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Biomedical subjects

P Kaleebu

Publications and source records attributed to P Kaleebu.

23 records · Page 2Linked to original sources

Identification of human immunodeficiency virus type 1 subtypes and their distribution in the Commonwealth of Independent States (Former Soviet Union) by serologic V3 peptide-binding assays and V3 sequence analysis.

Serologic V3 loop peptide-binding assays have been used to predict divergent human immunodeficiency virus type 1 (HIV-1) strains from the Commonwealth of Independent States (former Soviet Union) that have been subsequently confirmed by sequencing of the V3 region. Initial screening was done by MN V3 peptide binding; 12 parenterally infected HIV-1-positive subjects from Elista and Rostov (group 1) with low-titer MN binding and 6 heterosexually infected HIV-1-positive adults from Byelorussia (group 2) with high-titer MN binding were selected. A consensus sequence from the Elista and Rostov areas was generated; a corresponding 14-mer peptide was synthesized and used in an indirect ELISA to screen sera from 392 individuals from diverse geographic areas. Reactivity to the consensus peptide was 82% in subjects from the homologous areas and 11%-38% in other areas. Antibody binding to a panel of synthetic V3 peptides may be used to predict the presence of diverse strains of HIV-1 within virally heterogenous populations.

Amino Acid Sequence↗

Geographic diversity of human immunodeficiency virus type 1: serologic reactivity to env epitopes and relationship to neutralization.

The antibody recognition of the major neutralization epitopes of human immunodeficiency virus type 1 (HIV-1) in 829 HIV-1-seropositive subjects from North America (106), Europe (241), Africa (342), and Asia (100) was investigated. Peptides derived from diverse published V3 loop sequences were used as antigen, and serum reactivity was detected by sensitive ELISAs. Antibody binding to peptides derived from the V3 loop sequence of HIV-1 isolates varies considerably depending on the geographic origin of the antibody and is associated with neutralization titer against homologous isolates. Serotype reactivity to peptides may be a simple and rapid approach to investigation of HIV-1 env diversity worldwide and may assist the choice of immunogen for development of future AIDS vaccines.

Africa↗

Comparative humoral responses to HIV-1 p24gag and gp120env in subjects from East Africa and the UK.

We compared 1616 sera from HIV-1-infected subjects and matched HIV-negative local controls in Uganda, Kenya and the UK. Sera were screened for specific antibody to HIV-1 p24 Gag and gp120 Env proteins and for p24 antigenaemia. In contrast to the UK, the majority of African HIV-1-infected subjects maintained detectable anti-p24 antibodies. However, lower reactivity of anti-p24 was observed in African AIDS patients, compared with those with asymptomatic HIV-1 infection. This reduction in anti-p24 reactivity with more advanced clinical stage was less marked in African HIV-1 infection than in the UK. Correspondingly, p24 antigenaemia was more common in patients with AIDS from the UK than in African patients (65 versus 4%). Reductions in anti-gp120 reactivity were observed in African AIDS patients, compared with the asymptomatic group. However, median reactivity of anti-gp120 in UK patients remained unchanged in both asymptomatic and AIDS subjects. The differences in humoral response to p24 and gp120 between Africa and the UK are semi-quantitative rather than qualitative and could be explained by initial higher antibody response to HIV-1 in African subjects.

Cross-Sectional Studies↗

Toxoplasma serology in Zambian and Ugandan patients infected with the human immunodeficiency virus.

In the USA and Europe, toxoplasmosis is well recognized as an important cause of morbidity and mortality among immunocompromised individuals. Toxoplasma gondii has been shown to be a common opportunistic infection in patients infected with the human immunodeficiency virus (HIV) in the USA and Europe with published estimates ranging from 20% to 80%. The importance of Toxoplasma infection in East Africa has not yet been defined. The seroprevalence rates of toxoplasmosis in Zambian and Ugandan patients were determined using the dye test (DT) and the latex agglutination test (LAT). The geographical variation in seroprevalence rates noted in western countries was also found in these African countries, with Zambia showing significantly lower rates than Uganda. 34% of Ugandan (64/186) and 4% of Zambian (8/187) patients infected with HIV, compared with 27% of Ugandan (26/93) and 11% of Zambian (20/189) HIV-negative persons, had anti-Toxoplasma immunoglobulin G antibodies. With the LAT, 13% of the Ugandan and 7% of the Zambian sera gave a false positive result. The relevance of Toxoplasma serology in Africa is discussed.

Antibodies, Protozoan↗

Human immunodeficiency virus (HIV) in developing countries.

The human immunodeficiency virus (HIV) is causing the most destructive epidemic of recent times, having been responsible for the deaths of more than 25 million people since it was first recognised in 1981. This global epidemic remains out of control, with reported figures for 2005 of 40 million people infected with HIV. During 2005 there were 4.9 million new infections, showing that transmission is not being prevented, and there were 3.1 million deaths from the acquired immunodeficiency syndrome (AIDS), reflecting the lack of a definitive cure and the limited access to suppressive antiretroviral treatment in the developing countries that are most severely affected. The current state of the epidemic and the response to date are here reviewed. Present and future opportunities for prevention, treatment and surveillance are discussed, with particular reference to progress towards an HIV vaccine, the expansion of the provision of highly active antiretroviral therapy, and the need to focus control programmes on HIV as an infectious disease, rather than as a development issue.

AIDS Vaccines↗