The Development of Large Immature Mononuclear Cells in Mixed Leukocyte Cultures

1. When leukocytes from two normal, unrelated subjects are mixed together and cultured, some of them transform into large basophilic cells thatcan synthesize DNA and undergo mitosis.

2. The stimulus for this change is the presence of two sets of leukocytes.Foreign erythrocytes, plasma or platelets have no effect.

3. Studies with mixtures of leukocytes from pairs of identical and nonidentical twins indicate that the reaction may be related to genetic differencesbetween the two subjects.

4. It is suggested that the reaction in leukocyte mixtures may be relatedto homograft immunity.

Submitted on July 10, 1963 Accepted on September 17, 1963