Calorimetric analysis of phagocytosis of staphylococcal protein-A/IgG complexes.

We have analyzed calorimetrically the phagocytosis of the pseudoimmunecomplexes formed by staphylococcal protein A in presence of serum. Strong thermal effects were recorded during phagocytosis. They appear to be the sum of two distinct heat contributions. We have previously shown that these are the expression of two different non-mitochondrial O2 reduction pathways operating during the metabolic "burst" (Eftimiadi and Rialdi, 1982). Experiments carried out at different protein A/IgG ratios produced quantitatively and qualitatively different power-time curves. The data reported here indicate that although the immunoglobulins are essential for the triggering complex to form, the presence of complement is necessary to obtain maximal granulocytic metabolic activation.