Tuberculosis (TB) is one of the most common infectious diseases worldwide. The aim of the present work is to measure immune response of patients infected with meningitis tuberculosis (70 patients). 14 sera samples from healthy volunteers were used as controls. Localization of TB-55 mAb target antigens of lymph node tissues was demonstrated by using indirect immuno-peroxidase staining as a positive immuno-staining lymph tissue stained with TB-55 mAb. In the present study, an IgG mouse monoclonal antibody designed TB-55 mAb was used as a powerful probe for the identification of specific immunodominant antigen excreted in serum of patients infected with Mycobacterium tuberculosis. Western blot analysis revealed that TB-55 mAb reacted against an antigen at an apparent molecular weight of 55-kDa in serum samples of infected patients with M. tuberculosis but no reaction was observed in serum samples of the healthy control. The TB circulating antigen was detected in 24 (34 %) of 70 sera samples with meningitis, and 46 (66 %) of serum samples were negative TB circulating antigen by using ELISA technique. IFN-γ mAb was used as a probe in Western blot assay. An intense sharp band was in serum samples of meningitis patients at 26-kDa, but no reaction with the non-infected samples was observed. Of the 24 serum samples tested cases for IFN-γ cytokine, the cut-off level of IFN-γ cytokine above or below which the tested sample is considered positive or negative was calculated as 15.6 pg/ml. The serum levels of IFN-γ (55.75 ± 65.269) in patients positive for 55 kDa-circulating antigen, reach a statistical significant difference (P= 0.0283), where those in negative TB antigen reach (12.7 ± 0.675).
Key words: Tuberculosis; Immunostaining TB-55 mAb; Meningitis; Immune response; ELISA technique
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