Somatic cell genetic analysis of human cell surface antigens: chromosomal assignments and regulation of expression in rodent-human hybrid cells.

The expression of 13 newly defined human cell surface antigens identified by monoclonal antibodies was studied in a panel of reduced rodent-human somatic cell hybrid clones. For each antigenic system the segregation of antibody reactivity was concordant with the segregation of a specific human chromosome, permitting the chromosomal assignment of 13 gene loci determining antigen expression. The antigens can be placed in four groups on the basis of their patterns of control in the hybrid cells. (i) Presence of a single human chromosome is necessary and sufficient for antigen expression; L230 (assigned to chromosome 2), AJ425, K15 (chromosome 3), SR84 (chromosome 5), JF23, Q14 (chromosome 11), SV13 (chromosome 15), and F10 (chromosome 19). (ii) AJ2 (chromosome 10) and J143 (chromosome 17); two antigens coded for by separate human chromosomes but associated as a molecular complex on the surface of AJ2+/J143+ human cells. (iii) F8 (chromosome 19); antigen expression dependent on the growth characteristics of hybrid cells: substrate-adherent cells are F8+, whereas cells growing in suspension are F8-. (iv) AO122 and F23 (chromosome 15); antigen expression controlled by the permissive/inducing vs. nonpermissive/noninducing nature of the rodent fusion partner. Hybrids derived from both antigen-positive and antigen-negative human cells can express AO122 and F23 but only when specific rodent cell types are used for hybridization: N4TG-1 neuroblastoma and L cells, but not RAG renal carcinoma cells, permit AO122 expression, whereas RAG and L cells, but not N4TG-1 cells, permit F23 expression. The rapidly expanding list of monoclonal antibodies defining human cell surface molecules provides a range of markers to probe the genetic regulation of antigen diversity in somatic cells.