Browsing by Author "Antunes, F"
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- Baseline Susceptibility of Primary HIV-2 to Entry InhibitorsPublication . Borrego, P; Calado, R; Marcelino, JM; Bártolo, I; Rocha, C; Cavaco-Silva, P; Doroana, M; Antunes, F; Maltez, F; Caixas, U; Barroso, H; Taveira, NBACKGROUND: The baseline susceptibility of primary HIV-2 to maraviroc (MVC) and other entry inhibitors is currently unknown. METHODS: The susceptibility of 19 HIV-2 isolates obtained from asymptomatic and AIDS patients and seven HIV-1 clinical isolates to the fusion inhibitors enfuvirtide (ENF) and T-1249, and to the coreceptor antagonists AMD3100, TAK-779 and MVC, was measured using a TZM-bl cell-based assay. The 50% inhibitory concentration (IC(50)), 90% inhibitory concentration (IC(90)) and dose-response curve slopes were determined for each drug. RESULTS: ENF and T-1249 were significantly less active on HIV-2 than on HIV-1 (211- and 2-fold, respectively). AMD3100 and TAK-779 inhibited HIV-2 and HIV-1 CXCR4 tropic (X4) and CCR5 tropic (R5) variants with similar IC(50) and IC(90) values. MVC, however, inhibited the replication of R5 HIV-2 variants with significantly higher IC(90) values (42.7 versus 9.7 nM; P<0.0001) and lower slope values (0.7 versus 1.3; P<0.0001) than HIV-1. HIV-2 R5 variants derived from AIDS patients were significantly less sensitive to MVC than variants from asymptomatic patients, this being inversely correlated with the absolute number of CD4(+) T-cells. CONCLUSIONS: T-1249 is a potent inhibitor of HIV-2 replication indicating that new fusion inhibitors might be useful to treat HIV-2 infection. Coreceptor antagonists TAK-779 and AMD3100 are also potent inhibitors of HIV-2 replication. The reduced sensitivity of R5 variants to MVC, especially in severely immunodeficient patients, indicates that the treatment of HIV-2-infected patients with MVC might require higher dosages than those used in HIV-1 patients, and should be adjusted to the disease stage.
- Multicentre Study Highlighting Clinical Relevance of New High-Throughput Methodologies in Molecular Epidemiology of Pneumocystis Jirovecii PneumoniaPublication . Esteves, F; de Sousa, B; Calderón, EJ; Huang, L; Badura, R; Maltez, F; Bassat, Q; de Armas, Y; Antunes, F; Matos, OPneumocystis jirovecii causes severe interstitial pneumonia (PcP) in immunosuppressed patients. This multicentre study assessed the distribution frequencies of epidemiologically relevant genetic markers of P. jirovecii in different geographic populations from Portugal, the USA, Spain, Cuba and Mozambique, and the relationship between the molecular data and the geographical and clinical information, based on a multifactorial approach. The high-throughput typing strategy for P. jirovecii characterization consisted of DNA pooling using quantitative real-time PCR followed by multiplex-PCR/single base extension. The frequencies of relevant P. jirovecii single nucleotide polymorphisms (mt85, SOD110, SOD215, DHFR312, DHPS165 and DHPS171) encoded at four loci were estimated in ten DNA pooled samples representing a total of 182 individual samples. Putative multilocus genotypes of P. jirovecii were shown to be clustered due to geographic differences but were also dependent on clinical characteristics of the populations studied. The haplotype DHFR312T/SOD110C/SOD215T was associated with severe AIDS-related PcP and high P. jirovecii burdens. The frequencies of this genetic variant of P. jirovecii were significantly higher in patients with AIDS-related PcP from Portugal and the USA than in the colonized patients from Portugal, and Spain, and children infected with P. jirovecii from Cuba or Mozambique, highlighting the importance of this haplotype, apparently associated with the severity of the disease and specific clinical groups. Patients from the USA and Mozambique showed higher rates of DHPS mutants, which may suggest the circulation of P. jirovecii organisms potentially related with trimethoprim-sulfamethoxazole resistance in those geographical regions. This report assessed the worldwide distribution of P. jirovecii haplotypes and their epidemiological impact in distinct geographic and clinical populations.
- The Role of the Humoral Immune Response in the Molecular Evolution of the Envelope C2, V3 and C3 Regions in Chronically HIV-2 Infected PatientsPublication . Borrego, P; Marcelino, JM; Rocha, C; Doroana, M; Antunes, F; Maltez, F; Gomes, P; Novo, C; Barroso, H; Taveira, NBACKGROUND: This study was designed to investigate, for the first time, the short-term molecular evolution of the HIV-2 C2, V3 and C3 envelope regions and its association with the immune response. Clonal sequences of the env C2V3C3 region were obtained from a cohort of eighteen HIV-2 chronically infected patients followed prospectively during 2-4 years. Genetic diversity, divergence, positive selection and glycosylation in the C2V3C3 region were analysed as a function of the number of CD4+ T cells and the anti-C2V3C3 IgG and IgA antibody reactivity RESULTS: The mean intra-host nucleotide diversity was 2.1% (SD, 1.1%), increasing along the course of infection in most patients. Diversity at the amino acid level was significantly lower for the V3 region and higher for the C2 region. The average divergence rate was 0.014 substitutions/site/year, which is similar to that reported in chronic HIV-1 infection. The number and position of positively selected sites was highly variable, except for codons 267 and 270 in C2 that were under strong and persistent positive selection in most patients. N-glycosylation sites located in C2 and V3 were conserved in all patients along the course of infection. Intra-host variation of C2V3C3-specific IgG response over time was inversely associated with the variation in nucleotide and amino acid diversity of the C2V3C3 region. Variation of the C2V3C3-specific IgA response was inversely associated with variation in the number of N-glycosylation sites. CONCLUSION: The evolutionary dynamics of HIV-2 envelope during chronic aviremic infection is similar to HIV-1 implying that the virus should be actively replicating in cellular compartments. Convergent evolution of N-glycosylation in C2 and V3, and the limited diversification of V3, indicates that there are important functional constraints to the potential diversity of the HIV-2 envelope. C2V3C3-specific IgG antibodies are effective at reducing viral population size limiting the number of virus escape mutants. The C3 region seems to be a target for IgA antibodies and increasing N-linked glycosylation may prevent HIV-2 envelope recognition by these antibodies. Our results provide new insights into the biology of HIV-2 and its relation with the human host and may have important implications for vaccine design.
- Tuberculose Multirresistente por Estirpes da Família Beijing, em Doentes de Lisboa, Portugal: Estudo PreliminarPublication . Maltez, F; Martins, T; Póvoas, D; Cabo, J; Peres, H; Antunes, F; Perdigão, J; Portugal, IIntrodução: As estirpes de Mycobacterium tuberculosis da família Beijing estão associadas à multirresistência. As estirpes da família Lisboa prevalecem entre os doentes com tuberculose multirresistente e extensivamente resistente desta região, mas vários estudos documentam a presença da família Beijing, embora desconhecendo-se as características dos doentes donde foram isoladas. Material e Métodos: Estudo retrospectivo de 104 estirpes multirresistentes e extensivamente resistentes de Mycobacterium tuberculosis, isoladas e genotipadas, de 1993 a 2015, de igual número de doentes de Lisboa. Avaliámos a prevalência de ambas as famílias de estirpes e as características epidemiológicas e clínicas, dos infectados por estirpes Beijing. Resultados: Setenta e quatro estirpes (71,2%) pertenciam à família Lisboa, 25 (24,0%) apresentavam padrão genotípico único e cinco (4,8%) pertenciam à família Beijing, estas identificadas depois de 2009. Os infectados pela estirpe Beijing eram de nacionalidade angolana (n = 1), ucraniana (n = 2) e portuguesa (n = 2), na maioria jovens, quatro em cinco imunocompetentes e sem história de tuberculose anterior. Todos tinham tuberculose multirresistente. Não detectámos apresentações clínicas ou radiológicas diferenciadoras, nem padrão de resistências predominante. A taxa de cura foi alta (quatro doentes). Discussão: Apesar do número de doentes infectados pela estirpe Beijing ser reduzido, sugere proporção importante de tuberculose primária, potencial de transmissão na comunidade, mas, também, melhor evolução clínica do que a descrita para outras estirpes, como a W-Beijing ou a Lisboa. Conclusão: Apesar das estirpes da família Lisboa serem as principais responsáveis pelos casos de tuberculose multirresistente e extensivamente resistente na região de Lisboa, as estirpes Beijing transmitem-se na cidade e poderão modificar as características locais da epidemia.