Differential diagnoses of influenza A virus, influenza B virus, and respiratory syncytial virus infections by direct immunofluorescence using mixtures of monoclonal antibodies of different isotypes.

Differences between isotypes of monoclonal antibodies were employed to detect influenza A and B viruses and respiratory syncytial virus by direct immunofluorescence using fluorescein isothiocyanate or Texas Red conjugates. Examination of 56 specimens for influenza A and B viruses and 112 specimens for influenza A virus and respiratory syncytial virus showed the mixed-isotype test to be comparable to the conventional procedure.