Coreceptor use in nonhuman primate models of HIV infection

SIV or SHIV infection of nonhuman primates (NHP) has been used to investigate the impact of coreceptor usage on the composition and dynamics of the CD4+ T cell compartment, mechanisms of disease induction and development of clinical syndrome. As the entire course of infection can be followed, with frequent access to tissue compartments, infection of rhesus macaques with CCR5-tropic SHIVs further allows for study of HIV-1 coreceptor switch after intravenous and mucosal inoculation, with longitudinal and systemic analysis to determine the timing, anatomical sites and cause for the change in envelope glycoprotein and coreceptor preference. Here, we review our current understanding of coreceptor use in NHPs and their impact on the pathobiological characteristics of the infection, and discuss recent advances in NHP studies to uncover the underlying selective pressures for the change in coreceptor preference in vivo

CONOCIMIENTOS SOBRE LEISHMANIASIS VISCERAL: SUFICIENTE PARA EL CONTROL Y PREVENCIÓN?

A Leishmaniose Visceral (LV), zoonose com distribuição cosmopolita e responsável por milhões de casos em humanos todos os anos, tem como agente etiológico protozoários do gênero Leishmania, e sua transmissão ocorrem através da picada de flebotomíneos. Alterações no ambiente, como desmatamentos, expansão de zonas urbanas para bordas de matas, entre outros, tem conduzido a uma urbanização desta doença e a falta de conhecimento pode aumentar do risco de infecção humana. O objetivo desse estudo foi: i) avaliar o conhecimento de famílias estabelecidas no assentamento rural “Estrela da Ilha” de Ilha Solteira/SP sobre LV, ii) realizar o diagnóstico para leishmaniose visceral canina (LVC) nos cães dessas famílias e, iii) submeter os resultados à análise de dependência pelo teste qui-quadrado e prova exata de Fischer (p?0,05), para saber se tais conhecimentos são suficientes para o controle e prevenção desta zoonose no ambiente rural. Foram entrevistadas 39 famílias por meio de questionário e coletadas amostras de sangue de 93 cães submetidos ao ensaio imunoenzimático indireto (ELISA), para detecção de anticorpos anti-Leishmania. A presença de cães com LVC foi de 25,8% (24/93), sendo que 46,15% (18/39) das famílias eram tutores de cães com a doença. Pela análise de Fischer observou-se dependência entre as variáveis “cães das famílias, com LVC” versus “atitudes das famílias diante de um caso suspeito de LVC” (p = 0,0076) e sobre “como a população pode contribuir para o controle da LVC” (p = 0,0457). Em ambas as avaliações a maior porcentagem das famílias souberam responder como proceder, porém não foram suficientes para reduzir o número de cães infectados em suas residências. A variável “cães das famílias, com LVC” também esteve dependente em relação à falta de conhecimento das famílias sobre o “horário de alimentação do vetor” (p = 0,0312). Conclui-se que as famílias rurais deste estudo apresentam conhecimentos fragmentados sobre a doença, resultando em práticas pouco eficientes como medida profilática da LVC. Dessa forma, a falta de ação conjunta (conhecimento e medidas básicas preventivas) podem aumentar as chances de casos de leishmaniose em humanos e em cães nesta zona rural.Visceral leishmaniasis (VL), a zoonosis with cosmopolitan distribution responsible for millions of cases in humans every year, has the etiological agent protozoans of the genus Leishmania, which the transmission occurs through the bite of sandflies (phlebotomines). Changes in the environment such as deforestation, expansion of urban areas to edges of woods has led to the urbanization of the parasite and the increases of the risk for human infection. The aim of this study was: i) evaluate the knowledge of established families in the rural settlement "Estrela da Ilha" of Ilha Solteira, SP about LV, ii) diagnosis for canine visceral leishmaniasis (CVL) in dogs of these families and, iii) dependency analysis by Chi-squared test and  Fischer exact test (p ? 0.05), to know if such knowledge is sufficient for the control and prevention of this zoonosis in the rural environment. For this study, 39 families were interviewed through a questionnaire and blood samples of 93 dogs were collected and submitted to an indirect enzyme-linked immunosorbent assay (ELISA) for detection of anti-Leishmania antibodies. 25.8% (24/93) of dogs were positive to CVL and 46.15% (18/39) of the families own these infected dogs. Fischer's analysis showed dependence between the variables "dogs of the families with LVC" versus "attitudes of families faced with a suspected case of LVC" (p = 0.0076) and on "how the population may contribute to the control of the CVL" (p = 0.0457). In both evaluations, the highest percentage of families knew the answer how to proceed, but this knowledge was  not sufficient to reduce the number of infected dogs in their homes. The variable "dogs of the families with LVC" was also dependent in relation to the lack of knowledge of the families on the "vector" feeding period (p = 0.0312). It is concluded that the rural families of this study present fragmented knowledge about the disease, resulting in inefficient practices as a prophylactic measure of LVC. Thus, the lack of joint action, such as (knowledge and basic preventive measures) can increase the risk of cases of leishmaniasis in humans and dogs in this rural area.La leishmaniasis visceral (VL), zoonosis con una distribución en todo el mundo y responsable de millones de casos humanos cada año, tienes como agente etiológico protozoos del género Leishmania, y la transmisión se produce a través de la picadura de flebótomos. Los cambios en el medio ambiente, como la deforestación, la expansión de las zonas urbanas a los bordes del bosque, entre otros, ha llevado a la urbanización de esta enfermedad y la falta de conocimiento pueden aumentar el riesgo de infección humana. El objetivo de este estudio fue: i) evaluar el conocimiento de las familias establecidas en el asentamiento rural “Estrela da Ilha” de Ilha Solteira/SP acerca de VL, ii) realizar el diagnóstico de la leishmaniasis visceral canina (CVL) en perros de estas familias y, iii) someter los resultados a análisis de dependencia utilizando la prueba chi-cuadrado y la prueba exacta de Fischer  (p?0.05), para ver si ese conocimiento es suficiente para el control y prevención de esta zoonosis en un entorno rural. Se entrevistó 39 familias mediante cuestionario y muestras de sangre fueron recogidas de 93 perros sometidos a inmunoensayo enzimático (ELISA), para detección de anticuerpos anti-Leishmania. La presencia de perros com CVL fue 25.80% (24/93), donde 46.15% (18/39) de las familias eran proprietários de perros infectados. A través de la análisis de Fischer se observo dependencia entre las variables “perros de familias, con CVL” versus “actitudes de las familias mediante de un caso sospecho de CVL” (p = 0.0076) y acerca de “como la población puede contribuir al control de CVL” (p = 0.0457). En ambas evaluaciones el mayor porcentaje de familias que sabía responder acerca de cómo proceder, pero no fueron suficientes para reducir el número de perros infectados en sus hogares. La variable “perros de familias, con CVL” también dependía en relación con la falta de conocimiento de las familias acerca de “horario de alimentación del vector” (p = 0.0312). Se concluye que las familias rurales de este estudio presentan conocimiento fragmentado sobre la enfermedad, dando lugar a prácticas ineficientes como medida profiláctica de CVL. Por lo tanto, la falta de acción conjunta (conocimientos y medidas preventivas básicas) puede aumentar las posibilidades de casos de leishmaniasis en humanos y perros en esta zona rural

CONOCIMIENTOS SOBRE LEISHMANIASIS VISCERAL: SUFICIENTE PARA EL CONTROL Y PREVENCIÓN?

A Leishmaniose Visceral (LV), zoonose com distribuição cosmopolita e responsável por milhões de casos em humanos todos os anos, tem como agente etiológico protozoários do gênero Leishmania, e sua transmissão ocorrem através da picada de flebotomíneos. Alterações no ambiente, como desmatamentos, expansão de zonas urbanas para bordas de matas, entre outros, tem conduzido a uma urbanização desta doença e a falta de conhecimento pode aumentar do risco de infecção humana. O objetivo desse estudo foi: i) avaliar o conhecimento de famílias estabelecidas no assentamento rural “Estrela da Ilha” de Ilha Solteira/SP sobre LV, ii) realizar o diagnóstico para leishmaniose visceral canina (LVC) nos cães dessas famílias e, iii) submeter os resultados à análise de dependência pelo teste qui-quadrado e prova exata de Fischer (p?0,05), para saber se tais conhecimentos são suficientes para o controle e prevenção desta zoonose no ambiente rural. Foram entrevistadas 39 famílias por meio de questionário e coletadas amostras de sangue de 93 cães submetidos ao ensaio imunoenzimático indireto (ELISA), para detecção de anticorpos anti-Leishmania. A presença de cães com LVC foi de 25,8% (24/93), sendo que 46,15% (18/39) das famílias eram tutores de cães com a doença. Pela análise de Fischer observou-se dependência entre as variáveis “cães das famílias, com LVC” versus “atitudes das famílias diante de um caso suspeito de LVC” (p = 0,0076) e sobre “como a população pode contribuir para o controle da LVC” (p = 0,0457). Em ambas as avaliações a maior porcentagem das famílias souberam responder como proceder, porém não foram suficientes para reduzir o número de cães infectados em suas residências. A variável “cães das famílias, com LVC” também esteve dependente em relação à falta de conhecimento das famílias sobre o “horário de alimentação do vetor” (p = 0,0312). Conclui-se que as famílias rurais deste estudo apresentam conhecimentos fragmentados sobre a doença, resultando em práticas pouco eficientes como medida profilática da LVC. Dessa forma, a falta de ação conjunta (conhecimento e medidas básicas preventivas) podem aumentar as chances de casos de leishmaniose em humanos e em cães nesta zona rural.Visceral leishmaniasis (VL), a zoonosis with cosmopolitan distribution responsible for millions of cases in humans every year, has the etiological agent protozoans of the genus Leishmania, which the transmission occurs through the bite of sandflies (phlebotomines). Changes in the environment such as deforestation, expansion of urban areas to edges of woods has led to the urbanization of the parasite and the increases of the risk for human infection. The aim of this study was: i) evaluate the knowledge of established families in the rural settlement "Estrela da Ilha" of Ilha Solteira, SP about LV, ii) diagnosis for canine visceral leishmaniasis (CVL) in dogs of these families and, iii) dependency analysis by Chi-squared test and  Fischer exact test (p ? 0.05), to know if such knowledge is sufficient for the control and prevention of this zoonosis in the rural environment. For this study, 39 families were interviewed through a questionnaire and blood samples of 93 dogs were collected and submitted to an indirect enzyme-linked immunosorbent assay (ELISA) for detection of anti-Leishmania antibodies. 25.8% (24/93) of dogs were positive to CVL and 46.15% (18/39) of the families own these infected dogs. Fischer's analysis showed dependence between the variables "dogs of the families with LVC" versus "attitudes of families faced with a suspected case of LVC" (p = 0.0076) and on "how the population may contribute to the control of the CVL" (p = 0.0457). In both evaluations, the highest percentage of families knew the answer how to proceed, but this knowledge was  not sufficient to reduce the number of infected dogs in their homes. The variable "dogs of the families with LVC" was also dependent in relation to the lack of knowledge of the families on the "vector" feeding period (p = 0.0312). It is concluded that the rural families of this study present fragmented knowledge about the disease, resulting in inefficient practices as a prophylactic measure of LVC. Thus, the lack of joint action, such as (knowledge and basic preventive measures) can increase the risk of cases of leishmaniasis in humans and dogs in this rural area.La leishmaniasis visceral (VL), zoonosis con una distribución en todo el mundo y responsable de millones de casos humanos cada año, tienes como agente etiológico protozoos del género Leishmania, y la transmisión se produce a través de la picadura de flebótomos. Los cambios en el medio ambiente, como la deforestación, la expansión de las zonas urbanas a los bordes del bosque, entre otros, ha llevado a la urbanización de esta enfermedad y la falta de conocimiento pueden aumentar el riesgo de infección humana. El objetivo de este estudio fue: i) evaluar el conocimiento de las familias establecidas en el asentamiento rural “Estrela da Ilha” de Ilha Solteira/SP acerca de VL, ii) realizar el diagnóstico de la leishmaniasis visceral canina (CVL) en perros de estas familias y, iii) someter los resultados a análisis de dependencia utilizando la prueba chi-cuadrado y la prueba exacta de Fischer  (p?0.05), para ver si ese conocimiento es suficiente para el control y prevención de esta zoonosis en un entorno rural. Se entrevistó 39 familias mediante cuestionario y muestras de sangre fueron recogidas de 93 perros sometidos a inmunoensayo enzimático (ELISA), para detección de anticuerpos anti-Leishmania. La presencia de perros com CVL fue 25.80% (24/93), donde 46.15% (18/39) de las familias eran proprietários de perros infectados. A través de la análisis de Fischer se observo dependencia entre las variables “perros de familias, con CVL” versus “actitudes de las familias mediante de un caso sospecho de CVL” (p = 0.0076) y acerca de “como la población puede contribuir al control de CVL” (p = 0.0457). En ambas evaluaciones el mayor porcentaje de familias que sabía responder acerca de cómo proceder, pero no fueron suficientes para reducir el número de perros infectados en sus hogares. La variable “perros de familias, con CVL” también dependía en relación con la falta de conocimiento de las familias acerca de “horario de alimentación del vector” (p = 0.0312). Se concluye que las familias rurales de este estudio presentan conocimiento fragmentado sobre la enfermedad, dando lugar a prácticas ineficientes como medida profiláctica de CVL. Por lo tanto, la falta de acción conjunta (conocimientos y medidas preventivas básicas) puede aumentar las posibilidades de casos de leishmaniasis en humanos y perros en esta zona rural

Adoption of an “Open” Envelope Conformation Facilitating CD4 Binding and Structural Remodeling Precedes Coreceptor Switch in R5 SHIV-Infected Macaques

A change in coreceptor preference from CCR5 to CXCR4 towards the end stage disease in some HIV-1 infected individuals has been well documented, but the reasons and mechanisms for this tropism switch remain elusive. It has been suggested that envelope structural constraints in accommodating amino acid changes required for CXCR4 usage is an obstacle to tropism switch, limiting the rate and pathways available for HIV-1 coreceptor switching. The present study was initiated in two R5 SHIVSF162P3N-infected rapid progressor macaques with coreceptor switch to test the hypothesis that an early step in the evolution of tropism switch is the adoption of a less constrained and more “open” envelope conformation for better CD4 usage, allowing greater structural flexibility to accommodate further mutational changes that confer CXCR4 utilization. We show that, prior to the time of coreceptor switch, R5 viruses in both macaques evolved to become increasingly sCD4-sensitive, suggestive of enhanced exposure of the CD4 binding site and an “open” envelope conformation, and this correlated with better gp120 binding to CD4 and with more efficient infection of CD4low cells such as primary macrophages. Moreover, significant changes in neutralization sensitivity to agents and antibodies directed against functional domains of gp120 and gp41 were seen for R5 viruses close to the time of X4 emergence, consistent with global changes in envelope configuration and structural plasticity. These observations in a simian model of R5-to-X4 evolution provide a mechanistic basis for the HIV-1 coreceptor switch

R5X4 Viruses Are Evolutionary, Functional, and Antigenic Intermediates in the Pathway of a Simian-Human Immunodeficiency Virus Coreceptor Switch▿

To examine the pathway of the coreceptor switching of CCR5-using (R5) virus to CXCR4-using (X4) virus in simian-human immunodeficiency virus SHIVSF162P3N-infected rhesus macaque BR24, analysis was performed on variants present at 20 weeks postinfection, the time when the signature gp120 V3 loop sequence of the X4 switch variant was first detected by PCR. Unexpectedly, circulating and tissue variants with His/Ile instead of the signature X4 V3 His/Arg insertions predominated at this time point. Phylogenetic analysis of the sequences of the C2 conserved region to the V5 variable loop of the envelope (Env) protein showed that viruses bearing HI insertions represented evolutionary intermediates between the parental SHIVSF162P3N and the final X4 HR switch variant. Functional analyses demonstrated that the HI variants were phenotypic intermediates as well, capable of using both CCR5 and CXCR4 for entry. However, the R5X4 intermediate virus entered CCR5-expressing target cells less efficiently than the parental R5 strain and was more sensitive to both CCR5 and CXCR4 inhibitors than either the parental R5 or the final X4 virus. It was also more sensitive than the parental R5 virus to antibody neutralization, especially to agents directed against the CD4 binding site, but not as sensitive as the late X4 virus. Significantly, the V3 loop sequence that determined CXCR4 use also conferred soluble CD4 neutralization sensitivity. Collectively, the data illustrate that, similar to human immunodeficiency virus type 1 (HIV-1) infection in individuals, the evolution from CCR5 to CXCR4 usage in BR24 transitions through an intermediate phase with reduced virus entry and coreceptor usage efficiencies. The data further support a model linking an open envelope gp120 conformation, better CD4 binding, and expansion to CXCR4 usage

Selected Pool of Peptides from ESAT-6 and CFP-10 Proteins for Detection of Mycobacterium tuberculosis Infection

We have validated a new test for detecting Mycobacterium tuberculosis infection. A pool of synthetic peptides derived from ESAT-6 and CFP-10 proteins was used to detect the number of specific gamma interferon-producing T cells by means of an enzyme-linked immunospot assay. Sixty-eight individuals positive for M. tuberculosis infection, either human immunodeficiency virus-seropositive or -seronegative, were studied. The test results were highly specific (87.5%) and sensitive (93.1%), more so than a classical lymphoproliferative assay (specificity and sensitivity of 77.27%), opening new possibilities for diagnosis and screening of tuberculosis. Moreover, the test allowed us to distinguish individuals infected with M. tuberculosis from those vaccinated with BCG

Fitness Disadvantage of Transitional Intermediates Contributes to Dynamic Change in the Infecting-Virus Population during Coreceptor Switch in R5 Simian/Human Immunodeficiency Virus-Infected Macaques▿

Fitness disadvantage of the transitional intermediates compared to the initial R5 viruses has been suggested to constitute one of the blockades to coreceptor switching, explaining the late appearance of X4 viruses. Using a simian model for human immunodeficiency virus type 1 (HIV-1) coreceptor switching, we demonstrate in this study that similar molecular evolutionary pathways to coreceptor switch occur in more than one R5 simian/human immunodeficiency virus (SHIV)SF162P3N-infected macaque. In infected animals where multiple pathways for expansion or switch to CXCR4 coexist, fitness of the transitional intermediates in coreceptor usage efficiency influences their outgrowth and representation in the infecting virus population. Dualtropic and X4 viruses appear at different disease stages, but they have lower entry efficiency than the coexisting R5 strains, which may explain why they do not outcompete the R5 viruses. Similar observations were made in two infected macaques with coreceptor switch, providing in vivo evidence that fitness disadvantage is an obstacle to X4 emergence and expansion

Different Tempo and Anatomic Location of Dual-Tropic and X4 Virus Emergence in a Model of R5 Simian-Human Immunodeficiency Virus Infection▿

We previously reported coreceptor switch in rhesus macaques inoculated intravenously with R5 simian-human immunodeficiency virus SF162P3N (SHIVSF162P3N). Whether R5-to-X4 virus evolution occurs in mucosally infected animals and in which anatomic site the switch occurs, however, were not addressed. We herein report a change in coreceptor preference in macaques infected intrarectally with SHIVSF162P3N. The switch occurred in infected animals with high levels of virus replication and undetectable antiviral antibody response and required sequence changes in the V3 loop of the gp120 envelope protein. X4 virus emergence was associated with an accelerated drop in peripheral CD4+ T-cell count but followed rather than preceded the onset of CD4+ T-cell loss. The conditions, genotypic requirements, and patterns of coreceptor switch in intrarectally infected animals were thus remarkably consistent with those found in macaques infected intravenously. They also overlapped with those reported for humans, suggestive of a common mechanism for coreceptor switch in the two hosts. Furthermore, two independent R5-to-X4 evolutionary pathways were identified in one infected animal, giving rise to dual-tropic and X4 viruses which differed in switch kinetics and tissue localization. The dual-tropic switch event predominated early, and the virus established infection in multiple tissues sites. In contrast, the switch to X4 virus occurred later, initiating and expanding mainly in peripheral lymph nodes. These findings help define R5 SHIVSF162P3N infection of rhesus macaques as a model to study the mechanistic basis, dynamics, and sites of HIV-1 coreceptor switch