The demonstration of the spindle fiber attachments in the amphibian liver and sperm nuclei by the sera from scleroderma patients.

The isolated liver nuclei and the mature sperm nuclei from Rana nigromaculata and Bufo bufo asiaticus had been investigated by indirect immunofluorescence method with anti serum specific to the spindle fiber attachments (SFAs) from the scleroderma patients with CREST syndrome. It was found that in the isolated liver nuclei and the mature sperm nuclei of these animals there are discrete speckles which bind the antibody specific to the SFAs. The maximum number of these speckles counted in a single sperm nuclei of the frog corresponds with the haploid chromosome number of this animal (n = 13). The haploid chromosome complement of the toad is 11 and the maximum number of the speckles counted in a single sperm nucleus of this species is also 11. These findings suggest that the scleroderma serum can be used to identify the SFAs of the amphibias and the antigens of SFAs are conserved in the mature sperms of these animals. The implication of these conclusions is discussed.