Immunohistowax processing, a new fixation and embedding method for light microscopy, which preserves antigen immunoreactivity and morphological structures: visualisation of dendritic cells in peripheral organs
- Bernard Pajak1,
- Thibaut De Smedt2,
- Véronique Moulin1,
- Carl De Trez1,
- Roberto Maldonado-López1,
- Georgette Vansanten1,
- Emmanuel Briend3,
- Jacques Urbain1,
- Oberdan Leo1,
- Muriel Moser1
- 1The Département de Biologie Moléculaire, Université Libre de Bruxelles, B-1640 Rhode-Saint-Genése, Belgium
- 2Immunex Corporation, Seattle, Washington 98101, USA
- 3Cantab Pharmaceuticals Research LDT, Cambridge CB4 OWG, UK
- Dr Pajak, Laboratoire de Physiologie Animale, Institut de Biologie et Médecine Moléculaire, Université Libre de Bruxelles, Rue des Profs Jeener et Brachet, 12, B-6041 Gosselies, Belgium email: bpajak{at}dbm.ulb.ac.be
- Accepted 20 January 2000
Abstract
Aims—To describe a new fixation and embedding method for tissue samples, immunohistowax processing, which preserves both morphology and antigen immunoreactivity, and to use this technique to investigate the role of dendritic cells in the immune response in peripheral tissues.
Methods—This technique was used to stain a population of specialised antigen presenting cells (dendritic cells) that have the unique capacity to sensitise naive T cells, and therefore to induce primary immune responses. The numbers of dendritic cells in peripheral organs of mice either untreated or injected with live Escherichia coli were compared.
Results—Numbers of dendritic cells were greatly decreased in heart, kidney, and intestine after the inoculation of bacteria. The numbers of dendritic cells in the lung did not seem to be affected by the injection of E coli. However, staining of lung sections revealed that some monocyte like cells acquired morphological and phenotypic features of dendritic cells, and migrated into blood vessels.
Conclusions—These observations suggest that the injection of bacteria induces the activation of dendritic cells in peripheral organs, where they play the role of sentinels, and/or their movement into lymphoid organs, where T cell priming is likely to occur.
