Activation of guinea pig peritoneal macrophages by ribosomal extract of Salmonella typhi strain. Electron microscopy studies.

Normal macrophages and Salmonella typhi ribosomal antigen-activated (immune) ones were studied by electron microscopy. Examination of fine sections from samples incubated between 30 and 120 minutes at 37 degrees C, emphasized phagocytic ability of activated macrophages (29-69% activated macrophages phagocytized 3.7-5.6 bacteria/cell, in contrast to 23-43% with 2.6-4.4 bacteria/phagocytized by non-immune cells). The ultrastructural studies of activated macrophages, performed by electron microscopy, showed the following aspects: a) macrophages with pseudopodiform prolongations, presenting the tendency of bacterial sequestration: b) phagosomes with ingested virulent germs; c). bacteria presenting various degrees of wall and cytoplasm alterations; d). mitochondria with multiple cristae; e). cells with well developed Golgi apparatus and the presence of lysosomes in great numbers; f). existence of a space between the phagosome membrane and the bacterial wall. Experimental results demonstrated: I. an increased phagocytic activity of Salmonella typhi ribosomal antigen-activated macrophages and II. activation expressed as ultrastructural modifications at the level of immune macrophages and also of the bacteria phagocytized by them.