Variability in HIV-1 partial genomic sequences in Costa Rican patients: analysis with different bioinformatics tools.

OBJECTIVE: To estimate subtype and genomic variability in the HIV pol gene of Costa Rican patients by using different bioinformatics tools and to use this information to establish new policies to better manage these patients. METHODS: A total of 113 pol sequences available from Costa Rican patients under highly active antiretroviral therapy were analyzed by using the Genotyping, REGA, Stanford, and MEGA programs. The pol sequences came from 77 virologic failures (VF) and 36 basal samples (BS). Of the 77 VF, 22 also were sequenced in the env region. RESULTS: No major differences were found among the variables studied. However, there was a tendency for more variability in VF patients with a high baseline viral load. In the pol gene, 75%-83% of BS and 66%-75% of VF samples were pure B subtype by Genotyping and REGA, respectively. The other samples presented variations related mainly to circulating recombinant form CRF12 by genotyping or to CRF17 or -29 by phylogenetic analysis or a new possible BD recombinant with all programs. In the Stanford program, all variable samples showed a subtype B with high polymorphism. The variability in the env sequences was lower than that in the pol region. CONCLUSION: The B subtype is predominant in Costa Rican HIV-positive patients. There is high variability within sequences with potential recombination between B and F or D subtypes. The BD recombinant has not been previously reported. This high variability is likely the result of possible recombinant events, nonadherence to antiretroviral therapy, sexual intercourse without protection, and many sexual partners. Similar studies should be done in other countries in the Region, in particular in those places with extensive immigration, in order to decrease the possibility of virus variability as well as the cost of antiretroviral therapy.

Optimization of DNA delivery by three classes of hybrid nanoparticle/DNA complexes.

Plasmid DNA encoding a luciferase reporter gene was complexed with each of six different hybrid nanoparticles (NPs) synthesized from mixtures of poly (D, L-lactide-co-glycolide acid) (PLGA 50:50) and the cationic lipids DOTAP (1, 2-Dioleoyl-3-Trimethyammonium-Propane) or DC-Chol {3beta-[N-(N', N'-Dimethylaminoethane)-carbamyl] Cholesterol}. Particles were 100-400 nm in diameter and the resulting complexes had DNA adsorbed on the surface (out), encapsulated (in), or DNA adsorbed and encapsulated (both). A luciferase reporter assay was used to quantify DNA expression in 293 cells for the uptake of six different NP/DNA complexes. Optimal DNA delivery occurred for 105 cells over a range of 500 ng - 10 mug of NPs containing 20-30 mug DNA per 1 mg of NPs. Uptake of DNA from NP/DNA complexes was found to be 500-600 times as efficient as unbound DNA. Regression analysis was performed and lines were drawn for DNA uptake over a four week interval. NP/DNA complexes with adsorbed NPs (out) showed a large initial uptake followed by a steep slope of DNA decline and large angle of declination; lines from uptake of adsorbed and encapsulated NPs (both) also exhibited a large initial uptake but was followed by a gradual slope of DNA decline and small angle of declination, indicating longer times of luciferase expression in 293 cells. NPs with encapsulated DNA only (in), gave an intermediate activity. The latter two effects were best seen with DOTAP-NPs while the former was best seen with DC-Chol-NPs. These results provide optimal conditions for using different hybrid NP/DNA complexes in vitro and in the future, will be tested in vivo.

Variability in HIV-1 partial genomic sequences in Costa Rican patients: analysis with different bioinformatics tools / Variabilidad de secuencias genómicas parciales del VIH-1 en pacientes costarricenses: análisis con diferentes herramientas bioinformáticas

OBJECTIVE: To estimate subtype and genomic variability in the HIV pol gene of Costa Rican patients by using different bioinformatics tools and to use this information to establish new policies to better manage these patients. METHODS: A total of 113 pol sequences available from Costa Rican patients under highly active antiretroviral therapy were analyzed by using the Genotyping, REGA, Stanford, and MEGA programs. The pol sequences came from 77 virologic failures (VF) and 36 basal samples (BS). Of the 77 VF, 22 also were sequenced in the env region. RESULTS: No major differences were found among the variables studied. However, there was a tendency for more variability in VF patients with a high baseline viral load. In the pol gene, 75 percent-83 percent of BS and 66 percent-75 percent of VF samples were pure B subtype by Genotyping and REGA, respectively. The other samples presented variations related mainly to circulating recombinant form CRF12 by genotyping or to CRF17 or -29 by phylogenetic analysis or a new possible BD recombinant with all programs. In the Stanford program, all variable samples showed a subtype B with high polymorphism. The variability in the env sequences was lower than that in the pol region. CONCLUSION: The B subtype is predominant in Costa Rican HIV-positive patients. There is high variability within sequences with potential recombination between B and F or D subtypes. The BD recombinant has not been previously reported. This high variability is likely the result of possible recombinant events, nonadherence to antiretroviral therapy, sexual intercourse without protection, and many sexual partners. Similar studies should be done in other countries in the Region, in particular in those places with extensive immigration, in order to decrease the possibility of virus variability as well as the cost of antiretroviral therapy.

OBJETIVOS: Determinar el subtipo y la variabilidad genómica del gen pol del VIH de pacientes costarricenses mediante diferentes herramientas bioinformáticas y el uso de esta información para establecer nuevas políticas para mejorar el diagnóstico y el tratamiento de estos pacientes. MÉTODOS: Se analizaron 113 secuencias del gen pol de pacientes costarricenses bajo tratamiento antirretrovírico de gran actividad mediante cuatro programas: Genotyping, REGA, Stanford y MEGA. Las secuencias pol analizadas provenían de 77 casos considerados fracasos virológicos (FV) y 36 muestras iniciales (MI). También se secuenció la región env de 22 de los 77 FV. RESULTADOS: No se encontraron diferencias importantes entre las variables estudiadas. No obstante, se observó una tendencia a una mayor variabilidad en los pacientes FV que tenían una elevada carga viral inicial. Con respecto al gen pol, 77-83 por ciento de las MI y 66-75 por ciento de las muestras de los FV eran del subtipo B puro según Genotyping y REGA, respectivamente. Las otras muestras presentaron variaciones relacionadas principalmente con la forma recombinante en circulación CRF-12 según Genotyping, con la CRF-17 o la CRF-29 según el análisis filogenético, o una nueva posible forma recombinante BD según todos los programas. Con el programa Stanford, todas las muestras variables reflejaron un subtipo B con elevado polimorfismo. La variabilidad de la secuencia env fue menor que la de la región pol. CONCLUSIONES: El subtipo B fue el predominante en los pacientes positivos al VIH en Costa Rica. Existe una alta variabilidad en las secuencias con una posible recombinación entre los subtipos B, y F o D. La forma recombinante BD no se había notificado antes. Esta elevada variabilidad parece ser el resultado de posibles eventos de recombinación, la falta de adhesión al tratamiento antirretrovírico, las relaciones sexuales sin protección y numerosas parejas sexuales. Se deben emprender estudios similares en otros países de la Región, en particular en los lugares con mucha inmigración, para reducir tanto la posibilidad de que el virus varíe como el costo del tratamiento antirretrovírico.

Epstein-Barr Nuclear Antigen 1 modulates replication of oriP-plasmids by impeding replication and transcription fork migration through the family of repeats.

BACKGROUND: Epstein-Barr virus is replicated once per cell-cycle, and partitioned equally in latently infected cells. Both these processes require a single viral cis-element, termed oriP, and a single viral protein, EBNA1. EBNA1 binds two clusters of binding sites in oriP, termed the dyad symmetry element (DS) and the family of repeats (FR), which function as a replication element and partitioning element respectively. Wild-type FR contains 20 binding sites for EBNA1. RESULTS: We, and others, have determined previously that decreasing the number of EBNA1-binding sites in FR increases the efficiency with which oriP-plasmids are replicated. Here we demonstrate that the wild-type number of binding sites in FR impedes the migration of replication and transcription forks. Further, splitting FR into two widely separated sets of ten binding sites causes a ten-fold increase in the efficiency with which oriP-plasmids are established in cells expressing EBNA1. We have also determined that EBNA1 bound to FR impairs the migration of transcription forks in a manner dependent on the number of EBNA1-binding sites in FR. CONCLUSION: We conclude that EBNA1 bound to FR regulates the replication of oriP-plasmids by impeding the migration of replication forks. Upon binding FR, EBNA1 also blocks the migration of transcription forks. Thus, in addition to regulating oriP replication, EBNA1 bound to FR also decreases the probability of detrimental collisions between two opposing replication forks, or between a transcription fork and a replication fork.

An HIV/AIDS Prophylactic vaccine is possible.

One needs to think outside of the box, as one of us (Ronald B Luftig) learned from many years as a mathematician, and a biophysicist.In this short Review, the need to focus on producing high levels of neutralizing antibodies (NAbs) to incoming and conformationally altered virus after it has bound to CD4+ cells is essential.Increasing the number of gp120 molecules on the surface of L-2 particles, could allow for an enhanced number of NAbs.The attempt at increasing CD8+ T cell responses in recent vaccine trials has not worked perhaps because it may have allowed HIV to enter into remote sanctuaries. Our approach focuses on increasing NAbs, before high levels of CD8+ T cells are produced.

Reduced expression of Jak-1 and Tyk-2 proteins leads to interferon resistance in hepatitis C virus replicon.

BACKGROUND: Alpha interferon in combination with ribavirin is the standard therapy for hepatitis C virus infection. Unfortunately, a significant number of patients fail to eradicate their infection with this regimen. The mechanisms of IFN-resistance are unclear. The aim of this study was to determine the contribution of host cell factors to the mechanisms of interferon resistance using replicon cell lines. RESULTS: HCV replicons with high and low activation of the IFN-promoter were cultured for a prolonged period of time in the presence of interferon-alpha (IFN-alpha2b). Stable replicon cell lines with resistant phenotype were isolated and characterized by their ability to continue viral replication in the presence of IFN-alpha. Interferon resistant cell colonies developed only in replicons having lower activation of the IFN promoter and no resistant colonies arose from replicons that exhibit higher activation of the IFN promoter. Individual cell clones were isolated and nine IFN resistant cell lines were established. HCV RNA and protein levels in these cells were not altered by IFN- alpha2b. Reduced signaling and IFN-resistant phenotype was found in all Huh-7 cell lines even after eliminating HCV, suggesting that cellular factors are involved. Resistant phenotype in the replicons is not due to lack of interferon receptor expression. All the cell lines show defect in the JAK-STAT signaling and phosphorylation of STAT 1 and STAT 2 proteins were strongly inhibited due to reduced expression of Tyk2 and Jak-1 protein. CONCLUSION: This in vitro study provides evidence that altered expression of the Jak-Stat signaling proteins can cause IFN resistance using HCV replicon cell clones.

The RING finger ubiquitin ligase RNF125/TRAC-1 down-modulates HIV-1 replication in primary human peripheral blood mononuclear cells.

CXCR4-using HIV-1 was previously shown to replicate more efficiently in a healthy donor-derived CD4(+) CD38(+) than in a CD4(+) CD38(-) T-cell subset after stimulation with interleukin (IL)-4. Here, we identified 3 cellular genes, which were expressed to a higher level in an IL-4-stimulated CD38(-) subset. One of the 3 genes, RNF125/TRAC-1, was involved in the down-regulation of HIV-1 replication not only in cell lines, but also in peripheral blood mononuclear cells. RNF125/TRAC-1 bears the RING finger domain, important for E3 ubiquitin protein ligase. Mutations in this domain of RNF125/TRAC-1 led to the loss of HIV-1 down-modulatory activity, suggesting that E3 ligase activity is necessary. In addition, the results of Northern blotting and reporter gene analysis indicated that RNF125/TRAC-1 function occurs at the viral transcription step. These results suggest that RNF125/TRAC-1 could function to recruit host factor(s) controlling HIV-1 transcription to the ubiquitin-proteasome pathway.

Study of antiretroviral mutants in HIV patients with treatment failures and the effect of risk factors in the virological failures

En Costa Rica no se tiene información a cerca de genotipos de resistencia para los tratamientos anti-retrovirales disponibles y la influencia de diferentes factores de riego en la falla virológica (FV) de pacientes VIH positivos previo o durante su tratamiento.Ochenta y nueve muestras, 72 FV y 17 basales, fueron analizadas con Trugene o LIPA para la detección de mutantes de resistencia en la transcriptasa reversa (TR) y en la proteasa (PT) del VIH.Se seleccionaron sesenta y ocho controles y se recolectó información relevante en un cuestionario. La mala adherencia, la presencia de mutaciones y el número de cambios de tratamiento fueron los únicos factores con significancia encontrados. (p = 0.03, 0.04 and 0.04 respectively). De 66 muestras secuenciadas, 78%, 50% y 50% mostraron resistencia a los inhibidores análogos y no análogos de nucleótidos para la TR y la PT respectivamente. La mutaciones más frecuentes fueron M41L, M184V, y T215FY en la TR y L62PI, L10FIRV y M36I en la PT. La adherencia fue el factor más importante relacionado con la respuesta al tratamiento. Las mutaciones encontradas en la TR estaban relacionadas al tratamiento mientras que las de la PT fueron mutaciones secundarias que propician la aparición de las mutaciones asociadas a resistencia en esa región. Este estudio revela la necesidad de detectar mutantes de resistencia en pacientes con FV y de estudiar las muestras basales. Además la importancia de reforzar la adherencia en los pacientes para una mejor respuesta al tratamiento.

Amplification and overexpression of prosaposin in prostate cancer.

We identified prosaposin (PSAP) as a secreted protein expressed in androgen-independent (AI) prostate cancer cells by cloning/sequencing, after probing a PC-3 cDNA library expressed in the lambdaTriplEx phagemid expression vector with a polyclonal rabbit antibody generated against pooled human seminal plasma. PSAP is a neurotrophic molecule; its deficiency or inactivation has proved to be lethal in man and mice, and in mice, it leads to abnormal development and atrophy of the prostate gland, despite normal testosterone levels. We used Southern hybridization, quantitative real-time polymerase chain reaction, and/or single nucleotide polymorphism (SNP) array analysis, and we now report the genomic amplification of PSAP in the metastatic AI prostate cancer cell lines, PC-3, DU-145, MDA-PCa 2b, M-12, and NCI-H660. In addition, by using SNP arrays and a set of 25 punch biopsy samples of human prostate cancer xenografts (LAPC3, LuCaP 23.1, 35, 49, 58, 73, 77, 81, 86.2, 92.1, 93, 96, 105, and 115), lymph nodes, and visceral-organ metastases, we detected amplification of the PSAP locus (10q22.1) in LuCaP 58 and 96 xenografts and two lymph node metastases. In addition, AI metastatic prostate cancer cell lines C4-2B and IA8-ARCaP over-expressed PSAP mRNA without evidence of genomic amplification. Taken together with prior data that demonstrated the growth-, migration-, and invasion-promoting activities, the activation of multiple signal transduction pathways, and the antiapoptotic effect of PSAP (or one of its active domains, saposin C) in prostate cancer cells, our current observation of PSAP amplification or overexpression in prostate cancer suggests, for the first time, a role for this molecule in the process of carcinogenesis or cancer progression in the prostate.

HBx M130K and V131I (T-A) mutations in HBV genotype F during a follow-up study in chronic carriers.

BACKGROUND: Around 400 million people worldwide are chronically infected with Hepatitis B virus (HBV). An estimated 10% of these chronic patients develop progressive liver damage including cirrhosis and Hepatocellular Carcinoma (HCC). The HBx gene encodes a protein of 154 amino acids which is a transactivator and has been associated with HBV pathogenesis. A change in the amino acid sequences at positions 130 and 131 in the HBV-X protein (M130K and V131I) produced by T-A point mutations at the nucleic acids level has been associated with severe liver damage and HCC in patients from China and Africa. Further, such changes have been proposed as a prognostic marker for progressive liver damage and HCC. The purpose of this study was to determine if T-A mutations are present in HBV chronic carriers with genotype F (the major genotype in Costa Rica) and further, if these mutations are associated with HBV disease progression in Costa Rica HBV patients from 1972 to 1985. RESULTS: Serum samples from 50 HBV positive individuals were amplified and directly sequenced, 48 belonged to genotype F, 1 from genotype D and another was classified as D or E. T-A mutations were absent in 17 acute patients who recovered, but was present in 12 of 29 chronic carrier samples (42.8%), in one sample the T-A mutations were detected as early as 29 days after clinical onset of disease. In 17 carriers with available liver biopsies, T-A mutations were found in 8 sera of 13 (61.5%) classified as moderate or severe, and none in 4 biopsies with mild liver damage. However, it was not possible to demonstrate a statistical association between the presence of T-A mutations and moderate/severe liver damage, using a Fischer exact test, 1 tail, p = 0.05. In 4 patients HCC was diagnosed, and 2 of them presented the T-A mutations in their sera. CONCLUSION: T-A mutations were found in HBV genotype F in chronic carriers but not in patients who recovered from acute infection. These mutations could be developing early during infection although the possibility of infection with the mutant virus could not be excluded. More studies are necessary to establish if the T-A mutation can be used as a prognostic marker for severity of liver disease in patients infected with HBV.

Vibrio vulnificus load reduction in oysters after combined exposure to Vibrio vulnificus--specific bacteriophage and to an oyster extract component.

Oysters infected with Vibrio vulnificus can present a serious health risk to diabetic, immunocompromised, and iron-deficient individuals. Numerous studies have been conducted with the goal of eliminating this organism from raw oysters. We utilized two natural oyster-associated components: pooled Vibrio vulnificus-specific bacteriophage and an extract of the eastern oyster (Crassostrea virginica) that contains an antimicrobial component we named anti-Vibrio vulnificus factor, which is bactericidal for V. vulnificus. Although each component alone can reduce V. vulnificus numbers independently, the simultaneous use of both components in an in vitro system successfully more effectively reduced V. vulnificus bacterial loads.

Study of antiretroviral mutants in HIV patients with treatment failures and the effect of risk factors in the virological failures.

INTRODUCTION: Information about HIV phenotypes of resistant to available ART and the influence of different risk factors on virological failures (VF) in Costa Rican HIV positive patients prior or during HAART is unknown. MATERIALS AND METHODS: Eighty nine samples, 72 VF and 17 basal (before treatment) were analyzed by examining resistant mutants in reverse transcriptase (RT) and protease (PT) regions using Trugene or LIPA genotyping kits. Sixty eight control patients were selected and relevant information was collected in a questionnaire. RESULTS: Poor adherence, presence of resistant mutations and number of treatment's changes were the only significant factors found (p = 0.006, 0.04 and 0.01 respectively). From 66 sequenced samples, 78%, 50% and 50% showed resistance to NRTI (nucleoside reverse transcriptase inhibitors), NNRT (non-nucleoside reverse transcriptase inhibitors) and PI (protease inhibitors), respectively. The most frequent mutations were M41L, M184V, and T215FY in RT and L62PI, L10FIRV and M36I in PT. DISCUSSION: The most important factor related to treatment response in this study was adherence to treatment. Mutations in RT were related to the treatment failure while the ones found in PT were secondary mutations which have been previously described to influence the selection of primary resistance mutations in these regions. The study reveals the urgency to detect resistant mutations in VF to be considered by physicians for selection of treatment schedule, to analyze basal HIV patients for monitoring of the spread of resistant mutations and the importance to reinforce the adherence in the patients for overall treatment outcome.

Saposin C promotes survival and prevents apoptosis via PI3K/Akt-dependent pathway in prostate cancer cells.

BACKGROUND: In addition to androgens, growth factors are also implicated in the development and neoplastic growth of the prostate gland. Prosaposin is a potent neurotrophic molecule. Homozygous inactivation of prosaposin in mice has led to the development of a number of abnormalities in the male reproductive system, including atrophy of the prostate gland and inactivation of mitogen-activated protein kinase (MAPK) and Akt in prostate epithelial cells. We have recently reported that prosaposin is expressed at a higher level by androgen-independent (AI) prostate cancer cells as compared to androgen-sensitive prostate cancer cells or normal prostate epithelial and stromal cells. In addition, we have demonstrated that a synthetic peptide (prosaptide TX14A), derived from the trophic sequence of the saposin C domain of prosaposin, stimulated cell proliferation, migration and invasion and activated the MAPK signaling pathway in prostate cancer cells. The biological significances of saposin C and prosaposin in prostate cancer are not known. RESULTS: Here, we report that saposin C, in a cell type-specific and dose-dependent manner, acts as a survival factor, activates the Akt-signaling pathway, down-modulates caspase-3, -7, and -9 expression and/or activity, and decreases the cleaved nuclear substrate of caspase-3 in prostate cancer cells under serum-starvation stress. In addition, prosaptide TX14A, saposin C, or prosaposin decreased the growth-inhibitory effect, caspase-3/7 activity, and apoptotic cell death induced by etoposide. We also discovered that saposin C activates the p42/44 MAP kinase pathway in a pertussis toxin-sensitive and phosphatidylinositol 3-kinase (PI3K) /Akt-dependent manner in prostate cancer cells. Our data also show that the anti-apoptotic activity of saposin C is at least partially mediated via PI3K/Akt signaling pathway. CONCLUSION: We postulate that as a mitogenic, survival, and anti-apoptotic factor for prostate cancer cells, saposin C or prosaposin may contribute to prostate carcinogenesis at its early androgen-dependent or metastatic AI state.

Identification of proteases employed by dendritic cells in the processing of protein purified derivative (PPD).

Dendritic cells (DC) are known to present exogenous protein Ag effectively to T cells. In this study we sought to identify the proteases that DC employ during antigen processing. The murine epidermal-derived DC line Xs52, when pulsed with PPD, optimally activated the PPD-reactive Th1 clone LNC.2F1 as well as the Th2 clone LNC.4k1, and this activation was completely blocked by chloroquine pretreatment. These results validate the capacity of XS52 DC to digest PPD into immunogenic peptides inducing antigen specific T cell immune responses. XS52 DC, as well as splenic DC and DCs derived from bone marrow degraded standard substrates for cathepsins B, C, D/E, H, J, and L, tryptase, and chymases, indicating that DC express a variety of protease activities. Treatment of XS52 DC with pepstatin A, an inhibitor of aspartic acid proteases, completely abrogated their capacity to present native PPD, but not trypsin-digested PPD fragments to Th1 and Th2 cell clones. Pepstatin A also inhibited cathepsin D/E activity selectively among the XS52 DC-associated protease activities. On the other hand, inhibitors of serine proteases (dichloroisocoumarin, DCI) or of cystein proteases (E-64) did not impair XS52 DC presentation of PPD, nor did they inhibit cathepsin D/E activity. Finally, all tested DC populations (XS52 DC, splenic DC, and bone marrow-derived DC) constitutively expressed cathepsin D mRNA. These results suggest that DC primarily employ cathepsin D (and perhaps E) to digest PPD into antigenic peptides.

Determination of human cytomegalovirus genetic diversity in different patient populations in Costa Rica.

Seroprevalence of HCMV in Costa Rica is greater than 95% in adults; primary infections occur early in life and is the most frequent congenital infection in newborns. The objectives of this study were to determine the genetic variability and genotypes of HCMV gB gene in Costa Rica. Samples were collected from alcoholics, pregnant women, blood donors, AIDS patients, hematology-oncology (HO) children and HCMV isolates from neonates with cytomegalic inclusion disease. A semi-nested PCR system was used to obtain a product of 293-296 bp of the gB gene to be analyzed by Single Stranded Conformational Polymorphism (SSCP) and sequencing to determine the genetic polymorphic pattern and genotypes, respectively. AIDS patients showed the highest polymorphic diversity with 14 different patterns while fifty-six percent of HO children samples showed the same polymorphic pattern, suggesting in this group a possible nosocomial infection. In neonates three genotypes (gB1, gB2 and gB3), were determined while AIDS patients and blood donors only showed one (gB2). Of all samples analyzed only genotypes gB1, 2 and 3 were determined, genotype gB2 was the most frequent (73%) and mixed infections were not detected. The results of the study indicate that SSCP could be an important tool to detect HCMV intra-hospital infections and suggests a need to include additional study populations to better determine the genotype diversity and prevalence.

Determination of human cytomegalovirus genetic diversity in different patient populations in Costa Rica

La seroprevalencia de citomegalovirus es mayor del 95 por cento en la población adulta de Costa Rica; la infección primaria ocurre muy temprano en la vida y es la infección congénita más frecuente en recién nacidos. El objetivo de este trabajo fue determinar la variabilidad genética y los genotipos del gene gB del citomegalovirus humano. Se recolectaron muestras de sangre de mujeres embarazadas, alcohólicos, pacientes con SIDA, niños con trastornos hemato-oncológicos, donadores de sangre y se incluyeron aislamientos de citomegalovirus de neonatos con enfermedad congénita. Se utilizó un sistema de PCR semi-anidado para obtener una banda de 293-296 pares de bases, la cual fue analizada por la técnica de Polimorfismo conformacional de banda simple (PCBS) y secuenciada para determinar los patrones genéticos polimórficos y los genotipos, respectivamente. La mayor diversidad polimórfica se encontró en los pacientes con SIDA con 14 patrones diferentes mientras que en los niños con trastornos hemato-oncológicos se demostró el mismo patrón en el 56 por cento de los casos, sugiriendo una posible infección nosocomial en este grupo. En los neonatos se encontraron tres genotipos (gB1, gB2, gB3) mientras que en los pacientes con SIDA y en los donadores de sangre solo se demostró el gB2. En las muestras analizadas se determinaron los genotipos gB1, gB2 y gB3 y el gB2 se determinó en el 73 por cento de los casos, no se detectaron infecciones mixtas. Los resultados de este trabajo indican que la técnica del PCBS puede ser una herramienta importante para detectar el citomegalovirus humano en infecciones intrahospitalarias y se sugiere la importancia de incluir poblaciones de estudio adicionales para determinar mejor la diversidad genética y su prevalencia.

Dendritic cells: In the forefront of immunopathogenesis and vaccine development - A review.

Dendritic cellls (DCs) comprise an essential component of the immune system. These cells, as antigen presenting cells (APCs) to naïve T cells, are crucial in the initiation of antigen specific immune responses. In the past years, several DC subsets have been identified in different organs which exert different effects in order to elicit adaptive immune responses. Thus, identification of such DC subsets has led to a better understanding of their distribution and function in the body. In this review, several key properties of the immunobiology, immunopathogenesis and vaccine strategies using DCs will be discussed.

Oropharyngeal candidiasis in HIV(+) patients may influence the selection of HIV-1 protease variants.

Approximately 500 HIV-1 protease gene (pro) sequences were obtained from oral tissues (gingival cuff, buccal mucosa, tongue, palate) as well as saliva and peripheral blood mononuclear cells (PBMC) of 80 HIV-1 positive patients by nested amplification and manual sequencing of PCR products. By visual inspection each patient in this study exhibited a unique sequence profile. HIV-1 pro sequences obtained from patients with oropharyngeal candidiasis (OPC(+) patients) had significantly higher numbers of mutations than sequences from OPC(-) patients, but OPC(+) patients were no more likely to accumulate protease inhibitor resistance mutations than OPC(-) patients. Although the sequences for each patient were predominantly consistent between PBMC and oral tissues, approximately 10% of the patients demonstrated tissue specificity, and patients that demonstrated tissue specificity tended to be OPC(+). Furthermore, HIV-1 pro sequences derived from OPC lesions demonstrated unique mutations in approximately 30% of the patients who provided paired OPC(+/-) samples of the same tissue type. These data provide evidence for minimal compartmentalization of HIV-1 in oral tissues, yet some patients demonstrate minor variation between the HIV-1 pro sequences obtained from an OPC lesion and those obtained from a non-lesion site of similar tissue.

Hepatitis C virus (HCV) and human immunodeficiency virus type 1 (HIV-1) infections in alcoholics.

Approximately 400,000 individuals in the United States are co-infected with hepatitis C virus (HCV) and human immunodeficiency virus type 1 (HIV-1) and it is likely that almost one in two of these subjects consumes alcohol. The majority of these patients suffer an accelerated course of liver disease as manifested by the onset of cirrhosis within 5 to 10 years of developing HCV infection, as well as an increased risk of developing hepatocellular carcinoma (HCC). It is thought that chronic alcohol abuse mediates liver damage as a result of increased production of free radicals and proinflammatory cytokines. In the setting of chronic HCV infection, alcohol ingestion has an additional effect of diminishing immune clearance and increasing viral burden to hasten the onset of cirrhosis and HCC. Likewise, chronic HCV and HIV-1 co-infection results in a net increase in HCV burden; higher prevalence rates of HCV transmission to sexual partners and offspring, as well as an accelerated progression to end stage liver disease as compared to individuals with HCV infection alone. Thus, the synergistic effects of alcohol abuse and HIV-1 greatly impact on the morbidity and mortality for patients with HCV coinfection. Ultimately, this cumulative disease process will require far more aggressive management with abstinence and counseling for alcohol abuse; highly active antiretroviral therapy (HAART) for HIV infection and combination anti-viral therapy for HCV infection to stem the rapid progression to end stage liver disease.