The indirect immunofluorescent technique has been used to study the specific
immunoglobulin responses in nasal secretions from ten adults with acute
rubella. Titres of
IgA antibody in nasal washings usually exceeded those of
IgG, but both types of antibody were detected in all patients. They appeared a few days after the
rash, reached maximum titres during the second week and then declined.
IgA antibody was no longer detectable after 47 days and was not detected at all in nasal washings from adults who had experienced
rubella in the past. Low titres of
IgG antibody persisted in some patients for longer than
IgA and traces of
IgG were found in nasal washings from a minority of adults with a past history of
rubella. Nasal
antibodies in acute
rubella are therefore transient and unlikely to take part in resistance to
reinfection.In
sucrose-density gradients nasal
IgA antibody sedimented more rapidly than
IgG and there was little overlap between these two types of antibody.
IgA antibody in serum was more heterogeneous; it was found in nearly all the fractions which contained
IgG antibody and in many of those which contained
IgM.