Human chromosome 19 confers the CD2/E rosette receptor phenotype in interspecific cell hybrids

Interspecific cell hybrids between Chinese Hamster Ovary (CHO) and phytohaemagglutinin (PHA) stimulated human T lymphocytes were purified by preparative rosetting with sheep red blood cells (SRBC). The hybrid cell clone used in the present study consisted of cells containing a complete set of the 20 CHO chromosomes and one extra human chromosome, No 19. Hybrid cells constitutively expressed high levels of human CD2 surface receptor and formed multilayer rosettes with SRBC and human erythrocytes. In addition to CD2 they produced low levels of a small number of human extracellular proteins. These findings suggest that the factor(s) responsible for CD2 expression are produced by the hybrid and that genes responsible for CD2 expression are located on chromosome 19. However, the present work cannot exclude that material of chromosome 1, where the CD2 gene has been assigned previously, is integrated somewhere in the hybrid karyotype. Further work is needed to clarify this point.