GENETIC AND ANTIGENIC ANALYSIS OF ADENOVIRUS TYPE-3 STRAINS SHOWING INTERMEDIATE BEHAVIOR IN STANDARD SERONEUTRALIZATION TEST

During an epidemiological survey of acute respiratory infection in Rio de Janeiro, among 208 adenovirus isolates, we found two strains that we were not able, by a standard neutralization procedure, to distingui sh between type 3 or 7. However, DNA restriction pattern for the two s trains with different enzymes were analyzed and showed a typical Ad3h profile. Using a cross-neutralization test in which both Ad3p and Ad7p antisera were used in different concentration against 100 TCID50 of e ach adenovirus standard and both isolates, we were able to confirm tha t the two isolates belong to serotype 3. An hemagglutination inhibitio n test also corroborated the identification of both strains as adenovi rus type 3. Comparing Ad3h and Ad3p genome, we observed 16 different r estriction enzyme sites, three of which were located in genomic region s encoding polypeptides involved in neutralization sites.