ABSTRACT
Human pulmonary tuberculosis (TB) is a worldwide public health problem. In resistant individuals, control of the infection mainly requires development of a Th1 cell immune response with production of cytokines, of which interferon-gamma (IFN-gamma)plays an important role. Several antigens from Mycobacterium tuberculosis complex has been described for use in vaccine development or for diagnostic purposes, however little evaluation has been done in endemic area for TB. The proliferative and IFN-gamma human T cell immune responses, to four recombinant proteins (MBP-3, NarL, MT-10.3, 16 kDa) and PPD, of 38 Brazilian TB patients (6 untreated and 32 treated) and 67 controls (38 positive and 29 negative tuberculin skin test - TST) were compared. The highest reactivity mean rate was obtained with PPD followed by 16 kDa in TB patients. While most of the patients (87 percent) and controls (> 64 percent) respond to the PPD, 16kDa was more specifically recognized (> 21 percent) although less sensitive (54 percent). When TB patients were divided according to treatment status, opposite to PPD, higher average level of IFN-gamma was induced by 16kDa in untreated (505 pg/ml) compared to treated TB patients and TST+ (269.8 pg/ml x 221.6pg/ml, respectively), although the difference was not significant. These data show that in contrast with the other recombinant proteins, the stimulatory potency of 16kDa to induce proliferative and INF-gamma response was more effective and is more recognized by active TB untreated patients, eliciting in control individuals a more selective immune response than PPD.
Subject(s)
Humans , Female , Antigens, Bacterial/immunology , Cell Proliferation , Interferon-gamma/biosynthesis , Leukocytes, Mononuclear/microbiology , Recombinant Proteins/immunology , Tuberculosis, Pulmonary/diagnosis , Case-Control Studies , Cross Reactions , Enzyme-Linked Immunosorbent Assay , Leukocytes, Mononuclear/immunology , Tuberculin Test , Tuberculosis, Pulmonary/immunologyABSTRACT
The effect of the human immunodeficiency virus (HIV) infection on IgG production against purified protein derivative (PPD) and 2,3-diacil-trehalose (SL-IV) was investigated by an enzyme-linked immunosorbent assay (ELISA) test. Comparison between the antigens showed that immunocompetent patients produce preferentially antibodies to SL-IV than to PPD (73.3 por cento versus 63.3 por cento). Combination of the these results showed an increase of the sensitivity to 80 por cento, which decreased over the spectrum of immunodepression caused by HIV. In the tuberculous HIV seropositive group the sensitivities of SL-IV and PPD were 36.4 por cento versus 40 por cento and 0 por cento versus 22.2 por cento in the tuberculosis/acquired immunodeficiency syndrome (TB/AIDS) group. Combination of these results gave respectively 54.5 por cento and 20 por cento, showing that serological tests have limited value for diagnosis of tuberculosis in HIV infected patients. High antibody levels were observed in HIV seropositive asymptomatic group, but only two individuals were positive for both antigens. In the follow up, one of them tuberculous lymphadenitis, indicating that further work is needed to access the value of serological tests in predicting tuberculosis in HIV infected individuals.