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B F Semenov

Publications and source records attributed to B F Semenov.

At least 19 recordsLinked to original sources
PubMed2003

[New assumptions in the concept of vaccine prophylaxis of infantile infections].

An essential reduction in the incidence rate of six infantile infections within the Expanded Immunization Program was accompanied by occurrence of new problems in vaccine prophylaxis. 1. Vaccine-dependence--the reoccurrence of vaccine-prevented infections in those cases when vaccination was stopped. 2. A choice of strategy in the immune prophylaxis of poliomyelitis during the post-liquidation period bearing in mind the elimination of vaccine strains from the human population and a possible global refusal from vaccination. 3. Elaboration of regional programs for eliminating the measles in big territories. 4. Alteration of protective antigens Bordotella pertussis. The relationship of such alterations correlates with a rise in the Bordotella pertussis incidence rate with regard for multiple comprehensive vaccinations in the USA and Western Europe.

Bordetella pertussis↗
PubMed2002

[Use of the multi-component VP-4 vaccine to prevent acute respiratory diseases at preschool children's establishments].

The multicomponent VP-4 vaccine from Klebsiella pneumonia, Staphyloccocus aureus, Proteus vulgaris, Escherichia coli antigens was used to prevent acute respiratory diseases (ARD) at preschoolchildren's establishments. Prevention was effected during an influenza epidemic with a drastic rise in the incidence of ARD. The VP-4 use involved 3 nasal and 6-9 oral administrations of the drug at an interval of 3-4 days. The duration of the course was 26 +/- 4 days. The preventive action of VP-4 on the incidence of ARD was followed up for 14 months after vaccination. One group comprised 89 vaccinated children, a matched group included 69 children whose age was 2 to 6 years. Immunoprophylaxis was found to promote a reduction in the number of children who had 4 ARD episodes or more during the whole follow-up. Administration of VP-4 prevented the development of repeated episodes ARD in a group of children aged 2-3 years and in frequently ill children who had 3 infections or more in the previous year. The slight reactogenicity of the drug and its long-term preventive effect allow this method of immunoprophylaxis to be recommended for frequently ill children, for those at high risk, and for those in the junior age group (under 4 years) before going to preschoolchildren's establishments.

Bacterial Vaccines↗
PubMed2001

Drug sensitivity of Candida yeast isolated from patients with allergic diseases.

Viability of 40 Candida spp. cultures was studied after long-term exposure to antifungal drugs in minimum inhibitory concentrations. The fungicidal effect decreased in the series: pimafucin-nitrofungin-diflucan-orungal-levorine-clotrimazole-exoderil. Nizoral in a concentration of 4 microg/ml was ineffective; in the rest cultures the effect was either fungistatic (of different degree) or null. Pimafucin, diflucan, nitrofungin, orungal, levorine, and exoderil possessed individual fungicidal effects.

Antifungal Agents↗
PubMed2000

Yeast fungi in patients with allergic diseases: species variety and sensitivity to antifungal drugs.

Yeast microflora was studied in the skin of 91 patients with atopic dermatitis, in bronchial secretion of 13 patients with bronchial asthma and 8 patients with allergic bronchopulmonary mycosis. Forty-eight isolates were obtained. Alypophilic yeast fungi isolated from the skin were presented mainly by genera Candida spp. (48%) and Rhodotorula spp. (29%), while the cultures isolated from bronchial secretion mainly by Candida albicans. The sensitivity of yeast cultures to the antifungal drugs diflucan, clotrimazole, nizoral, orungal, exoderil, levorin, pymafuzin, and nitrofungin was determined. The most efficient drugs were diflucan, clotrimazole, nizoral, and orungal. More than half isolates were sensitive only to the high concentrations of levorin (48%), pymafuzin (75%), and nitrofungin (82%); 64% isolates were insensitive even to high concentrations of exoderil. Preliminary in vitro selection of the antifungal drugs is required for efficient elimination of the yeasts.

Adolescent↗
PubMed1998

[Protein E 98-113 sequence is a fusion site of tick-borne encephalitis virus with cellular membrane].

The synthetic peptide with the conservative 98-113 sequence of protein E of tick-borne encephalitis virus was studied in order to elucidate its role in the functioning of flaviviruses. The peptide was shown to inhibit the in vitro infection of macrophages with the virus. An antibody that specifically binds this peptide was found among the set of monoclonal antibodies produced against protein E. This antibody was found to prevent penetration of the virus into liposomes. A correlation was found between our results and data on the spatial structure of protein E and its interspecies homology. The protein E 98-113 sequence of the tick-borne encephalitis virus was found to be the fusion site of the viral envelope with a cellular membrane.

Amino Acid Sequence↗
PubMed1992

Toxicity and immunogenicity of Neisseria meningitidis lipopolysaccharide incorporated into liposomes.

To obtain nontoxic and highly immunogenic lipopolysaccharide (LPS) for immunization, we incorporated Neisseria meningitidis LPS into liposomes. Native LPS and its salts were incorporated by the method of dehydration-rehydration of vesicles or prolonged cosonication. The most complete incorporation of LPS into liposomes and a decrease in toxicity were achieved by the method of dehydration-rehydration of vesicles. Three forms of LPS (H+ form, Mg2+ salt, and triethanolamine salt) showed different solubilities in water, the acidic form of LPS, with the most pronounced hydrophobic properties, being capable of practically complete association with liposomal membranes. An evaluation of the activity of liposomal LPS in vitro (by the Limulus amoebocyte test) and in vivo (by monitoring the pyrogenic reaction in rabbits) revealed a decrease in endotoxin activity of up to 1,000-fold. In addition, the pyrogenic activity of liposomal LPS was comparable to that of a meningococcal polysaccharide vaccine. Liposomes had a pronounced adjuvant effect on the immune response to LPS. Thus, the level of anti-LPS plaque-forming cells in the spleens of mice immunized with liposomal LPS was 1 order of magnitude higher and could be observed for a longer time (until day 21, i.e., the term of observation) than in mice immunized with free LPS. The same regularity was revealed in a study done with an enzyme-linked immunosorbent assay. This study also established that antibodies induced by immunization belonged to the immunoglobulin M and G classes, which are capable of prolonged circulation. Moreover, liposomal LPS induced a pronounced immune response in CBA/N mice (defective in B lymphocytes of the LyB-5+ subpopulation). The latter results indicate that the immunogenic action of liposomal LPS occurs at an early age.

Animals↗
PubMed1991

T-cells of virus-infected mice produce a lymphokine which activates the autoreactivity of intact mouse lymphocytes.

The role of lymphokines was estimated in induction of autoreactive T-cells during Langat virus infection in mice. It was shown that in vitro cultured splenocytes from virus-infected animal containing autoreactive lymphocytes (ARL) spontaneously produce a lymphokine which is capable to activate the autoreactivity of lymphocytes derived from the spleen of intact syngeneic mice. The capacity of this lymphokine to activate the autoreactivity of acceptor cells within 2 hr was demonstrated by local graft-versus host reaction (GVHR) in the donor-recipient system. According to their surface markers (theta-antigen expression, absence of immunoglobulins) the lymphokine activating autoreactivity (LAA) producers may belong to T-lymphocyte population. Autoreactivity could be induced by the lymphokine only if the LAA producers and acceptors were compatible by the major histocompatibility complex antigens.

Animals↗
PubMed1990

Replication of Langat virus in immunocompetent cells of mice subjected to immobilization stress.

Immobilization stress (hypokinesis) in Balb/c mice may aggravate asymptomatic infection with Langat virus (strain TP-21) as evidenced by 4-fold increased lethality in comparison with control animals. The virus levels in the spleen and brain of stressed and infected mice and the in vitro yield of the virus in immunocompetent cells derived from stressed mice were significantly higher than in controls. Enhanced virus replication in latter cells may contribute to increased accumulation of the infectious agent in lymphatic tissues, which would facilitate virus invasion into CNS followed with acute disease and death of animals.

Animals↗
PubMed1989

[Antibody-dependent harmful effect of non-immune spleen cells in acute experimental tick-borne encephalitis in mice].

The injection of nonprotective dilutions of immune serum and nonimmune spleen cells into mice infected with tick-borne encephalitis virus induced a sharply pronounced immunopathological effect: the mean survival time of the recipients decreased by 3.6 days in comparison with the control animals. This effect was not linked with the increased replication of the virus in the brain. The antibody-dependent damaging action of spleen cells could be reproduced by using the cells of both syngeneic and allogeneic donors. This phenomenon developed only in those cases when antibodies to the infective agent under study were used. The combination of immune serum to Japanese encephalitis virus and nonimmune spleen cells produced no damaging effect. The hypothesis stating that the antibody-dependent damaging action of nonimmune spleen cells arises from the antibody-dependent cytotoxic action of immunocompetent cells on the infected cells of the central nervous system is discussed.

Acute Disease↗
PubMed1987

[Role of antigen-nonspecific suppressors occurring in stress in the pathogenesis of Langat virus infection in mice].

Stress factors of different nature activate antigen-nonspecific suppressors inhibiting different mechanisms of immune response in mice. The adoptive transfer of the population of immunocompetent cells containing stress-induced suppressors to mice infected with Langat virus has been found to lead to the activation of asymptomatic infection. The data obtained in this investigation indicate that the above-mentioned mechanism of the development of antigen-nonspecific immune deficiency is of importance in the pathogenesis of viral infections in man and it explains the onset of diseases (or their aggravation) under the conditions of stress.

Animals↗
PubMed1987

Formation of autoimmune effectors after transfer of virus-induced autoreactive precursors to syngeneic intact receptor animals.

We verified the assumption that autoimmune responses underlie immunosuppression developing in the course of virus infection. It has been shown by adoptive transfer that administration of Langat-virus-induced autoreactive lymphocytes (ARL) to the syngeneic recipient is followed by accumulation of autoreactive effectors (AE) eliciting a graft-verus-host reaction (GVHR) in the syngeneic system (AEgvhr). In addition, cytotoxic T-lymphocytes (AEc) appeared against the syngeneic macrophages. This effect was mediated by the H-2 restriction principle for ARL donors and their recipients. The infection triggered a T-suppressor-mediated reaction inhibiting the differentiation of precursors into mature autoreactive effectors. In the absence of T-cell suppressor effect (on consecutive syngeneic transfer) ARL will cause systemic pathologic changes in the recipients, namely, infiltrative and necrotic lesions in different organs and tissues. This mechanism is attributed to the activation of precursors in the body of intact recipient and to the formation of mature effectors owing to cytokines released by donor ARL.

Animals↗
PubMed1986

H-2 restricted regulation by soluble autoantigens of the tick-borne encephalitis virus-induced autoreactive T-effector and T-suppressor lymphocytes in mice.

Soluble autoantigens (mouse red blood cells lysed by sonication) blocked in vitro the antigen-recognizing receptors of tick-borne encephalitis (TBE) virus-induced autoreactive T-lymphocytes (ARTL), effectors of the local graft-versus-host reaction (GVHR) in a syngeneic system and prevented the development of GVHR in vivo. Antigen-recognizing receptors were also found on T-suppressors (Ts) that became activated during experimental tick-borne encephalitis in mice and inhibited the activity of ARTL. The interaction between these receptors and autoantigens in vitro resulted in a loss of the ability of Ts to inhibit in vivo the ARTL-mediated GVHR. A similar result was obtained with ARTL and Ts activated in mice infected with Langat, dengue type 2 (D2) and yellow fever (strain 17D) viruses. The block of the antigen-recognizing receptors of T-cells was reversible, and not associated with lymphokine production or effector death. The block of the antigen-recognizing receptors in vitro and the loss of the corresponding T-cell function in vivo occurred provided that the donors of soluble erythrocyte antigens (SEA) and of the lymphocytes had at least one common major histocompatibility complex (MHC) haplotype. Injection SEA from donors whose H-2 complex haplotypes were identical to those of TBE-infected recipients prevented in the latter the formation of ARTL or Ts. The autoantigens inhibiting the ARTL and Ts activities seemed to be products of the MHC genes. The role of soluble H-2 autoantigens in preventing virus-induced autoimmune reaction and maintaining a state of natural immunological tolerance is discussed.

Animals↗
PubMed1986

Changes of natural killer cell activity in different mouse lines by acute and asymptomatic flavivirus infections.

Effect of certain flaviviruses on the activity of mouse natural killer (NK) cells was investigated using the classical mouse splenocyte system and YAC-1 cells for demonstration of NK cell cytotoxicity. Infection of mice with Langat and West Nile (WN) viruses was accompanied by temporary activation of NK cells. In mice infected with tick-borne encephalitis (TBE) virus the stimulation phase of NK cell cytotoxicity on days 2-4 post-infection (p.i.) was followed by suppression of their activity. As to the surface markers (sensitivity to antitheta and antiimmunoglobulin serum, respectively), the flavivirus-activated NK cells did not differ from the endogenous NK cells of intact mice. The stimulatory effect of flaviviruses on cytotoxicity of NK cells varied in different mouse lines. An increased NK cell activity at early stages of TBE virus infection was observed in mouse lines characterized by low (C57B1/6) and medium (BALB/c)--but not by high (CBA)-activity of their non-stimulated NK cells. Suppression of NK cell activity at later stages of TBE virus infection was not associated with virus multiplication in mouse splenocytes.

Acute Disease↗
PubMed1986

[Study of immunological mechanisms of action of temperature and emotional stress factors in experimental flavivirus infections].

The influence of two stress factors, sharp changes in temperature and hypokinesia, on the course of experimental tick-borne encephalitis and Langat virus infections in mice has been studied. The data obtained in this study indicate that both factors produce defects in T- and B-cell-mediated immunity, accompanied by the activation of asymptomatic infection and the decrease of the mean survival time in acute infection. These two stress factors, differing in their intensity and nature (physical and emotional), have been shown to produce the same effect on the course of acute and asymptomatic flavivirus infections. In the former case the mean survival time of the animals decreases, and in the latter case clinically manifest infection develops. Under the conditions of hypokinesia (or changes in temperature), the death rate among the animals infected with langat virus has been found to increase 3- to 4-fold in comparison with the controls, the mortality level in the groups subjected to different stress factors being the same.

Animals↗