Single Dilution ELISA Research Articles

The development and standardization of an enzyme-linked immunosorbent assay for the detection of antibodies to bovine herpesvirus 2

A single dilution enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies to bovine herpesvirus 2 has been developed, standardized and compared with the virus neutralization test. The results of the two tests correlated well. A positive/negative threshold was established for the ELISA. The ELISA was reproducible, sensitive, rapid and specific.

A single dilution enzyme-linked immunosorbent assay for the quantitative detection of antibodies to bovine herpesvirus type 1

Three serological assays were compared for detection of antibodies to bovine herpesvirus type 1. These were virus neutralization (VN), enhanced complement fixation (CF) and enzyme-linked immunosorbent assay (ELISA). The ELISA was developed using an infected cell lysate antigen and purified virus and was optimized in relation to antigen and antisera dilutions. The CF assay was enhanced by the addition of bovine complement. These 3 assays were compared for detection of: (1) specific virus antibody titers; (2) sero-conversions; (3) early antibody respnse in experimentally-infected cattle. Both ELISA end-point titers and single dilution values were found to be more sensitive than the CF or VN assays for specific antibody level quantitation. With a single dilution ELISA test procedure a correlation was obtained between ELISA values and VN titers. Using the single dilution ELISA test the assay also detected antibodies in experimentally-infected cattle before either the VN or CF assays, and agreed with the VN test in 35/38 seroconversions found by 4-fold or more VN changes between acute and convalescent paired sera from naturally-infected animals. The single dilution ELISA was a rapid and sensitive test for routine antibody detection in bovine sera.

Viral antibody screening system that uses a standardized single dilution immunoglobulin G enzyme immunoassay with multiple antigens

We present an enzyme-linked immunosorbent assay (ELISA) system for the simultaneous determination of immunoglobulin G antibodies directed against several viruses. Antibodies to up to eight different viruses could be determined for three different sera on one microtitration plate. After subtraction of the absorbance values obtained with the control antigens, the viral antigen absorbancies were expressed as percentages of the absorbance obtained with a pooled immunoglobulin standard. This value, the relative antibody activity, was rapidly calculated by means of a computer directly connected to the ELISA photometer and was stored on magnetic disks, thereby facilitating seroepidemiological studies. The reproducibility of the relative antibody activity was calculated to at best +/- 3.6% (standard deviation) in an intraassay test and to at worst +/- 20.4% (standard deviation) in an interassay test. Each serum was analyzed only at a dilution of 1/75. The sensitivity of this single-dilution ELISA (SD-ELISA) method for the detection of titer rises was compared with those of conventional methods, mostly complement fixation but also hemagglutination inhibition. A total of 142 of 155 (92%) paired sera showing fourfold complement fixation or hemagglutination inhibition rises also showed significant results in SD-ELISA. A total of 22 of 57 (39%) significant relative antibody activity rises were significant in complement fixation or hemagglutination inhibition. Overall, up to twice as many significant titer rises could be detected with SD-ELISA. Most of these seemed to have a sound correlation with clinical data. The specificity of SD-ELISA was found to be similar to that of complement fixation, with some cross-reactions occurring between herpes simplex and varicella-zoster virus antigens and between parainfluenza viruses. We have found SD-ELISA to be a valuable clinical virological tool that supplements conventional serology.