Molecular analysis of an EL4 cell line that expresses H-2Db but not H-2Kb or beta 2-microglobulin

EL4/Mar is a variant cell line that expresses H-2Db but neither H-2Kb nor beta 2-microglobulin (beta 2m). Southern and RNA blot analysis and immunoprecipitation of metabolically labeled proteins established that the B2m gene(s), beta 2m mRNA, and beta 2m protein are normal in this cell line. Somatic cell hybridization showed that the defect in this cell line was in the synthesis of H-2Kb, and RNA blot analysis with an H-2Kb specific oligonucleotide established that the H-2Kb gene(s) in this cell line was not transcribed into a stable mRNA species. The apparent absence of beta 2m on the surface of this cell line suggests that there may be some feature of the H-2Db molecule that allows it to be expressed in the absence of detectable beta 2m.