High antibody levels to the mycobacterial fibronectin-binding antigen of 30–31 kD in tuberculosis and lepromatous leprosy

Abstract

SUMMARYImmunoblot assays showed that mycobacterial fibronectin-binding antigens are important targets of the humoral immune response in tuberculosis and leprosy. Using culture filtrate antigens of Mycotxuterium tuhcrcuto.sis. strong reactivitv with lhe tibronectin-binding of 30 31 kD (l-'n 30-31) was demonstrated in 55-9'!^. of tuberculosis sera and in 56-5'^A of lepromatous leprosy sera. Sera from patients with lubcrculoid leprosy and control sera gave very weak binding. Reactivity of tuberculosis and lepromatous leprosy sera with the fibronectin-binding antigen of 58-60 kD(Fn 5S 60) was less conspicuous. The ability to rcuci with fibroncctin of the anligcns of 58 60 and 30 3! kD was demonstrated by parallel labelling wilh a fibronectin biotin conjugate. Fn 30 31 was purified to homogeneity by a two-step procedure and used for ELISA, Positive titres were found in 63^, out of 65 tuberculosis sera and in 60 5"o out of 43 lepromatous leprosy sera. Antibody titres in lepromatous leprosy sera were higher than in tuberculosis sera. Our observations indicate indirectly that M. tepiae possess a highly immunogenic molecule homologous to M. tiihcrcutosis Fn 30-31, which elicits a high antibody response in leproniaious leprosy but not in tuberculoid leprosy. In this investigation, direct evidence for the presence of this antigen in M. leprae was obtained by immunochemistry of lepromatous leprosy lesions with a mono.specifk aniibody raised against .M. tuberculosis Fn 30 31,

Antibody response to a sterile filtered PPD tuberculin in M. bovis infected and M. bovis sensitized cattle

“…Espitia et al . and Al-Attiyah et al [ 41 , 42 ] also attributed environmental mycobacteria as a potential determinant for Ag85 complex antibody recognition in the sera of tuberculosis-free humans. Therefore, the presence of Ag85 in PPD tuberculin may contribute to the relatively low specificity of the TST.…”

Advances in leprosy immunology and the field application: A gap to bridge

“…45,46 Despite the cross-reactivity, which restricts its utility as a specific marker in the diagnosis of leprosy, seropositivity for anti-Ag 85 components have been observed in 50-100% of lepromatous and 0-38% of tuberculoid leprosy patients. [47][48][49] Interestingly, the use of combination of native gel purified Ag 85 components and the mycobacterial heat shock protein 65kDa (hsp65) in an ELISA serology have been reported to be capable of differentiating LL from TT forms of the disease. 44,50 Further studies revealed that the sera of >90% of LL/BL patients and > 85% of TT/BT leprosy patients reacted strongly to mycobacterial (29/33kDa doublet) and Hsp 65 (64-65kDa singlet) antigen fractions in Western blot assays (WB) combined with ELISA.…”

Vaccines against Mycobacterium Tuberculosis: Exploring Alternate Strategies to Combat a Near-perfect Pathogen

“…There is evidence to suggest that the stunting of the humoral response may be due to exposure to other environmental mycobacterial [ [28] have shown that while there is an initial antibody response to these antigens, the next steps involving the complement pathway are suppressed. In addition, Espitia et al [15], Al-Attiyah et al [26] and Rennie et al [25] have shown that antibodies to the Ag85 complex and other environmental mycobacteria can be found in the sera of subjects with no prior Mtb exposure. Furthermore, this presentation does not protect the individual from infection [9].…”

“…The memory B cell response in BCG-vaccinated individuals have been shown to be present even 45 years following vaccination [19]. Yet this response, which may initiate clearance, is not sufficient to prevent infection of the individual [15,25,26].…”

“…Antibodies are the primary component of humoral immunity [15] and aid in the development of an opsonized response [16]. Numerous studies investigated the role of antibodies against Mtb infection [17][18][19] and documented antigens recognized by antibodies included the Ag85 complex [15,[20][21][22], lipoarabinomannan (LAM) [23,24], arabinomannan (ARM) [18], the 6 kDa early secretory antigen target (ESAT-6) and the 10 kDa culture filtrate protein (CFP-10) [19]. The memory B cell response in BCG-vaccinated individuals have been shown to be present even 45 years following vaccination [19].…”