Reevaluation of quantitative flow cytometric analysis for TLR2 on monocytes using F(ab')2 fragments of monoclonal antibodies

Production and characterization of anti-human IgG F(ab')2 antibody fragment

In present study an optimized protocol for the separation of antibodies into antigen-binding fragments F(ab')2 using pepsin digestion was investigated. The production of these fragments is a consequential step in the development of medical research, treatment and diagnosis. For production of polyclonal antibody rabbit received antigen in four steps. The rabbit serum at 1/128000 dilution showed high absorbance in reaction with human IgG at the designed ELISA method. Rabbit IgG was purified by Ion-Exchange Chromatography (IEC) method. Purity was assessed by SDS-PAGE method. In non-reduced condition only one band was seen in about 150 kDa MW position and in reduced form, two bands were seen in 50 and 25 kDa MW positions. Rabbit IgG was digested by pepsin enzyme. The antibody fragments solution was applied to Gel filtration column to isolate the F(ab')2. Non-reduced SDS-PAGE for determining the purity of F(ab')2 fragment resulted in one band in 100 kDa corresponds to F(ab')2 fragment and a band in 150 kDa MW position corresponds to undigested IgG antibodies. The activities of FITC conjugated F(ab')2 fragment and commercial ones were compared using flowcytometry method. The activity results implied that the FITC conjugated- anti human F(ab')2 fragment worked as efficiently as the commercial one.

Expression of toll-like receptor 2 and plasma level of interleukin-10 are associated with outcome in tuberculosis

Toll-like receptor (TLR) 2-mediated innate immunity is an important defense system against Mycobacterium tuberculosis infection. Studies on TLR2 protein expression and downstream cytokines in tuberculosis patients are lacking. TLR2 expression in the peripheral blood monocytes of 87 tuberculosis patients and 94 healthy subjects was evaluated using flow cytometry. TLR2 expression and its downstream cytokines, including interleukin (IL)-6, IL-10, tumor necrosis factor (TNF)-alpha, and interferon-gamma, were correlated with the clinical manifestations and outcomes of tuberculosis. The TLR2 expression in peripheral blood monocytes was higher in tuberculosis patients than in healthy subjects. Among the tuberculosis patients, those aged ≥70 years with disseminated tuberculosis or aged <70 years with symptom duration ≥14 days had lower initial TLR2 expression. After two months of treatment, TLR2 expression decreased in most patients, except in those whose sputum samples remained culture-positive for M. tuberculosis. Proportional hazards regression analyses revealed that high initial TLR2 expression and IL-10 plasma level were associated with shorter survival. TLR2 may play an important role in the course of tuberculosis. Its expression on peripheral blood monocytes and the plasma level of the downstream anti-inflammatory cytokine IL-10 may be important outcome predictors and have potential use in the management of tuberculosis patients.