Detection of measles specific IgG in oral fluid using an FITC/anti-FITC IgG capture enzyme linked immunosorbent assay (GACELISA)

An IgG antibody capture enzyme linked immunosorbent assay (GACELISA) for th e detection of measles specific IgG in oral fluid was developed using an FI TC/anti-FITC amplification system. The GACELISA was evaluated by testing pa ired oral fluid and serum samples from 787 subjects in an epidemiological s tudy of measles in rural Ethiopia. Oral fluids were tested by GACELISA and corresponding serum samples by a sensitive indirect ELISA for measles IgG ( Behring Enzygnost). By comparison with the serum measles IgG assay, the ora l fluid GACELISA had a sensitivity of 97.4% (95% confidence intervals: 95.9 , 98.2) and a specificity of 90.0% (81.9, 94.3), with no significant differ ences observed by age group. Total IgG concentrations were measured on a su bset of 160 oral fluids by an in-house ELISA. This showed that false negati ve GACELISA results tended to occur in samples with low concentrations of t otal IgG, although the trend was not statistically significant. It is concl uded that the overall performance of the GACELISA was satisfactory, showing close agreement to the serum ELISA, and has potential to serve as an easil y transferable tool for large scale epidemiological studies as required for the World Health Organisation's programme for the global control of measle s. (C) 1999 Elsevier Science B.V. All rights reserved.