RESUMEN
Dipeptidyl peptidase IV (DPP IV) (CD26) plays a critical role in the modulation and expression of autoimmune and inflammatory diseases. We recently reported that sera from patients with rheumatoid arthritis and systemic lupus erythematosus contained low levels of DPP IV and high titers of anti-DPP IV autoantibodies of the immunoglobulin A (IgA) and IgG classes and found a correlation between the low circulating levels of DPP IV and the high titers of anti-DPP IV autoantibodies of the IgA class. Since streptokinase (SK) is a potent immunogen and binds to DPP IV, we speculated that patients with autoimmune diseases showed higher DPP IV autoantibody levels than healthy controls as a consequence of an abnormal immune stimulation triggered by SK released during streptococcal infections. We assessed this hypothesis in a group of patients suffering from acute myocardial infarction, without a chronic autoimmune disease, who received SK as part of therapeutic thrombolysis. Concomitant with the appearance of anti-SK antibodies, these patients developed anti-DPP IV autoantibodies. These autoantibodies bind to DPP IV in the region which is also recognized by SK, suggesting that an SK-induced immune response is responsible for the appearance of DPP IV autoantibodies. Furthermore, we determined a correlation between high titers of DPP IV autoantibodies and an augmented clearance of the enzyme from the circulation. Serum levels of the inflammatory cytokines tumor necrosis factor alpha (TNF-alpha) and interleukin 6 (IL-6) increased significantly after 30 days of SK administration, while the levels of soluble IL-2 receptor remained unchanged during the same period, suggesting a correlation between the lower levels of circulating DPP IV and higher levels of TNF-alpha and IL-6 in serum in these patients.
Asunto(s)
Autoanticuerpos/biosíntesis , Dipeptidil Peptidasa 4/inmunología , Infarto del Miocardio/tratamiento farmacológico , Estreptoquinasa/uso terapéutico , Terapia Trombolítica , Adulto , Anciano , Citocinas/sangre , Dipeptidil Peptidasa 4/sangre , Humanos , Inmunoglobulina A/sangre , Masculino , Persona de Mediana Edad , Infarto del Miocardio/inmunología , Estreptoquinasa/inmunología , Estreptoquinasa/farmacologíaRESUMEN
Streptokinase (SK) is an efficacious thrombolytic drug for the treatment of myocardial infarction. Because of its immunogenicity, patients receiving SK therapy develop high anti-SK antibody (Ab) titers, which might provoke severe allergic reactions and neutralize SK activity. In this report we studied the reactivity of a synthetic 42-residue peptide resembling SKC-2 C-terminus with patient sera. SKC-2(373-414) peptide was recognized by 39 and 64% of patients, before and after SKC-2 therapy, respectively. An SKC-2 deletion mutant (mut-C42), lacking the same 42 C-terminal residues, was constructed and expressed in Escherichia coli. Recognition of mut-C42 by preexisting Abs from patient sera was 51 and 68% of reactivity to SKC-2, as assessed by direct binding and competition assays, respectively. For most of the patients, mut-C42-neutralizing activity titer (NAT) significantly decreased with respect to SKC-2-NAT. This study opens the possibility of producing a less immunogenic variant of SK, which could constitute a preferred alternative for thrombolytic therapy.
Asunto(s)
Anticuerpos Antibacterianos/inmunología , Eliminación de Secuencia/genética , Estreptoquinasa/química , Estreptoquinasa/inmunología , Alérgenos/química , Alérgenos/inmunología , Anticuerpos Antibacterianos/sangre , Antígenos Bacterianos/química , Antígenos Bacterianos/inmunología , Unión Competitiva , Ensayo de Inmunoadsorción Enzimática , Humanos , Epítopos Inmunodominantes/química , Epítopos Inmunodominantes/genética , Epítopos Inmunodominantes/inmunología , Epítopos Inmunodominantes/aislamiento & purificación , Infarto del Miocardio/tratamiento farmacológico , Infarto del Miocardio/inmunología , Pruebas de Neutralización , Fragmentos de Péptidos/síntesis química , Fragmentos de Péptidos/química , Fragmentos de Péptidos/genética , Fragmentos de Péptidos/inmunología , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/inmunología , Proteínas Recombinantes/aislamiento & purificación , Estreptoquinasa/genética , Estreptoquinasa/uso terapéutico , Terapia TrombolíticaRESUMEN
Streptokinase (SK) is a streptococcal protein widely used as a thrombolytic agent. Anti-SK antibodies (Abs) are found in most individuals due to common streptococcal infections. The presence of these Abs increases the possibility of allergic reactions and may reduce the thrombolytic efficacy of SK upon a first therapy. Previous studies report on the immunodominance of the SK C-terminus and the role of this region in plasminogen (Plg) activation. The aim of this study was to assess the prevalence of circulating Abs to the SK C-terminus in normal blood donors. Sera from 1008 subjects aged 30 to 60 years were tested by Ultra-Micro-ELISA using a synthetic peptide resembling the SKC-2 C-terminus. An overall prevalence of 30. 4% was found. Prevalence was significantly higher among male than among female donors (RR = 1.70, 1.13 < CI < 2.55). No age effect was observed. This is the first extensive study about Abs directed against a particular region of SK in normal subjects.
Asunto(s)
Anticuerpos Antibacterianos/sangre , Donantes de Sangre , Fragmentos de Péptidos/inmunología , Infecciones Estreptocócicas/inmunología , Estreptoquinasa/inmunología , Adulto , Factores de Edad , Femenino , Humanos , Hipersensibilidad/etiología , Hipersensibilidad/inmunología , Epítopos Inmunodominantes , Masculino , Persona de Mediana Edad , Prevalencia , Factores Sexuales , Infecciones Estreptocócicas/epidemiología , Estreptoquinasa/efectos adversos , Terapia Trombolítica/efectos adversosRESUMEN
Streptokinase (SK) is efficaciously used as a thrombolytic drug for the treatment of myocardial infarction. Being a bacterial protein, SK is immunogenic in humans. Therefore, resulting from SK therapy, patients become immunized and anti-SK antibody (Ab) titers rise post-treatment. High Ab titers might provoke severe immune reactions during SK therapy and neutralize SK activity, preventing effective thrombolysis. Spot synthesis combined with peptide library techniques is a useful tool for studying protein-peptide interactions on continuous cellulose membranes. Here, we report on the mapping of antigenic regions of SK using a spot-synthesized peptide library and human total sera from patients receiving SK therapy. All tested samples have high anti-SK Ab titers and most of them show significant SK neutralizing capacity. Individual variations in peptide recognition were detected. However, patients treated with SK tend, in general, to show a common regional binding pattern, including residues 1-20, 130-149, 170-189, and 390-399. This is the first study reporting the probing of a cellulose-bound set of peptides with total human sera.
Asunto(s)
Mapeo Epitopo/métodos , Infarto del Miocardio/sangre , Estreptoquinasa/inmunología , Secuencia de Aminoácidos , Formación de Anticuerpos , Proteínas Bacterianas/inmunología , Cuba , Humanos , Datos de Secuencia Molecular , Infarto del Miocardio/terapia , Fragmentos de Péptidos/inmunología , Biblioteca de Péptidos , Unión Proteica/inmunología , Serología , Estreptoquinasa/uso terapéuticoRESUMEN
Streptokinase (SK) is the most widely used compound for the treatment of myocardial infarction and the least expensive thrombolytic agent, but a drawback to its use is the widespread presence of anti-SK antibodies (Abs). Clinical failure of the activation of the fibrinolytic system by SK has been reported due to the presence of a high titer of anti-SK neutralizing Abs. Patients receiving SK therapy develop high anti-SK antibody titers, which might provoke severe allergic reactions. These Abs are sufficient to neutralize a standard dose of SK up to four years after initial SK administration. This is a clinical problem because of the increasing number of patients who have been treated once with SK for acute myocardial infarction (AMI) and are likely to require plasminogen activator treatment in the future. In previous in vitro studies, we have shown that a deletion mutant (mut-C42), lacking the 42 C-terminal residues, was significantly less antigenic when compared with the native molecule (SKC-2). In this study, 14 monkeys were subjected to treatment with SKC-2 and mut-C42 in order to compare their humoral response by determining SK neutralizing activity in monkey's sera. All monkeys developed anti-SKC-2 Ab titers, but in the case where treatment induced Abs directed against the C-terminus of SKC-2, neutralizing activity against the native protein was significantly higher than that developed against mutant SK mut-C42.
Asunto(s)
Fibrinolíticos/inmunología , Mutación , Fragmentos de Péptidos/inmunología , Estreptoquinasa/genética , Estreptoquinasa/inmunología , Animales , Chlorocebus aethiops , Femenino , Fibrinolíticos/uso terapéutico , Masculino , Pruebas de Neutralización , Fragmentos de Péptidos/uso terapéutico , Ingeniería de Proteínas , Eliminación de Secuencia , Estreptoquinasa/uso terapéutico , Trombosis/tratamiento farmacológicoRESUMEN
OBJECTIVE: Fibronectin (FN) and the streptococcal plasminogen activator streptokinase (SK) share the epitope LTSRPA. This epitope is not reactive in native FN and it reacts with anti-SK antibodies only after plasmin digestion of the protein. To investigate a potential correlation between the high levels of anti-LTSRPA antibodies in sera of patients with rheumatoid arthritis (RA) and the perpetuation of the immune response characteristic of this disease, we analyzed their capacity to activate complement and the process of binding to the serum lectin mannan binding protein (MBP). METHODS: We used a radioimmunoassay to evaluate immune complexes between anti-LTSRPA IgG and FN, plasmin degraded FN, or the LTSRPA peptide for their capacity to activate complement C5 to C5a. Purified human serum lectin MBP was used to quantify the degree of exposed mannose or N-acetylglucosamine residues in the Fc region of anti-LTSRPA IgG of patients with RA and healthy controls. RESULTS: Anti-LTSRPA IgG from patients with RA have a greater capacity to activate complement C5 to C5a when bound to either the LTSRPA peptide or plasmin degraded FN in vitro. We found a very strong correlation between the complement activating capacity of the RA immune complexes and their binding to MBP. CONCLUSION: The enhanced capacity of RA anti-LTSRPA IgG immune complexes to activate complement C5 to C5a is directly correlated with their binding capacity to MBP. As MBP binding depends on exposed mannose or N-acetylglucosamine residues in the Fc region of the IgG molecule, these studies suggest that defective glycosylation of circulating anti-SK IgG may play a role in the etiology of RA.
Asunto(s)
Artritis Reumatoide/patología , Fibronectinas/inmunología , Inmunoglobulina G/metabolismo , Inmunoglobulina G/toxicidad , Estreptoquinasa/inmunología , Adulto , Secuencia de Aminoácidos , Artritis Reumatoide/etiología , Artritis Reumatoide/inmunología , Autoanticuerpos/inmunología , Proteínas Portadoras/metabolismo , Complemento C5/inmunología , Complemento C5/metabolismo , Reacciones Cruzadas , Ensayo de Inmunoadsorción Enzimática , Glicosilación , Humanos , Inmunoglobulina G/sangre , Inmunoglobulina G/inmunología , Masculino , Mananos/metabolismo , Persona de Mediana Edad , Datos de Secuencia MolecularRESUMEN
Streptococcus pyogenes es una bacteria conocida desde hace más de un siglo por los médicos. En la última década se ha presentado con un nuevo rostro asociado a cuadros clínicos invasores con una alta mortalidad. En el presente artículo se describe al agente, se clasifican estos cuadros clínicos, se discuten su etiopatogenia, tratamiento y prevención
Asunto(s)
Humanos , Infecciones Estreptocócicas/diagnóstico , Streptococcus pyogenes/patogenicidad , Choque Séptico/diagnóstico , Choque Séptico/microbiología , Desoxirribonucleasas/inmunología , Hialuronoglucosaminidasa/inmunología , Infecciones Estreptocócicas/clasificación , Infecciones Estreptocócicas/microbiología , Infecciones Estreptocócicas/tratamiento farmacológico , Leucocidinas/inmunología , Endopeptidasas/inmunología , Estreptoquinasa/inmunología , Estreptolisinas/inmunologíaRESUMEN
Using purified group A streptokinase (SKA) as the antigen, ELISA assays were carried out on the sera of normal unaffected children, acute poststreptococcal glomerulonephritis patients (APSGN) and acute rheumatic fever patients (ARF). The results demonstrate that antibody titers to SKA increase with age in normal children and by age 8 years the vast majority of children have antibodies to SKA. APSGN patients did not demonstrate unique reactivity to SKA when compared to ARF patients either at time of onset of disease or during convalescence. Polyclonal and monoclonal antibodies to SKA which recognize both group A and C streptokinase failed to detect the presence of streptokinase in the biopsy sections obtained from ten well-documented APSGN patients. We conclude that there is no unique reactivity to group A streptokinase in the sera of APSGN patients. Furthermore, we failed to demonstrate the presence of streptokinase in the biopsy specimens of an early case of APSGN patients.