摘要:

Thymus cells were examined for Ig by exposing them to purified anti‐mouse L chain Ig labeled with125I and examining, by bulk counting and radioautography, the amount of reagent bound. In addition, cell extracts were assayed for total Ig by a quantitative microprecipitin inhibition method. Most cells in thymus contained little Ig, but a minor subpopulation, varying in structure, did contain demonstrable Ig. This small proportion of cells (˜1%) appeared to be intrinsic to the thymus, and dose response data indicated that there was a hierarchy of Ig‐positive cells. They were enriched in the cortisone‐resistant fraction. Most were resistant to both anti‐θ and an anti‐B‐anti‐macrophage serum, leaving their identity in doubt. Some further properties, and suggestions as to the possible role of these cells in thymus

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1974.tb01236.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

The cytotoxicity of human peripheral blood lymphocytes (PBL), after a 6‐day allogeneic stimulation in unidirectional mixed lymphocyte culture (UMLC). was studied. PBLs stimulated with phytohemagglutinin (PHA) and labeled with51Cr were used .as target cells. The effector cells were incubated with the target cells at I 100:1 ratio for 6 In. The amount of isotope released into the supernatant was used to calculate lysis. Cell‐mediated lympholysis (CML) was specific, as shown by an innocent‐bystander experiment and by the lack of lysis of target alls autologous with the effector cells. The specific lysis had the following features: linear increase between 2 and H hr of incubation, linear increase with the logarithm of the number of effector cells, and inhibition by EDTA and by cytochalasm B. Under the UMLC conditions used, potent effector cells were present already on day 4. A reduction in the number of stimulating cells to one third of the number of responding Cells in UMLC resulted in a decrease of thymidine incorporation and in an increase of CML. The significance of CML for transplantation biology is disc

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1974.tb01237.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Amino acid composition, end‐group analysis, and antigenic analysis have been performed on isolated pFc' fragments (Cγ3 homology region) from the major allotypic variants of human IgG. A comparison of the amino acid composition of Gm(a+x+) and Gm(a+x−) pFc' fragments showed less serine and more glycine in the Gm(a+x+) proteins. Two IgG2 pFc' fragments were shown to resemble IgG1 Gm(f) pFc' fragments in their amino acid compositions, except that there was more threonine and less alanine in the IgG2 fragments. This was also observed in two IgG3 Gm(g) proteins and may be the basis for the expression of a non b antigen. IgG3 fragments of both Gm(g) and Gm(b) allotypes showed six amino acid differences from the IgG1 subclass. There was more arginine, serine, and isoleucine and less histidine, lysine, and valine in both allotypes. In addition, analysis of a single Gm(b) pFc' fragment showed differences from the Gm(g) proteins; there was more phenylalanine, alanine, and proline and less tyrosine, threonine, and, possibly, aspartic

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1974.tb01238.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Human IgG is shown to inhibit the cytotoxic activity in vitro of human lymphocytes for chicken erythrocytes sensitized with rabbit antibodies. The inhibitory activity depends on the degree of aggregation of IgG, small complexes of 9 to 10 S being more inhibitory than monomeric molecules or heavy‐weight aggregates. For the immunoglobulin to be inhibitory, an intact Fc fragment is required. It is suggested that the inhibition is due to the binding of aggregated human IgG to lymphocytes needed in the cytotoxic reacti

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1974.tb01239.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

An IgGl type of protein with the genetic marker combination Gm(f), non a, and (x) has been described. The evidence from studies on isolated IgGl Fc fragments showed that the IgGl protein was of normal size. No Gm markers other than the three mentioned were found. Thus, there was no evidence for deletions or duplications giving rise to the unusual IgGl protein. In contrast, the origin of the unusual genetic marker combination appears to be a rare IgGl geneGmf,non a, x, probably due to an intragenic recombination at the IgGl cistron.

ISSN:0300-9475    

DOI:10.1111/j.1365-3083.1974.tb01240.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY