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Biomedical subjects

J Andersson

Publications and source records attributed to J Andersson.

At least 253 records · Page 14Linked to original sources

Fluorinated 4-quinolones induce hyperproduction of interleukin 2.

The fluorinated 4-quinolones are a "new" group of antibiotics with a broad antibacterial spectrum. They are already widely used in clinical practice. Previous studies have shown that these drugs increase the uptake of [3H]thymidine into DNA of mitogen-stimulated lymphocytes but inhibit cell growth and immunoglobulin secretion. This study shows that the 4-quinolones strongly (up to 100 times) increase the recovery of interleukin 2 (IL-2) in culture supernatants of phytohemagglutinin (PHA)-stimulated normal human lymphocytes and also prolong the kinetics of IL-2 production. The effect was significant at clinically achievable concentrations (5 micrograms/ml). In addition to hyperproduction of IL-2, the level of RNA hybridizing with a human IL-2 cDNA probe was also intensely elevated (16-32 times) in PHA-stimulated lymphocytes cultured with ciprofloxacin (80 micrograms/ml). The mechanism responsible for 4-quinolone-mediated effects on T cells is at present unclear, but evidence is presented that suggests the effect is not exerted at the level of protein kinase C activation. Ciprofloxacin at 80 micrograms/ml also decreased the expression of IL-2 receptors measured by immunofluorescence with CD 25 antibodies and a radiolabeled IL-2 binding assay. At the same concentration of ciprofloxacin, there was a very low expression of the transferrin receptor and the cell size increased very little in human lymphocytes after PHA stimulation. The enhanced IL-2 production by 4-quinolones may contribute to side effects reported when these drugs are used for treatment of patients.

Ciprofloxacin↗

Detection of cell-free human immunodeficiency virus in cerebrospinal fluid by using immune scanning electron microscopy.

The cerebrospinal fluid of 52 patients with human immunodeficiency virus type 1 (HIV-1) infection was incubated with polystyrene microspheres coated with monoclonal antibodies specific for HIV-1 core or envelope antigens. The beads were then collected on a filter surface and inspected by scanning electron microscopy (SEM). In 37 of 51 samples from subjects with chronic HIV-1 infection and from all three patients with primary HIV-1 infection, with or without neurologic symptoms, particles of 50-75 nm and 100-125 nm were visualized on beads coated with antibodies to HIV-1 core and envelope antigens, respectively. No such binding of particles was detected in the controls. Findings using immune SEM, which was found to be as sensitive as virus isolation, indicate that HIV-1 can replicate in the central nervous system (CNS) of patients with primary or chronic HIV-1 infection without causing neurologic symptoms. Production of cell-free virus seems to occur in the CNS of the majority of HIV-1-infected patients.

Acquired Immunodeficiency Syndrome↗

Evaluation by immune scanning electron microscopy of foscarnet treatment of cytomegalovirus infection in patients with renal transplants.

Eight patients, 7 renal and 1 combined renal and pancreas allograft recipients with generalized cytomegalovirus (CMV) infection were treated with continuous intravenous foscarnet infusion (0.15 mg/kg/min) for 10-14 days. Antiviral effect was studied by immune scanning electron microscopy for detection of CMV antigen in serum and urine, by virus isolation in tissue culture in samples from buffy coat, broncholavage and urine and by serology. CMV antigen was detected in serum samples in 8 patients and 5 had positive virus isolation from buffy coat, before institution of therapy. The 3 patients with negative virus isolation in tissue culture had serological evidence of a reactivated CMV infection. Virus replication was inhibited by foscarnet treatment in 7 patients within a week (p less than 0.01) (Wilcoxon log rank test). 7/8 patients had no detectable CMV antigen in serum or urine after 7-10 days of treatment (p less than 0.01) (Wilcoxon log rank test).

Adolescent↗

Cytomegalovirus the predominant cause of pneumonia in renal transplant patients. A two-year study of pneumonia in renal transplant recipients with evaluation of fiberoptic bronchoscopy.

The microbiological etiology of pneumonia in 34 renal transplant patients with clinical and X-ray evidence of pulmonary parenchymal disease was studied. Fiberoptic bronchoscopy with bronchoalveolar lavage (BAL), transbronchial lung biopsy (TBB) and brushing was performed on 18 patients. Laboratory evaluation included histological and cytological methods, cultures for bacteria, fungus and virus and immunofluorescence techniques for the detection of Pneumocystis carinii, cytomegalovirus (CMV) and legionella. Serum samples were obtained concomitantly for antibody studies. CMV, the most common etiology, was considered to be the cause of disease in 18/34 patients. All but one of these patients had positive CMV isolates in culture on leucocytes. Pulmonary edema was found in 7 patients, bacterial pneumonia in 11 patients, P. carinii in 4 patients and Candida albicans in 1 patient. Multifactorial etiology was found in 12/34 cases. The overall mortality was 32%. Bronchoscopy gave correct diagnosis in 13/14 patients with infectious pulmonary diseases (93%). Bronchoscopy procedures were well tolerated and should be considered in transplant patients with evidence of pulmonary parenchymal disease.

Adult↗

Influenza B in transplant patients.

Six cases of influenza B occurred in transplanted patients in a period of 3 weeks. Three renal allograft recipients recovered within 5 days without antiviral therapy. Two allogeneic bone marrow recipients were treated with ribavirin inhalations during the leukopenic phase. Treatment was given until influenza B was no longer detected and fever disappeared after 5 and 6 days, respectively. Engraftment was not delayed and no side-effects were noted. One recipient of autologous marrow was treated for 2 days, but ribavirin was discontinued due to pleuritic pain. We conclude that influenza B can be spread by asymptomatic carriers in the nursing staff and in spite of reversed isolation with the use of gown, hand wash and gloves.

Adult↗

Management of Epstein-Barr virus infections.

Both oral and intravenous acyclovir administration for seven days in the early stages of infectious mononucleosis caused an inhibition of oropharyngeal Epstein-Barr virus (EBV) replication. Minimal effect on clinical symptoms was observed. Development of normal cellular and humoral EBV-specific immunity was seen in all patients. The combination of intravenous acyclovir and prednisolone treatment for 10 days in 11 patients with fulminant mononucleosis caused transient cessation of virus shedding in all patients. A dramatic clinical effect on pharyngeal symptoms and on fever was seen in nine of 11 patients within 72 hours. Treatment with chemotherapy or irradiation is recommended in EBV-associated B cell lymphomas seen in immunosuppressed, transplanted, and human immunodeficiency virus-I seropositive patients. No effect of acyclovir has been reported, but such therapy may be considered in the early stage when EBV induces a polyclonal B cell activation. Acyclovir treatment is effective in the EBV-genome positive hairy leukoplakia in human immunodeficiency virus-seropositive patients. No effect of antiviral therapy has been reported in the X-linked lymphoproliferative syndrome. Prophylactic use of immunoglobulin or acyclovir has been suggested in susceptible children.

Acquired Immunodeficiency Syndrome↗

Concomitant production of different lymphokines in activated T cells.

The intracellular accumulation of five different lymphokines in individual cells could be identified by lymphokine-specific antibodies and an indirect immunofluorescence technique with UV microscopy. When peripheral blood mononuclear cells from one healthy donor were activated in vitro by the T cell mitogen anti-CD3 monoclonal antibody, the maximal number of cells producing interleukin (IL)2, IL 6 or tumor necrosis factor (TNF)-alpha occurred 6 h after initiation of the cultures, while peak numbers of interferon-gamma, TNF-beta and a second wave of TNF-alpha-synthesizing cells were noted approximately 20 h later. By performing two-color immunofluorescence studies we observed a variegated production pattern with cells making no, one or several lymphokines simultaneously. All five cytokines accumulated in the Golgi organelle resulting in a very characteristic morphology of the staining with or without additional cytoplasmic immunofluorescence.

Antibodies, Monoclonal↗

Regulation of growth and differentiation of pre-activated B lymphocytes.

The differential effects of H-2 IAk-specific T helper cells, their soluble factors and Sepharose-coupled anti-mu antibodies on the growth and differentiation of pre-activated B cells were studied. It was found that the prolonged growth of pre-activated B cells required activation signals from major histocompatibility complex (MHC)-restricted T helper cells or Sepharose-coupled anti-mu antibodies. The MHC-restricted T helper cells induced both prolonged growth and differentiation of activated B cells. Anti-mu antibodies together with T helper cell-derived soluble factors induced prolonged growth of activated B cells, but no differentiation into Ig secretion was detected. The inhibition of Ig secretion in anti-mu cultures could be overcome to some extent by either MHC-restricted T helper cells or lipopolysaccharide together with soluble factors. It was also observed that T helper cell interactions were needed for long-term in vitro culture of pre-activated B lymphocytes.

Animals↗

Heterogeneity in the specificities of an alloreactive T helper cell line.

Heterogeneity in antigen recognition of an alloreactive helper T-cell line was studied by repeated limiting dilution cloning. Analysis of the fine specificities of these clones showed that the gain of reactivity to new antigens by the T-cell line included the generation of non-cross-reactive T cells specific to new major histocompatibility (MHC) antigens. Analysis of function revealed that all the T-cell clones studied had similar cell surface antigens and secreted interleukin 4 (IL-4) and IL-5/IL-3 but not IL-2 or gamma interferon (IFN-gamma). The T-cell clones served as helper cells for B cells expressing the appropriate MHC antigens to both clonal proliferation and differentiation into antibody-producing cells.

Animals↗

Intrasplenic immunization for production of monoclonal antibodies against mouse blastocysts.

Applying the intrasplenic immunization method monoclonal antibodies were raised against trophectoderm of mouse blastocysts. Adhesive C57BL/6 blastocysts, obtained 18 h after estrogen reactivation from an experimental delay of implantation, and irradiated with 5000 rad were used as immunogen. Male DBA/2 mice were immunized by four intrasplenic depositions of about ten blastocysts each. The sensitized spleen cells were fused with mouse plasmacytoma cells on the 5th day after the last booster, followed by isolation of hybridoma clones by conventional monoclonal antibody procedures. 82 hybridoma clones were obtained of which two produced IgM antibodies recognizing trophoblast determinants. Absorbing the monoclonal antibodies with C57BL/6 splenic leukocytes followed by immunolabelling of blastocysts demonstrated that the antibodies recognized neither MHC nor TLX antigens. Pre- and peri-implantation stages were mapped by indirect immunofluorescence microscopy. Morulae were negative while blastocysts were positively labeled. Adhesive blastocysts labeled more strongly than delayed blastocysts. Cultured blastocysts showed an intense labeling of some of the trophoblast cells, while other trophoblast cells were unlabeled.

Animals↗

Prolonged growth of activated B lymphocytes requires interaction with helper T cells.

Resting B lymphocytes acquire upon activation responsiveness to soluble factors that support their growth and differentiation. We have studied the growth requirements of anti-mu pre-activated B lymphocytes in vitro. We found that activated B lymphocytes did respond to soluble factors from helper T cells by entering the cell cycle but cell-cell contact with specific helper T cells was required for prolonged growth of activated B lymphocytes. Thus, activated B lymphocytes must receive activation signals from helper T cells in order to stay in the proliferative phase of the cell cycle.

Animals↗

Subclass reactivity to Epstein-Barr virus capsid antigen in primary and reactivated EBV infections.

A new method for analysis of virus-specific Immunoglobulin G (IgG) subclasses was developed using indirect immunofluorescence. Three hundred thirty-three serum samples from patients with different types of Epstein-Barr virus (EBV)-associated diseases and healthy controls were examined for subclass distribution to the virus capsid antigen (EBV VCA). EBV-VCA-expressing cell preparations were incubated with patient serum followed by monoclonal antibodies to human IgG1 through IgG4 and labelled anti-mouse IgG. Virus-specific IgG1 was found to be the dominant antibody. The titers for IgG1 and total Ig to EBV VCA correlated well. EBV VCA-specific IgG2 was not found. EBV VCA-specific IgG3 in a titer of greater than or equal to 10 was found in 33% of healthy seropositive donors, in 97% of patients with suspected reactivated EBV infection, and in 100% of symptomatic patients with suspected reactivated EBV infection. EBV VCA specific IgG3 occurred in 90% of placebo-treated compared to 30% in long-term acyclovir-treated bone marrow transplant recipients, indicating more frequent reactivations in the former group. IgG4 to VCA was infrequently found in seropositive persons. In serum samples from patients with nasopharyngeal carcinoma and high EBV VCA Ig and IgA titers, IgG4 to VCA was always present. Analysis of EBV VCA specific IgG subclasses seems to be valuable for the diagnosis of reactivated EBV infection.

Adolescent↗

Acyclovir treatment in infectious mononucleosis: a clinical and virological study.

Fifty-six patients with a clinical and laboratory diagnosis of infectious mononucleosis who had not been ill for more than seven days, were randomised for peroral treatment with acyclovir (800 mg five times daily) or placebo for seven days in a double blind trial. Clinical, virological and immunological parameters were monitored in each patient for six months. During treatment, shedding of Epstein-Barr virus' as assessed in 36 patients, was significantly reduced (p less than 0.001). However, virus production in the oropharynx returned to pre-treatment levels one week after the cessation of therapy. Virus was detected in 35 patients at enrollment and in 28 of 36 patients at the six-month control. No effect on the clinical course of the disease was noticed. The virus-specific antibody response was also unaffected. A significant reduction in spontaneous outgrowth of in vivo Epstein-Barr virus-infected B-lymphocytes was found at 180 days after treatment in four acyclovir-treated patients compared to six controls (p less than 0.001). In another three patients with over-whelming clinical symptoms causing airway obstruction and/or disseminated intravascular coagulopathy, treatment with intravenous acyclovir (10 mg/kg three times daily) was combined with prednisolone (0.7 mg/kg daily) for ten days. Virus shedding ceased transiently during treatment, but returned to initial levels within one week. A dramatic clinical effect on the pharyngeal oedema and general health of the two patients with airway obstruction was noticed, but was much less evident in a patient with intravascular coagulopathy.

Acyclovir↗

Rapid detection of cytomegalovirus using immune scanning electron microscopy.

Monoclonal antibodies, specific for human cytomegalovirus, were conjugated to latex microspheres that were already labelled with rabbit anti-mouse immunoglobulin. The beads were then incubated with serum or urine from patients, and then collected on a filter surface, which was analyzed in a scanning electron microscope. Size, immunological specificity, and relative quantity of virus particles were determined within 2 h after serum or urine collection by the visualization of virus particles specifically bound to the latex-bead surface. No such binding of virus particles was detected in the various controls. This method was compared with conventional virus isolation by tissue culture. It enables identification of viruses within a few hours in different body fluids. Even without specific antibodies, the filtration method may permit the rapid detection of particles and the determination of their size in various body fluids.

Antibodies, Monoclonal↗

Rapid detection of cytomegalovirus using immune scanning electron microscopy.

Monoclonal antibodies specific for human cytomegalovirus were conjugated to latex microspheres that were already labelled with rabbit anti-mouse immunoglobulin. The beads were incubated with serum or urine from patients, and then collected on a filter surface, which was analyzed in a scanning electron microscope. Size, immunological specificity, and relative quantity of virus particles were determined within 2 h after serum or urine collection by the visualization of virus particles specifically bound to the latex bead surface. No such binding of virus particles were detected in the various controls. This method was compared with conventional virus isolation by tissue culture. It enables identification of viruses within a few hours in different body fluids. Even without specific antibodies, the filtration method may permit the rapid detection of particles and the determination of their size in various body fluids.

Antibodies, Monoclonal↗

Antibody responses to Epstein-Barr virus-determined nuclear antigen (EBNA)-1 and EBNA-2 in acute and chronic Epstein-Barr virus infection.

Five distinct Epstein-Barr virus (EBV)-determined nuclear antigens (EBNA-1 to EBNA-5) were recently identified. Antibody responses to these antigens could conceivably differ, and thus prove of serodiagnostic value, in EBV-associated disease processes. As a first step, murine or human cell lines transfected with appropriate EBV DNA fragments and stably expressing either EBNA-1 or EBNA-2 were used to determine the frequency and time of emergence of antibodies to these two antigens in the course of acute and chronic infectious mononucleosis (IM) and to assess their titers in so-called chronic active EBV infections. Following IM, antibodies to EBNA-2 arose first and, after reaching peak titers, declined again in time to lower persistent or even nondetectable levels. Antibodies to EBNA-1 emerged several weeks or months after anti-EBNA-2 and gradually attained the titers at which they persisted indefinitely. The ratios between the anti-EBNA-1 and anti-EBNA-2 titers therefore were generally well below 1.0 during the first 6-12 months after IM and turned to well above 1.0 during the second year. In clear cases of chronic IM, the inversion of this ratio was delayed or prevented. In the less well-defined chronic EBV infections, low ratios were observed in only some of the patients. Because many of these illnesses were not ushered in by a proven IM and often showed EBV-specific antibody profiles within the normally expected range, a causal role of the virus in these cases remains doubtful.

Acute Disease↗