RESUMEN
When nonobese-diabetic (NOD) mouse embryos were implanted into pseudopregnant mothers of a nonautoimmune mouse strain, the progeny had a reduced type 1 diabetes (T1D) incidence, suggesting that transmission of maternal autoantibodies is important for T1D development. Whether eliminating islet autoantibody transmission in utero, or postnatally (through milk), prevented T1D is unknown. Herein, we show that fostering newborn NOD mice on B-cell deficient NOD.Igmu-/- dams does not prevent T1D, demonstrating that postnatally transmitted islet autoantibodies are not required for disease pathogenesis. Additionally, NOD.Igmu-/- mice reared on NOD dams did not develop T1D, indicating that autoantibody transmission to B-cell deficient NOD neonates is insufficient to trigger T1D. Interestingly, newborn NOD mice that were reared by ICR (but not NOD or C57BL/6) dams had reduced T1D incidence, although not as reduced as that reported after embryo transfer to ICR mice, suggesting that both prenatal and postnatal factors contribute to the observed reduction in T1D incidence. Thus, NOD mice have different risks for developing T1D depending on the strain of their foster mother, and both prenatal and postnatal maternal factors, other than islet autoantibodies, influence their T1D incidence. The results may be relevant for understanding the increasing incidence of T1D and designing interventions.
Asunto(s)
Autoanticuerpos/inmunología , Diabetes Mellitus Tipo 1/inmunología , Ratones Endogámicos NOD/inmunología , Animales , Femenino , Islotes Pancreáticos/citología , Islotes Pancreáticos/inmunología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos ICR , Leche/inmunología , EmbarazoRESUMEN
Temperate bacteriophage MAV1 is found in certain highly virulent strains of Mycoplasma arthritidis. Integration sites, portions of the right and left prophage ends, and flanking DNA from eight prophages in seven M. arthritidis strains were characterized in this study. attb and attp sites conformed for the most part to the consensus sequence TATTTTT, although minor polymorphisms were noted. Prophages were integrated into similar sites in four strains, suggesting that these strains may have had a common ancestor. Two strains had three prophage copies each, and integration sites were identical. Two strains had two copies each. One of these shared two of the integration sites occupied in the three-copy strains, while the other shared one of these sites and harbored a second prophage in a unique site. Integration sites in the two strains with one prophage each were unique. Four MAV1 copies contained extensive substitutions within a region encoding a putative structural protein and the putative repressor protein. A 3-kb fragment was deleted from the right side of two of these copies. It is proposed that polymorphisms within MAV1 prophage integration sites and within the prophages themselves may help to identify phylogenetic relationships among virulent M. arthritidis strains.
Asunto(s)
Lisogenia/genética , Mycoplasma arthritidis/virología , Polimorfismo Genético , Profagos/genética , Secuencia de Aminoácidos , Sitios de Ligazón Microbiológica/genética , Secuencia de Bases , Reordenamiento Génico/genética , Datos de Secuencia Molecular , Mycoplasma arthritidis/genética , Mycoplasma arthritidis/metabolismo , Profagos/metabolismo , Análisis de Secuencia de ADN , Eliminación de Secuencia/genéticaRESUMEN
Genes encoding the Mycoplasma arthritidis surface-exposed lipoprotein MAA1 were cloned and sequenced from MAA1-expressing strains 158p10p9 and PG6, from a low-adherence (LA) variant derived from 158p10p9 that expresses a truncated version of MAA1 (MAA1Delta) and from two MAA1-negative strains, 158 and H39. The deduced amino acid sequences of maa1 from 158p10p9 and PG6 predicted, respectively, 86.5- and 86.4-kDa basic, largely hydrophilic lipoproteins with 29-amino-acid signal peptides and predicted cleavage sites for signal peptidase II (Ala-Ala-Ala downward arrowCys). The truncation in the LA variant resulted from a G-->T substitution at nucleotide 695, which created a premature stop codon. This, in turn, generated a predicted 26.6-kDa prolipoprotein (23.6 kDa after processing), consistent with an M(r) of approximately 24,000 calculated for MAA1Delta. Similarly, absence of MAA1 expression in H39 and 158 resulted from C-->A substitutions at nucleotide 208, generating premature stop codons at that site in both strains.
Asunto(s)
Proteínas Bacterianas/genética , Lipoproteínas/genética , Proteínas de la Membrana/genética , Mycoplasma/química , Secuencia de Aminoácidos , Proteínas Bacterianas/química , Secuencia de Bases , Clonación Molecular , Lipoproteínas/química , Proteínas de la Membrana/química , Datos de Secuencia Molecular , Sondas de Oligonucleótidos , Reacción en Cadena de la PolimerasaRESUMEN
Earlier studies implied a role for Mycoplasma arthritidis surface protein MAA2 in cytadherence and virulence and showed that it exhibited both size and phase variability. Here we report the further analysis of MAA2 and the cloning and sequencing of the maa2 gene from two M. arthritidis strains, 158p10p9 and H606, expressing two size variants of MAA2. Triton X-114 partitioning and metabolic labeling with [3H]palmitic acid suggested lipid modification of MAA2. Surface exposure of the C terminus was indicated by cleavage of monoclonal antibody-specific epitopes from intact cells by carboxypeptidase Y. The maa2 genes from both strains were highly conserved, consisting largely of six (for 158p10p9) or five (for H606) nearly identical, 264-bp tandem direct repeats. The deduced amino acid sequence predicted a largely hydrophilic, highly basic protein with a 29-amino-acid lipoprotein signal peptide. The maa2 gene was expressed in Escherichia coli from the lacZ promoter of vector pGEM-T. The recombinant product was approximately 3 kDa larger than the native protein, suggesting that the signal peptide was not processed in E. coli. The maa2 gene and upstream DNA sequences were cloned from M. arthritidis clonal variants differing in MAA2 expression state. Expression state correlated with the length of a poly(T) tract just upstream of a putative -10 box. Full-sized recombinant MAA2 was expressed in E. coli from genes derived from both ON and OFF expression variants, indicating that control of expression did not include alterations within the coding region.
Asunto(s)
Proteínas Bacterianas , Genes Bacterianos , Variación Genética , Proteínas de la Membrana/genética , Mycoplasma/genética , Secuencia de Aminoácidos , Secuencia de Bases , Escherichia coli/genética , Biblioteca Genómica , Proteínas de la Membrana/biosíntesis , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Sondas de Oligonucleótidos , Reacción en Cadena de la Polimerasa , Proteínas Recombinantes/biosíntesis , Secuencias Repetitivas de Ácidos Nucleicos , Análisis de Secuencia de ADNRESUMEN
We previously identified two surface-exposed Mycoplasma arthritidis protein antigens, designated MAA1 and MAA2, that may be involved in cytadherence. Since adherence to host tissues is an important first step in most bacterial infections, we suggest that MAA1 and MAA2 may be virulence factors for M. arthritidis. In order to provide evidence for such a role, we conducted a series of experiments in which rats were actively immunized with each of these proteins purified from sodium dodecyl sulfate-polyacrylamide gels or passively immunized with poly- or monoclonal antibodies against MAA1 and MAA2. In each case, immunity against MAA1 and MAA2 conferred at least partial protection against M. arthritidis-induced disease. The greatest protection was achieved by passive immunization with monoclonal antibody A9a, directed against a surface-exposed epitope of putative adhesin MAA1. Because protective immunity in most bacterial infections is directed against major virulence factors, these results suggest that MAA1 and MAA2 may play a role in the pathogenesis of M. arthritidis-induced arthritis of rats, possibly by mediating initial colonization of joint tissues.
Asunto(s)
Antígenos Bacterianos/administración & dosificación , Antígenos de Superficie/administración & dosificación , Artritis Infecciosa/prevención & control , Infecciones por Mycoplasma/prevención & control , Mycoplasma/inmunología , Mycoplasma/patogenicidad , Adhesinas Bacterianas/administración & dosificación , Adhesinas Bacterianas/inmunología , Adhesinas Bacterianas/aislamiento & purificación , Animales , Anticuerpos Antibacterianos/administración & dosificación , Antígenos Bacterianos/aislamiento & purificación , Antígenos de Superficie/aislamiento & purificación , Artritis Infecciosa/inmunología , Inmunización Pasiva , Masculino , Infecciones por Mycoplasma/inmunología , Ratas , Ratas Endogámicas Lew , Factores de Tiempo , Vacunación , Virulencia/inmunologíaRESUMEN
Surface antigenic variation was investigated in Mycoplasma arthritidis, an agent that produces chronic arthritis in rats which shares several features with many mycoplasma-induced diseases and thus defines a well-characterized model system. Hyperimmune rabbit antisera (anti-ISR1, anti-PG6, anti-H606 and anti-158p10) to whole M. arthritidis organisms were used as immunological probes in Western immunoblots of four M. arthritidis prototype strains (ISR1, PG6, H606 and D263) and five rat-passaged substrains (ISR1p1, ISR1p7, ISR1p8, 158p10 and D263p1). Several prominent antigens were identified that varied in expression. By Triton X-114 phase fractionation and treatment of whole cells with trypsin and carboxypeptidase Y, these strain-variant antigens were shown to be integral membrane proteins with C-termini and portions of the polypeptide chains oriented outside the membrane. Western blot immunoscreening of a large number of randomly selected clonal isolates and well-established clonal lineages from stock cultures of M. arthritidis ISR1p7, 158p10, PG6 and H606 revealed an expanded repertoire of variant membrane proteins whose expression was subject to independent, reversible phase variation. Colony immunoblots of these clonal populations with a hyperimmune rabbit antiserum to a gel-purified variant membrane protein (P36) showed that this phase switching occurred at a high frequency (10(-4) to 10(-2) per generation). Detailed immunological and biochemical characterization of the phase-variant membrane proteins demonstrated that they are: (i) antigenically related or distinct; (ii) apparently specific to particular strain populations; (iii) proteins or lipoproteins; (iv) major immunogens of M. arthritidis, recognized by serum antibodies from convalescent rat; and (v) able to undergo variation in expression during in vivo passage. Thus, M. arthritidis possesses a complex system capable of creating large repertoires of cell surface phenotypes which may affect the multiple interactions of this organism with its host and dictate its potential as a successful infectious agent and pathogen.
Asunto(s)
Antígenos Bacterianos , Proteínas Bacterianas/inmunología , Mycoplasma/inmunología , Animales , Anticuerpos Antibacterianos , Variación Antigénica , Antígenos Bacterianos/genética , Proteínas Bacterianas/genética , Biomarcadores , Membrana Celular/inmunología , Epítopos/genética , Lipoproteínas/genética , Lipoproteínas/inmunología , Proteínas de la Membrana/genética , Proteínas de la Membrana/inmunología , Infecciones por Mycobacterium/inmunología , Infecciones por Mycobacterium/microbiología , Mycoplasma/genética , Mycoplasma/patogenicidad , Conejos , Ratas , Especificidad de la EspecieRESUMEN
Mycoplasma arthritidis causes a severe polyarthritis under natural conditions in rats and under experimental conditions in both rats and mice. Although the disease itself has been extensively studied, M. arthritidis virulence factors remain uncharacterized. Comparison of relative arthritogenicity of 20 strains of M. arthritidis revealed that the strains tended to fall into two groups, a highly arthritogenic group, inducing maximum arthritis scores of > or = 11 in rats, and a low-virulence group, inducing maximum scores of < 6. Chromosomal DNA from the more highly arthritogenic strains possessed sequences that hybridized by Southern analysis with a probe prepared from lysogenic M. arthritidis bacteriophage MAV1, while DNA from low-virulence strains did not. One of the low-virulence strains, 158, was experimentally lysogenized with MAV1. Lysogenized 158 showed a significant increase in arthritogenicity over nonlysogenized 158. These data suggest that MAV1 carries a factor that is important in pathogenesis of M. arthritidis-induced arthritis of rats.
Asunto(s)
Artritis Infecciosa/etiología , Bacteriófagos/patogenicidad , Lisogenia , Mycoplasma/patogenicidad , Animales , Bacteriófagos/genética , ADN Viral/análisis , Masculino , Mycoplasma/virología , Hibridación de Ácido Nucleico , Ratas , Ratas Endogámicas Lew , VirulenciaRESUMEN
Twenty Mycoplasma arthritidis strains or isolates were compared by a combination of enzyme-linked immunosorbent assay by an antiserum adsorption technique, Western immunoblotting, and restriction analysis of chromosomal DNA. Antigenic markers that defined strains related to strains 158p10p9, PG6, and H606 were identified. In addition, restriction analysis allowed all 20 strains to be divided into six groups. Results of restriction analysis corresponded generally with antigenic similarities, although the former did not allow grouping with as fine a precision as the latter. However, intrastrain antigenic variability, which is common among many Mycoplasma species, including M. arthritidis, introduced a complicating factor into our attempts at antigenic analysis. While serologic and antigenic analyses remain useful, we recommend that they be used with caution and in combination with other techniques for identifying and characterizing new isolates and newly acquired strains. Combinations of these techniques have proven to be useful in our laboratory for quality control and for uncovering interesting relationships among strains subjected to animal passage and their less virulent antecedents and among strains originally classified as the same but obtained from different sources and maintained, sometimes for decades, in different laboratories.
Asunto(s)
Mycoplasma/aislamiento & purificación , Animales , Antígenos Bacterianos/inmunología , Enzimas de Restricción del ADN , ADN Bacteriano/análisis , Ensayo de Inmunoadsorción Enzimática , Immunoblotting , Ratones , Mycoplasma/clasificación , Mycoplasma/inmunología , Ratas , Mapeo RestrictivoRESUMEN
Although other investigators have reported that Mycoplasma arthritidis failed to attach to several types of mammalian cells in vitro, we showed that it attached well to rat synovial fibroblasts, lung cells, and skin cells but not to kidney cells, suggesting that receptor sites are unequally expressed or distributed among different rat tissues. M. arthritidis also attached poorly to canine kidney and to baby hamster kidney cells, although it did attach to human fetal lung and fetal amnion cells. Four M. arthritidis strains, two virulent and two avirulent, all attached equally well to rat lung cells. Attachment was inhibited by trypsinization, suggesting that the major adhesins are protein. Fab' fractions of rabbit antisera against four M. arthritidis strains partially inhibited adherence of both homologous and heterologous strains, although not to the same extent, indicating some degree of antigenic heterogeneity among their adhesins. A filter-cloned variant of M. arthritidis 158p10p9, designated LC1, attached poorly compared with the parent strain. Missing from this variant were two proteins migrating within the 81- to 90-kDa range by polyacrylamide gel electrophoresis; in their place was a 24-kDa antigen that may be a truncated version of one of these proteins. A monoclonal antibody that partially inhibited attachment recognized all these peptides by Western immunoblotting. An additional attachment-inhibiting monoclonal antibody recognized a 71-kDa antigen present in both low-adherence and fully adherent populations. The low-adherence variant LC1 induced slightly but significantly less arthritis in Lewis rats than did a fully adherent clone.
Asunto(s)
Adhesión Bacteriana , Mycoplasma/patogenicidad , Animales , Anticuerpos Monoclonales/inmunología , Artritis Infecciosa/microbiología , Proteínas Bacterianas/metabolismo , Células Cultivadas , Humanos , Masculino , Ratones , Ratones Endogámicos BALB C , Mycoplasma/inmunología , Conejos , Ratas , Ratas Endogámicas Lew , Tripsina/farmacología , VirulenciaRESUMEN
The nature of Mycoplasma arthritidis antigens responsible for eliciting protective immunity in rats was studied by inoculation of rats with mycoplasmal components that had been subjected to a variety of physical and chemical treatments. All inocula tested induced good protection against development of clinical illness, as assessed by changes in body weight and appearance of joint swelling and/or temporary hind limb paralysis. Although all preparations stimulated development in inoculated rats of high titer of antimycoplasmal antibodies measured by ELISA, the complement-fixation antibody response was poor and, in some cases, lacking altogether. This indicated that completion-fixation antibodies may not be involved in protecting rats against M arthritidis-induced illness. Protective antigens were stable to heat (100 C for 10 minutes), formalin, and denaturation by sodium dodecyl sulfate (SDS). Inoculation with membrane and soluble cytoplasmic fractions was protective, as was inoculation with 5 M arthritidis fractions separated according to molecular weight by SDS-polyacrylamide gel electrophoresis (SDS-PAGE). For this latter experiment, rat antisera obtained after vaccination, but prior to challenge exposure, were tested by immunoblot analysis against electrophoretically separated M arthritidis membrane proteins. Interestingly, all antisera from these rats recognized antigens migrating far outside the molecular weight range of the cell fractions with which rats were inoculated. This indicated either that the protective antigens may be composed of numerous antigenically related subunits that separated by SDS-PAGE into a variety of molecular weight ranges or that a few major antigens may exist in several forms or phases within a given population of M arthritidis.
Asunto(s)
Artritis Infecciosa/veterinaria , Infecciones por Mycoplasma/veterinaria , Mycoplasma/inmunología , Ratas Endogámicas Lew , Enfermedades de los Roedores/prevención & control , Animales , Anticuerpos Antibacterianos/biosíntesis , Antígenos Bacterianos/inmunología , Artritis Infecciosa/prevención & control , Vacunas Bacterianas/inmunología , Peso Corporal , Membrana Celular/inmunología , Pruebas de Fijación del Complemento , Citoplasma/inmunología , Ensayo de Inmunoadsorción Enzimática , Inmunización Secundaria/veterinaria , Immunoblotting , Masculino , Infecciones por Mycoplasma/prevención & control , Ratas , Vacunación/veterinariaRESUMEN
Four Mycoplasma arthritidis strains, two virulent (158p10p9 and 14124p10) and two avirulent (PG6 and H606), were examined for differences in their antigenic compositions. Rabbit antisera prepared against each strain were compared for their reactivities against both homologous and heterologous strains by enzyme-linked immunosorbent assay and metabolism inhibition assay. These tests confirmed a close serologic relationship among the four strains. Only by cross-absorbing each antiserum with intact cells from both homologous and heterologous strains could serologic differences be detected. Interestingly, antigenic variability was minimal among those antigens involved in the metabolism inhibition reaction, suggesting that they may be highly conserved within this species. No differences in protein composition could be detected by one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis. However, slight variation was apparent on two-dimensional gels, and antigens possessing strain-specific epitopes were detected by two-dimensional immunoblotting experiments performed with cross-absorbed antisera. The enzyme-linked immunosorbent assay, two-dimensional electrophoresis, and immunoblotting experiments showed that the two virulent strains were closely related to each other, while the avirulent strains were more distantly related to each other and to the other two strains. The relationship of M. arthritidis serologic diversity to virulence remains unclear: however, this study has demonstrated that it may be possible to subdivide M. arthritidis into serogroups on the basis of cross-absorption patterns and to identify those antigens bearing strain-specific epitopes by immunoblotting with cross-absorbed antisera.
Asunto(s)
Antígenos Bacterianos , Mycoplasma/inmunología , Animales , Anticuerpos Antibacterianos , Proteínas Bacterianas/inmunología , Técnicas de Tipificación Bacteriana , Reacciones Cruzadas , Electroforesis en Gel de Poliacrilamida , Ensayo de Inmunoadsorción Enzimática , Immunoblotting , Mycoplasma/clasificación , Mycoplasma/patogenicidad , Especificidad de la Especie , Virulencia/inmunologíaRESUMEN
Four Mycoplasma arthritidis strains were examined for differences in virulence for LEW rats and elicitation of antibody responses in the immunoglobulin (Ig) M and G classes and in the four IgG subclasses. Two strains were highly arthritogenic and two were relatively avirulent. When the latter strains did induce arthritis, it was significantly less severe (P less than 0.05) and developed significantly later (P less than 0.001) than in rats injected with the two virulent strains, suggesting that the low-virulence organisms are able to persist asymptomatically in rats for several weeks. None of the M. arthritidis-injected rats developed metabolism-inhibiting (MI) antibodies at any time during the 6-week observation period. Responses to other M. arthritidis antigens from all four strains were measured by enzyme immunoassay (ELISA); they were similar qualitatively but differed quantitatively. Rats injected with the two avirulent strains showed significantly lower titers of IgM antibodies (P less than 0.01) throughout the 6-week observation period and significantly lower early titers of IgG antibodies (P less than 0.05) than rats injected with the two virulent strains. In addition, peak IgM antibody titers, IgM titers measured 1 and 6 weeks after injection and IgG antibody titers measured 1 week after injection all correlated significantly with peak arthritis scores (P less than 0.05). The IgG antibody response against all four strains appeared mostly in the IgG2a and IgG2b fractions, with very little in the IgG1 and IgG2c fractions. Using immunoblotting, the immunodominant antigens of the two virulent strains appeared very similar, but the avirulent strains differed slightly from each other and from the other two. This study indicates that immune responses of rats to virulent and avirulent strains are similar but not identical and that immunogenicity for LEW rats may be a strain-specific characteristic for M. arthritidis.
Asunto(s)
Anticuerpos Antibacterianos/biosíntesis , Artritis/veterinaria , Mycoplasma/inmunología , Ratas Endogámicas Lew/microbiología , Ratas Endogámicas/microbiología , Animales , Artritis/inmunología , Artritis/microbiología , Proteínas Sanguíneas/inmunología , Ensayo de Inmunoadsorción Enzimática , Immunoblotting , Inmunoglobulina G/inmunología , Inmunoglobulina M/inmunología , Mycoplasma/aislamiento & purificación , Mycoplasma/patogenicidad , Ratas , VirulenciaRESUMEN
Sera from rats convalescing from infection with Mycoplasma arthritidis were tested for their ability to react with M. arthritidis membrane antigens by immunoblotting and radioimmunoprecipitation. The absence of metabolism-inhibition (MI) antibody activity in these sera suggested that rats might fail to recognize those membrane antigens involved in eliciting MI antibodies therefore rabbit antisera, which are strongly MI positive for M. arthritidis, were used for comparison. Antigenic recognition patterns of M. arthritidis surface and membrane antigens were not identical for rats and rabbits. The most striking and reproducible difference was the failure of rats to produce IgG antibodies against a surface antigen migrating in the 47,000-50,000 molecular weight range on SDS-polyacrylamide gels. However, rats recognized at least 2 antigens which we had previously shown to be "MI antigens", therefore the inability to express MI antibodies probably cannot be explained by their inability to recognize M. arthritidis "MI antigens".
Asunto(s)
Antígenos Bacterianos/inmunología , Artritis Infecciosa/inmunología , Infecciones por Mycoplasma/inmunología , Mycoplasma/inmunología , Animales , Antígenos de Superficie/inmunología , Autorradiografía , Electroforesis en Gel de Poliacrilamida , Ensayo de Inmunoadsorción Enzimática , Femenino , Sueros Inmunes/inmunología , Immunoblotting , Masculino , Pruebas de Precipitina , Conejos , Ratas , Ratas Endogámicas LewRESUMEN
Shared antigens between Mycoplasma arthritidis and rat tissues may be responsible for the lack of metabolism-inhibition (MI) and other neutralizing antibodies in rats with M arthritidis-induced arthritis. We were not able to confirm such antigens or to detect cross-reacting antigens between M arthritidis and rat lymphocytes, thymocytes, and muscle tissue. Antisera of rabbit origin to rat lymphocytes, thymocytes, and skeletal muscle reacted by ELISA with M arthritidis only when the mycoplasmal antigens were prepared from organisms grown in medium containing horse serum. Such activity could be completely absorbed by horse serum. These antisera to rat tissues also failed to react by radioimmunoprecipitation with M arthritidis surface antigens. In addition, antibody activity against homologous antigens could not be absorbed by M arthritidis. Similarly, antisera of rabbit origin against M arthritidis failed to react by ELISA specifically with rat lymphocytes, thymocytes, and skeletal muscle or to react by radioimmunoprecipitation with 125I-labeled rat lymphocyte antigens. These rat tissues could not specifically absorb antibodies against M arthritidis from antisera of rabbit origin. These findings suggest that the lack of MI antibodies in rats probably can not be explained by rat tissue antigens that cross-react with M arthritidis MI antigens. Finally, antisera of rat origin against M arthritidis and other rat tissue components failed to block rabbit MI activity against M arthritidis, thus arguing against steric hindrance as a means of preventing recognition of MI antigens.
Asunto(s)
Anticuerpos Antibacterianos/inmunología , Antígenos Bacterianos/inmunología , Antígenos/inmunología , Artritis/inmunología , Linfocitos/inmunología , Músculos/inmunología , Mycoplasma/inmunología , Animales , Sitios de Unión de Anticuerpos , Unión Competitiva , Reacciones Cruzadas , Ensayo de Inmunoadsorción Enzimática , Ratas , Ratas EndogámicasAsunto(s)
Artritis Infecciosa/etiología , Modelos Animales de Enfermedad/inmunología , Infecciones por Mycoplasma/etiología , Mycoplasma/inmunología , Animales , Anticuerpos Antibacterianos/biosíntesis , Artritis Infecciosa/inmunología , Artritis Infecciosa/patología , Artritis Reumatoide/inmunología , Autoanticuerpos/biosíntesis , Modelos Animales de Enfermedad/patología , Humanos , Inmunidad Celular , Mycoplasma/patogenicidad , Infecciones por Mycoplasma/inmunología , Infecciones por Mycoplasma/patología , Conejos , Ratas , Ratas Endogámicas , Especificidad de la EspecieRESUMEN
LEW rats experimentally infected with Mycoplasma arthritidis failed to express metabolism inhibition (MI) antibodies. Our hypothesis was that rats failed to immunologically recognize the antigens responsible for eliciting those antibodies. LEW rats, injected i.v. with M. arthritidis, recognized only two low-MW surface antigens by radioimmunoprecipitation by 1 week after injection. However, by 6 weeks these rats recognized most of the same M. arthritidis surface antigens by Western blot and radioimmunoprecipitation as were recognized by immunized rabbits. The most important exception was a 47-to 50-kDa (kilodalton) surface protein that was antigenic only for rabbits. We had previously produced two monoclonal antibodies with MI activity that recognized two distinct M. arthritidis epitopes. However, neither of these corresponded to the antigen that rats failed to recognize, and LEW rats produced IgG antibodies against both monoclonal antibody-defined "MI antigens." Therefore, the failure of rats to express MI activity against M. arthritidis remains unexplained.
Asunto(s)
Antígenos Bacterianos/inmunología , Antígenos de Superficie/inmunología , Proteínas Bacterianas/inmunología , Proteínas de la Membrana/inmunología , Mycoplasma/inmunología , Animales , Anticuerpos Antibacterianos/biosíntesis , Anticuerpos Monoclonales/inmunología , Especificidad de Anticuerpos , Inmunoglobulina G/biosíntesis , Masculino , Conejos/inmunología , Ratas , Ratas Endogámicas Lew/inmunología , Especificidad de la EspecieRESUMEN
Previous studies established that Mycoplasma arthritidis produces a soluble T cell mitogen (MAM), and that response of murine T cells to MAM is genetically restricted. MAM appeared predominantly in the supernatants of senescent cultures, but was not extracted in significant amounts from whole cells. A quantitative assay of MAM activity was devised. MAM formed noncovalent complexes with nucleic acids and uncharacterized high m.w. constituents of sera and of complex media. Partially purified MAM was adsorbed or denatured by glass and plastic surfaces. MAM was protease-labile, had pI greater than or equal to 9, and had Mr ca 15,000 according to gel filtration experiments. MAM was a very minor component of culture supernatant proteins, and even after 200- to estimated 5 X 10(4)-fold purification was not identified as a stainable or ultraviolet-absorbing entity in electrophoretigrams or chromatograms. It was estimated that MAM was half-optimally active at less than 1000th the half-optimal concentration of concanavalin A or phytohemagglutinin. Culture supernatants and highly purified MAM exhibited the same haplotype specificity (H-2k-dependent response) for stimulated proliferation of lymphocytes and for induction of interferon in vitro.
Asunto(s)
Antígenos de Histocompatibilidad Clase II , Mitógenos/farmacología , Mycoplasma/análisis , Linfocitos T/efectos de los fármacos , Animales , Células Presentadoras de Antígenos/inmunología , Precipitación Química , Cromatografía en Gel , Cromatografía por Intercambio Iónico , Medios de Cultivo/análisis , Antígenos de Histocompatibilidad/inmunología , Interferón Tipo I/biosíntesis , Activación de Linfocitos/efectos de los fármacos , Ratones , Peso Molecular , Linfocitos T/metabolismoRESUMEN
The Mycoplasma arthritidis antigen(s) responsible for eliciting metabolism-inhibiting antibodies in rabbits has been partially characterized. Metabolism-inhibiting activity was absorbed from rabbit antisera by intact M. arthritidis cells and membranes but much less so by the soluble cytoplasmic fraction, indicating that the antigen is located on the outer membrane surface. It was stable to periodate and lipid extraction but labile to heat and proteolytic enzymes, indicating that it is protein in nature. Finally, it is most likely a tightly bound integral rather than a peripheral membrane protein, since it was not extracted by low-ionic-strength solutions or by the nonionic detergents Triton X-100, Nonidet P-40, and Tween 20. It was solubilized by both the anionic agent sodium deoxycholate and the zwitterionic detergent Zwittergent. Two two monoclonal antibodies with metabolism-inhibiting activity were produced. One recognized a 45,000-dalton surface protein; however, the other recognized an antigen which is probably of cytoplasmic origin, indicating that more than one cell component may be involved in the metabolism-inhibiting antibody response.
Asunto(s)
Antígenos Bacterianos/aislamiento & purificación , Mycoplasma/inmunología , Anticuerpos Monoclonales , Complejo Antígeno-Anticuerpo , Antígenos Bacterianos/inmunología , Membrana Celular/inmunología , Sueros Inmunes , Peso Molecular , RadioinmunoensayoRESUMEN
Rabbits exposed to Mycoplasma arthritidis either by active immunization with killed mycoplasmas or by primary infection in the right knee were protected against intra-articular challenge with viable M. arthritidis in the left knee. This protection extended to the challenged knees of preinfected rabbits even while highly active inflammation persisted in the initially injected joints. We propose that the protection is mediated by antibody, probably metabolic-inhibiting antibody, present in the joint at the time of challenge.
Asunto(s)
Artritis Infecciosa/etiología , Infecciones por Mycoplasma/etiología , Animales , Anticuerpos Antibacterianos/biosíntesis , Artritis Infecciosa/inmunología , Artritis Infecciosa/prevención & control , Inmunidad Celular , Inmunización , Inflamación/patología , Articulación de la Rodilla , Activación de Linfocitos , Infecciones por Mycoplasma/inmunología , Infecciones por Mycoplasma/prevención & control , ConejosRESUMEN
The use of inbred and congenic mouse strains established that toxicity and death induced by Mycoplasma arthritidis associates with the haplotype expressed at the murine major histocompatibility complex. Mice bearing H-2k and H-2d are susceptible, whereas those bearing H-2b are much more resistant. Mice susceptible to toxicity exhibited massive peritoneal adhesions and a decreased ability to clear organisms from the peripheral circulation. However, the severity of acute arthritis developing over a 3-month period was not statistically related to the haplotype expressed at the major histocompatibility complex. Lymphocyte activation in vitro by a soluble T-cell mitogen is also dependent on a similar haplotype expression.