Guy Leonard

PREVALENCE OF HUMAN T-LYMPHOTROPIC RETROVIRUSES TYPE III (HIV) AND TYPE IV IN IVORY COAST

Serological investigations in the Ivory Coast indicate that, despite the rarity of overt acquired immunodeficiency syndrome (AIDS), human immunodeficiency virus (HIV) is widely prevalent. So also is human T-lymphotropic virus type IV (HTLV-IV). The highest rates of HIV and HTLV-IV seropositivity were observed in female prostitutes. These findings suggest that, like HIV, HTLV-IV can be transmitted by heterosexual contact, and that the mobility of prostitutes may be an important factor in spread of the retroviruses in Africa. The incidence of HIV-associated AIDS in the Ivory Coast is likely to rise sharply in the next few years.

A STLV-III related human retrovirus, HTLV-IV: analysis of cross-reactivity with the human immunodeficiency virus (HIV).

A category of viruses has been identified which is related to human immunodeficiency virus (HIV) but is more closely related to a group of simian retroviruses (STLV-III). These viruses named HTLV-IV, LAV-II, or SBL-6669, are prevalent in West-Africa. In this study, we analysed the cross-reactivity at the protein level between HTLV-IV and HIV (HTLV-IIIB). The results indicate that most people infected with HTLV-IV have antibodies that react to the major gag protein of HIV p 24. There is also a high degree of immunologic cross-reactivity between the pol gene products of HIV and HTLV-IV. Among these the endonuclease/integrase is more conserved than the reverse transcriptase. In contrast, the envelope glycoproteins that are the most frequently detected antigens by antibodies from exposed individuals are serotype specific. These data make the env gene products the most interesting antigens for serotype specific diagnosis of human retroviruses infections.

HTLV-1 antibody class and subclass distribution in African TSP and control populations

The humoral immune responses in 44 sera from HTLV-1 seropositive African subjects were compared. The sample population was composed of 12 patients with HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP), 12 patients with other neurological conditions and 20 asymptomatic carriers. Samples HTLV-1 antigens were tested against all immunoglobulin classes and IgG subclasses, using the Western blot technique with polyclonal and monoclonal antibodies. Whilst IgG reacted with gag, env and tax products for the three groups studied, IgM and IgA were found to react more frequently with HTLV-1 in HAM/TSP patients. For these patients, IgM and IgA were particularly directed against tax and env proteins. Among IgG subclasses, IgG1 was most sensitive to gag, env and tax products reacting in similar proportions in all three groups. IgG2 and IgG4 were apparently not involved. IgG3 was most responsive in HAM/TSP patients. These data are similar to those observed in AIDS patients, LAS and HIV asymptomatic carriers and emphasize the role of HTLV-1 in HAM/TSP.

Competitive enzyme-immunoassays using native viral antigens to discriminate between HIV-1 and HIV-2 infections.

Human immunodeficiency virus (HIV) strains can be separated into two serotypes: HIV-1 and HIV-2. In the study reported herein, we developed and evaluated competitive enzyme-immunoassays (CEIA-1 for the detection of antibody to HIV-1, CEIA-2 for the detection of antibody to HIV-2) to discriminate serologically between HIV-1 and HIV-2 infections. In most of the cases, the serotyping of known reactive serum samples was done easily with the CEIAs, showing a similar specificity to the Western blot. Such competitive assays could represent alternative procedures for serotyping HIV infection and would limit the need for expensive Western blots, especially in economically poor countries.

HIV-1, HIV-2 and HTLV-I seroprevalence surveys in continental Ecuador and Galapagos.

To obtain a better estimate of the prevalence of human immunodeficiency virus (HIV)-1 and -2 and human T-cell lymphotropic virus type L (HTLV-I) in continental Ecuador and the Galapagos Islands sera were collected during 1988-90 from 1187 individuals. The sample included Indians blacks whites half-castes and mixed persons. An effort was made to include both healthy subjects recruited from the general population as well as members of groups at risk of infection--blood donors hospital staff prostitutes sexually transmitted diseases clinic patients. Any positive findings were confirmed by Western blot or radioimmunoprecipitation assay. HTLV-I seropositivity was a more common finding (5 cases) than infection with HIV (2 cases). The HTLV-I seroprevalence was 0.42% in Ecuador 0.28% in the continental areas and 1.57% in the Galapagos Islands; however all 3 of these rates are far lower than those reported from the Caribbean basin and other South American areas. The 2 subjects infected with HIV-1 were blood donors from Quito (0.5% prevalence rate). Subjects positive for HTLV-I infection included 1 sexually transmitted diseases clinic patient 2 white and half-caste prostitutes--all 3 from Quito--and 2 individuals from the general population in San Cristobal in Galapagos. As of March 1990 only 72 cases of acquired immunodeficiency syndrome (AIDS) had been reported from Ecuador. Of concern however is the impact seroprevalence among blood donors will have on the future course of the epidemic.