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Aim: Assessment of specific IgG levels in children with recurrent respiratory infections after immunization with Pneumo 23 and Act-HIB vaccines., Materials and Methods: Concentrations of IgG to polysaccharide capsular antigens and cell wall antigens of Streptococcus pneumoniae and Haemophilus influenzae were measured by solid-phase ELISA in sera of 256 immunized children., Results: Increase of levels of IgG to cell wall antigens and certain polysaccharide antigens was observed in patients with low or intermediate antibody levels at baseline., Conclusion: Obtained results allow to conclude that vaccination of children with recurrent respiratory and middle ear infections results in induction of IgG production that proves immunological effect of performed vaccination.

The retrospective evaluation of the intensity of postvaccinal immunity at different periods after the primary course of immunization against diphtheria and tetanus was made. In the sera taken from 130 children with systemic connective tissue diseases the content of antibodies to diphtheria and tetanus was determined. As revealed in this study, the protective levels of antibodies to diphtheria and tetanus toxoids were retained by both sick and healthy children for 5 years and longer. Significantly lower titers of antibodies to diphtheria and tetanus toxoids were registered in children undergoing therapy with glucocorticosteroids and cytostatics at the time of the study.

The procedure of obtaining monoclonal antibodies TT-1, TT-2, and TT-3 against tetanus toxin/toxoid is described. It is shown that both commercial DTP vaccine and tetanus toxoid conjugated with a low-molecular-weight hapten can be used an immunogens. Monoclonal antibodies TT-1 and TT-2 neutralized tetanus toxin in vivo. The monoclonal antibodies obtained were used to design and compare several schemes of quantitative determination of tetanus toxoid and toxin by ELISA. A more sensitive competitive ELISA allowed detecting as much as 0.01 EC/ml toxoid and 50 LD50/ml toxin.

The immunological effectiveness of the revaccination (made in two injections) of 488 adults aged 18-67 years with diphtheria-tetanus toxoid is discussed; the parallel study of the results of this revaccination was carried out in the diphtheria toxin neutralization test on Vero cells and in the passive hemagglutination (PHA) test. The specific features of the dynamics of the increase of diphtheria antitoxic antibodies, depending on the initial immunity level, the age and the sex of revaccinated persons, were determined. Among persons with the low level of circulating antibodies before revaccination four variants of immune response to the injection of diphtheria toxoid were registered: variant 1--rapid reaction like in secondary immune response (53.6%); variant 2--delayed but effective reaction like in primary immune response (27.3%); variant 3--slow weak response (6.5%); and variant 4--the absence of effective immune response to immunization made in 2-3 injections (12.6%). The immunological and neutralizing properties of diphtheria antitoxic antibodies in the process of immunization made in 2 injections were evaluated. Persons with abnormal immune response (variants 3 and 4) produced defective antibodies, displaying immunological activity in the PHA test, but in most cases unable to neutralize diphtheria toxin in vitro when tested on Vero cells.

The outbreak of diphtheria in the Republic of Belarus developed in the presence of a sharp deficiency of immunity among the population aged 35 years and over. In connection with a higher initial immunity level resulting from vaccination made in one injection the minimum antibody level (> or = 0.01 I.U./ml) was found in 79.7% of the examinees among the population under 35 years. For the age group of 35-60 years vaccination in one and two injections proved to be insufficiently effective (the minimum protective antibody titer was found, respectively, in 64.3% and 63.3% of the vaccinees). To achieve the full protection of this group of the population, vaccination in three injections was necessary; after that the minimum protective antibody titer was found in 90.7%, the protective antibody titer (0.1 I.U./ml) was found in 53.5% and the highly protective antibody titer (1.0 I.U./ml) was found in 11.6% of the examinees. The low level of highly protected persons among vaccinees receiving three injections was due to a low dose of diphtheria toxoid (2 Lf) in adsorbed DT-m vaccine with reduced antigen content.

The state of collective immunity to diphtheria and tetanus in children of preschool age, depending on the kind of vaccine preparation used for immunization, was studied. The immunological potency of adsorbed DPT vaccine (i.e. its capacity of forming prolonged and stable basic immunity) was shown to be higher in comparison with the potency of adsorbed DT toxoid with reduced antigen content (DT-R). The study revealed that in all groups of children the level of antitetanus immunity was higher than the level of antidiphtheria immunity, and 3 years later its decrease was less pronounced. A stricter approach to giving medical grounds for the use of low-reactive adsorbed DT-R in the immunization of children belonging to groups of risk is recommended.

An experiment of rabbits subjected to artificial lead intoxication revealed that after the immunization of the animals with adsorbed DPT vaccine myelopid and thymoptin exhibited practically the same immunomodulating activity with respect to antibody response to diphtheria and tetanus toxoids, exceeding that of rabbits without intoxication. Still the immunomodulators used in this experiment did not completely compensate the negative effect of intoxication on antibody response to the toxoids. For the first time after immunization with adsorbed DPT toxoid lymphocytes capable of binding diphtheria toxoid were detected and the specific features of their dynamics in comparison with the activity of antitoxin were established. Myelopid and thymoptin were found to modulate immune response, evaluated by the content of antigen-binding lymphocytes, the injection of thymoptin completely compensating the negative effect of intoxication.

The paper presents the data on the study, carried out on 383 guinea pigs, of the action of C.tetani cultures on immune reactions of the animals after the injection of tetanus toxoid. The state of the humoral and cell-mediated immunity of the animals (in the hemagglutination inhibition test, the neutralization test, the enzyme-linked immunosorbent assay and the skin allergic test with tetanin), as well as their resistance to challenge with C.tetani. The inhibiting effect of C.tetani on primary immune response to tetanus toxoid and their stimulating effect on secondary immune response have been established. This fact may be used for enhancing the quality of antitetanus preparations, such as toxoid and serum, as well as for working out tactical approaches for the rapid prevention of tetanus.

The extensive use of adsorbed diphtheria-tetanus toxoid with reduced antigen content was found to be ineffective in the prophylaxis of diphtheria: 86.3% of diphtheria patients among those who had been immunized with this preparation fell only a year after the first booster immunization, and the proportion of those who proved to be unprotected against diphtheria on years 3, 4 and 5 after immunization reached, respectively, 21.0%, 35.5% and 49.4%. The number of children immunized with this preparation at common preschool institutions may reach 50% and more, and with an increase in the coverage of children with immunization from 10% to 50% the proportion of unprotected children may rise from 7.4% to 17.8%. The proportion of preschool institutions, insufficiently protected from diphtheria and, as a consequence, running a considerable risk of becoming (in case of the penetration of this infection) the foci of diphtheria, was found to reach 32.9%.

The course of the vaccinal process was studied in 69 children with bronchial asthma and asthmatic bronchitis after the injection of adsorbed diphtheria-tetanus (DT) toxoid with reduced antigen content. After immunization all these children were found to form protective levels of anti-diphtheritic and antitetanus antibodies irrespective of the severity and duration of the remission of the main disease prior to vaccination; at the same time no obstructive changes in bronchial ventilation were observed after immunization with adsorbed DT toxoid with reduced antigen content. The schemes of the preparatory medicinal treatment of patients at the period of vaccination are given with due regard for the duration of the remissions of bronchial asthma and asthmatic bronchitis.

Comparative study of the immunological effectiveness of adsorbed diphtheria-pertussis-tetanus (DPT) vaccine and adsorbed diphtheria-tetanus toxoid with reduced antigen content (adsorbed DT toxoid R) in the immunization of children, carried out in accordance with the vaccination schedule, was made. Immune response to the injection of adsorbed DPT vaccine was higher than after immunization with adsorbed DT toxoid R, as evidenced by antibody titers. It was probably due to differences in the number of injections constituting the course of immunization: it consisted of 3 injections and 1 booster injection for adsorbed DPT vaccine and 2 injections and 1 booster injection for adsorbed DT toxoid R. Immunization with adsorbed DPT vaccine produced immunity which was retained for a longer period. These results are indicative of the expediency of the primary immunization of children with adsorbed DT toxoid R introduced in three injections in order to ensure more stable and prolonged postvaccinal (mainly antidiphtheria) immunity.

The dependence of immune response on commonly observed immunity characteristics prior to immunization has been established on the basis of the study of the kinetics of immune response in adults receiving injections of adsorbed diphtheria-tetanus (DT) toxoid with reduced antigen content, both for routine immunization and on epidemiological indications. The necessity of the practical use of immunological screening for the differentiated approach to the choice of a suitable preparation (adsorbed diphtheria toxoid, adsorbed DT toxoid or adsorbed DT toxoid with reduced antigen content) and immunization schedule for adults, especially in epidemic foci, has been substantiated.

The data on the influence of imuthiol on humoral and cell-mediated immunity developing after immunization against tetanus are presented. Experiments were made on 166 guinea pigs with the use of imuthiol in doses of 25 and 125 mg/kg and tetanus toxoid in doses of 1.5 and 6.0 BU/kg. The dynamic observation of the animals lasted 30 days. The data of the passive hemagglutination test and the neutralization test indicated that imuthiol had considerable influence on the formation of humoral immunity. The results of skin reactions with tetanin, in vitro cell reactions, as well as resistance tests, showed that imuthiol exerted influence on delayed hypersensitivity, the mechanisms of cell-mediated resistance and survival after challenge. The data on the influence of imuthiol could be registered even at early stages after immunization, the immunostimulating action of the preparation reaching its maximum with tetanus toxoid used in a dose of 6.0 BU/kg and imuthiol, in a dose of 125 mg/kg.

During a remission and drug therapy, 71 children suffering from allergic diseases were vaccinated with DT-M toxoid containing different dose of diphtheria (1, 2.5, 5 LF) and tetanus (1, 2.5, 5 EC) antigens. It has been shown that all the children responded to tetanus antigen by adequate serological tests, whereas as regards diphtheria toxoid, the patients immunized with the least dose of DT-M preparation (1 LF + + 1 EC antigens) produced specific antibodies later and at a lower level. During the postvaccinal period, they also manifested an increase of the content of IgE and exacerbation of the underlying disease in 17.8% of cases. The use of DT-M toxoid with 2.5 LF + EC antigens was shown to hold promise in vaccination of children suffering from allergic diseases.

The work was aimed at the comparative study of the intensity of immunity to diphtheria, tetanus and poliomyelitis, depending on the number of injections of adsorbed diphtheria-pertussis-tetanus (DPT) vaccine and poliomyelitis vaccine, for the purpose of finding out the possibility of reducing the antigenic load given to children without diminishing the intensity of immunity. To determine the level of immunity to diphtheria and tetanus, 1900 children under school age were serologically studied by the micromethod in the passive hemagglutination test. The intensity of immunity to poliomyelitis virus was studied in 333 children by means of the neutralization test. The immunogenic properties of the diphtheria component of adsorbed DPT vaccine were found to be less pronounced than those of the tetanus component of the vaccine, which made it impossible to reduce the antigenic load by decreasing the number of vaccinations against diphtheria. The results of the study of postvaccinal immunity to poliomyelitis suggest that during the first and second year of life the course of vaccination against poliomyelitis may be reduced to 3 injections.

The prolonged observations of the immunological effectiveness of adsorbed diphtheria-tetanus toxoid with reduced antigen content in children who had received the primary course of immunization with this preparation showed that the preparation induced the development of prolonged and intensive immunity to both infections. In 2-3 years after the first booster immunization the protective level of diphtheria antitoxin was registered in 89.9% and that of tetanus antitoxin, in 99% of children. 6 years later the level of immunity remained practically unchanged: the titers of diphtheria antitoxin above the protection level were determined in 92% and those of tetanus antitoxin, in 97% of children. These data made it possible to increase intervals between booster immunizations to 6-7 years in children of this category. The results of the epidemiological trial made to find out the possibility of a change in the timing of the second booster immunization confirmed the expediency of postponing booster immunization from 6 and 11 years to 9 and 16 years of age.

In experiments with mice a delay was noted in the development of secondary immune response to revaccination with a tetanic anatoxin after the combined effect of radiation and heat; the maximum antibody formation occurred at later times. The low level of antitoxins within the first 10 days after the combined effect of radiation and heat correlated with the low tetanus resistance of animals.

The possibility of decreasing the content of antigens in adsorbed diphtheria-tetanus toxoid, used for the booster immunization of children with allergically altered responsiveness and adults, is shown. Diphtheria toxoid in doses of 1-2.5 Lf and tetanus toxoid in doses of 1-2.5 binding units possessed sufficiently high immunological effectiveness in combination with low reactogenicity and good tolerance. In 6-12 months after booster immunization with decreased doses of toxoids 100% of children with allergy of different character and, respectively, 86-94% and 95% of adults have developed protective levels of antibodies to diphtheria and tetanus.

The results obtained in the study of the influence of histamine on the capacity of T-lymphocytes of guinea pigs immunized with DPT-vaccine and its components for spontaneous rosette formation are presented. Histamine at a concentration of 10(-3) M has been found to inhibit the capacity of blood and splenic lymphocytes of guinea pigs immunized with adsorbed DPT vaccine for spontaneous rosette formation. The inhibitory effect is more pronounced after the immunization of the animals with adsorbed DPT vaccine and Bordetella pertussis suspension.

The characteristics of antitetanus and antidiphtheria immunity in children, adolescents and adults in Perm have been determined by means of the passive hemagglutination test, and the tendency towards the decrease of their immunity to diphtheria with the increase of their age has been established. The registered and actual coverage of children and adolescents by immunization is characterized on the basis of the presence of antibodies to the tetanus component of combined vaccines. A considerable proportion of persons at boarding schools and vocational technical schools has been found to be seronegative with respect to diphtheria. The seasonal dynamics of antitoxic immunity is presented.

The immunological effectiveness of two batches of adsorbed DPT vaccine, the batch with the normal content of antigens (control) and the batch with the content of diphtheria and tetanus toxoids reduced to 20 Lf/ml and 5 BU/ml respectively (test batch), has been studied under the conditions of controlled trial. As a result, the reduction of the antigenic content of adsorbed DPT vaccine has been found to exert no negative influence on the immunological effectiveness of the diphtheria, tetanus, and pertussis components of this preparation under the conditions of the new immunization schedule.

The present article deals with the data on the duration of antidiphtheria immunity, induced by the primary cycle of immunization with adsorbed DPT vaccine, with the aim of considering the problems of optimizing the immunization schedule for children. The prolongation of the interval before the second booster immunization to 7-10 years produces no negative influence on the effectiveness of immunization. Besides, the study has shown that after the main complex of immunizations with adsorbed DPT vaccine protective immunity to diphtheria is retained in 90.3-96.8% of children covered by this study for 9-10 years. These data point to high immunological effectiveness of adsorbed DPT vaccine and to the possibility of prolonging the intervals between booster immunizations to 10 years, as well as decreasing the number of booster immunizations in the immunization schedule for children.

The content of antibodies to B. pertussis disintegrated cells, protein fraction and lipopolysaccharide in the blood of patients and convalescents has been studied. The study has revealed that in the blood sera of whooping cough patients the titers of antibodies to lipopolysaccharide considerably exceed the titers of antibodies to other antigenic fractions. The titers of IgM to lipopolysaccharide have been shown to exceed the titers of IgM to other fractions 1.5-2 times.

Adsorbed DPT vaccine and adsorbed DT toxoids with normal and reduced antigen content were used for the immunization of rabbits. The levels of IgM and IgG and the dynamics of antibodies to diphtheria and tetanus toxins and to Bordetella pertussis in the blood sera of the animals were studied in the postvaccinal period (on days 15 and 34). This study revealed that the reduction of the antigen content of adsorbed DT toxoid to 5 Lf of diphtheria toxoid and 5 binding units of tetanus toxoid did not decrease the capacity of the preparation for increasing the levels of IgG and IgM, antibodies to diphtheria and tetanus toxins in the sera of the rabbits. The reduced content of these toxoids in adsorbed DPT vaccine did not affect its capacity for inducing the enhanced synthesis of IgG, antibodies to diphtheria and tetanus toxins, while the production of IgM and IgA remained unchanged. At the same time an increase in the titers of antibodies to B. pertussis in the animals was less pronounced than that observed after the injection of commercial adsorbed DPT vaccine. Additional investigations are necessary in order to establish the protective potency of the pertussis component in adsorbed DPT vaccine with the reduced content of toxoids and to find out the optimum antigenic composition for this preparation.

The hyperimmunization of horses with large doses of tetanus toxoid is accompanied by an increase in the levels of both specific antitoxic antibodies and autoantibodies to the tissue antigens of the liver, the spleen, the heart. The reverse relationship between the level of autoantibodies and the titer of antitoxin has been established. The authors suggest that the synthesis of autoantibodies is stimulated by the presence of antigen-antibody immune complexes in the circulating blood, as well as by the action of exo- and endopolyclonal stimulators.

Monthly characteristics of antitoxic immunity to diphtheria and tetanus toxoids in 3,334 adults in Ryazan were determined. As a result, the following differences were established: the characteristics of antidiphtheria immunity were somewhat higher in the autumn-winter period and dropped to the minimal level in the winter-spring period; the maximal characteristics of antitetanus immunity clearly coincided with the hot season, its minimal characteristics with the cold season. For the first time the frequency and titers of normal antibodies to fraction I of Pasteurella pestis in humans were determined. Their monthly dynamics proved to be parallel to the curve indicating the characteristics of antitetanus immunity, but on a lower level: 1-10%. The presence of normal antibodies was accompanied by higher titers to tetanus toxoid, but not to diphtheria toxoid. According to the results of earlier studies, normal antibodies were shown to be the sign of homologous reactivity in inbred animals. Our data indicate that these antibodies can serve as the indirect sign of heterologous reactivity in humans.

The level and intensity of antitoxic immunity to diphtheria and tetanus in children and adolescents were determined. The presence of tetanus antitoxin in titers exceeding the protective level in 96.3-98.5% of the examined children and adolescents is indicative of a high actual coverage by immunization. Protective titers against diphtheria were lower. There was no essential difference in the levels of protection in children immunized according to the vaccination schedule and in those immunized with some deviations from this schedule. A considerable part of newborns and children aged 3 months had antibodies to diphtheria and tetanus antitoxins. After the third booster immunization changes in antidiphtheria immunity characteristics occurred only in 2.5% of the vaccines and no changes in antitetanus immunity characteristics were observed.

By immune chromatography fractions with various reaction rates of antigen precipitation and neutralization of toxin "in vivo" have been isolated from a common pool of antibodies. Antibodies of higher pI possessed an elevated relation of basis amino acid residues to unsubstituted dicarboxylic residues as well as greater affinity. The data suggest an important role of ion interaction and a general scheme of antigen and antibody molecules structure for immune reactions.

Experiments on guinea-pigs showed that 3 subcutaneous injections of adsorbed DPT vaccine resulted (on days 7-14 of the experiment) in the accumulation of cells, sensitized to brain extract, in the lymphoid tissue. The production of circulating anticerebral autoantibodies occurred, as revealed by the indirect immunofluorescent method, during the whole time of the experiment (35 days). On days 28-35 of the experiment cellular immune reaction to autologous erythrocytes was detected in the peripheral blood of the immunized animals. The intracardiac injection of smallpox vaccine to the animals resulted in the appearance of lymphoid cells, sensitized to brain extract, on days 3-7 of the experiment, as well as in the appearance of anticerebral autoantibodies, detected by immunofluorescence, which circulated in the blood for 28 days. Cellular immune reaction to autologous erythrocytes in the peripheral blood of the guinea-pigs immunized with smallpox vaccine was registered on days 3-28 of the experiment.

Inhibition of cellular and humoral immunity was established in children with grade I thymus enlargement syndrome (TES). The most pronounced changes were recorded in children aged 1-5 years. Vaccination against diphtheria and tetanus performed before the diagnosis of the TES was made were followed by satisfactory output of anatoxins, indicating the prospectiveness of the vaccination of the given children's group with DPT vaccine and DT- and DT-M-anatoxin.

Experiments in white mice have demonstrated an increase in the levels of damaged leukocytes in the body and in leukopoietic activity of the blood serum after primary immunization. An increase in the content of leukocyte decomposition products in the body, induced by the injection of neutrophil lysate, stimulated antibody formation in mice and enhanced phagocytic and cytotoxic activity of the peritoneal exudate macrophages in rats.

To decrease the antigenic load in booster immunizations of children against diphtheria and tetanus, the immunological effectiveness and reactogenicity of different doses of both antigens (i. e 1 Lf and 1 BU; 2.5 Lf and 2.5 BU; 5 Lf and 5 BU) were studied. The study revealed that all these doses of the preparation were practically nonreactogenic: the total of systemic reactions was 0.9%. The study of the immunological effectiveness of adsorbed DT toxoid with reduced antigen content revealed the advantage of the commercial dose of the preparation (5 Lf of diphtheria antigen and 5 BU of tetanus antigen) over such doses of diphtheria and tetanus antigens as, respectively, 1 Lf and 1 BU; 2.5 Lf and 2.5 BU. Still, this advantage disappeared as early as 6 months after booster immunization. The results of these investigations indicate that booster immunization of children aged 6 years and over may be made with lower doses of adsorbed DT toxoid with reduced antigen content.

Blood groups, including rhesus grouping, have been determined in 218 donors and HLA of loci A, B, C in 121 donors immunized with adsorbed tetanus toxoid (40 binding units). The presence of HLA Aw 32, B 8; HLA Bw 16, haplotypes A3 Bw 16 and A1, blank antigens of locus C is linked with the production of, respectively, high or low (less than or equal to 16 I.U./ml) antibody titers. The effectiveness of immunization is influenced by agglutinogen B, which is confirmed by its associations (in a complex with HLA Bw 16 or Bw 35) with low immune response.

The validity of immunizations, made in due time in children aged up to 7 years in accordance with the approved immunization schedule, is analyzed in this work. The content of antibodies to diphtheria, tetanus and poliomyelitis antigens in children immunized in accordance with the old and new schedules has been studied. This study has revealed that the injection of adsorbed DPT vaccine to children aged 3-4 months induces fully valid immune response to all antigens under study. The level of measles and parotitis antibodies after the injections of measles and parotitis vaccines, introduced separately and simultaneously, has been measured. The simultaneous administration of these preparations did not decrease the levels of immunity to parotitis and measles.

The epidemiological and immunological evaluation of two immunization schedules approved by the Orders of the USSR Ministry of Health No. 322 of April 24, 1973, and No. 50 of January 14, 1980, has been made on the basis of the results obtained in the Brest region of the Byelorussian SSR and in the Turkmen SSR. According to these results, the use of the schedule approved by Order No. 50 has made it possible to increase the groups of children receiving correct and timely immunization with measles vaccine by 8.3% and 28.8% and with adsorbed DPT vaccine by 17.2% and 5.5% in the Brest region of the Byelorussian SSR and in the Turkmen SSR respectively. Considerable groups of children have been found to be immunized with deviations from the approved schedules with respect to the scheme and time of immunization: 62.1% and 44.5% in the Brest region, 81.3% and 80.5% in the Turkmen SSR (during the periods of the implementation of Orders No. 322 and No. 50 respectively). Acute respiratory viral infections, bronchitis and pneumonia have proved to be the main reasons for medical exemption from immunization in both republics, these diseases constituting 61.6-71.1% of all medical contraindications. The negative influence of earlier infectious diseases on the level of postvaccinal immunity has been shown.

As the result of the study of tetanolysin-producing Clostridium tetani strains, their populations have been found to be markedly heterogeneous with respect to the hemolytic activity of clone cultures. On the basis of normal and dialyzed cultures of selected variants with maximum activity the preparations of tetanolysin have been obtained, and their hemolytic activity and antigenic properties have been studied. Antihemolytic rabbit sera have also been obtained and characterized. Partially purified preparations of tetanolysin with high hemolytic activity have been obtained by the fractionation of C. tetani dialyzed cultures with ammonium sulfate.

On the basis of the experimentally established dependence of the degree of binding of diphtheria toxoid with standard diphtheria antitoxin on the duration of their joint incubation with the maximum binding occurring in 3-4 hours of incubation at 37 degrees C, the method of the in vitro determination of the antigenic activity of diphtheria toxoid in liquid and adsorbed preparations is proposed. The method is based on the principle of double binding with the use of diphtheria antigenic (toxoid) erythrocyte diagnosticum. The antigenic activity of diphtheria toxoid, evaluated by the degree of its maximum binding with diphtheria antitoxin, correlated with its antitoxin-binding activity in animal experiments and did not correlate with its flocculating activity. The antigenic activity of diphtheria toxoid in adsorbed preparations, evaluated by their maximum binding with standard diphtheria antitoxin, was shown to be closely related to the immunogenic potency of these vaccines in animals.

The effectiveness of adsorbed DPT vaccine manufactured in the USSR, evaluated by its capacity of inducing the formation of the main classes of immunoglobulins and by the duration of immune response to the acellular complex of protective antigens (pertussis toxin and agglutinogen-2), was studied with the use of modified EIA. Out of 273 children immunized with adsorbed DPT vaccine in the course of this study, 87.2% had IgG-antibodies, 14.1% had IgA-antibodies and 3.2% of the children had IgM-antibodies. The level of immunity in children having received the full course of immunization with adsorbed DPT vaccine was significantly higher in comparison with children given only the primary course of immunization and nonimmunized children of the same age. Antipertussis immunity was found to decrease two years after the completion of the course of immunization with adsorbed DPT vaccine and in children over 5-6 years of age. Adsorbed DPT vaccine prevented the disease, but not infection. The level of postinfection immunity was higher than that of postvaccinal immunity.