Figure 2

Human lymph nodes tissue infected with M. tuberculosis showing the staining pattern of mycobacterial secreted antigens in the necrotic granulomas as detected by immunohistochemical staining. Right column shows higher magnification of the marked areas in the corresponding pictures. There is a differential staining of various secreted antigens. MPT64 is detected in epithelioid cells and multinucleated giant cells, while the necrotic centres do not contain this antigen. MPT59 (Ag85B) and MPT63 were detected in few cases and were located only in the necrotic centres in these cases. Granuloma cells were not stained by these antibodies. The majority of the lymphadenitis granulomas were not stained for secreted antigens. NC = necrotic centres.