title: Perforin expression in lymphocytes infiltrated to human colorectal cancer.
abstract: Perforin (PFP) is a cytotoxic protein released from killer cells. PFP immunoreactivity in human peripheral blood lymphocytes (PBL) and tumour infiltrating lymphocytes (TIL) was investigated immunocytochemically with the aid of an anti-PFP monoclonal antibody. PFP was detected in the cytoplasm of 10% of PBL. We performed a double staining of PFP+ cells with Leu11b/CD16, Leu2a/CD8, or Leu3a/CD4 and showed that PFP was produced by 9% of CD8+ cells and 18% of CD16+ cells but not by CD4+ cells. In 28 colorectal cancer tissues, PFP immunoreactivity was observed in the lymphocytes infiltrating to the tumour stroma. The PFP+ cells were most numerous in Dukes A and decreased in number according to the progression of tumours. The PFP+ cells in TIL exhibited the same phenotypes as those in PBL but the PFP+ cells were more numerous in CD8+ cells than in CD16+ cells at all stages. This study represents the first evidence that PFP is mainly secreted from CD8+ cells in tumour tissues. It is hypothesised that the decrease in the number of PFP+ cells in accordance with tumour progression may reflect the suppression of the hosts local immunity.
authors.affiliation: Department of Surgery II, Osaka University Medical School, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Nakanishi
authors.forename: T
authors.initials: T
authors.lastname: Monden
authors.forename: H
authors.initials: H
authors.lastname: Morimoto
authors.forename: T
authors.initials: T
authors.lastname: Kobayashi
authors.forename: T
authors.initials: T
authors.lastname: Shimano
authors.forename: T
authors.initials: T
authors.lastname: Mori
mesh_terms: D000911:Antibodies, Monoclonal; D015703:Antigens, CD / Q000032:analysis; D015179:Colorectal Neoplasms / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D016131:Lymphocyte Subsets / Q000276:immunology; D008214:Lymphocytes / Q000378:metabolism*; D008562:Membrane Glycoproteins; D008565:Membrane Proteins / Q000096:biosynthesis*; D054353:Perforin; D052899:Pore Forming Cytotoxic Proteins
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D052899:Pore Forming Cytotoxic Proteins; D054353:Perforin