The natural attachment of thymocytes and activated T lymphocytes to normal and malignant cells: An interspecies study

When mixed in vitro, thymocytes and allogeneic activated T cells attach to homologous normal and malignant cells. This was previously demonstrated also by in vivo immune activated T lymphocytes. The phenomenon designated as natural attachment (NA) was found to be expressed by low charged T cells, and seems to play an important part in the cellular immune response. Using xenogeneic reactants we found that the NA phenomenon is not entirely species restricted. Apart from the homologous interaction, there was cross reactivity between related species, as between man and other primates or between rodents like the rat and mouse. In some combinations interactions were found between non-related species also. The phylogenetic aspects emerging from these interactions are discussed.