摘要:

Human membrane cofactor protein (MCP, CD46) is a receptor for the measles virus and serves as a complement regulator which protects host cells from autologous complement attack. MCP is highly polymorphic due to a variety of mRNA splice products. The levels of MCP expression on T and myeloid cell lines are usually two‐eightfold higher than those on their normal counterparts, whereas Burkitt's lymphoma B cell lines express less MCP than B cell lineages carrying no EB virus. The molecule has a Ser/Thr‐rich (ST) domain adjacent to the functional domain, namely short consensus repeats (SCR). The ST domain and a cytoplasmic tail (CYT) contribute to the MCP polymorphism. The ST domain is encoded by three exons (A, B and C) and major ST iscforms are STABC, STBCand STC. The authors investigated the relationship between the expression levels and isoform usage of MCP by flow cytometry using specific antibodies against STAand STC, by reverse transcriptase‐polymerase chain reaction (RT‐PCR) with size markers for each splice variant, and by RT‐PCR/Southern blotting using a specific probe for STA. The results were (1) the profiles of mean shifts of myeloid and T cell lines were STC

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1995.tb03700.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The response of T cells to produce interferon‐γ, to proliferate and to become cytotoxic after specific stimulation with low dose (2%) autologous EBV‐B cells was investigated in 15 EBV seropositive and five seronegative patients. A significantly higher number of interferon‐γ producing cells (56 ± 24 per 105T cells) were found in a spot ELISA in EBV positive than in EBV negative patients (7 ± 2 spots, P<0.01) and it was only found with restimulation after 5–12 days of primary culture. No correlation was found between the extent of interferon‐γ production, cytotoxicity or profileration. Specificity of EBV‐induced interferon‐γ production was demonstrated by comparison of the response to allogeneic EBV‐B cells or IL‐2 in the reslimulation phase. The response was stronger in CDS+T cells than in CD4+T cells and could be blocked in the restimulation phase with HLA class I and class II

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1995.tb03701.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Studies by several groups have suggested that HIV infectionin vivoresults in a BV‐specific alteration of the TCR repertoire and that this might play a role in the pathogenesis of AIDS. Our earlier studies demonstrated tbat both a crude extract of HIV451as well as purified gp160 from HIV451could specifically activate,in vitro, T cells expressing a common set of TCRBV segments (TCRBV3, 12, 14, 15, and sometimes BV17 and 20) in individuals of disparate HLA type. Furthermore, purified gp120 from HIV451was shown to have a similar ability to activate T cells, although with a slightly diiferent TCRBV‐specific pattern. In order to determine whether gp120 from other HIV strains could similarly activate T cells in a TCRBV‐specific pattern, PBMC from HIV seronegative individuals of disparate HLA type were stimulated with gp120 from three strains of HIV (451, IIIB, and MN). The authors found that gp120 from all three strains activate T cells bearing TCRBV2 and BV3 in nearly every individual. T cells expressing other BV segments are also activated, but this is more variable and appears to be unique to each individual. Furthermore, gp120451and gp120 from HIVIIIBand HIVMNdiffer in their ability to activate T cells expressing these other TCRBV segments. These observations suggest that variation in the structure of gp120 and in the genetic and/or environmental background of the individual play an important role in determining which TCRBV segments are‘triggered' by gp120. Furthermore, these observations may have important implications for the rate of disease progression in HIV‐infected in

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1995.tb03702.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SCID and RAG‐2 deficient mice were transplanted intraperitoneally with human peripheral blood lymphocytes (hu‐PBL‐SCID and hu‐PBL‐RAG mice). Seven days after transplantation tbe mice were immunized with a pneumococcal polysaccharide vaccine. Flow cytometry analysis of cells from the peritoneal cavity and the spleen after 8–10 weeks revealed that human cells had more limited engraftment in RAG than in SCID recipient mice, and that more human cells were found in the spleen than in the peritoneal cavity. Functionality of the human cells recovered from these two locations was explored by the counting of human immunoglobulin secreting cells (hu‐ISC). A total of 83% of the hu‐PBL‐SCID mice and 29% of the hu‐PBL‐RAG mice had detectable hu‐ISC in the peritoneal cavity and/or the spleen. The kinetic profiles of human immunoglobulins in the mouse sera during the experiment showed donor dependency. More than 90% of the hu‐PBL‐SCID mice had detectable levels of human IgG, IgM and IgA, while 78% had detectable levels of IgE, whereas detectable levels of IgG, IgM, IgA and IgE were measured in 37%, 64%, 68% and 23% of the hu‐PBL‐RAG mice, respectively. Forty‐seven per cent of immunized hu‐PBL‐SCID mice showed a human antipneumococcal IgG level that was significantly above the background level in non‐immunized mice, while none of the hu‐PBL‐RAG mice produced any detectable levels of human antipneumococcal IgG. In short, human PBL showed a better engraftment and a better antibody response when tra

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1995.tb03703.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The benefit of re‐immunization with pneumococcal polysaccharide vaccine is an important question in clinical practice. In an experimental model, BALB/c and CBA/J mice were re‐immunized s. c. with a 23‐valent pneumococcal polysaccharide vaccine at various time intervals after a first immunization with the same vaccine. The antibody response after the secondary immunization showed similar kinetics as after primary immunization, and was mainly an IgM antibody response. Re‐immunization at 28 days or earlier induced a decrease in the serum antibody levels to the vaccine. Reimmunization at 120 days or later induced higher antibody levels than after the first immunization. Significant increases in antibody levels to serotypes 1, 4, 7F and 19F out of six serotypes tested were observed. In CBA/J mice, but not in BALB/c mice, the dose used for primary immunization appeared to influence the magnitude of the antibody response to secondary immunization. Our results indicate that the time interval between primary and secondary immunization is an important determinant with regard to the magnitude of the antibody response to re‐immunization with pneumococcal polysaccharid

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1995.tb03704.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The scientific interest in tbe pbysical interaction ofPlasmodium falciparum‐infected erytbrocytes with host cells stems from the suggestion ibat excessive binding in the microvasculature leads to severe malaria. Tbe authors studied, therefore, two parasites for their ability to adbere to normal human cells and to induce cytokine production, one parasite lacking a binding capacity (DD2) and one which adhered to CD36+transfected CHO cells (MCAMP). The MCAMP parasites readily bound to platelets and erytbrocytes and to monocytes, polymorphonuclear granulocytes and EBV‐transformed B cells as seen by ligbt and electron microscopy. Platelets were frequently attached in large numbers to the infected erythrocyte surface and groups of infected erytbrocytes were sometimes held together by several platelets. Nine out of 17 cytokines tested were found to be secreted into the culture supernatants after 35 h of co‐eultures containing monocytes or unfractionated peripheral blood mononuclear cells (PBMC) and parasites (IL‐lRA, IL‐6, IL‐8, IL‐10, TGFβ, TNFα, G‐CSF, IL‐1‐β, and GM‐CSF). Three additional cytokines were also present in low levels (<200pg/ml, IL‐2, IL‐4, IFNγ) in tbe culture supernatants after incubation of the cells for 4 days. TNFa, IL‐RA, and IL‐8 were secreted from polymorphonuclear granulocytes, LGLs and T cells. Platelets and, to a lesser degree, monocytes and T cells secreted large amounts of TGFβ (10–30 ng/ml). Cytokines may participate in tbe patbogenesis but also the suppression of immune responses s

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1995.tb03705.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Vaccination of five baboons with an anti‐idiotypic vaccine to irradiatedSchistosoma mansonicercariae resulted in nearly 19% protection compared to 39% protection conferred to five baboons vaccinated with an irradiated vaccine. Vaccination with the anti‐idiotypic antibodies resulted in a significant reduction of pathology and granuloma size following challenge with live unattenuated cercariae. Results presented in this work are considered highly significant because the anti‐idiotypic vaccine markedly influenced schistosomiasis morbidity which is the main consideration in this di

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1995.tb03706.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The kinetics of humoral immune responses were investigated in mice experimentally infected with five clones ofTrypanosoma cruziisolated from different sources in Panama. Sera were collected at different timepoints post‐infection. ELISA and IHA tests were used to detect antibodies againstT. cruziepimastigote antigens. The levels ofT. cruzispecific antibodies increased during the course of infection; at day 90 post‐infection the range was between 1:5120 and 1: 10240. A high correlation was evident between ELISA and IHA results. Western blots revealed that these antibodies recognized polypeptides of 81, 76 and 71 KDa during the first weeks and 81, 76, 71, 50, 40, 28 and 12 KDa after 30–50 days. Only minor differences in antigen recognition patterns were demonstrated, suggesting that the major antigens may be represented in all clones.T. rangeliantigens were also recognized byT. cruziseropositive sera. However, an ELISA test using antigens isolated from a genomic expression library ofT. cruzirevealed that a hyperimmune rabbit serum againstT. rangeliwas unable to recognize the repeat sequence of SAPA (Shed Acute Phase Antigen) peptides but did recognize a number of otherT. cruzisynthetic peptide antigens. The importance of these findings, in the context of Chagas' disease, is disc

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1995.tb03707.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

A hallmark of positive selection in T‐cell receptor (TCR)‐transgenic mice is a strong skewing towards the CD4+or the CD8+subset, depending on the class II or I restriction of the TCR, respectively. However, previous experiments in TCR transgenic mice specific for an Ig light chain (λ2315)/I‐Edclass II molecule did not fit into this scheme because the authors observed an anomalous skewing towards CD8. In this paper, the authors show that endogenous TCRα chains are expressed on>90% of CD4+and CDS+cells in this particular transgenic strain, even on a selecting H‐2dhaplotype. Endogenous TCRQ chains are first detected when double‐positive thymocytes down‐regulate either CD4 or CD8. Endogenous Vα seems to influence generation of T‐cell subsets because CD4+and CD8+cells express different frequencies of endogenous Vα2 and Vα8. In the absence of endogenous TCRα chains in recombination‐deficient TCR‐transgenic severe combined immunodeficiency (SCID) mice, a strong skewing towards CD4+T cells is seen, but such mice are severely T‐cell deficient. As an explanation for these results, the authors suggest that the transgenic TCR has a too low affinity for efficient positive selection, therefore, TCRa gene rearrangements proceed. Endogenous TCRa paired with transgenic TCRβ could bind to class I or class II molecules, enhance positive selection and thereby production of CD4+or CD8+cells. Most of the ‘mismatched’ CD8+cells are λ2315‐specific and I‐Edclass II restricted, and may function as idiotype‐specific suppressors of B cells. These results may help explain the origin of dual TCRα T cells. Furthermore, the authors suggest that T cells ‘mismatched’ for co‐receptor/TCR MHC‐speci

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1995.tb03708.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Interactions between homing receptors on circulating leucocytes and endothelial addressins regulate tissue‐specific cellular extravasation. Although integrin á4β7 appears to be the main receptor for guthoming T lymphocytes, less is known about molecules mediating mucosal B cell homing. Expression of integrin α4β7 on B lymphocytes, B cell blasts, and plasma cells in human gut‐associated lymphoid tissue (GALT; the Peyer's patches and appendix) and lamina propria was studied by multi‐colour immunofluorescence applied on cryosections. Isolated mononuclear cells from the same tissue compartments were examined by flow cytometry and compared with peripheral blood B cells. Integrin α4β7 was expressed by IgA+B cell blasts and plasma cells (CD38high) in the lamina propria, B cell blasts in GALT, and sIgD+B lymphocytes in peripheral blood. In contrast, GALT sIgD+B lymphocytes were negative or only weakly positive for α4β7. These results suggested that B lymphocytes down‐regulate αAβ7 upon extravasation in GALT but up‐regulate this integrin after antigen‐priming. Thus, α4β7 may be a homing receptor also for B cell blasts extravasating in the gut lamina propria, where this integrin is maintained on plasma cells, perhaps as a

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1995.tb03709.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY