Mycobacterium leprae-specific protein antigens defined by cloned human helper T cells

Pooled polyvalent sera from lepromatous leprosy patients were used to screen a Agtll recombinant DNA expression library of Mycobacterium leprae in order to identify the relevant antigens recognized by the human immune response. Of the 300,000 phages screened, 4 clones were identified that coded for fusion proteins of the same molecular mass. The fusion protein from clone LSR2 was tested for immunoreactivity in assays using peripheral blood cells and sera from 11 laboratory personnel and 105 patients across the leprosy spectrum. LSR2 protein appears to be predominantly a T-cell antigen. It evokes similar lymphoproliferative responses as the native bacillus both at the individual level and in the leprosy spectrum as a whole. Though only 50% of patient sera with anti-M. leprae antibodies reacted with the fusion protein, the pattern of reactivity in the antibody responses was also similar for the various clinical types. The coding regions of clones LSR1 and LSR2 are identical. They show no homology with sequences stored in data banks and encode a protein of 89 amino acids with a calculated molecular mass of -10 kDa.Leprosy is a chronic infectious disease caused by noncultivable Mycobacterium leprae. The clinicopathological spectrum observed in this disease reflects the variability in the host immune responses to the pathogen (1). Protective immunity is mainly effected by cellular responses as evidenced by the presence of optimal T-cell functions in the localized paucibacillary form of tuberculoid (TT) leprosy. In contrast, the generalized multibacillary lepromatous (LL) leprosy shows antigen-specific T-cell anergy concomitant with the presence of high levels of specific and crossreactive mycobacterial antibodies (2, 3). Young et al. (4) constructed a genomic library of M. leprae in the Agtll expression vector. By using monoclonal antibodies (mAbs) as screening reagents, genes coding for 12-, 18-, 28-, 36-, and 65-kDa proteins of M. leprae were identified. Whereas some of these have been shown to share homology with the heat shock proteins of various species (5-8), the 18-kDa protein has been found to be stimulatory for human T helper clones (9) and for peripheral blood cells from healthy contacts (10).With a view to identifying genes expressing proteins recognized by the human immune response to natural M. leprae infection, we have used polyclonal antibodies obtained from pooled sera of lepromatous patients to screen the Agtll DNA expression library. We have identified four clones coding for a fusion protein of the same molecular mass. § It appears to be a dominant T-cell antigen and mimics the native bacillus in lymphoproliferative responses of all clinical types of leprosy patients. It is also recognized by the sera of 50-70o of the patients having anti-M. leprae antibodies. MATERIALS AND METHODSSubjects. The study included 105 leprosy patients attending the Hansen disease clinic of Safdarjung Hospital (New Delhi) and 11 healthy laboratory personnel with >3 years of constant contact with patients. The type...

Section: Discussionmentioning

confidence: 99%

Recombinant fusion protein identified by lepromatous sera mimics native Mycobacterium leprae in T-cell responses across the leprosy spectrum.

Laal

Sharma

Prasad

et al. 1991

“…Antigen presentation by M and DCs was determined by measuring proliferation and IFN-␥ secretion of the HLA-DR2-restricted CD4 ϩ T cell clone R2F10 that is specific for the 60-kDa heat-shock protein (amino acids 418-427) of Mycobacterium leprae (21) or the HLA-DR1-restricted CD4 ϩ T cell clone HA1.7 that is specific for the hemagglutinin (amino acids 306-318) of influenza virus (22). Briefly, antigen-presenting cells were harvested and seeded in triplicates at 2.…”

Section: Methodsmentioning

confidence: 99%

Human IL-23-producing type 1 macrophages promote but IL-10-producing type 2 macrophages subvert immunity to (myco)bacteria

Verreck

Boer

Langenberg

et al. 2004

Self Cite

842

748

“…T lymphocytes cloned from patients or from volunteers immunized with killed mycobacteria have been tested for their ability to recognize the recombinant mycobacterial proteins. Lymphocyte-proliferation assays demonstrate that most of the antigens identified with monoclonal antibodies are involved in the T-cell response to mycobacterial infection or vaccination in mice (9,10) and in humans (11)(12)(13)(14)(15)(16)(17)(18)(19)(20). Limiting dilution analysis indicates that 20% of the mycobacterial-reactive CD4+ T lymphocytes in mice immunized with M. tuberculosis recognize a single protein, the 65-kDa antigen (9).…”

mentioning

confidence: 99%

Stress proteins are immune targets in leprosy and tuberculosis.

Young

Lathigra

Hendrix

et al. 1988

398

242

To understand the immune response to infection by tuberculosis and leprosy bacilli and to develop improved vaccines, the nature of antigens that are involved in humoral and cell-mediated immunity was investigated. We have determined that five immunodominant protein antigens under study are homologues of stress proteins. This finding and observations with other pathogens suggest that infectious agents may respond to the host environment by producing stress proteins and that these proteins can be important immune targets. We postulate that abundant and highly conserved stress proteins may have "immunoprophylactic" potential for a broad spectrum of human pathogens.