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Out of 1670 pregnant women contacts examined for antibodies to rubella virus, recent rubella infection was confirmed in 5.1% of subjects, 2.2% of which were symptomatic and 2.9% asymptomatic; 89.9% of tested women were seropositive. These results closely resembled those, obtained in serological surveys, carried out in Poland several times in the years 1969-82. Rubella antibodies were found in over 90% of women in childbearing age, with HI antibody geometric mean titre (GMT) 58.7-84.3 (depending on the epidemiologic situation). Especially high GMT--of 122--was detected in women of the 30-34 year age group after the rubella epidemic in 1980/81, which showed the highest rubella morbidity of 5-9 year-old children. Reactogenicity and immune response in 10-13 year-old vaccinated girls were investigated. Seroconversion among seronegatives, among subjects with low antibody level (less than 1:20) and among seropositives with antibody titres 40 or higher before vaccination occurred in 99.8%, 60% and 12.8% of cases, respectively. HI antibody GMT after immunization was 132.6-135, similar to GMT induced by naturally acquired infection in the women of 30-34 year age group after the rubella epidemic. The difference of GMT in vaccinated girls with joint symptoms (152) and without postvaccinal reactions (124) was statistically significant. Practical conclusions for rubella diagnostic and vaccination programmes based on the analogies and differences of antirubella immunity in infected pregnant women, in naturally infected children and adults, and in vaccinated subjects are discussed.

Monkeys and guinea pigs were immunized with various doses of measles and mumps viruses. A cell-mediated response measured by leukocyte migration inhibition occured during the first two weeks after immunization. In case of measles virus, marked migration inhibition occurred already on the 7th day in monkeys and guinea pigs immunized with high virus doses. The response declined as early as 14 days after immunization in contrast to the group of guinea pigs inoculated with a lower virus dose. In these animals the response sustained for up to 50 days. Immunization of animals with various doses of mumps virus was similar and positive responses were obtained in the absence of detectable antibodies. Even 2.5 TCID50 of mumps virus induced the response although more irregularly than 250 or 2500 TCID50 virus.

A high per cent of false positive results for rubella virus IgM antibodies determined by immune fluorescence were detected in sera of pregnant women. After absorption with Staphylococcus suspension, Cowan 1 strain, and aggregates of human immunoglobulins, the false positive reactions due to IgM antiimmunoglobulin were eliminated.

In immunoglobulin fractions or after elimination of IgG by absorption the immunofluorescence test for rubella IgM antibodies is more sensitive than in whole serum. Blocking of IgM activity by IgG antibodies was eliminated when the time of incubation of the serum with virus antigen was prolonged. After prolonged incubation higher titres of rubella antibodies were also obtained in the IgM immunoglobulin fractions. Protein A in Staphylococcus aureus suspension effectively absorbs antibodies of IgG class. The IgM antibody titres in absorbed sera of patients infected with rubella were in some cases 2 to 4 times higher than in unabsorbed sera.

Fluorescence antibodies (FA) were titrated in human sera against antigens synthesized in four different infected cell lines: SIRC, RK-13, Vero and BHK-21. The cells infected in suspension by rubella virus attained the optimal concentration of fluorescence staining antigen earlier, fluorescence was more intensive and the titers of the tested human sera were slightly higher than in monolayer cell cultures. FA titers were high and they were correlated with the antibody titers obtained by hemagglutination-inhibition test. Some practical implications of these findings are discussed.