Detection of immunoglobulin-secreting lymphocytes by the use of a hemolytic plaque assay in liquid phase

This paper describes a modification of the reverse hemolytic plaque assay allowing the enumeration of immunoglobulin (Ig)-secreting lymphocytes at rest or after in vitro stimulation. Ig-secreting cells are mixed with anti-Ig coated sheep red blood cells, developing anti-Ig antiserum and complement in liquid medium. This mixture is pipetted between two slides and the hemolytic plaques are numerated after incubation at 37 degrees C. The class of Ig secreted can be determined using a monospecific developing antiserum. This technique is easier to perform and more economical than the previously described method using agarose without loss of sensitivity, the number of plaques detected being about the same and the kinetic of their appearance comparable.