摘要:

Phosphatidylinositol‐specific phospholipase C (PI‐PLC) treatment of the human natural killer (NK) target cells Molt‐4, Jurkat, and U937 reduced their susceptibility to killing by human NK cells in a dose‐dependent fashion. This indicates that a cell surface Structure, anchored by a glycosyl‐Phosphatidylinositol (G‐P1) moiety, is important in NK cytotoxicity. In contrast, another common NK target cell line, K562, remained susceptible to NK killing after enzyme treatment, suggesting that distinct target structures are expressed by this cell line. PI‐PLC treatment of Molt‐4 cells also reduced their sensitivity to human lymphokine activated killer (LAK) cells, suggesting that NK and LAK cells share common specificity in the killing of Molt‐4. In contrast, PI‐PLC had no effect on the killing of the LAK target cell line. Daudi, which is only weakly sensitive to unactivated NK cells. Killing of a variety of murine target cells by murine NK cells was not affected by PI‐PLC treatment, but cross‐species killing of Molt‐4 by murine NK cells was inhibited by PI‐PLC, suggesting a common mechanism in the killing of this human target cell line. The PI‐PLC treatment of effector cells from either species did not reduce their NK activity. The reduction in sensitivity of the Molt‐4, Jurkat, and U937 target cells probably results from a loss of a target specific G‐PI linked membrane molecule, but other possible explanations for

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1989.tb01102.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AMycobacterium bovisantigen has been purified from culture filtrate by chromatofocusing. This antigen is a major component of culture filtrate and cell extracts and shows a considerable degree of micro‐heterogeneity in electric charge and molecular weight. Studies with monoclonal and polyclonal antibodies raised against the purified antigen show that some of its antigenic determinants also occur in higher molecular weight species in culture filtrate and particularly in whole cell preparations. Immunoblotting and ELISA studies, using sera fromM. bovis‐infected animals, showed that this antigen is one of the most immunoreactive components ofM. bovis, recognized by the majority of animals with detectable antibody response toM. bovis.The specificity of the purified antigen is far superior to that of the crude culture filtrate, with very few false positive results. The purified antigen also elicits strong in vivo and in vitro cell‐mediated responses The amino acid compositions of two variants of this antigen have been determined and found to be similar to that of M

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1989.tb01103.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

A panel of monoclonal anybodies directed against various lymphoid and non‐lymphoid cell subsets was used to study the lymph nodes of human fetuses of 16–40 weeks. B cells were of intermediate size and were present at all ages in primitive follicles and in the outer cortex. The fetal B‐cell immunophenotype is indicative of an intermediate stage of development, just preceding the differentiation to mature B cell. Forty to sixty percent Leu1+B cells were observed in the follicles until the end of the second trimester. At all stages, T cells showed an immunophenotype similar to type III thymocytes, different from adult peripheral T cells, with a marked predominance of CD4+T cells. Leu7+NK cells were generally absent. OKIa+interdigitating reticulum cells were present in T‐cell areas. Some axillary lymph nodes showed strongly CD1+dendritic cells, probably Langerhans'cells. Macrophages and granulocytes were present in varying numbers Altogether, our results indicate that fetal lymph nodes are quite well differentiated at an early fetal age, although T and H cells do not (yet) show adult immunophenotypes. The expression of the CD38 antigen may be a main marker related to the immaturity of fetal T and

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1989.tb01104.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

We have assigned the human serum amyloid A (SAA) gene family to a 90 kb region on the short arm of human chromosome 11(11p) by hybridization of defined genomic fragments of human SAA genes to DNA from rodent‐human somatic cell hybrids and to large DNA fragments separated by transverse alternating field gel electrophoresis. We have also characterized SAA probe hybridization patterns in human DNA cleaved with restriction endonucleasesHindIII,PstI,Bg/II,TaqI, andXbaI and found invariant patterns except for a two‐allele restriction fragment length polymorphism (RFLP) withHindIII. These studies show that the SAA gene family comprises at least three members in the haploid human genome and will be useful in identifying variant patterns and establishing linkage between members of the SAA gene family and other markers on chromosome

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1989.tb01105.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

IgG‐antibodies can efficiently suppress the antibody response against their specific antigen. The suppressive capacity is dependent on intact Fc regions. However, it is not clear which of the Fc‐mediated effector functions arc necessary for the induction of immunosuppression the monoclonal antibody 24G2, which binds to murine Fc receptors on macrophages and B cells, was used in the present study to address the question of whether IgG‐mediated suppression is in fact dependent on the binding of IgG antibodies to Fc receptors on splenocytes, In a murine in vitro immunization system, 24G2 is shown to reverse efficiently the suppression of the sheep erythrocyte‐specific antibody response. The role of B cells or macrophages as effector cells is di

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1989.tb01106.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY