ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1995.tb03618.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1995.tb03619.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1995.tb03620.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The pair of μH‐chain andkL‐chain transgenes encoding the Sp6 TNP/DN A‐specific IgM was bred onto the rearrangement‐deficient genetic background of RAG‐2T mice, and onto thekL‐chain expression‐deficient background of iEkT mice. Bone marrow of Sp6 transgenic RAG‐2T mice contained normal numbers of B220(CD45R)+c‐kit+pro/preB‐I‐like cells and normal numbers of B220(CD45R)+TAC+preB‐II‐like cells. Most strikingly, the numbers of immature sIgM+B cells in the bone marrow were at least five‐fold lower than normal, while mature B cells were almost undetectable in bone marrow as well as spleen. Hence, B cell development in these mice appears to be arrested at the transition from preB‐II to immature B cells. The contents of bone marrow and spleen of the different precursors, immature and mature B cell compartments in Sp6iEkT mice were found to be similar to those of normal mice except that all sIg+cells expressed μL‐chains, of which 40% coexpressed the transgenickL‐chain. It indicates that the repertoire of μL‐chain rearrangements and the μL‐chains expressed from it suffices to relieve the arrest of differentiation seen in Sp6RAG‐2T mice. The T cell‐independent antigen TNP‐Ficoll elicited within 5 days a response of the Sp6RAG‐2T mice to develop to IgM‐secreting cells and to fill the serum pool with the Sp6 transgenic IgM to 100 μg/ml, i. e. to normal serum levels of IgM in normal mice. TNP‐Ficoll appears to interfere with the arrest of differentiation. Two scenarios for this arrest of differentiation and its relief

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1995.tb03621.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

We have studied whether engagement of MHC class I (MHC—I) molecules on natural killer (NK) cells can influence the NK killing activity. Human NK effector cells, enriched by nylon wool passage, were incubated with monoclonal antibodies (MoAb) to MHC—I followed by cross‐linking with secondary rabbit anti mouse Ig or streptavidin. Cross linking of MHC—I molecules on NK cells resulted in a clear inhibition of the NK activity against the target cells K562, Molt‐4 and U937. The inhibitory effect was selective for MHC—I and was not seen with MoAb to MHC—II or CD56 molecules. The inhibition was not mediated via Fc receptors since F(ab)2fragments of the MHC—I MoAb W6/32 were as effective as the intact antibody. The best inhibition of NK activity was obtained using biotin‐labelled F(ab)2fragments of W6/32 and streptavidin as a cross‐linker, where up to 70 % reduction in NK cell activity was observed. Antibody dependent cellular cytotoxicity (ADCC) was also inhibited by cross‐linking MHC—I molecules on the effector cells.The results show that antibody mediated cross‐linking of MHC—I proteins on NK cells can inhibit their killing capacity. This indicates that MHC—I molecules on NK cells can be involved in the regulation of NK cytotoxicity, perhaps by transmitting inhibi

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1995.tb03622.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The enzyme‐linked immunospot (ELISPOT) assay was used to enumerate the number of IFN‐γ and IL–4 producing cells afterin vitrostimulation with a highly purified recombinant malaria vaccine candidate antigen (r‐Pf155/RESA) or synthetic peptides corresponding to its major T‐cell epitopes. Two groups of naturally primed individuals living in rural areas of Burkina Faso were studied. The donors comprised one group of healthy (non‐parasitemic) mainly adult people and one parasitemic mainly younger people. IL–4 producing cells were detected in response to PHA but no such cells were detected in response to the malarial antigens. The most frequent IFN–7 responses were seen with r‐Pf155/RESA. Thus, after stimulation with this antigen 52% of the donors responded positively in the ELISPOT assay, while only 17% responded to the synthetic peptides, suggesting that the r‐Pf155/RESA contained T‐cell epitopes not covered by the peptides used in this study. The number of IFN‐γ producing cells in response to the malarial antigens did not differ between the two groups. However, IFN‐γ levels found in sera from the parasitemic individuals were significantly higher than in those from healthy donors. This latter finding and the lack of differences seen in the number of IFN‐γ producing spots in the two groups indicate that IFN‐γ producing cells may have sequestered to oth

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1995.tb03623.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Isolation of MPB83 fromMycobacterium bovisBCG Tokyo culture fluid is described. MPB70 and MPB83 have similar molecular mass as judged by SDS‐PAGE but differ in isoelectric points. Peptides isolated after CNBr cleavage of MPB83 revealed extensive homology as well as distinct differences from corresponding parts of the amino acid sequence deduced from thempb70gene cloned by Terasakaet al.Antibodies produced by immunization with MPB70 and MPB83 had distinctly different fine specificity revealing cross‐reactivity between the proteins. These findings indicate that two distinct, homologous genes code for these proteins. Sensitization with live BCG Tokyo also induced T cell responses to MPB83 with development of delayed type hypersensitivity in guinea p

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1995.tb03624.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

A biopsy specimen from a patient with follicular lymphoma was divided into two fragments. DNA was extracted from one fragment and a 1.2 kb region of the functional heavy chain (IgH) gene was amplified, cloned and sequenced (eight clones). From the other fragment a cell line (HF‐1) was started. The IgH gene region was amplified from the cell line, and sequenced without cloning. The nine sequences obtained could be arranged into a genealogical tree where the individual sequences differed from the deduced ancestor by 16–29 single nucleotide changes, some also by an insertion and/or a deletion. It is apparent that the sequence alterations were caused by somatic mutations during the growth of the lymphoma.The comparison of the sequences with two published (allelic) germline sequences of the human JH region showed ∼20% non‐homology. The differences included five additional multinucleotide insertion/deletion changes, the longest of them a 101‐nucleotide insertion. Two long insertions were homologous to the adjacent germline sequences. We propose that most of the changes observed, including long deletions and insertions, represent or are linked to somatic hypermutation events of the Ig gene type. Although in a few cases large deletions and insertions (>2 bp) have been found in mutated immunoglobulin genes, our results, for the first time, firmly link these deletions/insertions to somatic hypermutations; their frequency was found to be 2.2% of the observed mutational events in the non‐translated gene regions. HF‐1 is the first follicular lymphoma line successfully established from a lymphoma known to have hypermutated its Ig genes during the malignant growth. It is a candidate cell line to be studied for its ability to generate mutations of B cell type in

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1995.tb03625.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

To study the immunoreactivity genes in a heterogeneous human population needs a large number of individuals. Associations between HLA antigens and immunoresponse to viral or bacterial antigens have been studied with controversial results. As a homogeneous population, the MHC class I, II and III allele distribution was studied in 153 end‐stage renal disease patients (ESRD, average duration of renal replacement: 8.2+5.1 years) immunized with a recombinant hepatitis B vaccine in accordance to the standard vaccination schedule. Thirty‐four patients with an antibody titre of less than 10 U/l following the last booster injection were considered as non‐responders while 119 patients with antibody titre equal to or more than 10 U/l were considered as responders. The responder group was divided into two subgroups: low responders (antibody titre: 1000 U/l) and high responders (antibody titre:>1000 U/ 1). Marked differences were observed between responders and non‐responders in the occurrence of carriers of different MHC class I, II and III alleles. Homozygotes for HLA—A1, HLA—B8, HLA—DR3 and HLA—DQ2 were found almost exclusively in the non‐responder group and significantly more heterozygotes for these alleles were found in the non‐responder group compared to the responders. Similar albeit less marked differences were found in the frequency of some MHC class III alleles (C4A*6, C4A*QO, Bf*F, BPS0.7). Within the responder group, carriers of HLA—A2, HLA—B7 and HLA—DR4 were found to be clustered in the low responder sub‐group whereas carriers of HLA—A1, HLA—B27, HLA—Cw2, C4A*6 and Bf*F were observed more frequently in the group of high responders. Similar differences were found with extended haplotypes as well. For example, the extended haplotypes HLA—Al, B8, BfS, C4AQO, C4B1, DR3, DQ2 and HLA—A1, B8, BfF, C4A6, C4B2, DR3, DQ2 were present in nine of 34 cases of non‐responders but only in one of 119 case of responders (P<0.000001). These observations indicate that the presence or absence of certain MHC alleles even in heterozygous form determine the responsiveness to hepatitis B vaccination in end‐stage renal disease patients, and among responders, the intensity of antibody response is also ma

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1995.tb03626.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

H‐2Kb‐transfected T2 cells, which lack both TAP1/2 and LMP2/7 genes, are able to efficiently process and present Sendai virus Antigen to Kb‐restricted Sendai virus‐specific CTL. This presentation is not inhibited by Brefeldin A (BFA). Here we extend our analysis of this novel antigen presentation pathway. We show that presentation of Sendai virus antigen was not due to sensitization of T2Kbcells by peptides in the virus preparation or peptides released from virus infected cells. Also, the ability to present Sendai virus in a BFA resistant fashion was specific for cells of the T2 lineage. Re‐expression of TAP1/2 genes in T2Kbcells did not alter the capability to present antigen in a BFA resistant fashion, i. e. the presence of a functional TAP transporter complex did not relocate (all) peptides to the classical pathway for antigen processing and presentation. We found that co‐infection of T2Kbcells with either Sendai virus plus influenza virus or Sendai virus plus VSV did not relocate presentation of influenza or VSV antigen to the TAP independent BFA resistant antigen presentation pathway. Peptide elution experiments and studies with peptide‐specific CTL firmly demonstrated that the antigen presented by T2Kbcells after infection with Sendai virus was the natural Sendai virus epitope NP324‐332. The same epitope, when expressed as a minigene in vaccinia virus, could be presented also by T2Kbcells but this presentation could be blocked by BFA. Thus, the TAP independent BFA resistant presentation of antigen seem cell (T2 lineage) and virus (Sendai virus) specific, but not epitope specific. The ability of T2Kbcells to present Sendai virus antigen in a TAP independent BFA resistant fashion was only partially blocked by lysosomal inhibitors such as methylamine, ammonium chloride and chloroquine. These findings demonstrate that TAP1/2‐independent and BFA‐resistant class I processing is only expressed in certain cell types, in parallel with classical MHC class I processing, and that Sendai virus selectively can enter this pathway. Hypothetical models for the TAP‐independent class I pro

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1995.tb03627.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY