Guinea pig cellular immune responses to proteins secreted by Mycobacterium tuberculosis

Abstract

To study the immunological activity of proteins secreted by Mycobacterium tuberculosis, we carried out comparative studies in guinea pigs infected intravenously with 2.5 ؋ 10 3 CFU of this organism or with 2.5 ؋ 10 4 CFU of Mycobacterium bovis BCG. Groups of infected guinea pigs were skin tested with fractions of secreted proteins covering well-defined narrow-molecular-mass regions, or such fractions were used for lymphocyte stimulation experiments. The lymphocyte stimulation experiments showed that the fraction containing proteins with molecular masses below 10 kDa had a superior stimulating capacity in tuberculous guinea pigs whereas the 24-to 30-kDa fraction gave significantly higher skin reactions in this group compared with BCG-vaccinated guinea pigs. A precise mapping within the region from 23 to 35 kDa by using a combination of narrow overlapping fractions and purified proteins enabled the identification of the 24-kDa antigen MPT64 as a molecule specific for tuberculous infection. Thus, MPT64 is a promising candidate for a specific diagnostic skin test reagent for human tuberculosis.

Comparison of Antigen‐Specific T‐Cell Responses of Tuberculosis Patients using Complex or Single Antigens of Mycobacterium tuberculosis

“…The present study extends these data to include humans and shows that ESAT-6 is also an important antigen during natural infection with M. tuberculosis. Similar data showing that MPT59, MPT64 and MPB70 are important antigens in animal models already exist [11,12,43,[46][47][48][49]. Our present data extend these findings and indicate that these antigens are important in human tuberculosis [50][51][52].…”

“…In a mouse model of TB infection with assay of memory immune responses, ESAT-6 has been demonstrated to be a strong T-cell immunogen [10,13]. In guinea pigs there was a strong recognition of the low-molecular-mass fraction of MT-CF containing ESAT-6 [43] and similar data from cattle infected with M. bovis indicate that a lowmolecular-mass culture filtrate fraction containing ESAT-6 is recognized in the first phase of infection in the majority of animals tested [44,45]. The present study extends these data to include humans and shows that ESAT-6 is also an important antigen during natural infection with M. tuberculosis.…”

Expression of Mycobacterium tuberculosis MPT64 in recombinant Myco. smegmatis: purification, immunogenicity and application to skin tests for tuberculosis

“…This is consistent with the recent report that nMPT64 also elicited DTH in Myco. tuberculosis-sensitized guinea pigs, but not in those exposed to BCG-Copenhagen, a strain which also lacks the mpb64 gene [21].…”

Host Responses and Antigens Involved in Protective Immunity to Mycobacterium tuberculosis

“…So far this approach has led to the identification of two important T cell antigens. Hasløv et al [197] mapped a 24-30 kDa region as highly reactive in guinea pigs infected with M. tuberculosis and identified the secreted 24 kDa molecule MPT64 as a molecule specific for tuberculosis infection. In the mouse model the method was used to map a low mass culture filtrate fraction recognized predominantly by memory immune T cells [194].…”