Effect of antibody emission rates on plaque morphology

Abstract

CUNNINGHAM and Fordham¹ have used a modified version of the haemolytic plaque technique to show that antibody diversity can be generated after B cells have been stimulated to proliferate. They tested antibody plaque forming cells (PFC) against a mixture of sheep red blood cells (SRBC) from two different sheep and obtained three morphological classes of direct plaques: clear (the plaque radii for both types of SRBC were equal), sombrero (the plaque radii were different for the two types of SRBC), and partial (there was only one plaque radius). For the clear and sombrero plaques both types of SRBC lysed to some extent, while for the partial plaques only one type of SRBC lysed. Cunningham and Fordham used plaque morphology as an antibody specificity marker, that is, if two plaques were different in morphology this was taken to mean that the antibodies produced by the two PFC differed in their specificity for the two types of SRBC. They studied clones produced from single PFC and found in most cases that the plaques produced by the progeny were of the same morphological class, differing only by slight variations in their plaque radii. In 10 of the 93 clones observed, however, the morphology of the plaques differed within the clone. In 7 clones two different morphological classes of plaque were observed, and in the others all three classes. Cunningham and Fordham suggested that within a given clone the antibodies emitted by different cells can have different specificities.