The localization of haemolytic antibody in sections of lymphoid organs: an improved method

A simple and sensitive method is described for detecting foci of haemolysin-producing cells in tissues. Frozen sections are mounted on glass, covered with an agar—red cell gel and complement, incubated, fixed, stained and mounted. The preparation is examined in toto.

In the primary response to sheep red cells, antibody appears first in the red pulp and subsequently in germinal centres. This sequence is repeated in the secondary response, but is accelerated.

In cyclophosphamide-treated mice injected with sheep red cells and 10⁷ isogeneic spleen cells, about five to twenty haemolytic foci are seen per transverse spleen section.