PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 9742527

[Host reactions affect cancer progression].

H Ohtani
View original source ↗Export metadata ↓

Abstract

The tumor-host relationship is one of the factors determining the biological behavior of malignant tumors. In colon cancer, the costimulatory molecules B7-1/B7-2 are expressed by macrophages distributed along the invasive margin (tumor-host interface). T-lymphocytes are also distributed in the same area with direct cell-to-cell contact with these B7+ macrophages. The distribution of these macrophages is lower in colon cancer patients with liver metastasis. CD8+ T cells are distributed within cancer cell nests of colon cancer. The survival rate of patients with higher levels of these T-cells is favorable. Our data suggest the presence of a host immune reaction by macrophages and T-lymphocytes, which diminishes the aggressiveness of cancer cells. As shown in the present paper, comparative analysis is required to assess the biological behavior of cancer.

Explore related subjects

Antigen PresentationAntigens, CDB7-1 AntigenB7-2 AntigenCD8-Positive T-LymphocytesColonic NeoplasmsHumansMacrophagesMembrane GlycoproteinsNeoplasm InvasivenessNeoplasm MetastasisPrognosisJournal ArticleReview

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

H Ohtani. 1998. [Host reactions affect cancer progression].. https://pubmed.ncbi.nlm.nih.gov/9742527/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2007

Immune surveillance via self digestion.

The adaptive immune system is orchestrated by CD4+ T cells. These cells detect peptides presented on Major Histocompatibility Complex (MHC) class II molecules, which are loaded in late endosomes with products of lysosomal proteolysis. One pathway by which proteins gain access to degradation in lysosomes is macroautophagy. We recently showed that constitutive macroautophagy can be detected in cells relevant for the immune system, including dendritic cells. In these antigen presenting cells, autophagosomes frequently fused with MHC class II antigen loading compartments and targeting of Influenza matrix protein 1 (MP1) for macroautophagy enhanced MHC class II presentation to MP1-specific CD4+ T cell clones up to 20 fold. Our findings indicate that macroautophagy is a constitutive and efficient pathway of antigen delivery for MHC class II presentation. We suggest that this pathway samples intracellular proteins for immune surveillance and induction of tolerance in CD4+ T cells, and could be targeted for improved MHC class II presentation of vaccine antigens.

Antigen Presentation↗
PubMed2007

Antigens and autophagy: the path less travelled?

The Epstein-Barr virus (EBV)-coded nuclear antigen (EBNA) 1, a latent cycle protein endogenously expressed in EBV-transformed B lymphoblastoid cell lines (LCLs), is reported to be processed for CD4(+) T cell recognition by an intracellular route involving antigen delivery to the endosome/lyosome (MHC class II loading) compartment via macroautophagy. In contrast we find that, in the same cell type, two other virus-coded nuclear proteins of the latent cycle, EBNA2 and EBNA3C, are processed by a different route that is unaffected by autophagy inhibition. This involves the intercellular transfer of an antigenic moiety, detectable in cell-free culture supernatants, and its uptake and processing as exogenous antigen by neighboring cells. The process is cumulative and leads over several days of LCL culture to high levels of CD4+ T cell epitope display. The presentation of certain EBV lytic cycle proteins to CD4+ T cells has also recently been found to involve a similar intercellular antigen transfer. It becomes important to know why, even in the same cell type, some antigens but not others appear to access the MHC class II presentation pathway by autophagy.

Antigen Presentation↗
PubMed2007

TLR ligands differentially affect uptake and presentation of cellular antigens.

Dendritic cells (DCs) have the unique ability to efficiently present T-cell epitopes from exogenous antigens on MHC class I molecules, a process called cross-presentation. In our study we demonstrate that stimulation of monocyte-derived DCs with Toll-like receptor (TLR) ligands differentially affects the uptake and cross-presentation of cellular antigens. Activation of DCs with TLR3 or TLR4 but not with TLR2 or TLR7/8 ligands inhibited phagocytosis of apoptotic tumor cells and resulted in a reduced cross-presentation of pp65-derived T-cell epitopes on MHC class I molecules upon engulfment of cytomegalovirus (CMV)-infected fibroblasts. These results have an important impact on the understanding of the interactions between the immune system and pathogens and the development of vaccination strategies to treat malignant diseases.

Antigen Presentation↗