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Biomedical subjects

G Roelants

Publications and source records attributed to G Roelants.

12 recordsLinked to original sources

Which health journals are most useful?

Records are kept in a database of the sources cited in publications currently being received at the library of the Institute of Tropical Medicine in Antwerp in the subject areas of health services and endemic diseases in developing countries. The frequency of citations shows which journals are most useful on these two subjects. Although such an analysis necessarily reflects the needs of the institution carrying it out, it helps to form a more complete idea of what is available.

Belgium

Genetic organization of a chimpanzee lentivirus related to HIV-1.

Simian immunodeficiency viruses have been isolated from four species of monkey, the 'captive' macaque and mangabey and the 'feral' African green monkey and mandrill. While none of these viruses is a replica of HIV-1, the macaque and mangabey viruses represent correct genetic models for HIV-2, possessing exactly the same complement of genes. Recently a lentivirus has been identified in two wild chimpanzees (Pan troglodytes troglodytes) in Gabon, west equatorial Africa, and isolated from one of them. This virus is referred to as SIVCPZ. Sera from these animals cross reacted with all the HIV-1 proteins including the envelope glycoproteins. Here, we describe the molecular cloning and sequencing of an infectious proviral clone of SIVCPZ. The overall genetic organization was the same as that of HIV-1, but phylogenetic analysis revealed that the sequence was more divergent than any HIV-1 sequence reported so far. The vpu gene product, found only in the type 1 viruses, was particularly different (64% divergent to HIV-1BRU) suggesting that the SIVCPZ represents a distinct subtype. These findings indicate that there is a larger pool of simian lentiviruses than previously suspected and revives debate as to the origins of HIV-1.

Amino Acid Sequence

Incidence of bovine leukemia virus-specific antibodies in West African cattle.

A sero-epidemiological survey of bovine leukemia virus (BLV) infection in indigenous West African cattle was undertaken using a radioimmunoassay and enzyme-linked immunosorbent assay. A high incidence of anti-BLV antibodies was found in the breeds tested and their crosses, whatever the test used. More extensive studies are needed to establish the prevalence of BLV infection in other parts of Africa; these may provide additional data on the similarities found between human and bovine leukemia viruses.

Africa, Western

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Abstracting and Indexing

Blocking and redistribution ("capping") of antigen receptors on T and B lymphocytes by anti-immunoglobulin antibody.

Antigen-binding T and B lymphocytes were studied by combined autoradiography and immunofluorescence; mouse spleen lymphocytes binding the antigens, [(125)I]MSH or [(125)I]TIGAL, were incubated with rhodamine-labeled anti-Ig reagents or with a rhodamine-labeled IgG fraction of anti-theta serum. B cells were identified as Ig+ or theta-, T cells as Ig- or theta+. It was found that: (a) 20% (1-2 mo after priming) to 30% (3.5-4 mo after priming) of the antigen-binding cells were T cells. (b) The range of antigen molecules bound by B and T cells was similar. (c) Binding of antigen to B and T cells was inhibited by polyvalent anti-Ig, anti-micro, or anti-L reagents. Binding to T cells was more readily inhibited than to B cells. Normal rabbit serum, antimouse lymphocyte serum, or anti-theta did not inhibit antigen binding. (d) When Ig at the surface of B cells was induced, by noninhibiting concentrations of anti-Ig reagents, to redistribute into polar caps and the cells subsequently exposed to [(125)I)antigen under noncapping conditions, the [(125)I]antigen silver grains were distributed in caps superimposed on the Ig fluorescent cap. Of crucial importance, antigen was found in cap in the same proportion of T cells as B cells. Significant capping of antigen receptors was not induced in B or T cells with normal rabbit serum or by anti-Ig reagents absorbed with mouse Ig. The main conclusions of this series of experiments using direct visualization of antigen-binding B and T lymphocytes is that T cells have antigen-specific receptors, probably of IgM nature, and that the number of these receptors appears to range in the order of thousands.

Animals