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Biomedical subjects

S F Lyons

Publications and source records attributed to S F Lyons.

47 records · Page 3Linked to original sources
PubMed1982

An indirect radioimmunoassay for interferon.

An indirect radioimmunoassay for testing the antiviral activity of interferon (IFN) is described. Vero cells are seeded in microtitre plates, treated with appropriate dilutions of interferon and challenged with Sindbis virus. Viral yield is measured using specific antibody and radiolabelled protein A. The assay is able to detect IFN levels of 5 international units (I.U.)/ml, has a high degree of reproducibility, and could be easily adapted to various cell and virus combinations. This microsystem is technically simple, allows testing of small volumes of test material, and eliminates subjectivity in reading of end-points.

Animals↗
PubMed1978

Role for macrophages and thymus-derived lymphocytes in cholera toxin-induced immunosuppression.

The exo-enterotoxin derived from Vibrio cholerae bacilli has marked immunomodulating activities, both in vivo and in vitro. In the present study, the mechanism whereby cholera toxin depresses the antibody-forming ability of murine splenocytes was investigated by in vitro reconstitution experiments. Spleen cells derived from mice treated with cholera toxin 2 days earlier were markedly deficient in their ability to respond to sheep erythrocytes upon challenge immunization in vitro. Addition of graded numbers of normal spleen cells to spleen cell cultures from toxin-treated mice partially restored the antibody response. Adherent splenocyte populations were even more effective in restoring antibody formation. Normal peritoneal exudate cells rich in macrophages were also capable of restoring the antibody-forming ability of toxin-pretreated splenocytes. Furthermore, thymus (T)-derived spleen cells from normal mice, as well as sheep erythrocyte "educated" T cells, were capable of restoring antibody formation to normal levels. The importance of T lymphocytes in restoring immune competence of spleen cell cultures from toxin-treated mice was shown by additional experiments in which T-depleted cell preparations were found to be ineffective in restoring antibody activity. These studies point to macrophages and T-derived lymphocytes as a major target for cholera toxin-induced immunosuppression.

Animals↗
PubMedDate not supplied

One year surveillance of HIV-1 infection in Johannesburg, South Africa.

A sero-epidemiological surveillance study to monitor the prevalence of HIV-1 infection in Johannesburg, South Africa, was commenced in February 1988. The population selected for study were attenders at clinics for sexually transmitted diseases (STD) and at family planning (FP) clinics. In the 12 months of the study 6631 sera were tested. Of the STD attenders, 15 of 1224 black females (1.2%) and 21 of 2482 black males (0.8%) were positive. Of the 449 white males tested 49 were homosexual, amongst whom 10 (20.4%) were positive; in the heterosexual white male group 4 of 400 (1.0%) were positive. Of the FP clinic attenders, 4 of 1459 black females (0.3%) were positive. 68 of the 6631 sera tested were indeterminate for infection. No attenders were positive for HIV-2 infection. These data confirmed the entry of HIV infection into the black population in South Africa.

Ambulatory Care Facilities↗
PubMedDate not supplied

An analysis of indeterminate western blot patterns of black African subjects.

The significance of indeterminate Western blotting results was assessed by determining their distribution in attenders of sexually transmitted diseases (STD) and family planning (FP) clinics. As expected, it was found that the former had a highly significantly greater prevalence of HIV infection. Indeterminate results were not found more frequently in STD attenders refuting any association with sexual promiscuity. They were, however, found significantly more frequently amongst black compared to white subjects, but no difference was found between males and females. Indeterminate results appear to be a feature of black African sera and what the significance is, still remains to be elucidated.

Black People↗
PubMedDate not supplied

Evaluation of a "dip-stick" methodology for detection of antibodies to HIV1.

An HIV1 antibody screening assay, the "ImmunoComb" HIV1 kit which uses a dip-stick methodology, was evaluated using a panel of selected sera. The ImmunoComb detected 144 of 147 (98%) Western-blot-confirmed positive sera. However, when the ImmunoComb was compared with a recombinant EIA capable of detecting early seroconversion, only 144 of 156 (92.3%) recombinant EIA or Western-blot-positive sera were ImmunoComb-positive. Thus, while the kit is suitable for serological surveys and prevalence studies, especially in areas where skilled laboratory staff and sophisticated equipment are unavailable, the low sensitivity precludes its use in blood banks and transfusion services.

Acquired Immunodeficiency Syndrome↗