Tissue kallikrein-like immunoreactive material decorates neuritic plaques of Alzheimer patients.

The neuroanatomical distribution of the proteinase kallikrein (EC. 3.4.21.35) in human brain was examined immunohistochemically by using antiserum against human tissue kallikrein. In normal nervous tissue only faint immunostaining of some neocortical and hippocampal neurons was observed. Glial cells were found to be immunonegative for kallikrein. In Alzheimer disease (AD) brains kallikrein-like immunoreactivity was associated, in some areas, with nerve cells and, especially in the neocortex, with numerous neuritic plaques. A possible function of the proteinase in AD-associated cascade of inflammatory response is supposed.