摘要:

Monocytes/macrophages can kill tumour cells and mediate tumour‐destructive host responses e. g. by releasing tumour necrosis factor‐γ (TNF‐γ). The underlying mechanisms of tumour cell recognition, however, are not clear. Previous work in our laboratory suggested that carbohydrate moieties associated with the T cell adhesion molecule CD2 of Jurkat cells induce TNF‐γ secretion by human monocytes. In this study we present data indicating that the stimulatory capacity for TNF‐γ secretion is confined to carbohydrate moieties of tumour cell CD2. Irradiated resting peripheral T cells did not display stimulatory activity in contrast to irradiated Jurkat cells although surface expression of CD2 was similar. Activated T cells, however, induced TNF‐γ production by monocytes via a CD2‐independent mechanism. Only affinity purified CD2 prepared from Jurkat cells but not from non‐transformed T cells activated monocytes to secrete TNF‐γ. This activation process was blocked by anti‐CD2 antibodies. Neuraminidase and PNGaseF treatment of isolated CD2 inhibited the stimulatory capacity whereas pronase treatment did not. These data suggest that carbohydrate moieties containing siaiic acid mediate stimulation of monocytes. Taken together, these results indicate a role for glycosylation patterns typical of tumour cells in the recognition process of tumour cells

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1995.tb03536.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Mycobacterium bovis infection in cattle continues to be a problem in several regions, partly due to inadequate diagnostic tests. The aim of this study was to use an experimental model of the natural disease to identify T‐cell epitopes from the mycobacterial 38 kDa antigen as potentially specific diagnostic reagents. A panel of overlapping synthetic peptides (16‐mers with a five‐residue overlap) were produced from the published amino acid sequence. It was found that peripheral blood lymphocytes from at least three of four experimentally infected animals, which were considered to be in either Th1‐ or Thl/Th2‐dominated stages of anti‐mycobacterial immunity, proliferated in response to five epitopes (residues 1–27, 88–107, 122–138, 243–260 and 307–328). However,in vitroproduction of IFN‐γ was detected only in response to epitope 122–138, indicating a role in protective immunity. The peptides were not recognized by control, uninfected animals, but all epitopes showed various degrees of recognition by animals which were field reactors to intradermal tuberculin testing. Furthermore, epitopes 1–27, 88–107 and 122–138 were recognized by four breeds of cattle and by animals from separate herds, suggesting genetic permissiveness in recognition which would be essential in the

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1995.tb03537.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Amyloid A protein (AA), the chief constituent of reactive amyloid deposits, is derived from serum amyloid A (SAA) and most commonly corresponds to the amino‐terminal 76 residues (AA76). Digestion of recombinant human SAAl with a lysosomal thiol protease, cathepsin B. and analysis of the products by SDS‐PAGE and amino‐terminal sequencing revealed that AA76 was generated as a minor and transient degradation product. Digestion with neutrophil eiastase generated intermediates different from AA76. This finding suggests that cathepsin B may play an important role in amyloid fibrilogenesis by converting SAA

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1995.tb03538.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Resting mouse B lymphocytes were stimulatedin vitrowith Upopoiysaccharide, Sepharose‐coupled anti‐γ antibodies or a combination of the two. B lymphocytes stimulated with anti‐γ entered the cell‐cycle with more rapid kinetics and at a higher frequency than did the corresponding cell population stimulated with lipopolysaccharide. Using cell cycle analysis after DNA staining combined with an M phase block, the cell‐cycle kinetics ofin vitrocultured B‐lymphocytes was studied. The labelling index of lipopoly saccharide stimulated B lymphocytes was 60% while that for anti‐γ Sepharose stimulated cells was 85%. The generation time of the actively cycling population from both types of cultures was constant and was of the order of 18 h. Thus, the fraction of B lymphocytes induced to proliferatein vitrovaries depending on the stimulus, while the growth kinetics of the actively proliferating populations are rem

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1995.tb03539.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.tb03540.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY