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Evidence for two trans-acting genes regulating HLA class II antigen expression.
Journal of Immunology (Baltimore, Md. : 1950)
|December 1, 1985
Summary
This study reveals that human leukocyte antigen (HLA) class II antigen expression in hybrid cells requires at least two trans-acting regulatory genes. One gene is supplied by the T-lymphoblastoid cell line (T-LCL) fusion partner, compensating for the defect in the B-lymphoblastoid cell line (B-LCL) mutant.
Area of Science:
- Immunogenetics
- Molecular Biology
- Cell Biology
Background:
- Human leukocyte antigen (HLA) class II molecule expression in B-lymphoblastoid cell lines (B-LCL) depends on trans-acting regulatory factors.
- Trans-acting factors from B-LCL can induce de novo synthesis of T-lymphoblastoid cell line (T-LCL)-encoded class II antigens in T-LCL x B-LCL hybrids.
Purpose of the Study:
- To investigate the genetic control of HLA class II antigen regulation.
- To characterize the regulatory defect in the class II antigen-negative B-LCL mutant 6.1.6.
Main Methods:
- Fusion of two distinct T-LCL lines with the B-LCL 6.1.6 mutant.
- Northern blot analysis to assess gene expression.
- Cell surface immunofluorescence to detect antigen expression.
Main Results:
- Hybrid cells derived from T-LCL and B-LCL 6.1.6 expressed HLA class II antigens encoded by both parent cell lines.
- The B-LCL 6.1.6 mutant is deficient in a trans-acting factor necessary for HLA class II gene transcription.
- Expression in hybrids is controlled by at least two trans-acting regulatory genes, one provided by the T-LCL.
Conclusions:
- A minimum of two trans-acting regulatory genes control HLA class II antigen expression.
- The 6.1.6 mutant has an inactivated regulatory gene, which is complemented by the T-LCL fusion partner.
- A second regulatory gene, potentially active in 6.1.6, is insufficient alone for maintaining class II antigen expression.