scholarly journals Molecular Epidemiology of Human Immunodeficiency Virus Type 1 Transmission in a Heterosexual Cohort of Discordant Couples in Zambia

2002 ◽  
Vol 76 (1) ◽  
pp. 397-405 ◽  
Author(s):  
Stanley A. Trask ◽  
Cynthia A. Derdeyn ◽  
Ulgen Fideli ◽  
Yalu Chen ◽  
Sreelatha Meleth ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Molecular Epidemiology ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Sub Saharan Africa ◽  
Immunodeficiency Virus ◽  
Discordant Couples ◽  
Sub Saharan ◽  
Hiv 1

ABSTRACT Most human immunodeficiency virus type 1 (HIV-1) transmissions in sub-Saharan Africa are believed to occur between married adults who are discordant for their HIV-1 infection status; however, no studies to date have investigated the molecular epidemiology of such transmission events. Here we report the genetic characterization of HIV-1 strains from 149 transmission pairs that were identified prospectively in a cohort of discordant couples in Lusaka, Zambia. Subgenomic gag, gp120, gp41, and/or long terminal repeat regions were amplified by PCR analysis of uncultured blood samples from both partners and sequenced without interim cloning. Pairwise genetic distances were calculated for the regions analyzed and compared to those of subtype-specific reference sequences as well as local controls. Sequence relationships were also examined by phylogenetic tree analysis. By these approaches, epidemiological linkage was established for the majority of transmission pairs. Viruses from 129 of the 149 couples (87%) were very closely related and clustered together in phylogenetic trees in a statistically highly significant manner. In contrast, viruses from 20 of the 149 couples (13%) were only distantly related in two independent genomic regions, thus ruling out transmission between the two partners. The great majority (95%) of transmitted viruses were of subtype C origin, although representatives of subtypes A, D, G, and J were also identified. There was no evidence for extensive transmission networks within the cohort, although two phylogenetic subclusters of viruses infecting two couples each were identified. Taken together, these data indicate that molecular epidemiological analyses of presumed transmission pairs are both feasible and required to determine behavioral, virological, and immunological correlates of heterosexual transmission in sub-Saharan Africa with a high level of accuracy.

scholarly journals CCR5- and CXCR4-Tropic Subtype C Human Immunodeficiency Virus Type 1 Isolates Have a Lower Level of Pathogenic Fitness than Other Dominant Group M Subtypes: Implications for the Epidemic

2009 ◽  
Vol 83 (11) ◽  
pp. 5592-5605 ◽  
Author(s):  
Awet Abraha ◽  
Immaculate L. Nankya ◽  
Richard Gibson ◽  
Korey Demers ◽  
Denis M. Tebit ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Ex Vivo ◽  
Sub Saharan Africa ◽  
Subtype C ◽  
Immunodeficiency Virus ◽  
Subtype A ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) subtype C is the dominant subtype globally, due largely to the incidence of subtype C infections in sub-Saharan Africa and east Asia. We compared the relative replicative fitness (ex vivo) of the major (M) group of HIV-1 subtypes A, B, C, D, and CRF01_AE and group O isolates. To estimate pathogenic fitness, pairwise competitions were performed between CCR5-tropic (R5) or CXCR4-tropic (X4) virus isolates in peripheral blood mononuclear cells (PBMC). A general fitness order was observed among 33 HIV-1 isolates; subtype B and D HIV-1 isolates were slightly more fit than the subtype A and dramatically more fit than the 12 subtype C isolates. All group M isolates were more fit (ex vivo) than the group O isolates. To estimate ex vivo transmission fitness, a subset of primary HIV-1 isolates were examined in primary human explants from penile, cervical, and rectal tissues. Only R5 isolates and no X4 HIV-1 isolates could replicate in these tissues, whereas the spread to PM1 cells was dependent on active replication and passive virus transfer. In tissue competition experiments, subtype C isolates could compete with and, in some cases, even win over subtype A and D isolates. However, when the migratory cells from infected tissues were mixed with a susceptible cell line, the subtype C isolates were outcompeted by other subtypes, as observed in experiments with PBMC. These findings suggest that subtype C HIV-1 isolates might have equal transmission fitness but reduced pathogenic fitness relative to other group M HIV-1 isolates.

scholarly journals High Levels of Human Immunodeficiency Virus Type 1 in Blood and Semen of Seropositive Men in Sub‐Saharan Africa

1998 ◽  
Vol 177 (6) ◽  
pp. 1742-1746 ◽  
Author(s):  
John R. Dyer ◽  
Peter Kazembe ◽  
Pietro L. Vernazza ◽  
Bruce L. Gilliam ◽  
Martin Maida ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Sub Saharan Africa ◽  
Immunodeficiency Virus ◽  
Sub Saharan

scholarly journals Review of Human Immunodeficiency Virus Type 1–Related Opportunistic Infections in Sub‐Saharan Africa

2003 ◽  
Vol 36 (5) ◽  
pp. 652-662 ◽  
Author(s):  
Charles B. Holmes ◽  
Elena Losina ◽  
Rochelle P. Walensky ◽  
Yazdan Yazdanpanah ◽  
Kenneth A. Freedberg
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Opportunistic Infections ◽  
Sub Saharan Africa ◽  
Immunodeficiency Virus ◽  
Sub Saharan

THE BURDEN OF CO-INFECTION WITH HUMAN IMMUNODEFICIENCY VIRUS TYPE 1 AND MALARIA IN PREGNANT WOMEN IN SUB-SAHARAN AFRICA

2004 ◽  
Vol 71 (2_suppl) ◽  
pp. 41-54 ◽  
Author(s):  
FEIKO O. TER KUILE ◽  
STEPHEN J. ROGERSON ◽  
ROBERT D. NEWMAN ◽  
RICHARD W. STEKETEE ◽  
ANNE M. VAN EIJK ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Pregnant Women ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Sub Saharan Africa ◽  
Immunodeficiency Virus ◽  
Sub Saharan

scholarly journals Regulation of Human Immunodeficiency Virus Type 1 Gene Expression by Clade-Specific Tat Proteins

2005 ◽  
Vol 79 (14) ◽  
pp. 9180-9191 ◽  
Author(s):  
Yan Desfosses ◽  
Mayra Solis ◽  
Qiang Sun ◽  
Nathalie Grandvaux ◽  
Carine Van Lint ◽  
...  
Keyword(s):  
Gene Expression ◽  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Sub Saharan Africa ◽  
Viral Gene ◽  
Subtype B ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The major group of human immunodeficiency virus type 1 (HIV-1) strains that comprise the current global pandemic have diversified during their worldwide spread into at least 10 distinct subtypes, or clades. Subtype C predominates in sub-Saharan Africa and is responsible for the majority of worldwide HIV-1 infections, subtype B predominates in North America and Europe, and subtype E is prevalent in Southeast Asia. Significant amino acid variations have been observed among the clade-specific Tat proteins. For the present study, we examined clade-specific interactions between Tat, transactivation-responsive (TAR) element, and P-TEFb proteins and how these interactions may modulate the efficiency of HIV-1 transcription. Clade-specific Tat proteins significantly modified viral gene expression. Tat proteins derived from HIV-1 clades C and E were strong transactivators of long terminal repeat (LTR) activity; Tat E also had a longer half-life than the other Tat proteins and interacted more efficiently with the stem-loop TAR element. Chimeric Tat proteins harboring the Tat E activation domain were strong transactivators of LTR expression. While Tat B, C, and E were able to rescue a Tat-defective HIV-1 proviral clone, Tat E was significantly more efficient at rescue than Tat C, possibly due to the relative stability of the Tat protein. Swapping the activation domains of Tat B, C, and E identified the cyclin T1 association domain as a critical determinant of the transactivation efficiency and of Tat-defective HIV-1 provirus rescue.

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