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Biomedical subjects

A Voller

Publications and source records attributed to A Voller.

At least 19 recordsLinked to original sources
PubMed1992

Comparison of an EBV transformed cell line and an EBV hybridoma cell line producing the same human anti-HBs monoclonal antibody.

A stable human-mouse heterohybridoma secreting human anti-HBs monoclonal antibody in continuous culture for 12 months was generated. It grew faster than the parent EBV transformed lymphoblastoid cell line (LCL) but produced the same level of specific antibody. The LCL was positive for the Epstein-Barr Virus Nuclear Antigen (EBNA), human CD 23 and contained a diploid number of human chromosomes. The heterohybridoma was negative for EBNA, CD 23 and mouse Ly-1 mouse, despite retaining a full complement of diploid mouse chromosomes and a limited number of human chromosomes.

Animals↗
PubMed1992

Development and characterization of human anti-HBs antibodies.

Peripheral blood mononuclear cells (PBMC) from 13 healthy hepatitis B vaccines were transformed with the Epstein-Barr virus (EBV) and lymphoblastoid cell lines (LCL) producing antibodies to hepatitis B surface antigen (anti-HBs antibodies). Seven LCL and two clones secreting human anti-HBs monoclonal antibody were generated and their antibodies purified. One clone was fused with a mouse myeloma and the antibody from a cloned anti-HBs secreting heterohybridoma purified. One of the 10 purified human anti-HBs antibodies was characterized as IgG4, the remainder were IgG1. The antibodies had either kappa or lambda light chains. Five of the antibodies which were conjugated to horseradish peroxidase recognised the "a" group determinants.

Antibody Specificity↗
PubMed1988

Studies of a common idiotype PR4 in autoimmune rheumatic disease.

A new common idiotype, designated PR4, is described. This idiotype was originally identified on a human hybridoma-derived monoclonal antibody from a patient with leprosy, which binds the major Mycobacterium leprae-derived antigen, phenolic glycolipid-1, poly(ADP)-ribose, DNA, and poly(dT). The PR4 idiotype was found in patients with systemic lupus erythematosus (SLE) (70%), rheumatoid arthritis (40%), and Sjögren's syndrome (15%). It was not, however, found in the spouses of the SLE patients or (unlike other lupus idiotypes) in their healthy first-degree relatives. Although no correlation between PR4 idiotype levels and disease activity in SLE was found, a subset of rheumatoid arthritis patients with high levels of the idiotype was identified.

Antibodies, Anti-Idiotypic↗
PubMed1987

An enzyme-linked immunosorbent assay for the detection of Entamoeba histolytica antigens in faecal material.

This paper describes a method for the detection of Entamoeba histolytica antigens in stool samples using a multi-layer ELISA. The method is sensitive and specific, showing no interference with other intestinal parasites, e.g. E. coli, E. hartmanni, Endolimax nana, Iodamoeba buetschlii, Hymenolepis nana, Giardia lamblia, Trichomonas and Ascaris. The method provides a rapid and simple screening assay for E. histolytica infections and should assist in diagnosis and epidemiological studies of the disease.

Animals↗
PubMed1986

A critical reappraisal of the use of enzyme-linked immunosorbent assays in the study of snake bite.

The enzyme-linked immunosorbent assay (ELISA) has been the most widely used serological test in snake bite immunodiagnosis and epidemiology. The technique has been applied, however, without due consideration of the many factors which would affect an inherently sensitive test system, especially in tropical rural areas where large scale snake bite studies are usually carried out. This review discusses the effects of non-specific reactivity, cross reactivity and the quality of reagents on both the sensitivity and specificity of venom antigen and antibody detection assays. Simple laboratory modifications to optimize the assays are described. The importance of using the predictive value to assess the validity of applying the same test system in different circumstances is stressed. To fulfil its potential as the most versatile immunoassay technique in snake bite research, the test conditions of the ELISA will have to be much more stringently controlled in future.

Antibodies↗
PubMed1986

Comparison of an ELISA with a RIA method for serum alpha-fetoprotein determination in screening for fetal neural tube defects.

An enzyme-linked immunosorbent assay (ELISA) was evaluated for serum alpha-fetoprotein determination in the antenatal screening for fetal open neural tube defects. The ELISA was used concurrently with an existing radioimmunoassay (RIA) method until serum specimens from 5000 pregnant women, between 15 and 20 weeks gestation, had been tested. The accuracy of the ELISA was similar to that of the RIA; the median AFP values by gestational week obtained with the ELISA were, on average, 2 KIU/L higher than the corresponding RIA values; the 10th and 90th percentiles, in terms of multiples of the median (MoM), were very similar. The precision of the two methods was also similar. The ELISA method yielded 1.8% results from unaffected pregnancies above 2.5 MoM compared with 1.4% by RIA, a small but statistically significant difference (P = 0.03). Both methods detected the same affected pregnancies identified during this period; five open neural tube defects, three with exomphalos and three intra-uterine deaths. The ELISA method was simple, required about one quarter less operator time than the RIA and enabled results to be generated in one day rather than the two days required by RIA. The ELISA method is a suitable alternative to RIA for routine use in screening for fetal neural tube defects.

Enzyme-Linked Immunosorbent Assay↗
PubMed1985

A comparison of chloroquine and pyrimethamine as malaria chemoprophylactics in young Nigerian children.

The efficacy of chloroquine and pyrimethamine as malaria chemoprophylactics was investigated in young Nigerian children. Chloroquine resistance had not been documented in the study area; pyrimethamine resistance was probably present but uncommon. Children who received weekly chemoprophylaxis with pyrimethamine had a lower prevalence of malaria parasitaemia and malaria antibodies than children who received weekly chemoprophylaxis with chloroquine. Pyrimethamine given monthly gave a comparable degree of protection to chloroquine given weekly. Chloroquine frequently induced vomiting in young children and this may have impaired its efficacy as a prophylactic. We conclude that, in an area where neither chloroquine nor pyrimethamine resistance is prevalent, pyrimethamine is a better chemoprophylactic for young children than chloroquine.

Antibodies↗
PubMed1985

Malaria chemoprophylaxis with chloroquine in young Nigerian children. I. Its effect on mortality, morbidity and the prevalence of malaria.

One hundred and ninety-eight Nigerian children who received weekly chemoprophylaxis with chloroquine from shortly after birth until the age of one year or two years and 185 age-matched controls were studied. Chemoprophylaxis with chloroquine was partially, but not completely, effective in controlling malaria. Clinical malaria was documented significantly less frequently in protected children than in control children, and only 9% of random blood films obtained from protected children were positive for Plasmodium falciparum while 41% of random blood films from control children were positive for this parasite. Mean malaria antibody levels were lower in protected than in control children; for ELISA and precipitin antibodies the difference between the two groups was less marked at two years than at one year. Mortality was similar among protected and among control children. No rebound mortality or morbidity was observed after chemoprophylaxis was stopped.

Antibodies↗
PubMed1985

Malaria chemoprophylaxis with chloroquine in young Nigerian children. II. Effect on the immune response to vaccination.

The immune response of 198 young Nigerian children protected against malaria by chemoprophylaxis with chloroquine to immunization with triple, poliomyelitis, measles, typhoid, meningococcal and BCG vaccines was compared with the immune response to vaccination of 185 control children. Good responses to triple, measles and BCG vaccines were shown by children in both groups; poorer responses were obtained to poliomyelitis, typhoid and meningococcal vaccines. The response to immunization of protected children was similar to that observed among control children for all the vaccines tested except for meningococcal polysaccharide vaccine. Protected children showed a significantly greater antibody response to both group A and group C meningococcal polysaccharides than control children. This finding supports the results of previous studies which have shown that the immune response to meningococcal polysaccharide vaccines is adversely affected both by acute malaria and by asymptomatic malaria parasitaemia.

Antibody Formation↗
PubMed1984

Serum C-reactive protein levels and falciparum malaria.

A microplate ELISA was developed to measure C-reactive protein (CRP) and it was used to establish the relationship between CRP levels and malaria. Highest serum CRP levels were found in African patients with high Plasmodium falciparum parastaemia. However, even African children with lower parasitaemia had higher CRP levels than others without parasitaemia. All African groups studied had CRP levels above those of a control UK group.

Adolescent↗
PubMed1983

Purified Trypanosoma cruzi specific glycoprotein for discriminative serological diagnosis of South American trypanosomiasis (Chagas' disease).

Chagas' disease, leishmaniasis, and Trypanosoma rangeli infection are endemic and their distributions overlap in vast regions of South and Central America. Serological cross-reactivities can confuse epidemiological studies of these infections, and their differential diagnosis has been assigned a high priority by the World Health Organisation. A lectin-affinity-purified, 90,000 molecular weight glycoprotein (GP90) is present in the known principal strains (zymodemes) of Trypanosoma cruzi and absent from Leishmania and T rangeli. Patients with T cruzi infection have antibody to GP90, whereas patients with leishmaniasis do not and the two infections can be distinguished in an ELISA system using this antigen. In a mouse model, the same test can differentiate between T cruzi and T rangeli infections. Antigens purified by affinity chromatography clearly provide a practical basis for very precise, even strain-specific, diagnostic tests.

Antibodies↗
PubMed1983

Coxsackie-B-virus-specific IgM responses in children with insulin-dependent (juvenile-onset; type I) diabetes mellitus.

Coxsackie B1-6 virus IgM responses were detected by an enzyme-linked immunosorbent assay (ELISA) in 11 of 28 (39%) children aged 3-14 years in whom insulin-dependent (juvenile onset; type I) diabetes mellitus (IDDM) developed in 1982. 5 patients had a homotypic response to Coxsackie B4 and 1 had a homotypic response to B5. A serum sample had been obtained from each patient 2 to 16 weeks after onset of IDDM symptoms. Islet-cell cytoplasmic antibodies (IgG) and complement fixing islet cell antibodies were detected in 15 of 18 sera tested, but only 6 of these sera were positive for Coxsackie-B-virus-specific IgM which suggests that Coxsackie-B-virus and islet-cell antibodies are not cross-reactive. Coxsackie-B-virus-specific IgM responses were present in only 16 of 290 (5.5%) age-matched non-diabetic London children whose sera were also collected during 1982. Sera from children with virologically confirmed Coxsackie-B-virus infections showed that development of homotypic or heterotypic Coxsackie B1-6 responses was age-related. 29 of 36 (81%) children aged 6 months to 4 years had a homotypic response, whereas 44 of 57 (77%) persons aged 15 years had heterotypic responses. Mothers of 2 children with Coxsackie-B-virus-induced neonatal myocarditis had Coxsackie-B-virus-specific IgM responses directed against serotypes 3 and 4, whereas their infants had a response to Coxsackie B2 virus alone.

Adolescent↗
PubMed1983

An enzyme-linked immunosorbent assay (ELISA) for field diagnosis of visceral leishmaniasis.

A simplified enzyme-linked immunosorbent assay (ELISA) was evaluated as a diagnostic test for visceral leishmaniasis in the field on 222 individuals with splenomegaly and 110 controls. The test was shown to have a sensitivity of 98.4% and specificity of 100% when compared with parasite identification by splenic aspiration. The data indicate that the ELISA is an accurate, safe, and economical alternative to splenic aspiration for the diagnosis of visceral leishmaniasis.

Enzyme-Linked Immunosorbent Assay↗