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Monitoring the circulation of the measles virus and studying its genetic diversity is an important component of the measles elimination program. A methodological approach to molecular genetic studies and their interpretation in the measles surveillance was developed in the early 2000s. During its development, clear areas of circulation of each genotype of the virus were identified, therefore, the determination of viruses' genotypes was proposed to monitor circulation and identify transmission pathways. However, in the future, due to a significant decrease in the number of active genotypes, an approach based on sub-genotyping was proposed: determining not only the genotype of the virus, but also its genetic lineage/genetic variant. The Global Measles and Rubella Laboratory Network (GMRLN) systematically monitors the circulation of the measles virus at the sub-genotypic level, depositing the results in a specialized database MeaNS2. It is this database that is the most complete and reliable source of information about the genetic characteristic of measles viruses. This review presents both historical information and the latest data on the global genetic diversity of the measles virus.

Aim: Evaluate effectiveness of measures specified by epidemiologic control for rubella in pregnant women., Materials and Methods: 585 pregnant women with suspected measles were laboratory examined in 10 Regional Centers of Control for Measles and Rubella by EIA., Results: 24 rubella infected pregnant women aged 16-36 years were detected among the examined pregnant women, most of those (91.7%) were either not immunized against rubella or had unknown immunization anamnesis: 16 women terminated pregnancy, in 8 women pregnancy ended with delivery at term. Of the 8 newborns only a single child had innate rubella infection (the child was clinically healthy)., Conclusion: Epidemiologic investigation of each rubella case in pregnant women with obligatory laboratory examination of women and source of infection revealed a significant number of women at childbearing age susceptible to rubella virus that retains the possibility of birth of children with innate rubella syndrome.

Nine commercial kits of "captured" and "indirect" format ELISA assay for the detection of specific IgM and IgG in sera of patients with measles were compared to each other. 72 sera specimens from typical medium-severity cases from a measles outbreak (2010) were collected on the 5-6th day after the rash onset. IgM was detected with "capture" tests (Vecto-Measles IgM, Vector Best, Measles IgM capture EIA, Microimmune Ltd) close to 100% of cases, irrespectively to the age and the initial vaccination status of the patients. The IgM result was negative in 23.6% by average while investigating using "indirect" format tests (Enzygnost Anti-Measles Virusll/IgM, Siemens; Anti-Measles Viruses ELISA (IgM), Eurominimum, Virion-Serion IgM (GmbH). These cases were in adults, the majority of which had 1-2 vaccinations in the past. The analysis of the presented data shows high correlation connection between the tests used and high confidence level for OD IgM and IgG of the sera of the patients with the primary and secondary immune response.

119 specimens of blood sera collected from measles cases with different vaccination history (aged 4 months to 48 years) on 5th-6th days after rash onset were Investigated using EIA. The obtained results showed that the primary immune response (PIR) was developed in 59 patients; the secondary immune response (SIR) was developed in 60 patients with a significant increase in the specific high avidity IgG (22.34 IU/ml +/- 3.2). The specific IgM were detected in 100% cases studied with capture ELISA in both previously vaccinated and unvaccinated individuals of different age. The specific IgM were detected by indirect ELISA in 100% cases in unvaccinated patients, while IgM positive sera was defined only in 23.3% of individuals with SIR. It was concluded that measles virus infection in previously vaccinated and unvaccinated adults had clinical differences. The role of patients with SIR in virus transmission was discussed.

A simple semiquantitative method for measuring anti-measles IgG subclasses is developed on the basis of commercial diagnostic test system for measurements of anti-measles IgG and a kit of peroxidase-labeled monoclonal antibodies to human IgG subclasses. During the acute phase of the disease specific antibodies are presented mainly by IgG2 antibodies, while in subjects with a history of measles more than 10 years before 2 subgroups were detected, which responded by production of IgG2 or IgG1 subclasses.

Eleven wild measles virus isolated, in 1988 and in 1999-2001 in the European territory of the Russian Federation, were investigated. On the basis of an analysis of N-gene region sequences, encoding the COOH terminal end of nucleoprotein, the isolates were divided into 2 subgroups. According to the WHO classification, subgroup 1 was in line with genotype A and subgroup 2--with genotype D. Subgroup 2 was close to genotype D4 but differed from it according to its composition of nucleotides on the average by 2.8%, and according to its amino-acid composition--by 2.6%. with respect to the WHO criteria, the latter can be referred to preliminarily as an independent genotype. Finally, the measles viruses' strains of genetic groups A and D circulated in the Russian Federation in 1988, and in 1999-2001.

In some measles virus strains protein synthesis is restricted or reduced at higher temperature incubation. But in wild-type Buk strain and L-16 vaccine strain no changes in viral protein synthesis at 40 degrees C were shown. Radiolabelled Buk and L-16 proteins were precipitated with reconvalescent sera, vaccinated children's sera, subacute sclerosing panencephalitis patients' sera and rabbit antisera. There are no differences in the autoradiograms. However, antigenic variations in Buk strain proteins were discovered by using mAbs in radioimmunoprecipitation analysis. Buk strain hemagglutinin (H protein) has low binding ability in epitopes II and III in comparison with L-16 strain. Analogous changes were found in the epitope II of Buk strain phosphoprotein. Nucleocapsid, fusion and membrane proteins of the two strains have the same interactions with mAbs. In order to investigate H protein affinity with antihemagglutinins and receptors for erythrocytes a modified test for HA-inhibiting antibodies was used. But incubation time for sera and tween-ether antigens was varied from 0 min to 1.5 h. In "0 min" incubation time hemagglutinin can bind with antihemagglutinins or receptors for erythrocytes. But H protein binds more readily with antibodies. Buk strain H protein revealed antihemagglutinins in higher titers than L-16 strain antigen.

The liposomal technology for preparing the immunostimulating complex (ISCOM) helped obtain a complex measles preparation whose antigens are represented by the structural proteins of measles virus in the bilayer phosphate-lipid membrane. Immunization of mice with the resultant preparation induced antimeasles antibodies with the maximum titer of antihemagglutinins 1:640 and of antihemolysins 1:1280. The biological activity of antibodies was confirmed in the neutralization test.

Nucleotide sequences of P/C gene of measles virus IL wild strain and L-16 vaccine strain were compared with the previously reported nucleotide sequence of Edmonston vaccine strain P/C gene. The primary structure of IL strain P/C gene was characterized by two substitutes in 395 (U-C) and 722 (G-A) positions in comparison with the primary structure of a similar Edmonston strain. Nucleotide sequence of L-16 vaccine strain P/C gene differed from the similar sequence of Edmonston vaccine strain by 3 substitutes in 90 (A-G), 399 (U-C), and 448 (U-C) positions. Comparative analysis of nucleotide substitutes in the P/C gene of L-16, IL, and Edmonston strains indicates that the mutations revealed in the L-16 strain P/C gene are not caused by the strain attenuation, but merely reflect the difference between the strains.

The examination of children in the Far North and moderate zones has revealed essential differences in the formation of humoral antimeasles postvaccinal immunity. After booster immunization with live measles vaccine specific anti-hemolysins are more intensively synthesized than anti-hemagglutinins under the conditions of the Far North. In the moderate climatic zone the repeated injection of live measles vaccine induces more intensive synthesis of specific anti-hemagglutinins, rather than anti-hemolysins. Serological examination made prior to booster immunization is also of great importance, as the most intensive synthesis of antimeasles antibodies is observed among children, seronegative to measles virus and children with low titers of antimeasles antibodies in their blood sera.

The qualitative and quantitative analysis of antibodies to measles virus (MV) structural proteins (SP) in sera from patients with chronic glomerulonephritis (CGN), chronic active hepatitis (CAH), and liver cirrhosis (LC) was done. The patients were shown to have neutralizing antibody titres (NAT) higher than those in healthy subjects. An analysis of antibodies to SP was carried out by the radioimmunoprecipitation assay. Antibodies were detected to hemagglutinin, nucleoprotein (NP), fusion protein and to matrix protein (M) both in sera from the patients with these chronic diseases, healthy subjects, and patients with active measles. (The two latter groups were selected for comparison). However, some patients with CAH and LC had no antibodies to M protein in spite of very high NAT. The quantitative analysis of MV antibodies to SP was done only for NP because this antibody had the least individual variations. The quantity of anti-NP antibodies was higher in most sera from patients with chronic diseases than in those from healthy subjects, and reached the level of that in patients with active measles. The presence of MV genome in the peripheral blood lymphocytes from patients CAH, CGN, and LC had been shown earlier. So it is assumed that MV persists in lymphoid tissue where the expression of all SP genes is realized.

Four isolates of measles virus (Gag, Il, Buk and Shed) were obtained from suspensions of mononuclear cells from patients at the active stage of the disease. Vero cells were used for the virus isolation. All the isolates caused in the infected cell culture the appearance of symplasts of differently sized, star- or spindle-shaped multinuclear cells. The specificity of cytopathic effect was proved by the adsorption of monkey erythrocytes on the surface of cells infected by virus. The isolates were identified in virus neutralization (VN) and haemagglutination inhibition (HI) tests with different immune preparations: measles-globulin (standard), hyperimmune sera to rubella and mumps viruses, Sch. Zonne and Sch. Flexneria, as well as with conjugates of sera from measles patients and those vaccinated with live measles vaccine (LMV) L-16.

Three measles strains Gag, Il, and Buk, were isolated from a suspension of mononuclear cells derived from measles patients in the active stage of the disease. Continuous Vero cell cultures were used for virus isolation. In the infected cell culture, all the isolates produced symplasts of different sizes and star-shaped or spindle-shaped multinuclear cells. The specificity of the cytopathic effect was proved by the adsorption of monkey erythrocytes on the surface of virus-affected cells. The isolates were identified in neutralization and HI tests with different immune preparations: measles gamma-globulin (national standard), hyperimmune rabbit sera to measles (Edmonston strain), rubella, and mumps viruses, S. sonnei and S. flexneri, as well as with sera from measles patients and subjects vaccinated with live measles vaccine L-16. The results of identification attest to isolation of 3 measles virus strains, one of which (Buk) possesses particularly high hemagglutinating activity.

The comparative study of the humoral and cellular characteristics of antimeasles immunity in children immunized with live measles vaccine Ji-16, and in children having had measles revealed that both "wild" and vaccine strains of measles virus induced similar changes in the organism of the child: the synthesis of specific antibodies belonging to different physico-chemical classes, changes in the content of different serum immunoglobulins and the suppression of the blastogenic response of peripheral blood lymphoyctes to phitohemagglutinins. The changes suggest that both T- and B-lymphocytes took part in the formation of antimeasles immunity, but all these processes were more pronounced during the formation of postinfection immunity.

To determine the physico-chemical nature of specific antimeasles antihemolysins, an enzyme immunoassay (EIA) system with the use of stable measles virus hemolysing antigen has been developed. The expedient method has been worked out: the antigen diluted 1:20 with the initial hemolytic activity in the direct hemolysis inhibition test equal to 1:64 and, for its fixation, 0.1 M carbonate-bicarbonate buffer solution, pH 9.6, are used; the fixation of the antigen is carried out at 4 degrees C for 16-20 hours. The final dilution of the serum, whose coloration significantly differs from that of the control, is considered to be the titer of antimeasles antihemolysins. Specific antihemolysins belonging to three classes of immunoglobulins, A, M and G, are synthesized in measles. The detection of IgM-antihemolysins in high titers on the first day of rash opens prospects for using the newly developed EIA system for the rapid diagnosis of measles.

The formation of postvaccinal measles immunity under the conditions of the uncomplicated development of the postvaccinal process and in cases of concomitant acute respiratory viral infection (ARVI) was studied. The peculiarities of immunological reaction to ARVI in the postvaccinal period in children were characterized by disturbances in measles antibody synthesis and changes in the ratio and content of immunoglobulins. The negative influence of ARVI especially in cases of its appearance at an early period after vaccination, was manifested in decreased antibody production and in the gradual loss of immunity to measles in some children as they grew older.

The physicochemical and immunological properties of the experimental batches of the preparations of placental immunoglobulin, obtained by some methods of chemical modification of the molecule of IgG, have been studied. The possibility of abolishing the anticomplement properties of the preparations treated with sulfitolytic agents manufactured in the USSR has been shown. The optimum conditions permitting the production of the preparation with faintly pronounced anticomplement properties and the full monomer structure of its molecule have been established.