Alzheimer's disease and senile brains: an immunofluorescence study.

The results obtained with direct immunofluorescence techniques on normal, senile and Alzheimer's disease brains are reported. The antisera used were directed against C3c, IgG (gamma chain), IgG Fc., kappa and lambda light chains and anti-Ig (total). The brain samples were prepared in different ways: formalin-fixed and paraffin embedded; fresh frozen samples and alcohol fixed, paraffin-embedded samples. The images obtained with the different processing methods did not coincide. In order to obtain a more complete picture, we suggest the use of different methods on the same samples. In Alzheimer's disease brains, abundant but probably not monoclonal Ig antigenic determinants were found. Ig were found diffusely in the tissue, connected to amyloid (both in senile plaques and blood vessel walls), in glial cells and neurons. The significance of such data in relation to the genesis of brain amyloid are discussed.