马尔尼菲青霉病12例临床回顾性分析

目的 分析我院马尔尼菲青霉病的临床特征和预后.方法 回顾性分析我院2003年1月～2012年12月10 a间诊断的12例马尔尼菲青霉病,分析其临床表现、实验室和辅助检查、治疗和预后.结果 除了既往报道的临床表现如发热、皮疹、咳嗽、气促、浆膜腔积液、肝脾淋巴结肿大、消化道症状、溶骨性损害外,还包括咽痛、双下肢水肿、血管闭塞或狭窄.实验室检查发现尿常规异常6例,其中4例血肌酐升高.4例HIV阳性患者中3例给予伊曲康唑单用或联合两性霉素B治疗好转出院.8例HIV阴性患者给予伏立康唑单用或联合其他抗真菌药物治疗,5例有效,3例在起始抗真菌治疗后2～11d死亡,其中2例有气促和腹水.结论 马尔尼菲青霉病除了既往报道累单核巨噬细胞系统外,也可累及咽部黏膜、泌尿系统、外周循环系统.应用伏立康唑或伊曲康唑治疗有效,气促和腹水可能提示预后差,早期诊治可能改变患者的预后.     

A novel approach for screening immunogenic proteins in Penicillium marneffei using the DeltaAFMP1DeltaAFMP2 deletion mutant of Aspergillus fumigatus

Using serum from guinea-pigs immunized with a DeltaAFMP1DeltaAFMP2 deletion mutant of Aspergillus fumigatus to screen a cDNA library of A. fumigatus, we cloned a novel immunogenic 57-kDa protein in A. fumigatus. We also cloned its 55-kDa homologue in Penicillium marneffei, which was possibly related to amino acid biosynthesis and metabolism, with homologues present only in the subphylum Pezizomycotina of Ascomycota. The recombinant 55-kDa protein of P. marneffei reacted strongly with guinea-pig serum immunized with P. marneffei and with the sera of patients with P. marneffei infection. A similar approach could be applied to immunogenic protein screening in other microorganisms for serological diagnosis, epidemiological studies and the study of vaccines.     

Engagement of Penicillium marneffei conidia with multiple pattern recognition receptors on human monocytes

P. marneffei is a thermal dimorphic fungus which causes penicilliosis, an opportunistic infection in immunocompromised patients in South and Southeast Asia. Little is known about the innate immune response to P. marneffei infection. Therefore, the initial response of macrophages to P. marneffei conidia was evaluated by us. Adhesion between monocytes from healthy humans and fungal conidia was examined and found to be specifically inhibited by MAbs against PRR, such as MR, (TLR)1, TLR2, TLR4, TLR6, CD14, CD11a, CD11b, and CD18. To study the consequences of these interactions, cytokines were also examined by ELISA. Binding of P. marneffei conidia to monocytes was significantly inhibited, in a dose-dependent manner, by MAbs against MR, TLR1, TLR2, TLR4, TLR6, CD14, CD11b and CD18. When monocytes were co-cultured with the conidia, there was an increase in the amount of surface CD40 and CD86 expression, together with TNF-α and IL-1β production, compared to unstimulated controls. In assays containing anti-TLR4 or anti-CD14 antibody, reduction in the amount of TNF-α released by monocytes stimulated with P. marneffei conidia was detected. In addition, it was found that production of TNF-α and IL-1β from adherent peripheral blood monocytes was partially impaired when heat-inactivated autologous serum, in place of untreated autologous serum, was added to the assay. These results demonstrate that various PRR on human monocytes participate in the initial recognition of P. marneffei conidia, and the engagement of PRR could partly initiate proinflammatory cytokine production.     

艾滋病并发马尔尼菲青霉败血症1例

目的：报道1例马尔尼菲青霉败血症。方法患者男性,39岁,主因“发热伴淋巴结肿大1个月”就诊。进行骨髓瑞士染色、血液接种于有氧及厌氧培养瓶、沙氏培养基培养等检查,并对培养物进行形态学及 rDNA 序列鉴定。结果骨髓涂片见细胞内分隔孢子,3种培养方法均见真菌生长。沙氏培养基上菌落为丝状菌,表面为黄绿色粉末状,背面为红色;脑心浸汁培养基为酵母样菌落,37℃培养受限制。经 DNA 序列分析,与马尔尼菲青霉相似性在100℅,鉴定为马尔尼菲青霉。患者诊断为艾滋病并马尔尼菲青霉败血症,立即给予氟康唑治疗,转入传染病医院后因极度衰弱死亡。结论败血症可作为马尔尼菲青霉病首发症状,临床应予以重视;患者血液极具传染性,应注意隔离;对于有冶游史的不明原因发热患者,注意考虑本病可能,必要时行血液培养及 HIV 检测。     

北部湾人群Dectin-1的基因多态性与马尔尼菲青霉菌病易感性的相关性研究

目的:探讨北部湾人群C型凝集素-1(Dectin-1)基因多态性与马尔尼菲青霉菌病易感性的相关性。方法:选取北部湾地区的马尔尼菲青霉菌(PM)病患者71例为病例组,另选北部湾地区的71例体检正常者为对照组,直接测序检测rs16910526、rs16910527位点的基因型及等位基因频率,并分析其与马尔尼菲青霉菌病易感性的相关性。结果:(1)对照组和病例组之间rs16910526有三种基因型GG、GT、TT,两组之间基因型和等位基因频率比较差异不显著(P0.05)。(2)对照组和病例组之间rs16910527有三种基因型AA、AC、CC,且病例组AC的基因型频率显著高于对照组(P0.05)。(3)局限性、播散性PM患者rs16910526、rs16910527基因型和等位基因频率比较差异不显著(P0.05)。(4)rs16910526、rs16910527的4种单倍型:GT、AC、AT、TT,位于同一连锁不平衡区域内,且对照组和病例组A/C的分布频率比较差异具有统计学意义(P0.05)。结论:北部湾人群Dectin-1的rs16910527位点与马尔尼菲青霉菌病易感性相关,且A/C能提高马尔尼菲青霉菌病的易感性。     

非HIV感染的马尔尼菲青霉病2例报道并文献复习

目的 探讨非HIV感染的马尔尼菲青霉病的临床特征,提高对本病的早期诊断与治疗水平.方法 分析广州医科大学附属第一医院广州呼吸疾病研究所收治的2例非HIV感染的马尔尼菲青霉病患者的临床、影像、微生物和病理资料,并复习相关文献.结果 例1,男,37岁,反复咳嗽、发热1个月,双肩关节疼痛伴消瘦,广谱抗生素治疗无效,左锁骨上及左腹股沟淋巴结肿大,头颅MR发现颅内及咽后脓肿,经纤维支气管镜肺活检及脓液培养确诊马尔尼菲青霉病,继发性癫痫.予两性霉素B脂质体静滴治疗后好转出院,继续予伊曲康唑口服液治疗3个月症状消失,复查胸部CT及头颅MRI病灶吸收,患者自行停药后复发,再次予两性霉素B脂质体治疗仍有效.例2,男,32岁,咳嗽、咳痰5月余,皮下肿块伴发热3月余,胸部CT示纵膈脓肿伴胸骨骨髓炎形成,抽吸脓液培养有马尔尼菲青霉生长.予两性霉素B脂质体抗真菌治疗过程中,患者继发感染性休克,弥漫性血管内凝血.结论 马尔尼菲青霉病属于少见病,侵犯颅内的是国内首例报道,经纤维支气管镜肺活检和脓液培养可确诊.复发病例予两性霉素B脂质体治疗仍有效.早期诊断是提高治愈率的关键.     

Trypanosoma lewisi: production of exoantigens during infection in the rat

Exoantigens are produced by Trypanosoma lewisi during infections in the rat. They were detected in rat serum and plasma by gel-diffusion techniques with hyperimmune rat sera and with rabbit antiserum to washed, living trypanosomes. Their parasite origin is indicated by their presence in trypanosome homogenates, which also contain bound antigens, the continued reactivity of rabbit antisera after absorption with normal rat serum, and the reactions of identity obtained with rat and rabbit antisera. Moreover, by immunoelectrophoresis, the exontigens are revealed as new components in infected rat serum with a mobility slightly anodal to the origin. The results also show that the exoantigens are continuously released in vivo and that the trypanosomes avidly bind non-antibody rat serum proteins to their surface. Unlike the complete qualitative changes in exoantigens that accompany antigenic variation of pathogenic species of trypanosomes, at least one exoantigen remains unchanged when antigenic variation occurs with T. lewisi although additional exoantigens may appear and disappear. The relation of the exoantigens to the known ablastic and trypanocidal antibodies is difficult to determine since these antibodies and the exoantigens occur simultaneously in the blood during and after the infection. Although it cannot yet be ruled out that the exoantigens elicit the formation of these antibodies, a review of all the available evidence suggests that the exoantigens of T. lewisi may not be immunogenic during a natural course of infection. Possibly they are hemolysins with a nutritive function.     

Immunoassays based on Penicillium marneffei Mp1p derived from Pichia pastoris expression system for diagnosis of penicilliosis

Background

Penicillium marneffei is a dimorphic fungus endemic in Southeast Asia. It can cause fatal penicilliosis in humans, particularly in HIV-infected people. Diagnosis of this infection is difficult because its clinical manifestations are not distinctive. Specialized laboratory tests are necessary to establish a definitive diagnosis for successful management. We have demonstrated previously that a cell wall mannoprotein Mp1p, abundant in P. marneffei, is a potential biomarker for diagnosis of P. marneffei infections. In the present study, we describe immunoassays based on Mp1p derived from the yeast Pichia pastoris expression system.

Methodology/Principal Findings

We generated monoclonal antibodies (MAbs) and rabbit polyclonal antibodies (PAbs) against Mp1p expressed in P. pastoris. Subsequently, we developed two Mp1p antigen capture ELISAs which employed MAbs for both the capture and detecting antibodies (MAb-MAb pair) or PAbs and MAbs as the capture and detecting antibodies (PAbs-MAb pair) respectively. The two Mp1p antigen ELISAs detected Mp1p specifically in cultures of P. marneffei yeast phase at 37–40°C and had no cross-reaction with other tested pathogenic fungi. The sensitivities and specificities of the two antigen assays were found to be 55% (11/20) and 99.6% (538/540) for MAb-MAb Mp1p ELISA, and 75% (15/20) and 99.4% (537/540) for PAbs-MAb Mp1p ELISA performed using 20 sera with culture-confirmed penicilliosis, and 540 control sera from 15 other mycosis patients and 525 healthy donors. Meanwhile, we also developed an anti-Mp1p IgG antibody ELISA with an evaluated sensitivity of 30% (6/20) and a specificity of 98.5% (532/540) using the same sera. Furthermore, combining the results of Mp1p antigen and antibody detection improved the sensitivity of diagnosis to 100% (20/20).

Conclusions/Significance

Simultaneous detection of antigen and antibody using the immunoassays based on Mp1p derived from P. pastoris greatly improves detection sensitivity. The procedures should be useful for the routine diagnosis of penicilliosis.     

AIDS合并马尔尼菲青霉病36例分析

目的探讨艾滋病合并马尔尼菲青霉病的临床表现,治疗与转归。方法回顾分析本院2008年8月～2009年8月收治的艾滋病合并马尔尼菲青霉36例。结果 36例艾滋病合并马尔尼菲青霉病平均年龄35.8岁。马尔尼菲青霉感染临床表现呈现非特异性,其中发热86.11%,贫血94.44%,GGT升高69.44%,AST升高63.89%,淋巴结肿大88.89%,脾大63.89%,低蛋白血症83.33%,咳嗽36.11%,皮损30.56%(其中典型改变仅5例,占13.89%),CD4+50cells/mm388.89%,骨髓培养(27/27)及皮损活检培养(2/2)阳性率100%,血液培养阳性率69.44%(25/36)。36例经抗真菌治疗,其中29例给予HAART治疗,28例治愈,7例好转,1例死亡。结论马尔尼菲青霉是艾滋病常见的机会性感染,早发现,早治疗,长程敏感抗真菌药物联合治疗可提高治愈率,减少复发。     

Association between sequence polymorphism in an epitope of Babesia divergens Bd37 exoantigen and protection induced by passive transfer

In Europe, Babesia divergens is the major agent responsible for babesiosis in cattle and can occasionally infect splenectomised humans. Recently, we reported the characterisation of a 37 kDa exoantigen (Bd37) anchored in the merozoite membrane of B. divergens by a glycosylphosphatidyl-inositol. After phospholipase hydrolyse of the glycosylphosphatidyl-inositol anchor, the Bd37 antigen could be isolated in the plasma of the infected host and from the in vitro culture supernatants. Immunisation of mice with a gel-filtration protective fraction of B. divergens exoantigens, produced a monoclonal antibody (MAb), called F4.2F8-INT, directed against Bd37. In the present study, we report data on passive protection using MAb F4.2F8-INT. This MAb was able to completely protect against virulent challenges with B. divergens isolates Rouen 1987 (Rouen87) and Weybridge 8843 (W8843) but had no protective effect against another French isolate from Massif Central (6303E). Physical characterisation of the epitope recognised by F4.2F8-INT allowed us to explain the differences observed between these isolates by western blotting and passive protection. These results suggest that the antigen carrying this epitope could be used as a target in the development of a recombinant vaccine against B. divergens babesiosis.     

马尔尼菲青霉病8例临床分析

目的分析总结马尔尼菲青霉病的临床及实验室特征。方法以回顾性分析的方法 ,对我科2003～2009年期间诊治的8名明确诊断为马尔尼菲青霉感染患者的临床特征、皮损组织病理学特点及其皮损组织、骨髓或咽拭子等进行真菌培养的菌落及真菌形态等实验室检查结果进行分析。结果①马尔尼菲青霉感染多发生于HIV感染患者或AIDS患者。②皮损可与全身症状同时或先后出现,皮损表现为淡红色丘疱疹、坏死性丘疹、传染性软疣样丘疹、皮肤溃疡及血痂。③多伴有多系统损害。④37℃培养呈酵母相,25℃呈菌丝相,皮损组织病理可以看到典型的"桑葚样"改变。结论马尔尼菲青霉感染好发于HIV感染患者或其他免疫功能低下的患者,常表现为特征性皮疹,皮损组织、骨髓或分泌物于25℃、37℃真菌培养结合皮肤病理是明确诊断的关键。     

Detection of circulating antigen in bancroftian filariasis by sandwich ELISA using filarial serum IgG

The utility of the IgG fraction of human filarial serum immunoglobulin in detecting circulating antigen by sandwich enzyme linked immunosorbent assay (ELISA) was studied. 27 of 33 sera from persons with microfilaraemia, 19 of 30 sera from clinical cases of filariasis, 4 of 30 sera from normal persons from a region endemic for filariasis showed the presence of circulating filarial antigen. All the 20 normal sera from the area where filariasis was not endemic gave negative reaction for filarial antigen. Those sera from persons with microfilaraemia that showed the presence of circulating antigen also showed an apparent positive correlation between the microfilarial density and the antigen titre.     

The detection of antibodies in human and animal filariases by counterimmunoelectrophoresis with Dirofilaria immitis antigens.

Counterimmunoelectrophoresis revealed the presence of precipitin antibody in all of 6 dogs and the 1 cat infected with Dirofilaria immitis and in the serum of 17 of 24 individuals living in a setting of hyperendemic subperiodic bancroftian filariasis. Antigens used in the test were prepared from microfilariae and adult male D. immitis. Some humans and animals had antibodies to both antigens while others had antibodies against microfilariae or adult worms only. The presence of soluble circulating antigen was detected in the sera of two dogs with high microfilaraemias.     

The human antibody response to uropathogenic Escherichia coli: a review

Urinary tract infections caused by Escherichia coli are associated with a local and systemic antibody response. We have studied the serum and urine antibody responses to Escherichia coli in men and women with pyelonephritis, cystitis, and asymptomatic bacteriuria. Protein immunoblots consistently demonstrated serum antibody response to lipopolysaccharide (LPS). Anti-LPS antibody titres rose significantly and progressively when comparing acute with convalescent sera in those who have had their first urinary infection. For those with repeated infections, high titre LPS antibodies were present and did not change significantly between acute and convalescent sera. Antibody responses to the major outer membrane proteins were present but did not differ significantly when compared with normal human serum. A specific anti-P pilus antibody response was demonstrated by immunoblotting. Anti-P pilus antibody was quantitated using ELISA and the titres were found to be very low. Three other techniques were also used to demonstrate the presence of serum antibody. Antibody was detectable by immunofluorescence, but the antigenic specificity of the antibody was more difficult to ascertain. Immunoprecipitation was more specific for determining the nature of the antibody response. Lastly, immunoelectron microscopy was valuable in demonstrating antipilus and antiflagellar antibodies. Immunoelectron microscopy and immunoblotting provided evidence that human antiserum to P pili was modestly cross-reactive and could bind heterologous P pili. These studies indicated that the major antibody response in humans occurs after pyelonephritis and is directed against LPS. An anti-P pilus response is frequently present and is cross-reactive to some extent with other P pili.     

Identification of immune complex antigens in sera of Indian kala-azar patients

Level of circulating immune complex (IC) in visceral leishmaniasis is much higher than that in control sera. In immunoblot experiment, treatment of kala-azar IC with patient sera showed at least 6 bands of which the band around 55 kDa region was most prominent. The band at 55 kDa is primarily due to the presence of an antigen recognized by its corresponding antibody present in the patient sera. This was confirmed by using radiolabelled antibody from kala-azar patient serum and antipromastigote serum. The heavy chain of IgG originating from IC is also present in the same region which was detected by its recognition with antihuman IgG. The IC gave a band at 55 kDa region with sea-urchin antitubulin. Kala-azar sera also reacted with purified rat brain tubulin. The present results suggest that a tubulin like protein is present at 55 kDa region along with the heavy chain of IgG.     

Antigenic relationships among Cladosporium species of medical importance

We analyzed the exoantigens of 54 isolates belonging to the pathogenic Cladosporium species. Cladophialophora ajelloi was found to be antigenically identical to Cladosporium carrionii. All human and cat isolates of C. bantianum and C. trichoides were found to share the same antigens. Although cross-reactions were observed among the four species of Cladosporium: C. carrionii, C. bantianum, c. herbarum, and C. cladosporioides they were identified and differentiated specifically with four monospecific factor sera obtained through absorption procedures. The exoantigen serologic procedure also permitted us to identify cultures of these four Cladosporium spp. within 8 days.     

Beta haemolytic streptococci of the Lancefield groups E. P and U:Streptococcus infrequens

The physiological and biochemical characteristics of isolates from swine in Sweden and The Netherlands were compared with those of strains from several culture collections. These characteristics were found to be similar for all three Lancefield groups and they form a well defined pattern distinct from other known streptococcal species. It is suggested that these streptococci be classified together in one species:Streptococcus infrequens.Group and type sera of Group E streptococci have no affinity to Group P and Group U streptococci, and vice versa. None of the sera prepared against group E type strains contains the group antibody. Group P and Group U streptococci have an antigen in common. This common antigen is present in formamide extracts. It is not demonstrable in acid extracts. None of the group P sera tested contains the common antibody. Group P serum has to be considered as a type serum. Group U sera contain the common antibody, and when absorbed with group P cells prove to contain another type antibody, which reacts with extracts of most group U strains.Isolates of all three Lancefield groups were obtained from a variety of pathological conditions in swine.     

Imported penicilliosis marneffei in the United States: report of a second human infection

The first natural infection due to Penicillium marneffei in a human was reported in the United States in 1973. We describe a second case of penicilliosis marneffei that was diagnosed in Florida. In both instances, the patients had a history of travel in Southeast Asia where P. marneffei is endemic. The Florida patient had recurrent episodes of hemoptysis attributed to bronchitis and bronchiectasis. In spite of therapy with various antibacterial antibiotics for tuberculosis, the granulomatous lesions in the left upper lobe of the lungs persisted. The diagnosis of penicilliosis marneffei was established by isolating and identifying the dimorphic species of Penicillium, P. marneffei. The histopathologic features of the lung tissue included granulomata with central areas of necrosis and neutrophilic infiltration with many yeast-like, tissue-form cells of P. marneffei, which multiplied by a fission rather than a budding process.     

Penicillosis marneffei: Serological and exoantigen studies

An immunodiffusion (ID) test has been developed to diagnose infections caused byPenicillium marneffei. A 20 X concentrated culture-filtrate of six-week-old shake cultures (25 C) ofP. marneffei was employed as an antigen. This preparation was found to be better in quality than that from still cultures of the same age (30 C). Anti-P. marneffei rabbit sera were produced by injecting rabbits with increasing dosages of the inoculum for at least six weeks. These sera demonstrated two to three precipitin lines following their reaction with their antigens for 24–48 h at 25 C. TheP. marneffei antigenic preparations did not react with rabbit antisera to five species ofAspergillus, which commonly cause aspergillosis, or to antisera for four dimorphic systemic fungi. Similarly, the antigens of these other fungi did not react against the anti-P. marneffei rabbit serum. However, the anti-P. marneffei rabbit sera demonstrated antibody titres (132 to 164) to histoplasmin, blastomycin and coccidioidin in the complement fixation test. Cross-reactions were not observed with any of the human sera in the suspected or proven cases of opportunistic or systemic mycotic infections. Therefore, the ID test for penicillosis marneffei is considered to be highly specific. Exoantigen studies demonstrated that, of a total of 34 isolates of ten species ofPenicillium tested, only the extracts ofP. marneffei (6 isolates) and one isolate (PLM 771) of aP. species reacted positively with the anti-P. marneffei rabbit serum, giving at least two lines of identity with reference reagents. Based on this analysis, theP. species (PLM 771) was identified as P. marneffei. The exoantigen test is considered to be a specific and rapid method for the identification and confirmation ofP. marneffei isolates.

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Zusammenfassung Eine Immun-Verbreitung (ID) Test war ausgearbeitet fur die Diagnose der Infektionen diePenicillium marneffei verursachen. Die 20 X conzentrierte Kultur-Fieltrier von der sechs Wochen alten schuttelten Kulturen (25 C) vonP. Marneffei war gebraucht fur Antigen. Diese Preparation war besser in Qualitat denn die stillen Kulturen von dem selben Alter (30 C). Die Anti-P. Marneffei Kaninchen Sera wurde produziert durch die Injektion der Kaninchen mit immer vergrosserden Dosen von dem Imfstoff-mindestebs wahrend sechs Wochen. Diese Sera zeigte zwei — drei Ubere sturzung Linien durch die Reaktion von ihrer Antigenen wahrend 24–48 Stunden im 25 C. Die Antigen-Preparationen vonP. Marneffei gaben keine Reaktionen mit Kaninchen Anti-sera fur funf Species vonAspergillus, die stellen an gewohnlich Aspergillosis, oder zu der Antisera fur fier dimorpische systemische Pilze. Gleichweis, die Antigenen von diese Plize gaben keine Reaktionen gegen die Kaninchen Antisera vonP. Marneffei. Jedoch die Kaninchen Antiserum vonP. marneffei zeigte Anti-Korper Titer (132 bis 164) zu Histoplasmin, Blastomycin und Coccidioidin in der Complement (Erganzung) Fixing Test. Kreuz-Reaktionen wurden nicht observiert mit keine menschlichen Sera in verdachtigen oder erwiesenen Krankengeschichten von passenden oder systematischen mycotischen Infectionen. Deswegen die ID Test fur Penicillosis marneffei ist sehr spezifisch. Die Untersuchungen haben demonstriert, dass 34 isolationen von zehn Species vonPenicillium — die untersucht waren — nur der Auszug vonP. Marneffei (6 Isolationen) und ein Isolation (PLM 771) vonP. Species eine positive Reaktion mit der Kaninchen Anti-Serum vonP. Marneffei, und es gab mindestens zwei identische Linen mit die Referenz Reagenten. An diese Analyse grunden wir dass, dieP. Species (PLM 771) war identifiziert wieP. Marneffei. Die Exo-Antigen Test ist anbetrachtet wie eine spezifische und schnelle Methode fur die Identifikation und Bestatigung der Isolierten vonP. Marneffei.

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Portion of a thesis submitted by the second author to the Canadian Society of Laboratory Technologists, Hamilton, Ontario, Canada, in partial fulfilment of the requirements for Advanced registered Technologist, Certification in Immunology.     

Synthesis of Recombinant P48 of Mycoplasma agalactiae by Site Directed Mutagenesis and its Immunological Characterization

Contagious agalactia caused by Mycoplasma agalactiae is an economically important disease of sheep and goats and has been prevalent worldwide including India. The present study was undertaken to evaluate the membrane protein P48 of M. agalactiae for specific diagnosis of disease. For this, p48 gene of the organism was amplified by PCR and subjected to site directed mutagenesis to convert three TGA codons to TGG’s and, subsequently, cloned into prokaryotic expression vector pPRO EX HTb. Purified recombinant P48 protein reacted to anti-P48 serum in western blotting, which confirmed its immunogenic nature. Furthermore, the immune-blotting of the cell lysates from various Indian isolates of M. agalactiae against anti-P48 serum resulted in a single band at ～ 48 kDa among all isolates, indicating the conserved nature of P48 antigen in M. agalactiae. Also, the cross reactivity of P48 antigen among various Mycoplasma spp. was checked by western blotting which revealed reactivity only with M. agalactiae and M. bovis. Hence, this antigen could be exploited to differentiate M. agalactiae from other pathogenic Mycoplasma species except M. bovis. However, the inability of P48 to distinguish M. agalactiae from M. bovis does not downgrade the significance of P48 as the two species are usually host specific.