Development of biotinylated polyclonal anti-ribonucleoprotein IgG for detection of rabies virus antigen by direct rapid immunohistochemical test.

The direct rapid immunohistochemical test (dRIT) has been recommended for laboratorial diagnosis of rabies, especially in developing countries. The absence of commercial primary antibodies, however, still represents a major limitation to its wider use in testing. We describe here the development of a biotinylated polyclonal antibody against Rabies lyssavirus (RABV) ribonucleoprotein (RNP) and its use as a primary reagent in dRIT. Anti-RNP polyclonal horse IgG was purified by ionic exchange chromatography followed by immunoaffinity column chromatography, and its affinity, diagnostic sensitivity, and specificity were evaluated. CNS samples (120) of suspected rabies cases in different animal species were tested by dRIT, with the positive (n = 14) and negative (n = 106) results confirmed by direct fluorescence antibody testing (dFAT). Comparing the results of dRIT and dFAT, we found that the biotinylated anti-RNP IgG delivered 100% diagnostic specificity and sensibility for rabies diagnosis. Our findings show that the biotinylated anti-RNP polyclonal IgG can be produced with the quality required for application in dRIT. This work represents an important step in efforts to diagnose rabies in developing countries.

Evaluation of polyclonal anti-RNP IgG antibody for rabies diagnosis by indirect rapid immunohistochemistry test.

Rabies still represents a major public health threat and estimated to cause 60,000 human deaths annually, particularly in developing countries. Thus, adequate surveillance based on rapid and reliable rabies diagnosis for both humans and animals is essential. The WHO and OIE recommended gold standard diagnostic technique for rabies is the direct immunofluorescence assay (dFAT). However, dFAT is expensive and requires a high level of expertise. As an alternative, the rapid immunohistochemistry technique is a promise to be a simple and cost effective diagnostic tool for rabies, and can be performed on field conditions prevalent in developing countries. However, no validated commercial conjugate antibody for rabies is available to meet the laboratory demand. Here, we evaluated the polyclonal anti-rabies virus ribonucleoprotein (RNP) IgG antibody for Rabies lyssavirus (RABV) detection by indirect rapid immunohistochemistry test (iRIT). We tested polyclonal anti-RNP IgG antibody against a batch of 100 brain specimens representing a wide phylogenetic origin in the State of São Paulo, Brazil. The purified IgG obtained 100% of diagnostic specificity and sensibility for RABV antigen detection in iRIT compared with the gold standard dFAT. In conclusion, our results demonstrate that the polyclonal anti-RNP IgG antibody may be used as a diagnostic reagent for rabies using iRIT, with the expectation of increase in availability and cost reduction of the epidemiological surveillance for developing countries.

Evaluation of polyclonal anti-RNP IgG antibody for rabies diagnosis by indirect rapid immunohistochemistry test

Rabies still represents a major public health threat and estimated to cause 60,000 human deaths annually, particularly in developing countries. Thus, adequate surveillance based on rapid and reliable rabies diagnosis for both humans and animals is essential. The WHO and OIE recommended gold standard diagnostic technique for rabies is the direct immunofluorescence assay (dFAT). However, dFAT is expensive and requires a high level of expertise. As an alternative, the rapid immunohistochemistry technique is a promise to be a simple and cost effective diagnostic tool for rabies, and can be performed on field conditions prevalent in developing countries. However, no validated commercial conjugate antibody for rabies is available to meet the laboratory demand. Here, we evaluated the polyclonal anti-rabies virus ribonucleoprotein (RNP) IgG antibody for Rabies lyssavirus (RABV) detection by indirect rapid immunohistochemistry test (iRIT). We tested polyclonal anti-RNP IgG antibody against a batch of 100 brain specimens representing a wide phylogenetic origin in the State of São Paulo, Brazil. The purified IgG obtained 100% of diagnostic specificity and sensibility for RABV antigen detection in iRIT compared with the gold standard dFAT. In conclusion, our results demonstrate that the polyclonal anti-RNP IgG antibody may be used as a diagnostic reagent for rabies using iRIT, with the expectation of increase in availability and cost reduction of the epidemiological surveillance for developing countries.

Evaluation of polyclonal anti-RNP IgG antibody for rabies diagnosis by indirect rapid immunohistochemistry test

Rabies still represents a major public health threat and estimated to cause 60,000 human deaths annually, particularly in developing countries. Thus, adequate surveillance based on rapid and reliable rabies diagnosis for both humans and animals is essential. The WHO and OIE recommended gold standard diagnostic technique for rabies is the direct immunofluorescence assay (dFAT). However, dFAT is expensive and requires a high level of expertise. As an alternative, the rapid immunohistochemistry technique is a promise to be a simple and cost effective diagnostic tool for rabies, and can be performed on field conditions prevalent in developing countries. However, no validated commercial conjugate antibody for rabies is available to meet the laboratory demand. Here, we evaluated the polyclonal anti-rabies virus ribonucleoprotein (RNP) IgG antibody for Rabies lyssavirus (RABV) detection by indirect rapid immunohistochemistry test (iRIT). We tested polyclonal anti-RNP IgG antibody against a batch of 100 brain specimens representing a wide phylogenetic origin in the State of São Paulo, Brazil. The purified IgG obtained 100% of diagnostic specificity and sensibility for RABV antigen detection in iRIT compared with the gold standard dFAT. In conclusion, our results demonstrate that the polyclonal anti-RNP IgG antibody may be used as a diagnostic reagent for rabies using iRIT, with the expectation of increase in availability and cost reduction of the epidemiological surveillance for developing countries.