A simple method for the detection of antibodies to Encephalitozoon cuniculi in rabbits.

Rabbit antibodies against Encephalitozoon cuniculi were detected in an indirect microagglutination test using a bead substrate to which anti-rabbit immunoglobin G light and heavy chain antibodies were coupled. The test was positive using immune whole serum or F(ab)' and F(ab)'2 fragments of immunoglobin G but negative using the F(c) fragment. The reaction was blocked by saturating the beads with rabbit serum or by absorbing positive sera with excess Encephalitozoon cuniculi. The test provided a simple method to detect antibodies to Encephalitozoon cuniculi, did not require elaborate equipment and could be performed using frozen antigen.