MAC-ELISA and ELISA inhibition methods for detection of antibodies after yellow fever vaccination.

The IgM antibody capture ELISA (MAC-ELISA) and ELISA inhibition methods for the detection of antibodies against dengue virus were modified to detect antibodies against yellow fever virus. Tests were carried out in 21 persons vaccinated with 17D and compared with the Plaque reduction neutralizing test. Of 17 naive subjects vaccinated, 16 (94%) seroconverted using the MAC-ELISA test and 14 (82%) seroconverted (or ≥fourfold titer increase) in the ELISA inhibition method. Cross-reactivity was evaluated by both tests and resulted in a high specificity to IgM antibodies against yellow fever, when all the samples from vaccinated individuals were negative by MAC-ELISA using dengue antigen. However, 10.7% of the positive dengue sera from the Santiago de Cuba epidemic cross-reacted by MAC-ELISA using yellow fever antigen. ELISA inhibition method showed high cross-reactivity when the 21 sera pairs were worked with yellow fever and dengue antigens. The MAC-ELISA and ELISA inhibition methods have become indispensable tools in our laboratory in order to maintain a surveillance system for dengue and dengue hemorrhagic fever. They are relatively rapid, simple, and they do not require sophisticated equipment. Both MAC-ELISA and ELISA inhibition methods for yellow fever could be useful for diagnosis, surveillance and yellow fever vaccine evaluation.