Modified dot assay with increased sensitivity: detection of small amounts of immunoglobulin molecules and the importance of different detection systems.

The original method of the dot assay described by Hawkes et al. enabled the detection of 100 pg of immunoglobulin molecules. We compared different enzyme detection systems based on the avidin-biotin complex, in conjunction with different substrates.

[Retrospective (1970-1984) serological study of delta antigen and antibody. Observations on seroconversion and absence of delta in non-A, non-B hepatitis].

335 serum samples collected between 1970 and 1984 from 278 HBsAg positive patients were tested for HDV antigen and HDV antibody (HDV = hepatitis D virus; also referred to as delta virus). The first positive sample was obtained in February 1974. The prevalence of the delta coinfection fluctuated in the following years between 0 and 52% of HBV-infected subjects.

Detection of anti-HTLV-III/LAV antibody by enzyme-linked immunosorbent assay in high-risk individuals in Switzerland 1974-1985.

Anti-HTLV-III antibody was tested in frozen sera from high-risk individuals, collected between 1974 and 1985 in Switzerland. All but one of the 262 sera of a control group were negative. Among drug addicts, none of the 78 samples collected from 1974 to 1979 was positive.