HBZ to study the immunogenic potential of this viral-derived protein in BALB/c mice model. Mice were immunized in a prime-boost heterologous protocol and their splenocytes (T CD4+ and T CD8+) were immunophenotyped by flow cytometry and the humoral response was evaluated by ELISA using HBZ protein produced in prokaryotic vector as antigen. RESULTS: T CD4+ and T CD8+ lymphocytes cells stimulated by HBZ-peptides (HBZ42-50 and HBZ157-176) showed polyfunctional double positive responses for TNF-α/IFN-γ, and TNF-α/IL-2. Moreover, T CD8+ cells presented a tendency in the activation of effector memory cells producing granzyme B (CD44+High/CD62L-Low), and the activation of Cytotoxic T Lymphocytes (CTLs) and cytotoxic responses in immunized mice were inferred through the production of granzyme B by effector memory T cells and the expression of CD107a by CD8+ T cells. The overall data is consistent with a directive and effector recall response, which may be able to operate actively in the elimination of HTLV-1-infected cells and, consequently, in the reduction of the proviral load. Sera from immunized mice, differently from those of control animals, showed IgG-anti-HBZ production by ELISA. CONCLUSIONS: Our results highlight the potential of the HBZ multiepitope protein expressed from plasmid DNA and a poxviral vector as candidates for therapeutic vaccine.

Reverse transcriptase droplet digital PCR to identify the emerging vesicular virus Senecavirus A in biological samples.

Senecavirus A (SVA) belonging to the family Picornaviridae, genus Senecavirus was incidentally isolated in 2002 from the PER.C6 (transformed foetal retinoblast) cell line. However, currently, this virus is associated with vesicular disease in swine and it has been reported in countries such as the United States of America, Canada, China, Thailand and Colombia. In Brazil, the SVA was firstly reported in 2015 in outbreaks of vesicular disease in swine, clinically indistinguishable of Foot-and-mouth disease, a contagious viral disease that generates substantial economic losses. In the present work, it was standardized a diagnostic tool for SVA based on RNA reverse transcriptase droplet digital PCR (RT-ddPCR) using one-step and two-step approaches. Analytical sensitivity and specificity were done in parallel with real-time PCR, RT-qPCR (one-step and two-step) for comparison of sensitivity and specificity of both methods. In the standardization of RT-ddPCR, the double-quenched probe and the temperature gradient were crucial to reduce background and improve amplitude between positive and negative droplets. The limit of detection and analytical specificity of techniques of one-step techniques showed superior performance than two-step methods described here. Additionally, the results showed 94.2% concordance (p < 0.001) for RT-ddPCR and RT-qPCR using the one-step assay approach and biological samples from Brazilian outbreaks of Senecavirus A. However, ddRT-PCR had a better performance than RT-PCR when swine serum pools were tested. According to the results, the one-step RT-ddPCR and RT-qPCR is highlighted to be used as an auxiliary diagnostic tool for Senecavirus A and for viral RNA absolute quantification in biological samples (RT-ddPCR), being a useful tool for vesicular diseases control programs.

Genetic variability and phylogeny of the 5' long terminal repeat from Brazilian bovine leukemia virus.

We conducted a phylogenetic analysis of 22 strains of bovine leukemia virus obtained by polymerase chain reaction to amplify a 582-base pair fragment of the transcriptional regulatory region 5' long terminal repeat (LTR). Twenty-two samples of proviral DNA from peripheral blood mononuclear cells containing bovine leukemia virus from naturally infected bovine from 4 distinct geographic regions in Brazil were investigated. The products obtained by polymerase chain reaction were subjected to direct sequencing and sequence alignment. Fragments of 422 nucleotides were obtained, located between positions -118 and +303 base pairs of the 5'LTR. These fragments corresponded to 80% of the LTR region and included 56% of sub-region U3, 100% of R, and 82.5% of U5. Phylogenetic analysis of these sequences showed a high conservation degree in the 5'LTR region, with 5 well defined groups. However, a hotspot occurrence in the R-U5 region was also observed, which contained 40% of all nucleotide variability observed.

Sorologia para o vírus da língua azul em bovinos de corte, ovinos e veados campeiros no Pantanal sul-mato-grossense / Bluetongue virus serosurvey in beef cattle, sheep, and pampas deer from Brazilian Pantanal

This investigation was carried out in beef cattle (n=219), sheep (n=55), and pampas deer (Ozotoceros bezoarticus) (n=49) from Nhecolândia, sub region of Brazilian Pantanal in Mato Grosso do Sul State, Brazil. It was aimed to assess the seropositivity of these species to bluetongue virus (BTV) by agar gel immunodiffusion test. Seropositivity rates were 42.0% for cattle and 10.9% for sheep. The pampas deer showed to be all seronegative. In cattle, seropositivity to BTV significantly increased with age (P<0.001). These data, the favorable environmental conditions to development of BTV vectors, and the bovine reproductive disorders reported by farmers may indicate that BTV infection occurrs in herds of Brazilian Pantanal, and probably induces to economical losses.(AU)

Sorologia para o vírus da língua azul em bovinos de corte, ovinos e veados campeiros no Pantanal sul-mato-grossense / Bluetongue virus serosurvey in beef cattle, sheep, and pampas deer from Brazilian Pantanal

This investigation was carried out in beef cattle (n=219), sheep (n=55), and pampas deer (Ozotoceros bezoarticus) (n=49) from Nhecolândia, sub region of Brazilian Pantanal in Mato Grosso do Sul State, Brazil. It was aimed to assess the seropositivity of these species to bluetongue virus (BTV) by agar gel immunodiffusion test. Seropositivity rates were 42.0% for cattle and 10.9% for sheep. The pampas deer showed to be all seronegative. In cattle, seropositivity to BTV significantly increased with age (P<0.001). These data, the favorable environmental conditions to development of BTV vectors, and the bovine reproductive disorders reported by farmers may indicate that BTV infection occurrs in herds of Brazilian Pantanal, and probably induces to economical losses.

Sorodiagnóstico de doenças da reprodução em rebanhos de bovinos leiteiros de assentamentos rurais de Corumbá, MS / Reproductive diseases serosurvey in dairy cattle from rural settlements of Corumbá city, Mato Grosso do Sul state, Brazil

This investigation was carried out in dairy cattle from four rural settlements of Corumbá, MS, Brazil, in order to assess the seroprevalence of bovine herpesvirus 1 (BoHV-1), bluetongue virus (BTV), and Leptospira; and the prevalence was 50.9 per cent (179/352), 51.3 per cent (181/353), and 35.8 per cent (125/349), respectively. Association between frequency of seropositive animals and evaluated rural settlements (P<0.01) was found for Leptospira, and indicated the influence of environmental factors in bovine infection. Age was significantly related to BoHV-1 (P<0.001), BTV (P<0.001), and Leptospira infection (P<0.01), showing higher number of infection among older animals. Once the bovine herds were not vaccinated, the presence of seropositive animals indicated that these infections occurred in rural settlements herds of Corumbá assayed, and certainly induced economical loss.(AU)

Meningoencefalite por Herpesvirus bovino 5 em Minas Gerais: relato de caso clínico / Meningoencephalitis by Bovine herpesvirus 5 in Minas Gerais state: clinical case report

Relata-se um caso de meningoencefalite causada por Herpesvirus bovino 5 (BoHV-5) heritabilityem uma vaca com cinco anos de idade. O animal manifestou quadro clínico inicial de síndrome medular baixa, caracterizada por incoordenação dos membros pélvicos, sinais estes ainda não descritos para a enfermidade. Dentro de pouco tempo a doença evoluiu para síndrome cerebral, e o óbito ocorreu seis dias após o inicio dos sintomas. Na histopatologia, evidenciou-se meningoencefalite difusa, não supurada, e a confirmação do diagnóstico foi feita por reação em cadeia de polimerase e sequenciamento do segmento parcial da glicoproteína G do vírus. O trabalho confirma a presença do BoHV-5 em Minas Gerais, descreve características clínicas novas para a enfermidade e ressalta sua importância no diagnóstico diferencial das neuropatias bovinas.(AU)

A clinical case of meningoencephalitis by Bovine herpesvirus 5 (BoHV-5) in a five-year-old cow was reported. The disease began with low spinal cord signs, characterized by incoordination, and these symptoms had never been related to this illness before. Signs of a brain syndrome were observed and the cow died in six days. At the histopathology, a spread non-supurative meningoencephalitis was diagnosed, and the virus identification was made by PCR and partial sequence of the glycoprotein G. This study confirm the BoHV-5 presence in the State of Minas Gerais, Brazil, describes new clinic characteristics, and show the importance of the disease in the differentiate diagnosis with others bovine central nervous system affections.(AU)

Meningoencefalite por Herpesvirus bovino 5 em Minas Gerais: relato de caso clínico / Meningoencephalitis by Bovine herpesvirus 5 in Minas Gerais state: clinical case report

Relata-se um caso de meningoencefalite causada por Herpesvirus bovino 5 (BoHV-5) heritabilityem uma vaca com cinco anos de idade. O animal manifestou quadro clínico inicial de síndrome medular baixa, caracterizada por incoordenação dos membros pélvicos, sinais estes ainda não descritos para a enfermidade. Dentro de pouco tempo a doença evoluiu para síndrome cerebral, e o óbito ocorreu seis dias após o inicio dos sintomas. Na histopatologia, evidenciou-se meningoencefalite difusa, não supurada, e a confirmação do diagnóstico foi feita por reação em cadeia de polimerase e sequenciamento do segmento parcial da glicoproteína G do vírus. O trabalho confirma a presença do BoHV-5 em Minas Gerais, descreve características clínicas novas para a enfermidade e ressalta sua importância no diagnóstico diferencial das neuropatias bovinas.

A clinical case of meningoencephalitis by Bovine herpesvirus 5 (BoHV-5) in a five-year-old cow was reported. The disease began with low spinal cord signs, characterized by incoordination, and these symptoms had never been related to this illness before. Signs of a brain syndrome were observed and the cow died in six days. At the histopathology, a spread non-supurative meningoencephalitis was diagnosed, and the virus identification was made by PCR and partial sequence of the glycoprotein G. This study confirm the BoHV-5 presence in the State of Minas Gerais, Brazil, describes new clinic characteristics, and show the importance of the disease in the differentiate diagnosis with others bovine central nervous system affections.

IL-10 produced by CD4+ and CD8+ T cells emerge as a putative immunoregulatory mechanism to counterbalance the monocyte-derived TNF-alpha and guarantee asymptomatic clinical status during chronic HTLV-I infection.

Although it is believed widely that distinct patterns of the host immune response are associated with the outcome of chronic human T cell lymphotropic virus type 1 (HTLV-I) infection toward asymptomatic or symptomatic neurodegenerative myelopathy (HAM/TSP), the exact mechanism underlying these immunological events still remains unknown. In this study, we have evaluated the cytokine pattern [interleukin (IL)-12, interferon (IFN)-gamma, tumour necrosis factor (TNF)-alpha, IL-4 and IL-10] of innate and adaptive immunity cells present at the peripheral blood from non-infected (NI) and HTLV-I infected individuals [asymptomatic (AS), oligosymptomatic (OL) and HAM/TSP-HT], following in vitro short-term incubation in the absence/presence of phorbol myristate acetate (PMA) pan-leucocyte stimulation. In the absence of PMA stimulation, our data demonstrate that despite the overall immunological profile of AS mimicry that observed for NI, the high frequency of IL-12(+) neutrophils and TNF-alpha(+) monocytes are also a hallmark of this group of individuals. However, the outstanding positive correlation between the high frequency of TNF-alpha(+) monocytes and high levels CD4(+) IL-10(+) and CD8(+) IL-10(+) T cells suggests the establishment of immunoregulatory mechanisms that guarantee their asymptomatic clinical status. On the other hand, OL and HT did not present any association between the high frequency and TNF-alpha(+) neutrophils and monocytes and this immunoregulatory profile at their adaptive immunity cells. Upon PMA-index analysis, high levels of type 1 CD4(+) T cells, as well as higher IFN-gamma/IL-10 and TNF-alpha/IL-10 ratios, were observed in HT, and re-emphasize the role of Th1-cytokines from CD4(+) cells to HTLV-I immunity and disease. Moreover, increasing frequency of CD8(+) IFN-gamma(+) and CD8(+) TNF-alpha(+) cells were observed in the HT, which corroborates the marked inflammatory profile underlying this pathological condition and the role of CD8(+) T cells in the pathogenesis of HAM/TSP.

Design of novel hybrid organic-inorganic nanostructured biomaterials for immunoassay applications.

The purpose of this study was to develop novel hybrid organic-inorganic materials based on poly(vinyl alcohol) (PVA) polymer chemically crosslinked network to be tested as solid support on bovine herpesvirus immunoassay. Hybrids were synthesized by reacting PVA with three different alkoxysilanes modifying chemical groups: tetraethoxysilane (TEOS), 3-mercaptopropyltrimethoxysilane (MPTMS) and 3-glycidoxypropyltrimethoxysilane (GPTMS). PVA-derived hybrids were also modified by chemically crosslinking with glutaraldehyde (GA) during the synthesis reaction. In order to investigate the structure in the nanometer-scale, PVA-derived hybrids were characterized by using small-angle x-ray scattering synchrotron radiation (SAXS) and x-ray diffraction (XRD). PVA hybrids' chemical functionalities and their interaction with herpesviruses were also characterized by Fourier transform infrared spectroscopy (FTIR). The bioactivity assays were tested through enzyme linked immunosorbent assay (ELISA). SAXS results have indicated nano-ordered disperse domains for PVA hybrids with different x-ray scattering patterns for PVA polymer and PVA-derived hybrids. FTIR spectra have shown major vibration bands associated with organic-inorganic chemical groups present in the PVA, PVA-derived by silane modifier and PVA chemically crosslinked by GA. The immunoassay results have shown that PVA hybrids with chemically functionalized structures regulated to some extent the specific bioimmobilization of herpesvirus onto solid phase. We think that it is due to the overall balance of forces associated with van der Waals interaction, hydrophilic and hydrophobic forces and steric hindrance acting at the surface. PVA and PVA-derived hybrid materials were successfully produced with GA crosslinking in a nanometer-scale network. Also, such a PVA-based material could be advantageously used in immunoassays with enhanced specificity for diagnosis.

Padronizacão da técnica de imunoistoquímica para o diagnóstico etiológico de rotina da diarréia bovina a vírus / Bovine viral diarrhea diagnostic: immunohistochemistry standardization for routine

The immunohistochemistry standardization for bovine viral diarrhea virus (BVDV) diagnostic was described. The formalin-fixed tissue samples from a heifer with mucosal disease were used as positive control. The validation of the first phase results was performed using samples from an aborted fetus and a calf infected with reference strains of BVDV. The best results were seen using monoclonal antibodies and a commercial kit consisting of labelled streptavidin biotin (LSAB) reagents and the diaminobenzidine (DAB) substrate-chromogen reagent. The immunohistochemistry demonstrated to be an useful method for routine diagnosis for the controll and detection of BVDV infection.(AU)

Padronizacão da técnica de imunoistoquímica para o diagnóstico etiológico de rotina da diarréia bovina a vírus / Bovine viral diarrhea diagnostic: immunohistochemistry standardization for routine

The immunohistochemistry standardization for bovine viral diarrhea virus (BVDV) diagnostic was described. The formalin-fixed tissue samples from a heifer with mucosal disease were used as positive control. The validation of the first phase results was performed using samples from an aborted fetus and a calf infected with reference strains of BVDV. The best results were seen using monoclonal antibodies and a commercial kit consisting of labelled streptavidin biotin (LSAB) reagents and the diaminobenzidine (DAB) substrate-chromogen reagent. The immunohistochemistry demonstrated to be an useful method for routine diagnosis for the controll and detection of BVDV infection.

Utilização de parte da região codificadora da glicoproteína b na diferenciação do herpesvírus bovino 1.1, herpesvírus bovino 1.2 e herpesvírus bovino 5 / Utilization of part of the region which codes for glycoprotein b in bovine herpesvirus 1.1, bovine herpesvirus 1.2 and bovine herpesvirus 5

Utilizou-se uma reação em cadeia de polimerase (PCR) previamente desenvolvida para a amplificação de parte da região única longa 27 (UL27) do genoma de herpesvírus bovino 1.1 (BoHV-1), que codifica a glicoproteína B, buscando a diferenciação entre isolados de BoHV-1.1 e BoHV-5. Os produtos de PCR gerados a partir de isolados de BoHV-1.1 e BoHV-5 mostraram padrão de amplificação diferenciado em seus tamanhos moleculares. Analisando as seqüências de nucleotídeos dos produtos de PCR obtidos de dois isolados de BoHV-5, juntamente com as seqüências dos produtos de PCR obtidos de um isolado de BoHV-1.1 e de três isolados de BoHV-1.2, previamente depositados no GenBank, verificou-se que a diferença observada na amplificação se deve ao número de repetições de G-C presentes no final da região codificadora da gB, particularmente nas seqüências 5'–G(A/T)CC–3'. A análise dessas seqüências-motivo desponta como uma ferramenta auxiliar na diferenciação entre isolados de BoHV-1.1, BoHV-1.2 e BoHV-5.(AU)

A previously-developed PCR was used for the amplification of part of the UL27 region of the BoHV-1.1 genome, which codes for glycoprotein B, seeking the differentiation between BoHV-1.1 and BoHV-5 isolates. The PCR products generated from the BoHV-1 and BoHV-5 isolates showed a pattern of differentiated amplification of their molecular size. The PCR of the BoHV-5 products were sequenced and the results compared with the sequence of the BoHV-1.1 and BoHV-1.2 isolates previously deposited in the GenBank. It was verified that the difference between the PCR products is due to greater number of repetitions of G-C present at the end of the gB codifier region. The most common repeat sequences were 5'-G(A/T)CC–3'. The analysis of these repetitions was shown to be an auxiliary tool in the differentiation between BoHV1.1, BoHV-1.2 and BoHV-5 isolates.(AU)

Utilização de parte da região codificadora da glicoproteína b na diferenciação do herpesvírus bovino 1.1, herpesvírus bovino 1.2 e herpesvírus bovino 5 / Utilization of part of the region which codes for glycoprotein b in bovine herpesvirus 1.1, bovine herpesvirus 1.2 and bovine herpesvirus 5

Utilizou-se uma reação em cadeia de polimerase (PCR) previamente desenvolvida para a amplificação de parte da região única longa 27 (UL27) do genoma de herpesvírus bovino 1.1 (BoHV-1), que codifica a glicoproteína B, buscando a diferenciação entre isolados de BoHV-1.1 e BoHV-5. Os produtos de PCR gerados a partir de isolados de BoHV-1.1 e BoHV-5 mostraram padrão de amplificação diferenciado em seus tamanhos moleculares. Analisando as seqüências de nucleotídeos dos produtos de PCR obtidos de dois isolados de BoHV-5, juntamente com as seqüências dos produtos de PCR obtidos de um isolado de BoHV-1.1 e de três isolados de BoHV-1.2, previamente depositados no GenBank, verificou-se que a diferença observada na amplificação se deve ao número de repetições de G-C presentes no final da região codificadora da gB, particularmente nas seqüências 5'-G(A/T)CC-3'. A análise dessas seqüências-motivo desponta como uma ferramenta auxiliar na diferenciação entre isolados de BoHV-1.1, BoHV-1.2 e BoHV-5.

Establishing phenotypic features associated with morbidity in human T-cell lymphotropic virus type 1 infection.

The human T-cell lymphotropic virus type 1 (HTLV-1) is the causative agent of HTLV-1-associated myelopathy/tropical spastic paraparesis (HT). Although it is widely believed that virus infection and host immune response are involved in the pathogenic mechanisms, the role of the immune system in the development and/or maintenance of HT remains unknown. We performed an analysis of the peripheral blood leukocyte phenotype for two different subcohorts of HTLV-1-infected individuals to verify the existence of similar immunological alterations, possible laboratory markers for HT. The leukocyte population balance, the activation status of the T lymphocytes, and the cellular migratory potential of T lymphocytes, monocytes, and neutrophils were evaluated in the peripheral blood of HTLV-1-infected individuals classified as asymptomatic individuals, oligosymptomatic individuals, and individuals with HT. Data analysis demonstrated that a decreased percentage of B cells, resulting in an increased T cell/B cell ratio and an increase in the CD8+ HLA-DR+ T lymphocytes, exclusively in the HT group could be identified in both subcohorts, suggesting its possible use as a potential immunological marker for HT for use in the laboratory. Moreover, analysis of likelihood ratios showed that if an HTLV-1-infected individual demonstrated B-cell percentages lower than 7.0%, a T cell/B cell ratio higher than 11, or a percentage of CD8+ HLA-DR+ T lymphocytes higher than 70.0%, this individual would have, respectively, a 12-, 13-, or 22-times-greater chance of belonging to the HT group. Based on these data, we propose that the T cell/B cell ratios and percentages of circulating B cells and activated CD8+ T lymphocytes in HTLV-1-infected patients are important immunological indicators which could help clinicians monitor HTLV-1 infection and differentiate the HT group from the asymptomatic and oligosymptomatic groups.

Bovine herpesvirus 5 (BoHV-5) in bull semen: amplification and sequence analysis of the US4 gene.

Bovine herpesvirus type 5 (BoHV-5), which is potentially neuropathogenic, was detected in clinical samples of bovine semen, both directly and after isolation in cell culture, using a nested PCR system for amplifying the US4 gene. Nucleotide sequences generated from the amplicons were analysed and deposited at GenBank (NCBI, Bethesda, MD, USA) under the accession numbers AF298174 and AF330157. Alignment of these sequences and previously deposited sequences of BoHV-1 and BoHV-5 showed 82% and 98% similarity, respectively. The bulls, which were maintained at an artificial insemination centre, had presented no clinical signs, indicating that bovine semen should be screened for BoHV-5 to prevent transmission of the virus.

Padronização da técnica de imunoperoxidase para detecção do vírus da diarréia bovina a vírus em cultura de células: Standardization of immunoperoxidase test to detection bovine viral diarrhea virus in cell culture

The aim of this study was to standardize the immunoperoxidase in cell monolayer assay (IPMA) for the etiological diagnosis of bovine viral diarrhea (BVD). The method was standardized in monolayer of primary bovine fetal lung culture inoculated with cytophatic and non-cytophatic classical strains of BVD virus and tested using samples that were considered suspected in the classical technique of viral isolation. The IPMA successfully identified BVD virus and presented better results when heat was used for fixation, BSA 4% solution in PBS was used for blocking and AEC chromogen was used for revelation. Both monoclonal and polycloral antibodies gave good results when used as primary antibodies.

Este estudo teve como objetivo a padronização do ensaio de imunoperoxidase em monocamada de células (IPM) para o diagnóstico etiológico da diarréia bovina a vírus (DBV). O teste foi padronizado em monocamada de cultivo primário de pulmão fetal bovino (PFB) inoculada com as amostras clássicas, citopatogênica (CP) e não citopatogênica (NCP), do vírus da DBV e testado em amostras biológicas suspeitas processadas no teste clássico de isolamento viral (IV). O método de IPM identificou o vírus da DBV, apresentando melhores resultados com a utilização do calor como agente fixador, a soroalbumina bovina a 4% em PBS como bloqueador e a revelação com o cromógeno 3-amino-9-etil-carbazol (AEC). Como anticorpos primários, tanto o anticorpo policlonal como o monoclonal forneceram bons resultados.

Padronizaçäo da técnica de imunoperoxidase para detecçäo do vírus da diarréia bovina a vírus em cultura de células / Standardization of immunoperoxidase test to detection bovine viral diarrhea virus in cell culture

Este estudo teve como objetivo a padronizaçäo do ensaio de imunoperoxidase em monocamada de células (IPM) para o diagnóstico etiológico da diarréia bovina a vírus (DBV). O teste foi padronizado em monocamada de cultivo primário de pulmäo fetal bovino (PFB) inoculada com as amostras clássicas, citopatogênica (CP) e näo citopatogênica (NCP), do vírus da DBV e testado em amostras biológicas suspeitas processadas no teste clássico de isolamento viral (IV). O método de IPM identificou o vírus da DBV, apresentando melhores resultados com a utilizaçäo do calor como agente fixador, a soroalbumina bovina a 4 por cento em PBS como bloqueador e a revelaçäo com o cromógeno 3-amino-9-etil-carbazol (AEC). Como anticorpos primários, tanto o anticorpo policlonal como o monoclonal forneceram bons resultados

Phenotypic study of peripheral blood leucocytes in HTLV-I-infected individuals from Minas Gerais, Brazil.

The human T-cell lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) associated with the HTLV-I is a well-defined clinical-pathological entity in which the virus and host immune responses contribute to the pathological mechanism. In this study, flow cytometric analysis of whole peripheral blood leucocytes (PBL) was performed to evaluate the immunological status of HTLV-I-infected individuals in an effort to better understand the role of the immune system in the development of HAM/TSP. We have evaluated three groups of infected patients including asymptomatic (AS = 18), ambulatory/oligosymptomatic (AM = 14) and hospitalized HAM/TSP individuals (HO = 42). Noninfected healthy blood donors were used for the control group (NI = 32). Our results demonstrated that the HO group presents an increased percentage of circulating T cells and a decreased percentage of B and natural killer (NK) cells, leading to the highest T/B-cell ratio in comparison with the other groups. Interestingly, while an increased percentage of activated CD4+HLA-DR+ T lymphocytes was observed in both AM and HO, only HO presented higher percentage of activated CD8+HLA-DR+ in combination with the highest CD18 surface expression. This was true for all cell populations analysed, including T lymphocytes, monocytes and neutrophils. Moreover, the HO group was distinguished by a dramatic decrease in the percentage of CD8+CD28+ lymphocytes. Taken together, these findings demonstrate a potent cellular immune activation response involving primarily CD8+ T cells that is concomitant with disease progression in HAM/TSP. We also show that an upregulation of CD18 expression, a hallmark for increased cell migratory potential, might play a critical role in the development/maintenance of HAM/TSP.