RESUMO
The aim of this study was to determine HIV-1 V3 sequences, in vitro biological characteristics and co-receptor usage of virus isolates from Tanzania. Virus was isolated from 14 of 17 samples investigated. Four of the isolates induced syncytia in MT-2 cells and used the CXCR4 co-receptor, while the remaining 10 isolates used the CCR5 co-receptor characteristic of non-MT-2 tropic viruses. One of the four MT-2 tropic isolates also used the CCR5 and CCR3 co-receptors. Proviral DNA was detected in all 14 isolates and PCR products were subjected to DNA sequencing. Unambiguous V3 amino acid sequences were obtained from 11 amplificates. Phylogenetic analysis indicated that these sequences were divergent and clustered in HIV-1 subtypes A, C or D. Sequences from the viruses that induced syncytia in MT-2 cells presented characteristic V3 phenotype-associated amino acids. Results of co-receptor analysis are in concordance with the isolate phenotype as determined by replication and induction of syncytia in MT-2 cells. The considerable diversity illustrated by a limited number of isolates from Tanzania is in accordance with reports from other regions of Africa.
Assuntos
Proteína gp120 do Envelope de HIV/genética , Infecções por HIV/virologia , HIV-1/genética , Fragmentos de Peptídeos/genética , Receptores CXCR4/metabolismo , Adolescente , Adulto , Sequência de Aminoácidos , Animais , Efeito Citopatogênico Viral , DNA Viral/genética , DNA Viral/isolamento & purificação , Variação Genética , Células Gigantes/virologia , Proteína gp120 do Envelope de HIV/metabolismo , HIV-1/classificação , HIV-1/isolamento & purificação , Humanos , Pessoa de Meia-Idade , Dados de Sequência Molecular , Pan troglodytes/virologia , Fragmentos de Peptídeos/metabolismo , Fenótipo , Filogenia , Reação em Cadeia da Polimerase , Provírus/genética , Provírus/isolamento & purificação , Receptores CCR5/genética , Receptores CCR5/metabolismo , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , TanzâniaRESUMO
The biological properties and amino acid sequences of the third variable domain (V3 loop and flanking regions) of the env region of 34 HIV-1 isolates obtained from Romanian children were analyzed. Unambiguous nucleic acid sequences were obtained from 31 isolates. The derived V3 amino acid sequences were highly homologous (93-100%) and clustered with the HIV-1 subtype F Romanian consensus. Five of the 31 isolates presented a syncytium-inducing phenotype in MT-2 cells and established continuous viral replication in various CD4+ cell lines (rapid/high phenotype). The V3 sequence from one of these isolates showed a slightly lesser degree of homology with the consensus sequence. The presence of positively charged amino acids at positions 306 and 320 has been strongly associated with the ability to induce syncytia in MT-2 cells, whereas negatively or uncharged amino acids at these positions are present in non-syncytium-inducing isolates (slow/low phenotype). There was, however, no correlation between phenotype and amino acid sequence in the five syncytium-inducing isolates; negatively or uncharged amino acids were conserved at positions 306 and 320 for all 31 isolates in sequences obtained from PBMCs. A tendency toward a more positive net charge in the V3 loop of syncytium-inducing isolates was noted. These data confirm the recent observations that HIV-1 isolates from Romania not only cluster in subtype F, but also show a high degree of interpatient homogeneity in the V3 region.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Proteína gp120 do Envelope de HIV/genética , Soropositividade para HIV/virologia , HIV-1/fisiologia , Fragmentos de Peptídeos/genética , Sequência de Aminoácidos , Sequência de Bases , Linhagem Celular , Criança , Pré-Escolar , DNA Viral , Células Gigantes/virologia , Soropositividade para HIV/sangue , HIV-1/genética , HIV-1/isolamento & purificação , Humanos , Dados de Sequência Molecular , Filogenia , Romênia , Homologia de Sequência de AminoácidosRESUMO
Sera from 250 patients admitted to Muhimbili hospital in Dar es Salaam; Tanzania; with viral hepatitis were examined for hepatitis B virus surface antigen (HBsAg); antibodies to hepatitis D (delta) virus; antibodies to hepatitis B virus core and for antibodies to hepatitis A virus; The latter two of the IgM class. Using the ELISA technique; 102 (40.8 percent) of the cases were verified as acute hepatitis B and 16 (6.4 percent) as acute hepatitis A. The aetiology of the remaining 131 (52 percent) of the patients could not be established and was due to either non-A; non-B viruses or other viruses. Only one of the HBsAg positive patients had antibodies to the hepatitis D virus. the results show the necessity of testing for markers of acute hepatitis infection (specific Igm) when acute hepatitis is diagnosed in a community where hepatitis B is endemic
RESUMO
A total of 542 serum samples from healthy adults (medical students and medical staff, blood donors and pregnant women) residing in or near the city of Dar es Salaam, Tanzania were examined for markers of hepatitis B virus (HBV) infection. Of these samples, 95 (17.5%) were not found to contain any HBV marker when examined by enzyme-linked immunoassay for hepatitis B surface antigen (HBsAg), antibody to hepatitis B surface antigen (anti-HBs) and antibody to hepatitis B core antigen (anti-HBc). HBsAg was demonstrated in 52 (9.6%) samples of which 7 (13.5%) were positive for hepatitis Be antigen (HBeAg) and 17 (32.7%) were positive for anti-HBc IgM. None of 9 HBsAg positive pregnant women were carriers of HBeAg. These results show that hepatitis B infection is very common in this country. The relatively low prevalence of HBeAg among HBsAg carriers may indicate that transmission of hepatitis B at birth is not of major importance.
