AEGiS-13IAC: A highly-conserved clade B human immunodeficiency virus type 1 (HIV-1) is heterosexually transmitted in Trinidad & Tobago.

13th International AIDS Conference

Durban, South Africa - July 9-July 14, 2000

A highly-conserved clade B human immunodeficiency virus type 1 (HIV-1) is heterosexually transmitted in Trinidad & Tobago.

Int Conf AIDS 2000 Jul 9-14; 13:(abstract no. TuOrA413)

Cleghorn FR, Jack N, Carr JK, Edwards J, Mahabir B, Sill AM, McDanal CB, Connolly SM, Greenberg M, Goodman D, Bennetts R, O'Brien T, Weinhold K, Blattner WA, Bartholomew C
F.R. Cleghorn, Institute of Human Virology, 725 West Lombard St., MBC Building Rm., Baltimore, MD 21201, United States, Tel.: (410) 706-1941, Fax: (410) 706-1944, E-mail: sill@umbi.umd.edu

BACKGROUND:The predominant risk behavior associated with HIV-1 spread worldwide is heterosexual activity, and non-Clade B viruses account for the majority of transmission. The epidemic of HIV-1 in Trinidad & Tobago and the Caribbean shares many features with such heterosexual epidemics, including a prominent role for coincident sexually transmitted diseases and frequent partner turnover. However, only clade B HIV-1 isolates have been recovered from this region.

METHODS: The current study evaluates the molecular epidemiology of HIV-1 in Trinidad & Tobago during a period when there was a rapid transition from homosexual to heterosexual transmission in the absence of injecting drug use, with a rapid rise in HIV-1 prevalence in the heterosexual population documented in 1990/91. Isolates of HIV-1 were recovered from stored PBMC shipped fresh to Duke University representing different time points and risk categories in the epidemic. All samples were collected with informed consent from STD clinic attenders enrolled in a series of epidemiologic studies between 1987 and 1997.

RESULTS: Of 31 viral isolates studied during the period 1987-1995, all cluster significantly with subtype B reference strains. In the analysis of full env genes from 22 early seroconverters, the Trinidad isolates constitute a significant subcluster within the B subtype. The isolates are highly conserved over time, and the Trinidad V3 consensus sequence differs by only a single amino acid from the prototype B V3 consensus sequence. In the majority of isolates, the V3 loop of env contains an unusual threonine deletion that clearly marks the lineage of the Trinidad HIV-1 clade B epidemic from its earliest days. No specific phenotypic features, including syncitium induction, neutralization profiles and chemokine receptor usage, distinguish this virus population from other subtype B viruses.

CONCLUSION: While the subtype B HIV-1 viruses responsible for the epidemic in Trinidad are genetically distinguishable from other subtype B viruses, this is likely to be the result of a strong founder effect in a geographically circumscribed population rather than genetic selection for heterosexual transmission. These results demonstrate that a typical clade B HIV-1 can generate a heterosexual epidemic.

Keywords: AEGIS, HIV-1, Genes, env, Heterosexuality, Serotyping, HIV-1 Reverse Transcriptase, Prevalence, Homosexuality, Risk-Taking, Trinidad and Tobago, Epidemiologic Studies, Caribbean Region, Human, genetics
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TuOrA413