Effect of plasma lysozyme on live Mycobacterium tuberculosis

The role of plasma lysozyme of normal healthy subjects (NHS, n = 12) and ac tive pulmonary tuberculosis (ATB) patients (n = 15) on the innate immune me chanism was studied by the binding activity of lysozyme on live Mycobacteri um tuberculosis. Plasma samples of NHS and ATB patients treated with live M . tuberculosis for 4 h and 24 h time points showed a significant decrease i n the plasma lysozyme level when compared to the untreated samples (4 h, P < 0.001; 24 h, P < 0.001). Pretreatment of live M. tuberculosis with plasma of NHS and ATB patients showed a trend in the reduction of viability of li ve M. tuberculosis. Moreover, M. tuberculosis pretreated plasma of NHS show ed a trend towards an increased spontaneous as well as antigen-induced lymp hocyte response when compared to ATB plasma. The enzymatic action of the ly sozyme and other enzymes on the cell wall may induce M. tuberculosis to rel ease some antigenic components which may be immunogenic and induce lymphocy te proliferation. The present study suggests that lysozyme and other enzyme s may play an important role in the first line defence, i.e. the innate imm unity, against M. tuberculosis infection.