A modification of the hemolytic plaque test to investigate simultaneously secretion and morphological characteristics of individual cells.

A simple modification of the hemolytic plaque test is proposed which provides a morpho-functional approach to the study of secreting cells. The experimental procedure described here, an 'open system' with glass coverslips, involves the association of the reverse hemolytic plaque test performed in liquid medium with Feulgen's reaction used to reveal the nuclear characteristics of the secreting cells. A monolayer cell carpet, prepared with hepatocytes and sheep red blood cells coated with specific antibodies to transferrin, was attached to glass coverslips coated with 2 substrates, collagen and poly-L-lysine. Incubation was performed in a routine liquid culture medium. Under the conditions reported here to obtain an optimal attachment of the cells to the substrates, it was possible to stain hepatocytes after the formation of hemolytic plaques, whilst maintaining the monolayer cell structure intact. This technical modification should be of value in establishing correlations between secretory activity and cellular characteristics.