A. Voller

Bio: A. Voller is an academic researcher from University of London. The author has contributed to research in topics: Antigen & Malaria. The author has an hindex of 26, co-authored 45 publications receiving 4149 citations. Previous affiliations of A. Voller include Makerere University & Zoological Society of London.

Enzyme immunoassays in diagnostic medicine. Theory and practice.

Abstract: Serological methods are playing an increasingly important role in the diagnosis and epidemiological assessment of diseases. Simple, inexpensive methods for large-scale application are urgently needed. The enzyme immunoassay methods developed recently and reviewed here hold great promise for application in a wide variety of conditions. Under laboratory conditions they can be as sensitive as radio-immunoassay, but they can also be adapted as simple field screening procedures. These methods are based on the use of antibodies or antigens that are linked to an insoluble carrier surface. This is then used to "capture" the relevant antigen or antibody in the test solution and the complex is detected by means of an enzyme-labelled antibody or antigen. The degradation of the enzyme substrate, measured photometrically, is proportional to the concentration of the unknown "antibody" or "antigen" in the test solution. The application of these techniques to endocrinology, immunopathology, haematology, microbiology, and parasitology is reviewed.

Enzyme immunoassays with special reference to ELISA techniques.

Abstract: In this review outlines are given on various types of enzyme immunoassay. The applications to such enzyme immunoassays, especially ELISA, are dealth with in detail. It is concluded that these techniques have high sensitivity and will be suitable in due course as routine laboratory tests.

Enzyme immunoassays for parasitic diseases.

Abstract: It is only in recent years that serology has come to play a major role in parasitic diseases. At first complement fixation was most used but gradually more convenient and sensitive techniques such as gel precipitation (DRAPER, 1976), and agglutination methods (KAGAN, 1974) were introduced. Probably the serological test most used by parasitologists has been immunofluorescence, particularly the indirect fluorescent antibody method (KAGAN, 1974; AMBROISE-THOMAS, 1976). Certain factors must be taken into consideration when assessing the usefulness of serological methods for parasitic diseases. The major parasitoses such as malaria, schistosomiasis, trypanosomiasis, infect millions of people in poor areas of the world where technical expertise is, at present, very limited. In these areas serological methods can be of most use in establishing epidemiological indices and for monitoring disease control programmes. Tests for use in such areas should be suitable for mass screening, should be simple and cheap, and .the results should be available quickly. Under these conditions some degree of precision may have to be sacrificed in the interests of practicability. There is also a place for more sophisticated methods suitable for individual diagnosis of parasitic infections especially in the more privileged areas of the world. We feel that enzyme-immunoassays, especially the enzyme-linked immunosorbent assay, have a part to play in both the above situations.

The detection of viruses by enzyme-linked immunosorbent assay (ELISA).

Abstract: Summary The use of enzyme-linked antibodies for the detection of two morphologically different plant viruses is described The technique is extremely sensitive, enabling assay of the viruses at concentrations as low as 10 to 100 ng/ml both in purified preparations and in crude plant extracts

Characteristics of the microplate method of enzyme-linked immunosorbent assay for the detection of plant viruses.

Abstract: Some characteristics of a microplate method for the detection and assay of plant viruses using enzyme-labelled antibodies are described. The method enabled the highly sensitive detection of a number of morphologically different viruses in purified preparations and in unclarified extracts of herbaceous hosts and of infected crop plants. Virus concentrations were estimated by photometric measurement of the colour intensity of the hydrolysed substrate. The suitability of the tehcnique for various field and research applications is considered.

The distribution of tau in the mammalian central nervous system.

Abstract: We have determined the biochemical and immunocytochemical localization of the heterogeneous microtubule-associated protein tau using a monoclonal antibody that binds to all of the tau polypeptides in both bovine and rat brain. Using immunoblot assays and competitive enzyme-linked immunosorbent assays, we have shown tau to be more abundant in bovine white matter extracts and microtubules than in extracts and microtubules from an enriched gray matter region of the brain. On a per mole basis, twice-cycled microtubules from white matter contained three times more tau than did twice-cycled microtubules from gray matter. Immunohistochemical studies that compared the localization of tau with that of MAP2 and tubulin demonstrated that tau was restricted to axons, extending the results of the biochemical studies. Tau localization was not observed in glia, which indicated that, at least in brain, tau is neuron specific. These observations indicate that tau may help define a subpopulation of microtubules that is restricted to axons. Furthermore, the monoclonal antibody described in this report should prove very useful to investigators studying axonal sprouting and growth because it is an exclusive axonal marker.

Enzyme immunoassay ELISA and EMIT.

Abstract: Publisher Summary This chapter discusses the enzyme immunoassay ELISA and EMIT. Enzyme immunoassays can be classified into two fundamentally different types of assays: heterogeneous and homogeneous enzyme immunoassays (EIA). The heterogeneous EIA that include the enzyme-linked immunosorbent assay (ELISA) are based on the same principles as are used in radioimmunoassays (RIA). After incubation of antigen and antibodies, the antigen–antibody complexes formed are separated from free antigen and antibody by one of a number of different techniques and the activity in one or both of the fractions is determined. In the homogeneous enzyme immunoassay that includes enzyme multiplied immunoassay technique (EMIT), no such separation is necessary. The principle of EMIT is similar to the modified bacteriophage technique. Antigen-coupled enzyme shows a change in activity (infectivity) upon incubation with antibody. This change is inhibited when the binding of antibody to the antigen-coupled enzyme is prevented by the addition of free antigen. ELISA is generally applicable to the measurement of almost any antigen. In ELISA, the enzyme is a passive passenger through the actual immunoassay. In EMIT, the enzyme plays a key role throughout the assay process. ELISA requires very little knowledge of enzyme technology, whereas enzymology is the key to success in EMIT.

Dual variable domain immunoglobulins and uses thereof

Abstract: The present invention relates to engineered multivalent and multispecific binding proteins, methods of making, and specifically to their uses in the prevention, diagnosis, and/or treatment of disease.

Top 10 plant viruses in molecular plant pathology

Abstract: Many scientists, if not all, feel that their particular plant virus should appear in any list of the most important plant viruses. However, to our knowledge, no such list exists. The aim of this review was to survey all plant virologists with an association with Molecular Plant Pathology and ask them to nominate which plant viruses they would place in a 'Top 10' based on scientific/economic importance. The survey generated more than 250 votes from the international community, and allowed the generation of a Top 10 plant virus list for Molecular Plant Pathology. The Top 10 list includes, in rank order, (1) Tobacco mosaic virus, (2) Tomato spotted wilt virus, (3) Tomato yellow leaf curl virus, (4) Cucumber mosaic virus, (5) Potato virus Y, (6) Cauliflower mosaic virus, (7) African cassava mosaic virus, (8) Plum pox virus, (9) Brome mosaic virus and (10) Potato virus X, with honourable mentions for viruses just missing out on the Top 10, including Citrus tristeza virus, Barley yellow dwarf virus, Potato leafroll virus and Tomato bushy stunt virus. This review article presents a short review on each virus of the Top 10 list and its importance, with the intent of initiating discussion and debate amongst the plant virology community, as well as laying down a benchmark, as it will be interesting to see in future years how perceptions change and which viruses enter and leave the Top 10.