Assuntos
Anticorpos Antibacterianos/sangue , Antígenos de Bactérias , Borrelia burgdorferi/imunologia , Imunoglobulina G/imunologia , Neuroborreliose de Lyme/diagnóstico , Proteínas da Membrana Bacteriana Externa/química , Proteínas da Membrana Bacteriana Externa/genética , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Borrelia burgdorferi/genética , Borrelia burgdorferi/isolamento & purificação , DNA Bacteriano/química , DNA Bacteriano/genética , Humanos , Immunoblotting/métodos , Imunoglobulina G/sangue , Neuroborreliose de Lyme/imunologia , Reação em Cadeia da Polimerase , Proteínas Recombinantes , Sensibilidade e EspecificidadeRESUMO
BACKGROUND: Annexin A7 is a Ca2+- and phospholipid-binding protein expressed as a 47 and 51 kDa isoform, which is thought to be involved in membrane fusion processes. Recently the 47 kDa isoform has been identified in erythrocytes where it was proposed to be a key component in the process of the Ca2+-dependent vesicle release, a process with which red blood cells might protect themselves against an attack by for example complement components. RESULTS: The role of annexin A7 in red blood cells was addressed in erythrocytes from anxA7-/- mice. Interestingly, the Ca2+-mediated vesiculation process was not impaired. Also, the membrane organization appeared not to be disturbed as assessed using gradient fractionation studies. Instead, lack of annexin A7 led to an altered cell shape and increased osmotic resistance of red blood cells. Annexin A7 was also identified in platelets. In these cells its loss led to a slightly slower aggregation velocity which seems to be compensated by an increased number of platelets. The results appear to rule out an important role of annexin A7 in membrane fusion processes occurring in red blood cells. Instead the protein might be involved in the organization of the membrane cytoskeleton. Red blood cells may represent an appropriate model to study the role of annexin A7 in cellular processes. CONCLUSION: We have demonstrated the presence of both annexin A7 isoforms in red blood cells and the presence of the small isoform in platelets. In both cell types the loss of annexin A7 impairs cellular functions. The defects observed are however not compatible with a crucial role for annexin A7 in membrane fusion processes in these cell types.
Assuntos
Anexina A7/fisiologia , Plaquetas/fisiologia , Eritrócitos/fisiologia , Animais , Anexina A7/análise , Anexina A7/genética , Anexina A7/metabolismo , Plaquetas/química , Plaquetas/metabolismo , Tamanho Celular , Membrana Eritrocítica/química , Eritrócitos/química , Eritrócitos/metabolismo , Feminino , Humanos , Masculino , Camundongos , Camundongos Knockout , Pressão Osmótica , Agregação Plaquetária , Vesículas Secretórias/metabolismoRESUMO
We investigated whether the recombinant Borrelia Western blot test previously described (B. Wilske, C. Habermann, V. Fingerle, B. Hillenbrand, S. Jauris-Heipke, G. Lehnert, I. Pradel, D. Rössler, and U. Schulte-Spechtel, Med. Microbiol. Immunol. 188:139-144, 1999) can be improved by the addition of VlsE and additional DbpA and OspC homologues. By using a panel of sera from 36 neuroborreliosis patients and 67 control patients, the diagnostic sensitivity of the recombinant immunoblot test was significantly increased (86.1% versus 52.7%) without loss of specificity and was higher (86.1% versus 63.8%) than that of the conventional whole-cell lysate immunoblot test (U. Hauser, G. Lehnert, R. Lobentanzer, and B. Wilske, J. Clin. Microbiol. 35:1433-1444, 1997). Improvement was mainly due to the presence of VlsE and DbpA.
