Antibody response to rubella virion (V) and soluble (S) antigens in rubella infection and following vaccination with live attenuated rubella virus

Degradation of rubella virus envelope components

Tween-ether treatment of rubella virus, which has no effect on the antigenic and electrophoretic properties of the two envelope glycoproteins, destroys infectivity and enhances haemagglutinating activity. Trypsin treatment alters the electrophoretic pattern of the envelope glycoproteins so that the VPI peak is no longer evident and the VPII peak is reduced. At the same time, both the properties of haemagglutination and infectivity are inactivated but the capacity to combine with neutralizing antibody is retained, which suggests that VPII may be responsible for inducing the production of neutralizing antibody.

Evaluation of solid-phase enzyme-immunoassay procedure in immunity surveys and diagnosis of rubella

In the development of optimized micro-and macromethods for solid-phase rubella enzyme-immunoassay (EIA), the effect of various technical parameters was studied. Special emphasis was placed on elimination of defective polystyrene material, purity and quantity of immobilized antigen, use of reference sera in each microplate or macroprocedure, use of nonionic detergent in washing and diluent buffers, and use of a colourless enzyme substrate. A single serum dilution, analysed in duplicate, was sufficient provided the procedure was standardized. In quantitation of serum rubella antibodies, EIA gave values correlating well with those obtained with the single radial haemolysis test but not with low haemagglutination inhibition titres. The EIA procedure proved to be a useful and reliable serological tool in immunity surveys. When complemented by a rubella IgM test, EIA could also be used in diagnosis of recent rubella infections as a convenient primary serological test.

Diagnosis of postnatal rubella by the enzyme-linked immunosorbent assay for rubella IgM and IgG antibodies

A semi-automated enzyme-linked immunosorbent assay (ELISA) was established for the detection of rubella IgM antibodies in non-fractionated sera. A cut-off level between rubella IgM positive and negative sera was determined by a study of sera without rheumatoid factor from 200 blood donors. Testing of 12 donor sera containing rheumatoid factor showed that 5 sera gave a positive result in the rubella IgM assay. Rubella IgM antibodies were quantified by ELISA in a study of 214 serial serum specimens drawn from 16 patients with rubella during a period of up to 10 years after the infection. Peak values of the IgM antibodies were reached approximately 8 days after onset of the rash, and the persistence of the IgM antibodies ranged from 17-90 days, with the exception of one patient with a prolonged IgM response. The rubella IgG antibodies increased slowly after the rash and reached maximum levels about 50-120 days, after which a monor decrease was observed. The results of the present study indicate that ELISA is suitable as a routine procedure for the serodiagnosis of recent rubella.

Antibody responses in patients with rubella infection determined by passive hemagglutination, hemagglutination inhibition, complement fixation, and solid-phase radioimmunoassay tests

Antibody responses in serial serum specimens collected from 31 patients with an acute rubella infection were determined by passive hemagglutination (PHA), hemagglutination inhibition (HI), complement fixation (CF), radioimmunoassay (RIA) immunoglobulin G (IgG), and RIA immunoglobulin M (IgM) tests to evaluate the effectiveness of these tests in diagnosing a recent infection. The HI, RIA IgG, and RIA IgM antibodies appeared almost simultaneously and reached the maximum level about 1 week after the onset of rash. Compared to these, the CF antibodies developed only slightly later, whereas the development of the PHA antibodies was much more delayed. The RIA IgM response was shown to be transient, lasting approximately 1.5 to 2.5 months postinfection. The results of this study indicate that demonstration of specific IgM antibodies is the best method for diagnosing a recent infection, one within 2 months after the onset of the illness. If an IgM test is not available, a combination of the HI and PHA tests is recommended.

Persistence of immunoglobulin G and immunoglobulin M antibodies after postnatal rubella infection determined by solid-phase radioimmunoassay

The appearance and persistence of immunoglobulin M (IgM) and IgG antibodies in postnatal rubella infections were studied by employing a solid-phase radioimmunoassay test. Altogether, 222 serial serum specimens from 51 patients with acute rubella infection were tested. Both IgG and IgM antibodies developed rapidly and appeared in all patients within 4 days after the onset of rash. In some patients, the IgM antibodies clearly preceded the IgG antibodies; however, the reverse situation was also noticed in a few cases. The IgG antibodies showed only minor changes after 8 to 10 days from the onset of rash. The IgM titers also reached a maximum level at approximately 8 to 10 days after the onset of rash, after which time a rapid decrease was normally seen. The mean half-life of IgM antibodies after 15 days from the onset of rash was 4.5 days, giving for IgM antibodies persistence times from 43 to approximately 80 days. Two patients with a prolonged IgM antibody response were detected. One of these patients had bilateral arthritis of the knee as a complication, whereas in the other patient no complication caused by rubella virus was detected. The IgM antibody response and its value in diagnosis are discussed.

Specific immunoglobulin responses in serum and nasal secretions after the administration of attenuated rubella vaccine

The indirect immunofluorescent technique has been used to study the specific immunoglobulin responses in the sera of 63 non-immune adult women who received either Cendehill rubella vaccine subcutaneously, RA27/3 rubella vaccine subcutaneously, or RA27/3 vaccine intranasally. IgG, IgA and IgM antibodies increased virtually simultaneously, starting about 2 weeks after vaccination. IgG antibody appeared in all subjects and reached maximum titres 4-6 weeks after vaccination. The mean IgG titres elicited by the three different methods of vaccination did not differ significantly. IgA and IgM antibodies reached their highest titres between 21 and 28 days after vaccination and then declined to low or undetectable titres within about 9 weeks. The maximum IgA titres observed after intranasal administration of RA27/3 vaccine were significantly higher than those which occurred when the same vaccine was given subcutaneously, but no significant difference in IgM titres was observed. When unfractionated sera were examined IgA antibody was detected in 57 cases (91%) and IgM in 51 (81%). Fluorescent examination of fractions obtained by centrifugation on sucrose density gradients frequently revealed small amounts of IgA and IgM antibody which could not be detected by staining unfractionated serum, and with the inclusion of these results IgA antibody was detected in 61 cases (97%) and IgM in 59 (94%).When 39 adults with pre-existing serum antibody were challenged with vaccine a definite IgA response was detected in only one subject and in no case was there any evidence of the appearance of IgM antibody.Nasal antibody, consisting of IgG or IgA or both, was detected in 17 out of 23 non-immune subjects (74%) who received RA27/3 vaccine, either subcutaneously or intranasally. Titres were much lower than those which occur in the natural disease and there was no evidence that nasal antibody was elicited more readily by intranasal than by subcutaneous vaccination.

IgG, IgA and IgM responses in acute rubella determined by the immunofluorescent technique

The indirect immunofluorescent technique has been used to study the specific immunoglobulin responses in twelve adult cases of acute uncomplicated rubella. IgG, IgA and IgM antibodies increased virtually simultaneously. IgG antibody persisted throughout the period of study but showed a slight tendency to fall in titre after 7 months. IgM antibody was detected in nine cases. In these patients it was present in high titre 5-15 days after the rash but was not detected after 20 days. IgA antibody was detected in all cases. It was present in high titre 5-20 days after the rash but was no longer detectable after 29 days except in one patient who had a very low titre at 78 days. The presence of specific IgA and IgM indicates recent rubella in uncomplicated cases, and if the immunofluorescent method is used both types of antibody should be sought.