Comparative analysis of CD4-mediated down-regulation of T cell adhesion to B cells by flow cytometry and fluorescence microscopy.
Cytometry
; 23(1): 39-47, 1996 Jan 01.
Article
em En
| MEDLINE
| ID: mdl-14650439
ABSTRACT
We have previously shown by means of fluorescence microscopy that antigen-independent adhesion of resting CD4 T cells to EBV-transformed B cells can be down-regulated by ligand interaction with CD4. In this study we used flow cytometry analysis of conjugate formation to confirm these findings. No conjugates between resting CD4 + T cells and B cells were initially detected in the latter method, because flow velocity in the flow chamber induces hydrodynamic elongation forces which disrupt low-affinity conjugates. After forcing cell conjugation by low-speed centrifugation of T and B cells, conjugates became detectable although in smaller numbers than in fluorescence microscopy. "Forced" cell conjugates had similar characteristics to their unforced counterparts, i.e., 37 degrees C temperature dependency, mediation by LFA-1/ICAM-1 and CD2/LFA-3 pathways, and transiency. The latter characteristic was at least partly mediated by CD4/HLA class II interaction, since adhesion of CD4 + T cells to HLA class II-B cells was more stable. In addition, adhesion was inhibited by anti-CD4 antibodies but not by an HLA DR-derived peptide known to inhibit unforced CD4 + T cell adhesion to B cells. This blocking effect was partially reproduced by reducing the centrifugation time prior to the adhesion assay. These results show that a) CD4-mediated down-regulation of T cell adhesion can be observed by means of two different techniques, and b) analysis of cell-cell adhesion after increasing centrifugation times (and possibly speeds) is a simple way of measuring adhesion forces semiquantitatively.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Linfócitos B
/
Linfócitos T CD4-Positivos
/
Antígenos CD4
/
Regulação para Baixo
/
Adesão Celular
Limite:
Adult
/
Humans
Idioma:
En
Revista:
Cytometry
Ano de publicação:
1996
Tipo de documento:
Article