[The serosubtyping of serogroup B meningococci]. / Serosubtipirovanie meningokokkov serogruppy B.

The results of the study of 116 Neisseria meningitidis strains, isolated from patients at different territories of Russia at the period of 1983-1992, by the method of the enzyme immunoassay are presented. 13.8 +/- 3.2% of the strains were found to have stereotype proteins and 59.5 +/- 4.5%, subtype proteins. In the population of circulating meningococcal strains no absolute prevalence of any single serotype or subtype was established. The comparison of the tendency in the course of morbidity rate and the state of the serosubtype composition of isolated group B N. meningitidis stains is indicative of the favorable situation with respect to meningococcal infection and the importance of further observation of the circulating strains.

[Intragroup serotyping of meningococci]. / Vnutrigruppovoe serotipirovanie meningokokkov.

The method for obtaining antisera to meningococci of different serotypes are described and the scheme for the preparation of serotyping is presented, as well as the method for the preparation of the determinate fraction of serotype 2. Antisera to typing antigens 1, 2, 2-7, 2-10, 4, 5, 6, 8 (1) have been obtained, their specificity tested in parallel experiments with American and French typing sera. When typing meningococci, the use of antisera to purified protein antigen 2 is recommended.

[Specific activity of colored variants of N. meningitidis colonies]. / Spetsificheskaia aktivnost' tsvetnykh variantov kolonii N. meningitidis.

The character of fluorescence of the colonies formed by serogroup A meningococci (229 strains) in oblique light and their activity in the agglutination test with group specific S and RD antisera to the meningococcal dissociant of the same serogroup were studied. Orange and orange-green colonies were found to have pronounced group-specific activity, and faint gray colonies changed the character of their agglutination with the group-specific antiserum up to the loss of agglutinability; and simultaneously their capacity for agglutination with the antiserum to the dissociant was revealed. The study of the character of fluorescence and the group-specific activity of meningococcal colonies belonging to other serogroups provided similar results.

[Epidemiological surveillance of meningococcal infection and the prediction of the development of an epidemic process]. / Epidemiologicheskii nadzor za meningokokkovoi infektsii i prognozirovanie razvitiia épidemicheskogo protsessa.

The signs necessary for the prognostication of the development of the epidemic process have been formulated on the basis of the epidemiological analysis of materials obtained in the process of trials of the system for the surveillance of meningococcal infection with the use of previously established characteristics. The data on the prevalence of meningococcal infection among different age groups and on the seasonal distribution of the infection as well as on the serogroups of meningococci isolated from patients, have been shown to be of importance for prognostication.

[The type subtyping of meningococci by means of whole-cell immunoenzyme analysis]. / Tipo-subtipirovanie meningokokkov metodom tsel'nokletochnogo immunofermentnogo analiza.

In this work the method of the whole-cell enzyme immunoassay, used for the serotype-subtyping of meningococci by means of specific monoclonal antibodies, is described. High specificity of the method, the simplicity of the assay procedure and evaluation of its results, as well as the availability of this method for practical use, have been demonstrated. The results of this investigation confirm the importance of the evaluation of type-subtype appurtenance of reference and laboratory strains used in experiments. Study of 72 meningococcal strains obtained from patients has revealed their polyclonal character in respect of their type-subtype signs.

[An analysis of the epidemic cycle of meningococcal infection in Russia (1969-1993)]. / Analiz épidemicheskogo tsikla meningokokkovoi infektsii v Rossii (1969--1993).

In this work the specific features of the epidemiological rise of morbidity in meningococcal infection in Russia for the period of 25 years are analyzed. Some factors influencing the intensity of the disease, such as etiology, specific features arising from the age of patients, social and territorial factors, are analyzed. Two waves of epidemic have been established in a single epidemic cycle. The first wave of epidemic was caused by meningococci of group A and characterized by the prevalence of city-dwellers among the patients; the second wave was caused by meningococci of groups A and B with the prevalence of the latter, especially during the period of the slump of the wave. The "Asiatic" and "European" types of morbidity were distinguished (in Moscow and St. Petersburg). The analysis of the epidemic cycle of meningococcal infection indicates the expediency of the development of new specific wide-profile preparation for prophylaxis.

[Antigenic affinity of meningococci and human A- and B-group erythrocytes]. / Antigennoe rodstvo meningokokkov i éritrotsitov cheloveka gruppy A i B.

The use of the modified method of isohemagglutinin adsorption by microbial antigens in experiments with the causative agent of meningococcal infection has led, for the first time, to the detection of meningococcal antigens affined to the antigens of human erythrocytes, groups A and B. The antigenic affinity of group A erythrocytes and meningococci has proved to be more pronounced in meningococcal strains isolated from the spinal fluid of patients than in cultures obtained from the nasopharynx of healthy persons. The detection of the affinity of these antigens makes it possible to explain the mechanism of differences in the susceptibility of persons with different blood groups to meningococcal infection by "antigenic mimicry".

[Meningococcal serogroup B infection]. / Meningokokkovaia infektsiia serogruppy B.

The results obtained in the examination of patients with meningococcal infection during the period of 1980-1985 are analyzed. The increasing role of serogroup B meningococci in the etiology of the generalized forms of infection, especially in children aged under 3 years and in adults over 50 years, is shown. As noted in this investigation, the disease induced by group B meningococci runs a more severe course. Morbidity caused by this serogroup of meningococci does not result in epidemics in our country. The distribution of patients among different age groups and specific features of the clinical course of the disease in connection with the serogroup of the causative agent make it possible to regard the risk groups as groups with decreased reactivity, which raises doubts concerning the possibility of forming effective postvaccinal immunity against group B meningococci in such persons.

[Biological properties and serological types and groups of pneumococci isolated from suppurative meningitis patients]. / Biologicheskie svoistva i serologicheskie tipy i gruppy pnevmokokkov, vydelennykh ot bol'nykh gnoinymi meningitami.

The results of the study of the biological and serological properties of pneumococci isolated from the cerebrospinal fluid and the blood of patients with purulent meningitides are presented. Serological types were determined in 64 pneumococcal strains. They were found to belong to 16 known serological types and groups; of these, 10 had been included into the existing 14-component polysaccharide capsular pneumococcal vaccine. Serotypes 1, 19, 6, 12 and 20 were most frequently isolated from patients irrespective of their age; from children meningococci of serotype 12 were most frequently isolated. In lethal cases types 1, 19 and 2 were isolated from adults and type 12, from children. At the moment of isolation pneumococci possessed biological characteristics typical of this species.

[Increased specificity of immunoenzyme analysis for diagnosing meningococcal infection]. / Povyshenie spetsifichnsoti immunofermentnogo analiza dlia diagnostiki meningokokkovoi infektsii.

The ELISA test system for the detection of polysaccharide antigens of meningococci, groups A and C, on the basis of the neutralization of specific antibodies has been developed. The specificity of this reaction is determined by the chemically pure preparations of group A and C meningococcal polysaccharides. The sensitivity of this test system based on the neutralization of antibodies is not inferior to that of ELISA with the use of double antiserum.

[Specific latex preparations in the etiological diagnosis of suppurative bacterial meningitis]. / Spetsificheskie lateks-preparaty v étiologicheskoi diagnostike gnoinykh bakterial'nykh meningitov.

The results of the evaluation of the diagnostic latex preparations Bactigen, manufactured by Wampole Laboratories (USA) and intended for the detection of meningococcal antigens, serogropus A, B, C, Y, pneumococcal polyantigens and type b Haemophilus influenzae antigens in the spinal fluid and blood of patients with meningococcal infection and purulent bacterial meningitides, are presented. The pathological material was studied by traditional methods and by the latex agglutination (LAG) test. 522 LAG tests were made, including 414 tests for meningococcal infection, 60 tests for pneumococcal infection and 48 tests for type b H. influenzae. The results of this study revealed that the latex preparations were highly specific with respect to type b H. influenzae antigens and meningococcal antigens (false positive reactions constituted 0.96%). The simplicity of the test and the rapid techniques making it possible to obtain results within 30-40 minutes indicate good prospects of using the LAG test in laboratory practice.

[Evaluation of the toxicity of meningococcal antigens by the development of paw edema in white mice]. / Otsenka toksichnosti meningokokkovykh antigenov po razvitiiu oteka lap belykh myshei.

The comparative evaluation of group A meningococcal antigens of different chemical nature (protein, polysaccharide, lipopolysaccharide and complex fraction) was made by the method of paw edema. The preparations were introduced in a dose of 100 micrograms/0.05 ml. The dynamics of the development of edema was observed. The chemical nature of the injected antigen was found to be related to changes in the character of edema in time: edema reached its maximum 3 hours after the injection of protein and 48 hour after the injection of lipopolysaccharide. The animals showed practically no reaction to polysaccharide.

[Epidemiological characteristics of meningococcal infection in Cuba]. / Epidemiologicheskie isibennosti meningokokkovoi infektsii na Kube.

The results of the epidemiological analysis of the morbidity rate in meningococcal infection for 1976-1984 are presented. The maximum rise of morbidity rate, equal to 14.4 per 100000 of population, was observed in 1983. Primarily, the rise of morbidity rate in 1979 was induced by meningococci of two serogroups: C (44.6%) and B (36.4%). The vaccinal prophylaxis of the population, carried out in 1979 with the use of polysaccharide vaccine A + C, did not affect morbidity caused by group B meningococci. The isolation rate of these organisms reached 98.7% from patients and 81.0% from carriers. The characteristic feature of the epidemic process of meningococcal infection in Cuba was a considerable increase in the number of patients under 1 year of age and the absence of seasonal fluctuations in morbidity rate.

[Epidemiologic analysis morbidity with meningococcal infections in the USSR]. / Epidemiologicheskii analiz zabolevaemosti meningokokkovoi infektsii v SSSR

The authors present the analysis of the incidence of epidemic cerebrospinal meningitis in the USSR from 1937 to 1974, and of meningococcus infection from 1965 to 1974. A rise of the meningococcus infection incidence from 1969 to 1974 was recorded 28 years after the elevation of 1940-1942 and was 1.5 times below this latter rise. The rise in 1969-1974 was characterized by marked signs peculiar to the infection with the droplet transmission mechanism; among those who contracted the disease prevalence was seen among children aged under 14 years (63-72%). A marked affection of juveniles was noted. Three types of the dynamic of the meningococcus infection incidence in the republics located in different climatic-geographical zones of the USSR were noted: slow, gradual increase of the level, interrupted and explosive. Such character was determined in the dynamics of the seasonal elevations of morbidity. Antiepidemic measures including a complex of nonspecific measures could not be assessed as sufficiently effective. This finds reflection in the natural course of the epidemic process of the meningococcus infection which remains uncontrolled. From the patients with generalized form of the disease meningococci of group A were isolated in 80-100% of cases, from the number of those typed. The group-specific reference of the nasopharyngeal strains depended on the epidemic situation: strains of serological group A prevailed at the period of the morbidity elevation, and other serological groups (particularly of C and B) increased at its decline.

[Neuraminidase activity of N. meningitidis]. / Neiraminidaznaia aktivnost' N. meningitidis

The work was aimed at the study of the neuraminidase activity of meningococci. The optimal conditions for detection of this enzyme in meningococci were chosen preliminarily. In experiments carried out with the observance of these conditions it was shown that meningococci of the main serological groups possessed neuraminidase activity revealed in the exponential growth phase of the microorganisms and was apparently of great pathogenetic significance providing a possibility of overcoming the physiological barrier of the host organism by the microbes.

[The epidemiological characteristics of meningococcal infection in the USSR]. / Epidemiologicheskie osobennosti meningokokkovoi infektsii v SSSR.

The epidemiological analysis of morbidity in meningococcal infection in the USSR in the period of 1969-1987 showed that the second rise of the morbidity level occurred in 1984 and was followed by its decrease in most of the regions of the USSR. This study also revealed that the characteristic feature of the second rise of morbidity in meningococcal infection was a considerable involvement of young children (aged up to 3 years), as well as the increased etiological role of group B meningococci in cases of meningococcal infection and the circulation of these microorganisms among the population. Besides, the preservation of the etiological importance of group A meningococci in many regions of the USSR, especially among adults, was noted. In this connection, the use of Soviet group A meningococcal polysaccharide vaccine on epidemiological indications was considered to be epidemiologically substantiated.

[Serotypes of meningococci isolated in the USSR and the Republic of Cuba]. / Serotipy meningokokkov, vydelennye v SSSR i Respublike Kuba.

The results of serotyping of 101 meningococcal strains isolated in the Soviet Union and 23 strains isolated in the Republic of Cuba are presented. Typing within groups was carried out by Frasch's method in the double diffusion test in gel. For this purpose serotype antigens were prepared from each strain. These antigens were used in the test only after their purification by ultracentrifugation. In all cases the prevalence of serotype 2 was revealed. A great number of Cuban strains contained a wide spectrum of type antigens of both protein and lipopolysaccharide nature. Serotype antigen 15 occurred in meningococci isolated both in the USSR and in Cuba. In most cases type 15 occurred in combination with types 2 and 8. The comparison of the results obtained in the serotyping of meningococci isolated in situations, nonepidemic (USSR) and epidemic (Cuba) for serogroup B, gives no grounds for considering type 2 as the "marker of virulence". Probably, this problem will be solved by the differentiation of subtypes within type 2. Attention should be paid to the serotype antigens of the lipopolysaccharide nature with a view to their epidemiological evaluation.

[Determination of meningococcal antibodies by a radial hemolysis method]. / Opredelenie protivomeningokokkovykh antiel metodom radial'nogo gemoliza.

The possibility of using, on principle, the reaction of radial hemolysis for the determination of antibodies to meningococci has been shown. The sensitivity and resolution of this method has been found to depend on the dose of the antigen used for the sensitization of erythrocytes, on the concentration of the erythrocyte suspension introduced into the gel and on the amount of complement. The optimum conditions for the reaction of optimum hemolysis, used for the determination of antibodies to serogroup A Neisseria meningitidis polysaccharide, have been established: the sensitizing dose of the antigen must be 50-100 micrograms/ml, the concentration of sensitized erythrocytes 25%, and the amount of complement 20-40 HU.

[Immunoepidemiological characteristics of the duration of a meningococcal carrier state]. / Immunoépidemiologicheskaia khrakteristika dlitel'nosti meningokokkovogo nositel'stva.

The duration of meningococcal carriership in children and adults in the foci of infection and outside such foci and the immunological characteristics relating to group-specific meningococcal antigens A, C, X, Y and Z at different periods after the detection of the infective agent in the nasopharynx have been studied. Carrier state has been shown to last, on the average, 11 days. The duration of the release of meningococci from the nasopharynx has proved to be influenced by the epidemic situation in a given group. Differences in the time course of the immunological reorganization of the body in response to antigenic challenge in prolonged and short-term carrier state have been detected. These data suggest that rapid immune response to meningococcal antigens in the process of short-term carrier state is probably one of the factors preventing the prolonged colonization of the nasopharynx by the infective agent.

[The characteristics of the serological diagnosis of meningococcal infection in children in the 1st years of life]. / Osobennosti serologicheskoi diagnostiki meningokokkovoi infektsii u detei pervykh let zhizni.

The results of clinico-immunological examination of 181 children, aged 1 month to 6 years, with generalized forms of meningococcal infection are presented. In children under observation antimeningococcal antibodies to group-specific meningococci of the main groups A, B and C were determined over the course of the disease by passive hemagglutination (PHA) test and enzyme immunoassay (EIA). The level and frequency of seroconversion were found to depend on the patient's age and the severity of the clinical course of meningococcal infection. Antibody level was found to increase simultaneously with respect to several meningococcal polysaccharides: A, B in 18.5% and A, B, C in 3.3% of cases. In the clinical interpretation of data obtained in the PHA test and EIA not only the patient's age, the form and duration of meningococcal infection, but also serotherapy should be taken into consideration, as the latter may distort the serological results.