J. Ongrádi - Academia.edu (original) (raw)
Papers by J. Ongrádi
Archives of Dermatology, May 1, 2000
We read with great interest the article by Ru-zicka et al1 on the possible role of human her-pesv... more We read with great interest the article by Ru-zicka et al1 on the possible role of human her-pesvirus (HHV) 6 in the etiology of papular-purpuric gloves-and-socks syndrome (PPGSS). This is a newly recognized dermatosis. Nearly 30 cases have been described in the European literature1 ...
International Journal of Immunopharmacology, 1992
Biochemical Society Transactions, 1995
International Journal of Immunopharmacology, 1991
MIMP is a new thymomimetic purine under development for immunorestorative therapy. Lymphocytes we... more MIMP is a new thymomimetic purine under development for immunorestorative therapy. Lymphocytes were obtained from 8 patients with acquired immunodeficiency disease (AIDS), 8 with asymptomatic pre-AIDS (ARC), and 8 normal controls and were stimulated in vitro with phytohemagglutinin (PHA). AIDS patients (mean CD 4 counts of 44) showed PHA responses <10% of control while ARC patients (mean CD 4 counts of 444) showed responses approximately 50% of the control responses. MIMP (0.I, I, i0, and I00 ug/m]) progressively augmented the PHA responses in all these groups. The augmentation of the responses of the leukocytes of AIDS patients while statistically significan~ was minimal. The augmentation of the responses of ARC patients was significant and their maximal responses approached control levels. The effect of 1 ug/ml MIMP was comparable to that observed with indomethacin (10-6 M) and interleukin 2 (IL2-4 units/ml) and was additive with each of these stimulants. In a parallel manner, MIMP restored the suppression of control lymphocytes induced by the immunosuppressive 17 amino acid fragment of the P41 peptide of HIV. In vivo experiments indicate that Mlb~ delayed death in s murine FLV AIDS model. MIMP is under preclinical development for early HIV disease.
Acta Microbiologica et Immunologica Hungarica, 2001
Orvosi hetilap, Jan 29, 1999
Virus infections of the immune system may alter the normal cytokine profile, which leads to sympt... more Virus infections of the immune system may alter the normal cytokine profile, which leads to symptoms of illnesses. HHV-7 revealed lately has been known as one of the causative agents of exanthem subitum and pityriasis rosea, while its latent infection can be reactivated in immunocompromised conditions. Their pathomechanism has not been explored yet, therefore, the production of some cytokines by separated leukocytes was studied upon primary and secondary infections. After combined treatments with live or inactivated viruses and/or mitogens, the cytokines were quantitated in the supernatant of cells by sandwich ELISA. It was established that, individual cytokines were produced at maximal output at different times postinfection. The quantity of their molecules depended on the primary or repeated infections. Inactivated viral particles also induced cytokine release. Production of IL-2 and IFN-gamma due to mitogen activation could be augmented in primary, but was diminished in secondary...
Orvosi Hetilap, Mar 19, 1995
Restoration of immune functions through promoting cell cycle might delay acquired immunodeficienc... more Restoration of immune functions through promoting cell cycle might delay acquired immunodeficiency syndrome development. Therefore, stimulation of peripheral lymphocytes of human immunodeficiency virus-1 infected patients in successive clinical stages was studied by phytohaemagglutinin and other stimulants. In vitro blastogenesis was quantitated by 3H-thymidine uptake. Stimulation by phytohaemagglutinin decreased in patients with AIDS related complex to 63.1%, with AIDS to 13.6% of control values. Small amount of recombinant interleukin-2 or indomethacin solely not promoting lymphocytes, increased response to phytohaemagglutinin minimally. Alone ineffective methyl-ester and methyl-phosphonate inosine derivatives augmented phytohaemagglutinin-response of controls and patients with AIDS related complex by approx. 1.5-fold, but the effect in the case of AIDS patients was minimal. Radio-detoxified endotoxin alone or in combination with phytohaemagglutinin stimulated lymphocytes of both controls and patients with AIDS related complex slightly. Lymphocyte stimulation of patients with AIDS related complex was augmented in concentration-dependent manner, and by synergic effect it approached phytohaemagglutinin-stimulated blastogenesis of controls. Anergy due to human immunodeficiency virus-1 infection damages synchronisation of secondary messenger systems induced on cell surface receptors, therefore their selective influence by recombinant interleukin-2 or indomethacin is less efficient. Inosine derivatives promote cell cycle by inhibiting cyclic adenosine 3',5'-monophosphate production. In the early stage of virus infection, radio-detoxified endotoxin might bind to receptors of immature T cells and facilitate cell cycle through cyclic guanosine 3',5'-monophosphate stimulation. The clinical trials of radio-detoxified endotoxin (Tolerin) have already been launched.
Orvosi Hetilap, 1999
HHV-6A in vitro augments expression of CD4 molecules on the surface of immune cells, facilitates ... more HHV-6A in vitro augments expression of CD4 molecules on the surface of immune cells, facilitates HIV replication and cell death in dual infections. It is hardly known whether these processes take place in vivo; does HHV-6A enhance HIV infection and AIDS progression? To study HHV-6A fresh infections and reactivation, IgM, IgG and low avidity IgG were quantitated in the serum samples of patients with asymptomatic HIV infection, early and terminal AIDS, that of their HIV seronegative homo- or bisexual partners and healthy adults (altogether 65 persons). Indirect immunofluorescent assay on JJHAN cells infected with HHV-6A U1102 was used. It was found that as compared to controls, the mean level of IgM in the sexual partners of HIV infected subjects raised 30-fold, that of IgG increased 10-fold, and 80% of persons had low avidity IgG indicating fresh HHV-6A infection. These suggest that they are frequently infected through sexual intercourse. As compared to healthy adults, mean titre of ...
Pathology & Oncology Research, 1998
Both marijuana and retroviruses impair natural killer (NK) cell functions. No data on their simul... more Both marijuana and retroviruses impair natural killer (NK) cell functions. No data on their simulataneous effects are available. Similarities to human AIDS induced early by Friend leukemia complex (FLC) and its replication competent helper Rowson-Parr virus (RPV) provides a mouse model to study drug-virus action. Leukemia susceptible BALB/c and resistant C57BL/6 mice were infected, then at time intervals their nylon wool-separated splenocytes were exposed to tetrahydrocannabinol (THC) for 3h. Natural killer (NK) cell activity against Yac-1 cells was assayed by 51Cr-release for 4 and 18h. Recovery of splenocytes was found to be suppressed by FLC, but in BALB/c only by RPV. After a transient enhancement in C57BL/6 by FLC, NK cell activity of both mice became suppressed early (2 to 4 days), normalized subsequently and enhanced late (11 to 14 days) postinfection. A moderate increase in BALB/c, no change in C57BL/6 were induced by low (1-2.5 microgram/ml) THC doses. NK cell activity of BALB/c became suppressed exponentially by higher (5-10 microgrtam/ ml) THC doses in 18h as compared to 4h assays, while its proportional and moderate impairment was seen in C57BL/6. The magnitude of NK cell activity of infected mice was determined by THC: enhancement or impairment followed those of untreated, infected counterparts, but on the level of THC-treated cells. Low doses hardly, high doses additively influenced NK cells of infected BALB/c. THC hardly affected very early and late enhancement in NK cell activiy of FLC infected C57BL/6, but augmented RPV induced suppression late in 18h assays. Genetic factors similar to endotoxin resistance, altered cytokine profile might determine these effects. Similar phenomena in humans might result in earlier manifestation of AIDS.
Orvosi hetilap, Jan 14, 1999
Simultaneous HHV-6A infection can activate HIV-1 latency and promote AIDS progression, but in thi... more Simultaneous HHV-6A infection can activate HIV-1 latency and promote AIDS progression, but in this process the effects of HHV-6A induced soluble mediators on HIV-1 have not been studied yet. Recently, supernatants of HSB-2 cultures infected with HHV-6A and/or treated with endotoxin have been filtered virus free at time intervals until the cytopathic effect developed. Biological activity of some cytokines which might participate in HIV-1 activation was quantitated. Filtered supernatants were mixed into CEM-ss cultures, which had been HIV-1 infected at 1:1 cell:virus ratio, subsequently HIV-1 replication was quantitated and compared to controls. Supernatants filtered during the first 96 hours of HHV-6A replication without visible cytopathic effect augmented HIV-1 syncytium formation by tenfold, reverse transcriptase activity by threefold, p24 antigen production by 6-fold. Filtered supernatants obtained at onset of HHV-6A cytopathic effect did not modify HIV-1 replication. HSB-2 cultur...
Pathology & Oncology Research, 1998
The occurrence and the possible role in promoting HIV infection by human herpesvirus type 6 (HHV-... more The occurrence and the possible role in promoting HIV infection by human herpesvirus type 6 (HHV-6) have not yet been revealed in Hungary. In different groups of patients, serum titre of IgM and IgG antibodies, as well as avidity of IgG were quantitated by indirect immunofluorescence and an enzyme-linked immunosorbent assay, using isolate Ul102 of HHV-6 variant A as antigen. In 60% of HIV-seronegative adult controls, high avidity IgG antibodies were found in low titre suggesting childhood infection. In HIV-seronegative persons
Journal of the European Academy of Dermatology and Venereology, 2004
increase in androgen receptor levels or their distribution between lesional and normal skin. In t... more increase in androgen receptor levels or their distribution between lesional and normal skin. In the present study, the expression of androgen receptors within lesional skin was not increased. Our findings cannot rule out the possibility of an endocrine influence at the microvascular level and we believe that unopposed androgenic stimulation might still contribute to the pathogenesis of rosacea.
Journal of the European Academy of Dermatology and Venereology, 2004
with leucocytes from eight pemphigus patients, showing that they do indeed have T-cells reactive ... more with leucocytes from eight pemphigus patients, showing that they do indeed have T-cells reactive against desmoglein antigens, which might contribute to the severity of the disease. 5
JAIDS Journal of Acquired Immune Deficiency Syndromes, 1999
AIDS Research and Human Retroviruses, 1990
Infectivity of free and cell-associated human immunodeficiency virus type 1 (HIV-1) treated in vi... more Infectivity of free and cell-associated human immunodeficiency virus type 1 (HIV-1) treated in vitro at pH 7.4 to 4.9 for 2 hours was assessed on susceptible CEM-ss cells. Viral activity was monitored by cytopathology and production of reverse transcriptase and p24 antigen. The infectivity of cell-free virus was gradually inactivated and at pH 5.4 was completely lost, with or without subsequent adjustment of pH to neutral. Virus-producing cells also gradually lost their ability to infect as the pH decreased; however, restoration of neutral pH resulted in regained infectivity. Since the pH values used in the study are similar to those found at various entry sites of the human body, the data may be relevant to the mode of transmittal of HIV.
Journal of General Virology, 1985
The roles of the L and NS polypeptides in transcription by vesicular stomatitis virus New Jersey ... more The roles of the L and NS polypeptides in transcription by vesicular stomatitis virus New Jersey were studied using a mutant, tsE1, which contains a temperature-sensitive transcriptase and an altered NS polypeptide, both phenotypic changes being the consequence of the ts mutation. Mutant tsE1, its revertant (tsE1/R1) and the wild-type virus were dissociated into sub-viral fractions and, after reconstitution of these fractions in all combinations, the transcriptase was assayed in vitro at the permissive (31 degrees C) and restrictive (39 degrees C) temperatures. Reconstitution of the pellet fractions (containing polypeptide N complexed with the virion RNA) and the supernatant fractions (containing polypeptides L and NS) restored transcriptase activity at 31 degrees C in all combinations, but at 39 degrees C transcription was observed only in the presence of the supernatant fractions of wild-type and revertant viruses but not in the presence of the supernatant fractions of tsE1. When the pellet fractions and the L fractions were reconstituted, the transcriptase activity was restored in all combinations both at 31 degrees C and 39 degrees C. However, in vitro transcription at 39 degrees C by reconstituted pellet and L fractions was strongly inhibited when the NS fraction of tsE1 was also added, while addition of the NS fractions of wild-type and revertant viruses had no effect. Since only traces of polypeptide NS were present in the L fractions and none in the pellet fractions, the results strongly suggest that polypeptide L is the transcriptase itself while polypeptide NS exerts some control over transcription.
Acta Physiologica Hungarica, 2011
The global population is ageing. Elderly people suffer from more severe infections than younger p... more The global population is ageing. Elderly people suffer from more severe infections than younger persons. The major reason for the increased susceptibility to infections in the elderly is the deregulated functions of the immune system. Immunosenescence affects both innate and adaptive immune reactions. Among these, quantitative alterations of B lymphocyte subsets determine outcome of infections and vaccination. The overall number of B cells seems to be stable or the decrease is moderate. Reduced input of naive B lymphocytes is compensated by anergic, exhausted memory cells. Concerning B lymphocyte subsets, experimental data obtained in the mouse model and in vivo studies conducted in old-age humans are frequently controversial. Further analysis of human B lymphocyte subpopulations is required that could be regarded as an important biomarker of human life span.
Acta Microbiologica et Immunologica Hungarica, 2009
The sharp increase of life expectancy and the increasing ratio of ageing population pose new chal... more The sharp increase of life expectancy and the increasing ratio of ageing population pose new challenges for the public health system. The elderly suffer from more frequent and severe infections than young people. Theoretically, vaccination could protect the elderly against several infectious diseases, but due to their age-related immune impairment, vaccination might fail in many cases. Instead of ineffective vaccination campaigns, exploration and restoration of age-dependent dysregulation of their immune functions have to be placed into the focus of recent research. Frequent comorbidities in these people augment immune defects. Immunosenescence affects both the innate and adaptive immunity. Disturbances in macrophage-derived cytokine release and reduction of the natural killer cell mediated cytotoxicity lead to increased frequency of respiratory, gastrointestinal and skin infections. Although the humoral immunity retains most of its original activity through life span, ageing dampens the ability of B cells to produce antibodies against novel antigens. Age-related declination of the cellular immunity is the consequence of thymic atrophy, reduced output of new T lymphocytes, accumulation of anergic memory cells, deficiencies in the cytokine production and uncertain antigen presentation. Persistent infection by different herpesviruses and other parasites contribute to the loss of immunosurveillance and premature exhaustion of T cells.
Archives of Dermatology, May 1, 2000
We read with great interest the article by Ru-zicka et al1 on the possible role of human her-pesv... more We read with great interest the article by Ru-zicka et al1 on the possible role of human her-pesvirus (HHV) 6 in the etiology of papular-purpuric gloves-and-socks syndrome (PPGSS). This is a newly recognized dermatosis. Nearly 30 cases have been described in the European literature1 ...
International Journal of Immunopharmacology, 1992
Biochemical Society Transactions, 1995
International Journal of Immunopharmacology, 1991
MIMP is a new thymomimetic purine under development for immunorestorative therapy. Lymphocytes we... more MIMP is a new thymomimetic purine under development for immunorestorative therapy. Lymphocytes were obtained from 8 patients with acquired immunodeficiency disease (AIDS), 8 with asymptomatic pre-AIDS (ARC), and 8 normal controls and were stimulated in vitro with phytohemagglutinin (PHA). AIDS patients (mean CD 4 counts of 44) showed PHA responses <10% of control while ARC patients (mean CD 4 counts of 444) showed responses approximately 50% of the control responses. MIMP (0.I, I, i0, and I00 ug/m]) progressively augmented the PHA responses in all these groups. The augmentation of the responses of the leukocytes of AIDS patients while statistically significan~ was minimal. The augmentation of the responses of ARC patients was significant and their maximal responses approached control levels. The effect of 1 ug/ml MIMP was comparable to that observed with indomethacin (10-6 M) and interleukin 2 (IL2-4 units/ml) and was additive with each of these stimulants. In a parallel manner, MIMP restored the suppression of control lymphocytes induced by the immunosuppressive 17 amino acid fragment of the P41 peptide of HIV. In vivo experiments indicate that Mlb~ delayed death in s murine FLV AIDS model. MIMP is under preclinical development for early HIV disease.
Acta Microbiologica et Immunologica Hungarica, 2001
Orvosi hetilap, Jan 29, 1999
Virus infections of the immune system may alter the normal cytokine profile, which leads to sympt... more Virus infections of the immune system may alter the normal cytokine profile, which leads to symptoms of illnesses. HHV-7 revealed lately has been known as one of the causative agents of exanthem subitum and pityriasis rosea, while its latent infection can be reactivated in immunocompromised conditions. Their pathomechanism has not been explored yet, therefore, the production of some cytokines by separated leukocytes was studied upon primary and secondary infections. After combined treatments with live or inactivated viruses and/or mitogens, the cytokines were quantitated in the supernatant of cells by sandwich ELISA. It was established that, individual cytokines were produced at maximal output at different times postinfection. The quantity of their molecules depended on the primary or repeated infections. Inactivated viral particles also induced cytokine release. Production of IL-2 and IFN-gamma due to mitogen activation could be augmented in primary, but was diminished in secondary...
Orvosi Hetilap, Mar 19, 1995
Restoration of immune functions through promoting cell cycle might delay acquired immunodeficienc... more Restoration of immune functions through promoting cell cycle might delay acquired immunodeficiency syndrome development. Therefore, stimulation of peripheral lymphocytes of human immunodeficiency virus-1 infected patients in successive clinical stages was studied by phytohaemagglutinin and other stimulants. In vitro blastogenesis was quantitated by 3H-thymidine uptake. Stimulation by phytohaemagglutinin decreased in patients with AIDS related complex to 63.1%, with AIDS to 13.6% of control values. Small amount of recombinant interleukin-2 or indomethacin solely not promoting lymphocytes, increased response to phytohaemagglutinin minimally. Alone ineffective methyl-ester and methyl-phosphonate inosine derivatives augmented phytohaemagglutinin-response of controls and patients with AIDS related complex by approx. 1.5-fold, but the effect in the case of AIDS patients was minimal. Radio-detoxified endotoxin alone or in combination with phytohaemagglutinin stimulated lymphocytes of both controls and patients with AIDS related complex slightly. Lymphocyte stimulation of patients with AIDS related complex was augmented in concentration-dependent manner, and by synergic effect it approached phytohaemagglutinin-stimulated blastogenesis of controls. Anergy due to human immunodeficiency virus-1 infection damages synchronisation of secondary messenger systems induced on cell surface receptors, therefore their selective influence by recombinant interleukin-2 or indomethacin is less efficient. Inosine derivatives promote cell cycle by inhibiting cyclic adenosine 3',5'-monophosphate production. In the early stage of virus infection, radio-detoxified endotoxin might bind to receptors of immature T cells and facilitate cell cycle through cyclic guanosine 3',5'-monophosphate stimulation. The clinical trials of radio-detoxified endotoxin (Tolerin) have already been launched.
Orvosi Hetilap, 1999
HHV-6A in vitro augments expression of CD4 molecules on the surface of immune cells, facilitates ... more HHV-6A in vitro augments expression of CD4 molecules on the surface of immune cells, facilitates HIV replication and cell death in dual infections. It is hardly known whether these processes take place in vivo; does HHV-6A enhance HIV infection and AIDS progression? To study HHV-6A fresh infections and reactivation, IgM, IgG and low avidity IgG were quantitated in the serum samples of patients with asymptomatic HIV infection, early and terminal AIDS, that of their HIV seronegative homo- or bisexual partners and healthy adults (altogether 65 persons). Indirect immunofluorescent assay on JJHAN cells infected with HHV-6A U1102 was used. It was found that as compared to controls, the mean level of IgM in the sexual partners of HIV infected subjects raised 30-fold, that of IgG increased 10-fold, and 80% of persons had low avidity IgG indicating fresh HHV-6A infection. These suggest that they are frequently infected through sexual intercourse. As compared to healthy adults, mean titre of ...
Pathology & Oncology Research, 1998
Both marijuana and retroviruses impair natural killer (NK) cell functions. No data on their simul... more Both marijuana and retroviruses impair natural killer (NK) cell functions. No data on their simulataneous effects are available. Similarities to human AIDS induced early by Friend leukemia complex (FLC) and its replication competent helper Rowson-Parr virus (RPV) provides a mouse model to study drug-virus action. Leukemia susceptible BALB/c and resistant C57BL/6 mice were infected, then at time intervals their nylon wool-separated splenocytes were exposed to tetrahydrocannabinol (THC) for 3h. Natural killer (NK) cell activity against Yac-1 cells was assayed by 51Cr-release for 4 and 18h. Recovery of splenocytes was found to be suppressed by FLC, but in BALB/c only by RPV. After a transient enhancement in C57BL/6 by FLC, NK cell activity of both mice became suppressed early (2 to 4 days), normalized subsequently and enhanced late (11 to 14 days) postinfection. A moderate increase in BALB/c, no change in C57BL/6 were induced by low (1-2.5 microgram/ml) THC doses. NK cell activity of BALB/c became suppressed exponentially by higher (5-10 microgrtam/ ml) THC doses in 18h as compared to 4h assays, while its proportional and moderate impairment was seen in C57BL/6. The magnitude of NK cell activity of infected mice was determined by THC: enhancement or impairment followed those of untreated, infected counterparts, but on the level of THC-treated cells. Low doses hardly, high doses additively influenced NK cells of infected BALB/c. THC hardly affected very early and late enhancement in NK cell activiy of FLC infected C57BL/6, but augmented RPV induced suppression late in 18h assays. Genetic factors similar to endotoxin resistance, altered cytokine profile might determine these effects. Similar phenomena in humans might result in earlier manifestation of AIDS.
Orvosi hetilap, Jan 14, 1999
Simultaneous HHV-6A infection can activate HIV-1 latency and promote AIDS progression, but in thi... more Simultaneous HHV-6A infection can activate HIV-1 latency and promote AIDS progression, but in this process the effects of HHV-6A induced soluble mediators on HIV-1 have not been studied yet. Recently, supernatants of HSB-2 cultures infected with HHV-6A and/or treated with endotoxin have been filtered virus free at time intervals until the cytopathic effect developed. Biological activity of some cytokines which might participate in HIV-1 activation was quantitated. Filtered supernatants were mixed into CEM-ss cultures, which had been HIV-1 infected at 1:1 cell:virus ratio, subsequently HIV-1 replication was quantitated and compared to controls. Supernatants filtered during the first 96 hours of HHV-6A replication without visible cytopathic effect augmented HIV-1 syncytium formation by tenfold, reverse transcriptase activity by threefold, p24 antigen production by 6-fold. Filtered supernatants obtained at onset of HHV-6A cytopathic effect did not modify HIV-1 replication. HSB-2 cultur...
Pathology & Oncology Research, 1998
The occurrence and the possible role in promoting HIV infection by human herpesvirus type 6 (HHV-... more The occurrence and the possible role in promoting HIV infection by human herpesvirus type 6 (HHV-6) have not yet been revealed in Hungary. In different groups of patients, serum titre of IgM and IgG antibodies, as well as avidity of IgG were quantitated by indirect immunofluorescence and an enzyme-linked immunosorbent assay, using isolate Ul102 of HHV-6 variant A as antigen. In 60% of HIV-seronegative adult controls, high avidity IgG antibodies were found in low titre suggesting childhood infection. In HIV-seronegative persons
Journal of the European Academy of Dermatology and Venereology, 2004
increase in androgen receptor levels or their distribution between lesional and normal skin. In t... more increase in androgen receptor levels or their distribution between lesional and normal skin. In the present study, the expression of androgen receptors within lesional skin was not increased. Our findings cannot rule out the possibility of an endocrine influence at the microvascular level and we believe that unopposed androgenic stimulation might still contribute to the pathogenesis of rosacea.
Journal of the European Academy of Dermatology and Venereology, 2004
with leucocytes from eight pemphigus patients, showing that they do indeed have T-cells reactive ... more with leucocytes from eight pemphigus patients, showing that they do indeed have T-cells reactive against desmoglein antigens, which might contribute to the severity of the disease. 5
JAIDS Journal of Acquired Immune Deficiency Syndromes, 1999
AIDS Research and Human Retroviruses, 1990
Infectivity of free and cell-associated human immunodeficiency virus type 1 (HIV-1) treated in vi... more Infectivity of free and cell-associated human immunodeficiency virus type 1 (HIV-1) treated in vitro at pH 7.4 to 4.9 for 2 hours was assessed on susceptible CEM-ss cells. Viral activity was monitored by cytopathology and production of reverse transcriptase and p24 antigen. The infectivity of cell-free virus was gradually inactivated and at pH 5.4 was completely lost, with or without subsequent adjustment of pH to neutral. Virus-producing cells also gradually lost their ability to infect as the pH decreased; however, restoration of neutral pH resulted in regained infectivity. Since the pH values used in the study are similar to those found at various entry sites of the human body, the data may be relevant to the mode of transmittal of HIV.
Journal of General Virology, 1985
The roles of the L and NS polypeptides in transcription by vesicular stomatitis virus New Jersey ... more The roles of the L and NS polypeptides in transcription by vesicular stomatitis virus New Jersey were studied using a mutant, tsE1, which contains a temperature-sensitive transcriptase and an altered NS polypeptide, both phenotypic changes being the consequence of the ts mutation. Mutant tsE1, its revertant (tsE1/R1) and the wild-type virus were dissociated into sub-viral fractions and, after reconstitution of these fractions in all combinations, the transcriptase was assayed in vitro at the permissive (31 degrees C) and restrictive (39 degrees C) temperatures. Reconstitution of the pellet fractions (containing polypeptide N complexed with the virion RNA) and the supernatant fractions (containing polypeptides L and NS) restored transcriptase activity at 31 degrees C in all combinations, but at 39 degrees C transcription was observed only in the presence of the supernatant fractions of wild-type and revertant viruses but not in the presence of the supernatant fractions of tsE1. When the pellet fractions and the L fractions were reconstituted, the transcriptase activity was restored in all combinations both at 31 degrees C and 39 degrees C. However, in vitro transcription at 39 degrees C by reconstituted pellet and L fractions was strongly inhibited when the NS fraction of tsE1 was also added, while addition of the NS fractions of wild-type and revertant viruses had no effect. Since only traces of polypeptide NS were present in the L fractions and none in the pellet fractions, the results strongly suggest that polypeptide L is the transcriptase itself while polypeptide NS exerts some control over transcription.
Acta Physiologica Hungarica, 2011
The global population is ageing. Elderly people suffer from more severe infections than younger p... more The global population is ageing. Elderly people suffer from more severe infections than younger persons. The major reason for the increased susceptibility to infections in the elderly is the deregulated functions of the immune system. Immunosenescence affects both innate and adaptive immune reactions. Among these, quantitative alterations of B lymphocyte subsets determine outcome of infections and vaccination. The overall number of B cells seems to be stable or the decrease is moderate. Reduced input of naive B lymphocytes is compensated by anergic, exhausted memory cells. Concerning B lymphocyte subsets, experimental data obtained in the mouse model and in vivo studies conducted in old-age humans are frequently controversial. Further analysis of human B lymphocyte subpopulations is required that could be regarded as an important biomarker of human life span.
Acta Microbiologica et Immunologica Hungarica, 2009
The sharp increase of life expectancy and the increasing ratio of ageing population pose new chal... more The sharp increase of life expectancy and the increasing ratio of ageing population pose new challenges for the public health system. The elderly suffer from more frequent and severe infections than young people. Theoretically, vaccination could protect the elderly against several infectious diseases, but due to their age-related immune impairment, vaccination might fail in many cases. Instead of ineffective vaccination campaigns, exploration and restoration of age-dependent dysregulation of their immune functions have to be placed into the focus of recent research. Frequent comorbidities in these people augment immune defects. Immunosenescence affects both the innate and adaptive immunity. Disturbances in macrophage-derived cytokine release and reduction of the natural killer cell mediated cytotoxicity lead to increased frequency of respiratory, gastrointestinal and skin infections. Although the humoral immunity retains most of its original activity through life span, ageing dampens the ability of B cells to produce antibodies against novel antigens. Age-related declination of the cellular immunity is the consequence of thymic atrophy, reduced output of new T lymphocytes, accumulation of anergic memory cells, deficiencies in the cytokine production and uncertain antigen presentation. Persistent infection by different herpesviruses and other parasites contribute to the loss of immunosurveillance and premature exhaustion of T cells.