Somatic cell hybrids between human lymphoma lines. IV. Establishment and characterization of a p3HR‐1/daudi hybrid

A new human B‐lymphoma hybrid line designated DIP‐1 was derived from the fusion of the Burkitt lines Daudi and P3HR‐1. Cytogenetic analyses proved hybridity and showed that the hybrid was nearly complete from the chromosomal point of view. Hybridity was also confirmed by isozyme marker tests. The Daudi‐derived IgM‐kappa ring was fully exposed on DIP‐1, together with the P3HR‐1‐derived human beta‐2‐microglobulin. Expression of C3 receptors was intermediate between the two parents and EBV receptors were some what reduced in comparison with both. The spontaneous low‐level EBV antigen (EA and VCA) production of the parents was maintained and amplified in the hybrid. The hybrid, like its Daudi parent, was highly inducible with IdUrd. In P3HR‐1 virus super‐infection experiments, the Daudi parent was more permissive than the BU‐P3HR‐1 parent. The hybrid was intermediate, resembling the previously studied Raji/Daudi hybrid and contrasting with Raji/Namalwa and Raji/BJAB hybrids. Virus DNA replication patterns after P3HR‐1 virus superinfection resembled the antigen pattern. The implication of these findings for the understanding of virus‐host cell relationships and the regulation of the viral cycle is discussed The findings are meant to imply that genetically determined isozyme markers are autonomously expressed, as in other systems. Differentiation‐related markers and EBV‐cycle‐related characteristics are autonomously expressed in some cases (surface immunoglobulin, beta‐2‐microglobulin, spontaneous EBV‐production, IdUrd inducibility) and appear to be under a restrictive control in others (EA inducibility by P3HR‐1 virus superinfection, C3 and EBV receptors, viral DNA replication).