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Identification of 3' alpha-hs4, a novel Ig heavy chain enhancer element regulated at multiple stages of B cell differentiation.

ABSTRACT: In addition to E mu, several elements downstream of the IgH cluster, i.e. 3' of the C alpha gene, are involved in regulating IgH gene rearrangement and expression. This entire downstream regulatory region was shown to be deleted in the mutant myeloma cell line, LP1.2. The deletion encompasses approximately 34 kb and is presumably responsible for the reduced levels of IgH expression in this cell line. An additional regulatory element, included in the LP1.2 deletion, was identified by investigation of a DNase I hypersensitivity site located approximately 33 kb downstream of the alpha gene and present in pre-B and plasma cells. This novel IgH gene enhancer element, termed 3' alpha-hs4, is capable of activity throughout B cell development. Transient transfection of 3' alpha-hs4 in a CAT reporter gene construct shows transcriptional enhancement activity approximating that of E mu in S194 plasmacytoma and M12.4.1 and A-20 B cell lines; while in a pre-B cell line, 18-81, the average activity is 25% that of E mu. Enhancer activity was localized to an 800 bp fragment. The activity of 3' alpha-hs4 is orientation independent and appears to be B cell specific. Tight regulation of 3' alpha-hs4 is inferred from its variable activity in different plasmacytoma cell lines and within the pre B cell line, 18-81.

SUBMITTER: Michaelson JS

PROVIDER: S-EPMC306794 | biostudies-other | 1995 Mar

REPOSITORIES: biostudies-other

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Identification of 3' alpha-hs4, a novel Ig heavy chain enhancer element regulated at multiple stages of B cell differentiation.

Michaelson J S JS Giannini S L SL Birshtein B K BK

Nucleic acids research 19950301 6

In addition to E mu, several elements downstream of the IgH cluster, i.e. 3' of the C alpha gene, are involved in regulating IgH gene rearrangement and expression. This entire downstream regulatory region was shown to be deleted in the mutant myeloma cell line, LP1.2. The deletion encompasses approximately 34 kb and is presumably responsible for the reduced levels of IgH expression in this cell line. An additional regulatory element, included in the LP1.2 deletion, was identified by investigatio ...[more]

PMID: 7731812

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Project description:An understanding of the antigen-specific B-cell response to the influenza virus hemagglutinin (HA) is critical to the development of universal influenza vaccines, but it has not been possible to examine these cells directly because HA binds to sialic acid (SA) on most cell types. Here, we use structure-based modification of HA to isolate HA-specific B cells by flow cytometry and characterize the features of HA stem antibodies (Abs) required for their development. Incorporation of a previously described mutation (Y98F) to the receptor binding site (RBS) causes HA to bind only those B cells that express HA-specific Abs, but it does not bind nonspecifically to B cells, and this mutation has no effect on the binding of broadly neutralizing Abs to the RBS. To test the specificity of the Y98F mutation, we first demonstrated that previously described HA nanoparticles mediate hemagglutination and then determined that the Y98F mutation eliminates this activity. Cloning of immunoglobulin genes from HA-specific B cells isolated from a single human subject demonstrates that vaccination with H5N1 influenza virus can elicit B cells expressing stem monoclonal Abs (MAbs). Although these MAbs originated mostly from the IGHV1-69 germ line, a reasonable proportion derived from other genes. Analysis of stem Abs provides insight into the maturation pathways of IGVH1-69-derived stem Abs. Furthermore, this analysis shows that multiple non-IGHV1-69 stem Abs with a similar neutralizing breadth develop after vaccination in humans, suggesting that the HA stem response can be elicited in individuals with non-stem-reactive IGHV1-69 alleles.Universal influenza vaccines would improve immune protection against infection and facilitate vaccine manufacturing and distribution. Flu vaccines stimulate B cells in the blood to produce antibodies that neutralize the virus. These antibodies target a protein on the surface of the virus called HA. Flu vaccines must be reformulated annually, because these antibodies are mostly specific to the viral strains used in the vaccine. But humans can produce broadly neutralizing antibodies. We sought to isolate B cells whose genes encode influenza virus antibodies from a patient vaccinated for avian influenza. To do so, we modified HA so it would bind only the desired cells. Sequencing the antibody genes of cells marked by this probe proved that the patient produced broadly neutralizing antibodies in response to the vaccine. Many sequences obtained had not been observed before. There are more ways to generate broadly neutralizing antibodies for influenza virus than previously thought.

Dataset Information

Identification of 3' alpha-hs4, a novel Ig heavy chain enhancer element regulated at multiple stages of B cell differentiation.

Publications

Identification of 3' alpha-hs4, a novel Ig heavy chain enhancer element regulated at multiple stages of B cell differentiation.

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