NS-7 (nervous system antigen-7): A cell surface antigen of mature brain, kidney, and spermatozoa shared by embryonal tissues and transformed cells

Abstract

Xenogeneic immunization of rabbits with cells of a mouse undifferentiated neural tumor, MUNTAD, produces antisera which after appropriate absorption bind to the cell surfaces of MUNTAD cells and to three normal adult mouse tissues: brain, kidney, and spermatozoa. Any one of these tissues quantitatively absorbs all of the activity for MUNTAD cells from the antisera, indicating that a single antigen or antigens is shared. This is designated NS-7. The adult tissues positive for NS-7 are the same as those that carry NS-6, but NS-7 is distinguished serologically from NS-6 by being present on many embryonic tissues, tumors, and cell lines which completely lack NS-6. Blocking and capping studies show that on the MUNTAD cell surface, some NS-7 antigenic sites and all NS-6 sites are physically related.