Preparation of Fluorescent Antibody Conjugate in Rabbits

The World Health Organization (WHO) recommends the direct fluorescent antibody test (DFA) for the detection of lyssaviruses such as rabies virus (RABV) in the central nervous system of suspect animals, and the rapid fluorescent focus inhibition test (RFFIT) to determine the titer of neutralizing antibodies in serum and cerebrospinal fluid (CSF). These tests can be performed with the use of fluorescent antibody conjugates produced from anti-RABV or anti-ribonucleoprotein polyclonal antibodies (PAbs), or from mixtures of monoclonal antibodies (MAbs). Described here is the production of an anti-ribonucleoprotein fluorescent antibody conjugate, obtained by the purification and conjugation of PAbs of animals, such as rabbits, immunized with viral ribonucleoprotein concentrated by cesium chloride (CsCl) gradient ultracentrifugation. This method makes it possible to obtain a fluorescent PAb conjugate with excellent specificity and sensitivity, besides a high titer.