Identification of a trans-acting function regulating HLA-DR expression in a DR-negative B cell variant

Gladstone, Paul; Pious, Donald

doi:10.1007/bf01538802

Cited by 78 publications

(31 citation statements)

References 20 publications

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“…Coordinated expression of all MHCII genes is controlled by a conserved promoter region. 7,8 This promoter contains the socalled X, X2, and Y boxes, which bind the heterotrimeric RFX complex 9 consisting of RFX5, RFXAP, and RFXANK, [10][11][12][13] CREB (cAMP-responsive element-binding protein), [14][15][16] and NF-Y. 17 Transcriptional activity of MHCII genes is, however, not only dependent on these DNA-binding molecules but requires the cell type-specific 18,19 or inducible presence 20,21 of the transcriptional coactivator CIITA.…”

Section: Introductionmentioning

confidence: 99%

MHC class II expression through a hitherto unknown pathway supports T helper cell-dependent immune responses: implications for MHC class II deficiency

Buch

Polić

Clausen

et al. 2006

Blood

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IntroductionMHC class II (MHCII) molecules play a pivotal role in the development of protective T-cell immunity by displaying antigenic peptides from the endocytic pathway to CD4 ϩ T helper (Th) cells. 1 MHCII gene expression is tightly regulated and mostly restricted to thymic epithelium 2,3 and professional antigenpresenting cells (APCs) [4][5][6] but inducible also in other cell types. Coordinated expression of all MHCII genes is controlled by a conserved promoter region. 7,8 This promoter contains the socalled X, X2, and Y boxes, which bind the heterotrimeric RFX complex 9 consisting of RFX5, RFXAP, and RFXANK, 10-13 CREB (cAMP-responsive element-binding protein), [14][15][16] and NF-Y. 17 Transcriptional activity of MHCII genes is, however, not only dependent on these DNA-binding molecules but requires the cell type-specific 18,19 or inducible presence 20,21 of the transcriptional coactivator CIITA. 22 Defects in one of the genes of the RFX proteins or CIITA led to almost complete absence of MHCII expression. This phenomenon was first observed in a human hereditary immunodeficiency, called MHCII deficiency or bare lymphocyte syndrome (BLS). 5,23,24 BLS patients have reduced Th-cell numbers and are extremely susceptible to infections with bacterial, viral, and fungal pathogens. 25 The development of Th-cell-dependent class-switched immunoglobulin responses is impaired in these patients, despite reports of residual MHCII expression on B-cell lines from some patients and the presence of CD4 ϩ T cells. 26,27 It seems unlikely that the Th cells of BLS patients develop in the thymus since the thymic cortex, which is normally responsible for positive selection, showed no MHCII expression in BLS patients. [28][29][30] To date, the only available treatment for this fatal disease is allogeneic BM transplantation (BMT), which in the case of BLS has a low success rate. 27,31 To further investigate the mechanisms underlying this immunodeficiency and to test novel treatment strategies, we and others have generated mouse models of BLS by inactivating the genes coding for CIITA and for RFX5. [32][33][34][35] Similar to the human disease, CIITA Ϫ/Ϫ and RFX5 Ϫ/Ϫ mice lack MHCII expression on the majority of peripheral APCs. Unexpectedly, residual MHCII expression was found in the thymic medulla, on a subset of dendritic cells (DCs) in peripheral lymphoid organs, and on in vitro-activated RFX5 Ϫ/Ϫ B cells. Due to the absence of MHCII in thymic cortex, both mutants are unable to generate Th cells and thus fail to mount Th-cell-dependent immune responses. [32][33][34] To test whether the residual MHCII expression in RFX5 Ϫ/Ϫ and CIITA Ϫ/Ϫ mice ("BLS mice"), and potentially also in Patients, materials, and methods Mouse maintenance and typingRFX5 Ϫ/Ϫ mice 33 and CIITA Ϫ/Ϫ mice 32 were on a mixed 129/Ola/C57BL/6 or 129/Sv/C57BL/6 background, respectively, and were intercrossed to generate CR Ϫ/Ϫ mice. The double knock out was confirmed by polymerase chain reaction (PCR) and Southern blot. For the RFX5 deficiency, the primers RFX...

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Section: Introductionmentioning

confidence: 99%

MHC class II expression through a hitherto unknown pathway supports T helper cell-dependent immune responses: implications for MHC class II deficiency

Buch

Polić

Clausen

et al. 2006

Blood

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“…In addition, there may be multiple genes outside the MHC that are required for optimal antigen presentation, such as the invariant chain ( 16) Lymphocyte Syndrome and are members of complementation groups I, II, and IV, respectively (7). The class II-null B-LCL 6.1.6 was generated after in vitro mutagenesis (19). 6.1.6 (classified as complementation group III [7]) has a mutation resulting in the absence of class II transcription and thus exhibits the class II null phenotype of BLS patient cells.…”

Section: Introductionmentioning

confidence: 99%

Deficient antigen-presenting cell function in multiple genetic complementation groups of type II bare lymphocyte syndrome.

et al. 1995

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“…These elements bind factors that are responsible for the regulation of expression of these loci (5,9,10,17,19,21,(26)(27)(28). Transgenic mice in which one or more of these elements have been deleted show abnormal tissue expression of class II products (29).In humans, regulatory mutants have been induced in cultured B-cell lines (1,4,11) (Table 1). The two primers always spanned at least one intron-exon boundary.…”

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“…In humans, regulatory mutants have been induced in cultured B-cell lines (1,4,11) (Table 1). The two primers always spanned at least one intron-exon boundary.…”

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Transcription analysis of class II human leukocyte antigen genes from normal and immunodeficient B lymphocytes, using polymerase chain reaction.

Bull¹,

Hoef²,

Gorski³

1990

Mol. Cell. Biol.

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The RNA transcript levels of all human leukocyte antigen class II loci were determined from class II congenital immunodeficient B cells by polymerase chain reaction amplification of cDNA. No mRNA was observed under conditions in which 0.01% normal levels could be visualized. Pre-mRNA could be amplified from normal B cells but not from immunodeficient B cells, indicating a transcription defect.Class II A number of cis elements have been described in the regions 5' of the class II loci. These elements bind factors that are responsible for the regulation of expression of these loci (5,9,10,17,19,21,(26)(27)(28). Transgenic mice in which one or more of these elements have been deleted show abnormal tissue expression of class II products (29).In humans, regulatory mutants have been induced in cultured B-cell lines (1,4,11) (Table 1). The two primers always spanned at least one intron-exon boundary. Only the normal B-cell RNA lanes showed a cDNA amplification band of the expected size (Fig. 1), although the CID actin mRNA control was normal. Some primer combinations generated bands other than those expected. These bands often appeared stronger in the CID lanes and represent alternate cDNA primings-amplifications, which are enhanced when normal templates are not available. A faint band in the DRa CID sample migrated close to the position expected for the actual transcript. Use of another pair of primers and blot hybridizing with a DRa probe showed that this band was not DRa (data not shown).The limit of resolution of the PCR technique was determined by mixing experiments wherein normal B-cell RNA was diluted with CID RNA. Amplified HLA-DR cDNA bands were still visible (Fig. 2) in the 1/10,000 dilution, indicating that even 0.01% of normal mRNA levels in the CID cells would have been detected.Analysis of pre-mRNA by using PCR. Initial protocols used primers proximal to the promoter region, with the cDNA synthesis primer in the first intron and the amplification primer in the signal sequence. This would detect premRNAs that had elongated into the first intron. However, this protocol also amplifies any DNA contamination in the RNA preparation, since controls in which the reverse transcriptase is left out of the reaction mixture often show bands almost equal in intensity to those reactions that are reverse transcribed.The polyadenylation of pre-mRNA was used to preferentially amplify RNA and not DNA contamination. One primer consisted of the last six bases of the 3' untranslated region of the pre-mRNA and oligo(dT). The other primer was in the last intron in the pre-mRNA. The presence of amplified DNA bands of the correct size would indicate the presence of pre-mRNAs that had undergone 3'-end maturation but had not yet spliced out the last intron. Pre-mRNA was converted to cDNA by using oligo(dT) and reverse transcriptase. Using primers specific for DR transcripts, the pre-cDNA was amplified from normal B cells (Fig. 3,

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Identification of a trans-acting function regulating HLA-DR expression in a DR-negative B cell variant

Cited by 78 publications

References 20 publications

MHC class II expression through a hitherto unknown pathway supports T helper cell-dependent immune responses: implications for MHC class II deficiency

MHC class II expression through a hitherto unknown pathway supports T helper cell-dependent immune responses: implications for MHC class II deficiency

Deficient antigen-presenting cell function in multiple genetic complementation groups of type II bare lymphocyte syndrome.

Transcription analysis of class II human leukocyte antigen genes from normal and immunodeficient B lymphocytes, using polymerase chain reaction.

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