Robino Patrizia, Alberti Alberto, Pittau Marco, Chessa Bernardo, Miciletta Marco, Nebbia Patrizia, Le Grand Dominique, Rosati Sergio
Dipartimento di Produzioni Animali, Epidemiologia ed Ecologia, Università degli Studi di Torino, Facoltà di Medicina Veterinaria, Via Leonardo da Vinci 44, 10095 Grugliasco (Torino), Italy.
Vet Microbiol. 2005 Aug 30;109(3-4):201-9. doi: 10.1016/j.vetmic.2005.05.007.
The presence of a membrane lipoprotein homologous to the P48 of Mycoplasma agalactiae was investigated in different Mycoplasma bovis isolates selected by geographical locations and biological properties. Its potential as a diagnostic tool was also discussed. The presence of a specific signal observed in all M. bovis field isolates probed with a rabbit antiserum raised against the M. agalactiae recombinant P48 demonstrated that this protein is structurally and antigenically conserved within the M. bovis cluster. No signal was detected when testing six different mycoplasma species found in cattle. The p48 gene was identified by PCR approach and partially sequenced. Full length gene sequence was obtained by direct bacterial chromosome sequencing. Five UGAs were selectively mutated into UGG and the full length mutated gene, lacking the signal peptide, was cloned and expressed in Escherichia coli. The purified recombinant antigen (r-P48) was evaluated as a potential marker of infection using a panel of 86 well-characterized sera from experimentally and naturally infected cattle. Specific IgM antibodies were detected within 6-9 days after experimental infection followed by an IgG response lasting from the third/fourth week after contact. Although antibody titers were well below those observed in sheep or goats infected with M. agalactiae, results suggest that M. bovis r-P48 can be used as a specific marker of infection.
研究了在根据地理位置和生物学特性挑选出的不同牛支原体分离株中，是否存在与无乳支原体P48同源的膜脂蛋白。还讨论了其作为诊断工具的潜力。用针对无乳支原体重组P48产生的兔抗血清检测所有牛支原体田间分离株时，观察到特定信号的存在，这表明该蛋白在牛支原体菌群中在结构和抗原性上是保守的。检测牛中发现的六种不同支原体时未检测到信号。通过PCR方法鉴定了p48基因并进行了部分测序。通过直接细菌染色体测序获得了全长基因序列。五个UGA被选择性地突变为UGG，缺失信号肽的全长突变基因被克隆并在大肠杆菌中表达。使用一组来自实验感染和自然感染牛的86份特征明确的血清，评估纯化的重组抗原（r-P48）作为感染潜在标志物的情况。实验感染后6-9天内检测到特异性IgM抗体，随后在接触后第三/四周开始出现持续的IgG反应。尽管抗体滴度远低于感染无乳支原体的绵羊或山羊中观察到的滴度，但结果表明牛支原体r-P48可作为感染的特异性标志物。
