Antibody Titers In Individuals Research Articles

Measurement of IgG Subclasses in the Sera of Laboratory Workers Exposed to Rats

Human IgG antibody subclasses have been measured in the sera of workers exposed to rats, using a crude extract of rat urinary protein antigens, in an ELISA system. The antibody titres in individuals either with or without specific IgE were similar, with the exception of IgG4 where the mean level of this subclass was lower in those individuals with measurable titres of IgE (p less than 0.01). Symptomatic individuals, with specific IgE, also had lower titres of IgG4 than the corresponding asymptomatic, IgE-positive subjects (p less than 0.05). The frequency of positives in each subclass assay was similar in both groups. These findings suggest that higher levels of IgG4 may have a protective rôle.

Effect of low level immunity on response to live rubella virus vaccine

Serum specimens of 1075 young adults representing nursing and medical staff were collected for determination of rubella immunity using the radial haemolysis (RH) technique, also known as the haemolysis in gel (HIG) test. Of the sera 84 (7.8%) were negative (RH titre <4 mm) and an additional 93 (8.7%) gave an RH titre of 4–5 mm, which was regarded as the limit of immunity. Initially, 64 persons of these 177 were vaccinated with the RA27/3 strain of live attenuated rubella virus. Their serum samples were collected at the time of vaccination and at three weeks and three months after vaccination. Altogether 54 vaccinees could be followed for their immune response throughout the study. It became obvious that vaccination generally caused seroconversion only after three months rather than within three weeks. Only one person remained seronegative - even after a booster dose of vaccine. The mean final antibody titres in individuals with pre-existing low level immunity was 6 mm whereas in initially seronegative persons the antibody titre after vaccination was 8.5 mm on average. Thus a pre-existing low level immunity will effectively block the immune response to live rubella virus vaccine and this phenomenon may explain some apparent vaccination failures.