The influence of HLA/HIV genetics on the occurrence of elite controllers and a need for therapeutics geotargeting view

The interaction of HIV-1, human leukocyte antigen (HLA), and elite controllers (EC) compose a still intricate triad. Elite controllers maintain a very low viral load and a normal CD4 count, even without antiretrovirals. There is a lot of diversity in HIV subtypes and HLA alleles. The most common subtype in each country varies depending on its localization and epidemiological history. As we know EC appears to maintain an effective CD8 response against HIV. In this phenomenon, some alleles of HLAs are associated with a slow progression of HIV infection, others with a rapid progression. This relationship also depends on the virus subtype. Epitopes of Gag protein-restricted by HLA-B*57 generated a considerable immune response in EC. However, some mutations allow HIV to escape the CD8 response, while others do not. HLA protective alleles, like HLA-B*27, HLA-B*57 and HLA-B*58:01, that are common in Caucasians infected with HIV-1 Clade B, do not show the same protection in sub-Saharan Africans infected by HIV-1 Clade C. Endogenous pathway of antigen processing and presentation is used to present intracellular synthesized cellular peptides as well as viral protein fragments via the MHC class I molecule to the cytotoxic T-lymphocytes (CTLs). Some epitopes are immunodominant, which means that they drive the immune reaction to some virus. Mutation on an anchor residue of epitope necessary for binding on MHC class I is used by HIV to escape the immune system. Mutations inside or flanking an epitope may lead to T cell lack of recognition and CTL escape. Studying how immunodominance at epitopes drives the EC in a geographically dependent way with genetics and immunological elements orchestrating it may help future research on vaccines or immunotherapy for HIV. 2021 Sociedade Brasileira de Infectologia. Published by Elsevier España, S.L.U. This is an open access article under the CC BY-NC-ND license

Construction and identification of HSV-1 vector vaccine carrying HIV-1 antigen / 生物工程学报

To construct an HSV-1 vector vaccine carrying HIV-1 antigens, HIV-1 gp160, gag, protease and the expression elements were chained together, and then inserted into the internal inverted repeat sequence region of HSV-1 by bacterial artificial chromosome technology. Firstly, HIV-1 gp160 (including type B and C), gag and protease genes were cloned into pcDNA3 in series to generate the pcDNA/gBgp and pcDNA/gCgp, then the recombinant plasmids were transfected into 293FT cells, and HIV-1 antigen was detected from transfected cells by Western blotting. Then the expression cassettes from pcDNA/gBgp and pcDNA/gCgp, comprising HIV-1 antigen genes and expression elements, were cloned into pKO5/BN to generate the shuttle plasmids pKO5/BN/gBgp and pKO5/BN/gCgp. The shuttle plasmids were electroporated into E. coli cells that harbor an HSV-BAC, the recombinant bacteria were screened, and the recombinant DNA was extracted and transfected into Vero cells. The recombinant virus was purified through picking plaques, the virus' DNAs were identified by Southern blotting; HIV-1 antigen was detected from the recombinant HSV-1 infected cells by Western blotting, and the virus' replication competent was analyzed. As the results, gp160 and gag proteins were detected from 293FT cells transfected with pcDNA/gBgp and pcDNA/gCgp by Western blotting. The recombinant bacteria were generated from the E. coli electroporated with pKO5/BN/gBgp or pKO5/BN/gCgp. The recombinant HSV was purified from the Vero cells transfected with the recombinant DNA, the unique DNA fragment was detected from the genome of recombination HSV by Southern blotting; gp120 and gp41 were detected from the infected cells by Western blotting, and the recombinant HSV retained replication competent in mammalian cells. The results indicate that the recombinant HSV carrying HIV-1 gp160, gag and protease genes was generated, the virus retains replication competent in mammalian cells, and could be used as a replicated viral vector vaccine.

Subtype and sequence analysis of the gag genes for HIV-1 strains isolated in Hubei province / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To investigate the characteristic of subtypes and genetic diversity of HIV-1 circulating in Hubei province and its molecular epidemiological linkages with regard to risk factors of viral transmission.</p><p><b>METHODS</b>plasma samples of 80 diagnosed individuals was characterized. The gene fragments of gag were amplified by reverse transcriptase polymerase chain reaction (RT-PCR) and HIV-1 genotypes were determined based on the nucleotide sequences of gag region.</p><p><b>RESULTS</b>Seven HIV-1 group M subtypes or CRF including B, B', G, CRF01-AE, CRF07-BC, CRF08-BC and CRF15-01B were identified. CRF01-AE was found to be the most dominant subtype (48.4%) followed by CRF7-BC (22.6%) and B' (12.9%).</p><p><b>CONCLUSION</b>The data from this study indicate the existence of multiple HIV-1 subtypes or CRFs in Hubei province and the surveillance of HIV-1 gene variation should be paid more attention to.</p>

Subtype and sequence analysis of gag gene of HIV-1 among men who have sex with men in Zhengzhou, Henan Province / 病毒学报

To investigate the subtype distribution of human immunodeficiency virus-1(HIV-1) infection among men who have sex with men (MSM) in Zhengzhou, Henan Province, forty blood samples were collected from HIV-1 carriers, who acknowledged to have sex with men. The complete gag gene was amplified by RT-PCR and nested-PCR and sequenced. All sequences were edited by BioEdit and subtyped by genotyping software. Phylogenetic analysis of gag gene were then performed using the MEGA 3.1 software, the gene distances were calculated by Distance program. There were three different HIV-1 subtypes including B, CRF01-AE and CRF07-BC present among twenty four MSMs in Zhengzhou. Genotyping results showed that 33.33% (8/24) were B, 41.67% (10/24) were CRF01-AE and 25% (6/24) were CRF07-BC, and subtype CRF01-AE had become the most prevalent HIV-1 subtype in Zhengzhou, Henan province. In conclusion, recombinant HIV-1 strains are circulating in Henan province and the epidemiology is complicated.

Analyses on antigen epitopes and drug resistance mutations of HIV-1 gag and pol genes / 病毒学报

To study the CTL antigen epitopes and drug resistance mutations of HIV-1 gag and pol genes through analyzing gag and pol gene sequences. The HIV-1 gag and pol gene fragments were amplified using nested polymerase chain reaction. A total of 23 PCR sequences, 449 cloned gag sequences and 402 cloned pol sequences were obtained. Sequence analyses showed the 23 samples were subtype B or B'. A total of 4 in 8 CTL antigen epitopes appeared 8 mutations in consensus sequence of subtype B and B'. There were no mutations found in the PCR sequences, whereas a few mutations were found in clone sequences (9.80%) in 5 antigen epitopes in p24 region. Eighteen PIs-related mutations and 24 RTIs-related mutations were found in PCR sequences and clone sequences in pol gene region, in which 17 (94.44%) PIs-related mutations and 15 (62.50%) RTIs-related mutations were found only in the clone sequences, respectively. The results showed that the prevalence of HIV-1 drug resistance strains in this study was at a higher level (17.39%), suggesting that some samples were resistant.to existing antiviral drugs.

Anti-adenovirus neutralizing antibodies and Gag-specific cellular immune responses in Macaca fascicularis immunized with Ad5-HIVgag / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To observe the level of anti-adenovirus neutralizing antibodies and Gag specific cellular immune responses in Macaca fascicularis immunized with different dosage of recombinant adenovirus vaccine Ad5-HIVgag by repeated intramuscular injection.</p><p><b>METHODS</b>The Macaca fascicularis were randomly divided into four groups of 6. Different amount of the purified Ad5-HIVgag (0.99 x 10(11) VP, 4.94 x 10(11) VP, 24.68 x 10(11) VP) or PBS were administered in 3 weeks interval and five times. The level of anti-adenovirus neutralizing antibodies and Gag-specific cellular immune responses at different time points were detected by neutralization assay and Elispot assay respectively.</p><p><b>RESULTS</b>High level of anti-adenovirus neutralizing antibodies could be detected in three groups immunized with Ad5-HIVgag at 3 weeks after first immunization. The neutralizing antibodies reached peak at 8 weeks after primary immunization, and declined slightly at late time. Significant HIV-1 Gag-specific cellular immune responses were detected in all Ad5-HIVgag immunized groups at 5 weeks post first immunization. The Gag-specific cellular immune responses declined at 12 weeks and then increased with time.</p><p><b>CONCLUSION</b>Anti-adenovirus neutralizing antibodies could be induced in Macaca fascicularis immunized with Ad5-HIVgag by repeated intramuscular injection. And the Gag-specific cellular immune responses tended to increase with the injection times. The presence of anti-adenovirus neutralizing antibodies induced by vaccination with adenovirus vectors in Ad5-naive animals did not further reduce Gag-specific cellular immune responses.</p>

The role of structural protein Gag and related gene (protein) in late stages of the HIV-1 replication cycle and the inhibitors / 药学学报

The late stages of the HIV-1 replication cycle are important to the overall replication cycle. During the late stages, HIV-1 replication undergoes the processes of assembly, release, and maturation, resulting in the production of a mature virus particle capable of infecting a new target cell. The structural protein Gag and its related gene (protein) play a central role in these pathways. The different regions of Gag worked in concert to drive production of a mature infectious particle through protein-protein, protein-RNA and protein-lipid interactions. The designed drug aimed directly at these stages can efficiently block the maturation and infectivity of HIV-1. In this article, the role of structural protein Gag and related gene (protein) in late stages of the HIV-1 replication cycle and related inhibitors is reviewed.

Establishment and application of a high-throughput screening assay for premature activation of HIV-1 precursors / 药学学报

Strict regulation of HIV-1 PR function is critical for efficient production of mature viral particles. During viral protein expression and viral assembly, HIV-1 PR located within Gag-Pol precursor must be inactive to prevent premature cytoplasmic processing of the viral Gag and Gag-Pol precursors. Premature activation of HIV-1 precursors leads to major defects in viral assembly and production of viral particles. A cell-level premature activation of HIV-1 precursors assay using bioluminescence resonance energy transfer (BRET) was established. Three thousand compounds were screened to evaluate this assay. The results showed that the assay is sensitive, specific and stable (Z' factor is 0.905).

High genetic diversity in human immunodeficiency virus: type 1 in Jamaica / Elevada diversidad genética del virus de la inmunodeficiencia humana: tipo 1 en Jamaica

The subtypes of the human immunodeficiency virus - type 1 (HIV-1) strains from 54 HIV-1 - infected persons including 44 strains which were typed previously by heteroduplex mobility assay (HMA) were determined by DNA sequencing and phylogenetic analysis. Of 54 HIV- infected persons, 92.5% were infected with HIV-1 subtype B and 7.5% with other HIV-1 subtypes including subtypes D (3.7%), A (1.9%) and J (1.9%). In the phylogenetic analysis, the subtype A virus found in the sample clustered with subtype A reference strains and a circulating recombinant form (CRF) reference strain which originates in Central Africa and is circulating in Cuba indicating a close relationship between these viruses. There was 86% concordance between HMA and DNA sequencing in assigning subtype B viruses. For the non-B subtype viruses, there was less concordance between the two methods (67%). The results confirm the predominance of HIV-1 subtype B strains and the high genetic diversity of HIV-1 strains in circulation in Jamaica. The efficacies and some limitations of the HMA as a method of HIV-1 subtyping also were noted. It is important that the HIV/AIDS epidemic in Jamaica be monitored meticulously for possible expansions in non-B subtypes and the emergence of inter-subtype recombinant forms. We recommend that the more expensive DNA sequencing and phylogenetic analysis, including HIV-1 genotyping for antiretroviral drug resistance testing, be used as an adjunct to the more cost-effective HMA to track the HIV/AIDS epidemic in Jamaica.

Los subtipos de cepas de virus de la inmunodeficiencia humana-tipo-1 de 54 personas infectadas con el VIH-1, que incluyeron 44 cepas previamente clasificadas según su tipo mediante ensayo de movilidad de heterodúplex (HMA), fueron determinados mediante secuenciación de ADN y análisis filogenético. De 54 personas infectados con VIH, 92.5% estaban infectadas con VIH-1 subtipo B y 7.5% con otros subtipos de VIH-1 incluidos los subtipos D (3.7%), A (1.9%), J (1.9%). En el análisis filogenético, el virus de subtipo A hallado en la muestra, se agrupa con las cepas de referencias del subtipo A y una cepa de referencia de forma recombinante circulante (CRF), que tienesu origen en África Central y está circulando en Cuba, lo que indica una estrecha relación entre estos virus. Hubo un 86% de concordancia entre el HMA y la secuenciación del DNA en la asignación de virus de subtipo B. Para los virus de subtipo no B, hubo menos concordancia entre los dos métodos (67%). Los resultados confirman el predominio de las cepas del subtipo B del VIH-1, y la alta diversidad genética de las cepas del VIH-1 en circulación en Jamaica. También se señalaron las eficacias y algunas limitaciones del HMA como método de clasificación del VIH-1 en subtipos. Es importante monitorear meticulosamente la epidemia de VIH/SIDA en Jamaica, a fin de detectar posibles expansiones de subtipos no B y la aparición de formas recombinantes inter-subtipos. Recomendamos que por ser ambos métodos más costosos, tanto la secuenciación de ADN como el análisis filogenético - incluyendo el genotipado del VIH-1 para probar la resistencia antiretroviral del medicamento - sean usados como complementos del HMA, el cual es más costo-efectivo, para seguir de cerca el rastro de la epidemia VIH/SIDA en Jamaica.

Comparison of the immnunogenicity of rAAV2/1 and rAd5 rad5 expressing HIV-1 gag / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To compare the immunogenicity of rAAV2/1 and rAd5 expressing HIV-1 gag in BALB/c mice.</p><p><b>METHODS</b>BALB/c mice were immunized with rAAV2/1-gag or rAd5-gag once or twice. HIV-1 specific cellular immune responses were analyzed by in vivo CTL and intracellular cytokine staining assays. HIV-1 Gag specific antibodies were tested by ELISA.</p><p><b>RESULTS</b>Mice immunized with rAd5-gag once induced stronger Gag specific cellular immune responses and similar level of Gag specific antibody compared with rAAV2/1-gag. Mice immunized with rAd5-gag reached the peak immune responses more rapidly than rAAV2/1-gag. However, mice immunized with rAAV2/1-gag twice elicited better Gag specific IgG.</p><p><b>CONCLUSION</b>rAd5-gag induced strong HIV-1 specific cellular and antibody responses, and rAAV2/1-gag induced high level of HIV-1 specific IgG and moderate cellular immune responses.</p>

Genetic variation of gag gene in HIV-1 subtype B infections from Henan and Shanxi provinces of China / 病毒学报

The 109 whole blood samples were collected from HIV-1 infected former blood donors in Henan and Shanxi. The RNA templates were extracted from plasma and used for the full gag gene amplification and sequencing. The sequences were divided into 3 groups according to sampling year. The Entropy software was used to identify the amino acids with composition difference among different groups of amino acid sequences. The results showed that there existed 8 and 13 amino acid sites with the statistical significance difference, respectively, in sequences in year 2004 and 2005, compared to those in 2002. Among them, there existed 5 amino acid sites in two groups. Of 16 amino acid sites, the increasing polymorphism and the decreasing polymorphism along the sampling year were observed in 10 and 6 amino acid sites respectively. Of 10 sites with increased polymorphism, 8 sites were located in the CTL epitopes recognized and presented by the main HLA alleles existed in Chinese population. The 6 sites with decreasing polymorphism all existed in main domains of Gag proteins.

Study of Gag gene antigen epitypes variation and the quasispecies group characteristics in Henan area HIV-1 strains / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To study the characteristics of the variation of antigen epitopes and quasispecies group in the HIV-1 viruses in Henan province in China.</p><p><b>METHODS</b>The region of the p17-p24 of the HIV-1 gag gene was amplified by nested polymerse chain reaction (PCR), purified products were cloned into the vector, the obtained were analyzed by MEGA soft wares.</p><p><b>RESULTS</b>B' subtype strains were predominant in Henan province, the mutations in antigen epitypes of the p17 region of the gag gene focus on E62g (55.8%), Y79f (48.9%), T84V (48.9), I44V (44.2%), the p24 region had not found the distinct mutation.</p><p><b>CONCLUSION</b>Both the PCR sequences and clone strains sequences demonstrated that four antigen epitopes mutations in p17 region of the HIV B' subtype gag gene, and the region of p24 was more conservative, which was suitable for development of the epitope vaccien.</p>

A mouse model based on replication-competent Tiantan vaccinia expressing luciferase/HIV-1 Gag fusion protein for the evaluation of protective efficacy of HIV vaccine / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Developing an effective vaccine against human immunodeficiency virus type 1 (HIV-1) remains a grand challenge after more than two decades of intensive effort. It is partially due to the lack of suitable animal models for screening and prioritizing vaccine candidates. In this study, we aim to develop a mice model to test HIV-1 vaccine efficacy.</p><p><b>METHODS</b>We constructed a recombinant vaccinia expressing firefly luciferase and HIV-1 Gag fusion protein based on Tiantan strain, an attenuated but replication-competent poxvirus (rTTV-lucgag). By quantifying the luciferase activity as its read out, we defined the biodistribution of Tiantan strain poxvirus in mice inoculated intraperitoneally and attempted to apply this model to evaluate the HIV-1 vaccine efficacy.</p><p><b>RESULTS</b>Our data demonstrated that the rTTV-lucgag was able to express high level of luciferase (< or = 10(6) relative luciferase units (RLU)/mg protein) and HIV-1 Gag (> 3 folds increase comparing to the control). After intraperitoneal inoculation, this virus had dominant replication in the ovary, uterus, and cervix of mice and the luciferase activities in those organs are significantly correlated with viral titers (r(2) = 0.71, P < 0.01). Pre-immunization with an HIV gag DNA vaccine reduced the luciferase activity in ovary from (6006 +/- 3141) RLU/mg protein in control group to (1538 +/- 463) RLU/mg protein in vaccine group (P = 0.1969).</p><p><b>CONCLUSIONS</b>The luciferase activity in ovary could represent viral replication in vivo; this rTTV-lucgag/mice model may be suitable to assess the protective efficacy of cytotoxic T-cell responses to HIV Gag with less tedious work and high through-put.</p>

Subtype and sequence analysis of gag genes among HIV-1 strains circulating in Beijing during 2007 / 病毒学报

To investigate the subtype distribution and sequence characteristics of HIV-1 strains prevalent in Beijing during 2007 and to analyze the relationship between distribution of HIV-1 subtypes and transmission routes, we collected the anti-conglutinated whole blood samples from HIV-1 newly infected individuals in Beijing during 2007 and separated plasma specimens from the aamples. RNAs were extracted and the gag genes from the various samples were amplified by RT-PCR and nest-PCR. The PCR products were sequenced directly and phylogenetic analyses of gag genes were performed using the MEGA2 software. Among 200 HIV-1 plasma samples,161 gag HIV-1 gene fragments were amplified and analyzed. Seven HIV-1 subtypes or circulating recombinant forms (CRFs) of HIV-1 including A1 (1 strains), B (35 strains), Thai B (19 strains), C (3 strains), CRF01_AE (49 strains), CRF07_BC (51 strains), CRF08_BC (3 strain) were identified circulating in Beijing. The gene divergences inside the subtypes were different, with 7.7%, 6.5%, 6.7%, 6.7%, 5.5%, 4.3%, 5.8%, in subtype A1, B, Thai B, C, CRF01_AE, CRF07_BC, CRF08_BC, respectively. Subtypes CRF07_BC and CRF01_AE were predominant in Beijing account for 31.7% and 30.4% among samples. Seven HIV-1 subtypes exist in Beijing and the surveillance of HIV-1 gene variation should be paid more attention.

The action of TSG101 on HIV-1 budding and related inhibitors / 药学学报

tsg101 gene is a newly found tumor suppressor gene whose product TSG101 has many important biological functions. Recent research of TSG101 has revealed that TSG101 aids HIV-1 budding from infected cells by attaching to Gag. HIV-1 budding is arrested in the cells with mutant TSG101 or without TSG101. So TSG101 would be a useful target for anti-HIV drug design. Now there is already some research on anti-HIV agents based on TSG101 structure. In this article the structure and function of TSG101 as well as the related inhibitors were reviewed.

Optimization of induction and purification of HIV-1 Gag protein in Escherichia coli expression system / 生物工程学报

To investigate the effects of induction temperature on the expression product and the impact of urea concentration on the purification, HIV-1 Gag inclusion bodies from E. coli induced at 30 degrees C (IB30) and 37 degrees C (IB37) were dissolved with urea of different concentrations. The solubility and yield of refolding were compared. IB30 were dissolved with 2 mol/L and 8 mol/L urea, and then purified with chromatography. IB30 were found easier to be solubilized in low concentration of urea and easier to be refolded than IB37. Furthermore, compared to the IB30 dissolved in 8 mol/L urea, Gag protein solubilized in 2 mol/L urea was purified to higher purity with gel filtration (GF) and ion exchange (IEX) chromatography. Gag inclusion body induced at lower temperature may contain more protein with native-like or reversibly-denatured structures, and solubilization in the presence of low concentrations of urea can help to retain these structures. This study has provided new insights into the purification of proteins from inclusion bodies.

Association between sequence variation of Env, Gag genes from the same source and HIV-1 disease progression and host genetic polymorphism / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To understand the relationship between the HIV-1 viral sequence variation and host factors associated with HIV-1 disease progression.</p><p><b>METHODS</b>Env and gag fragments of HIV-1 were amplified with PCR, cloned and sequenced. Bioinformatics was employed to find the genetic variation, N-linked glycosylation, hypermutation etc. Host gene polymorphism was analysed by using restricted fragment length polymorphism (RFLP).</p><p><b>RESULTS</b>Significant difference was found in genetic divergence between Env PCR dominant and clonal sequences (0.1 and 0.06, respectively) in non-treated group, but no significant difference was found in the HAART treated group. V3 GPGQ accounted for the most part in both treated and nontreated groups, rare V3 loop such as GPGH, GQGR and GLGR was found in treated group, V3 substitutions of I/V (position 12) and Y/H (position 21) was associated with the relatively rapid progression (RRP). Glycosylation was significantly higher in RRP than in TP for Env region, GA substitution in RRP was also significantly higher than that in TP group. SDF1-3primeA and CCR2 V64I gene frequency was higher in TP than in RRP, but the difference was not significant.</p><p><b>CONCLUSION</b>Disease progression was associated with V3 AA change, glycosylation and GA substitution in env gene. SDF1-3primeA, CCR2 V64I and CX3CR1 V249I/M280T was not associated with disease progression significantly.</p>

Subtype and sequence analysis of gag and env genes among HIV-1 strains circulating in Beijing residents during 2006 / 中华流行病学杂志

<p><b>OBJECTIVE</b>To investigate the subtype distribution and the prevalence of sequence characteristics of HIV-1 strains in Beijing residents during 2006 and to analyze the relationship between distribution of HIV-1 subtypes and transmission routines.</p><p><b>METHODS</b>Blood samples from 32 new confirmed HIV-1 infected individuals from Beijing residents in 2006 and separated plasma specimens were collected. RNAs were extracted and the gag and env gene were amplified by RT-PCR and nest-PCR. PCR products were sequenced directly and phylogenetic analyses of gag and env gene were performed using the MEGA2 software.</p><p><b>RESULTS</b>Among 32 HIV-1 plasma samples, 22 gag and 4 env gene fragments were amplified and analyzed. Five HIV-1 subtypes or circulating recombinant forms(CRFs) of HIV-1 including Thai B (2 strains), B (9 strains), C (2 strains), CRF07_BC (5 strains), CRF01 AE (4 strains) were identified being circulated in Beijing. The gene divergences of gag gene inside the subtypes were 6.6%, 4.3%, 6.8%, 4.9% and 3.0% in subtype B, Thai B, C, CRF01_AE and CRF07_BC respectively. Subtypes B were predominant in Beijing, accounted for 40.9% among 22 samples.</p><p><b>CONCLUSION</b>Five HIV-1 subtypes were identified in Beijing and the surveillance of HIV-1 gene variation should be paid more attention to.</p>

Antibody recognition of synthetic peptides mimicking immunodominant regions of HIV-1 p24 and p17 proteins / Reconocimiento por anticuerpos de péptidos sintéticos que imitan regiones inmunodominantes de las proteínas p24 y p17 de VIH-1

The gag gene of HIV-1 encodes a single open reading frame of 55 kDa that contains three subdomains: the matrix domain (p17), the capsid domain (p24) and the nucleocapsid domain (p15). The p24 and p17 proteins have a predominant a-helical structure and perform important functions throughout thevirallife-cycle. The determination of gag-specific antibodies is important because declining titers of these antibodies herald clinical deterioration.In this work we present the results obtained on immunoreactiviy of synthetic peptides that mimic immunogenic a-helical regions of p24 and p17. The influence on the immunoreactivity of structural modifications in native sequences, including the addition of non immunogenic side chains: AAAC- and -CAAA on both side of minimal epitopes was evaluated in indirect and competitive enzymeimmunoassays. The conformational characteristcs to the peptides were analysed by circular dichroism and these results were correlated with that obtained in the immunoassays. It was shown that the reactivity of peptides mimicking short a-helical regions of p24 and p17 is improved by adding short non immunogenic chains on both N- and C- terminus. These modifications enhanced the immobilization of the peptides onto the solid support and allowed more accesibility to the minimal epitopes byspecific antibodies, in solution.

El gen gag del VIH-1 codifica una región de 55kDA que contiene tres subdominios: matriz (p17), cápside (p24) y nucleocápside (p15). Las proteínas p24 y p17 tienen una estructura predominante helicoidal y cumplen un rol importante en el ciclo de vida del virus. En este trabajo presentamos los resultados de inmunorreactividad de péptidos sintéticos que imitan regiones helicoidales de p24 y p17. Utilizando enzimoinmunoensayos se evaluó la influencia de modificaciones en las secuencias nativas sobre la capacidad de reconocimiento de anticuerpos específicos en solución y en fase sólida, incluyendo el agregado de cadenas no inmunogénicas en ambos extremos de los epitopes mínimos. La conformación de los péptidos se determinó por dicroísmo circular y los resultados se correlacionaron con los de inmunorreactividad. Se observó que la capacidad de reconocimiento de anticuerpos por péptidos pequeños que imitan estructuras helicoidales de p24 y p17 mejoró con el agregado de cadenas no inmunogénicas en ambos extremos de los epitopes. Estas modificaciones mejoran la inmovilización sobre las superficies sólidas y permiten una mayor accesibilidad de los anticuerpos a los epitopes mínimos en solución.

A survey of children with HIV/AIDS in highly epidemic villages of AIDS / 中华儿科杂志

<p><b>OBJECTIVE</b>To estimate prevalence of HIV/AIDS among children and the transmission routes in a highly endemic villages of AIDS.</p><p><b>METHODS</b>Totally 208 high-risk women of child bearing age and 159 of their children aged 0 - 14 years were investigated. Their medical histories of blood donation or transfusion were collected, blood samples were taken and sera were separated for HIV test. Enzyme-linked immunosorbent assay (ELISA) and Western blot assay were performed for HIV antibody. The Nested-polymerase chain reaction (PCR) assay amplifying gag gene p17 was performed on samples of children aged less than 18 months.</p><p><b>RESULTS</b>Thirty-seven HIV infected cases were found among 159 children aged 0 - 14 years of whom 33 were infected by mother-to-child transmission (89.2%, 33/37), 3 by blood transfusion (8.1%, 3/37) and one by iatrogenic route (2.7%, 1/37). Sixty seven mothers who were seropositive for HIV and their 86 children who were born after 1992 were investigated, 33 cases of them were infected with HIV. The rate of vertical transmission was 38.4% (33/86). The HIV vertical transmission rate among mothers with AIDS (68.8%, 22/32) was significantly greater than that among mothers with asymptomatic HIV infection (20.4%, 11/54, P < 0.05). The number of children infected with HIV through vertical transmission increased from 1993 to 2001. Among 37 children infected with HIV, 12 cases developed AIDS and 4 of them died, of whom 2 cases died from tuberculosis. The morbidity of AIDS was 27.3% (9/33). Ninety three point nine percent (31/33) of infected mothers didn't know their HIV seropositive status before pregnancy and delivery. Of 8 pregnant women infected with HIV, one had aggravation of AIDS, 2 miscarried, 2 terminated their pregnancy and 3 continued their pregnancy.</p><p><b>CONCLUSION</b>Mother-to-child transmission of HIV was the major route of HIV/AIDS transmission to the children. The main reason leading to HIV infection in children was the lack of prenatal HIV counseling and testing for the high-risk women of childbearing age and lake of interventions. The countermeasures must be taken to control the further transmission of AIDS in order to protect the health of women and children in the highly endemic areas of AIDS.</p>