ABSTRACT
The in situ function of tumour-infiltrating leukocytes (TIL) in human colorectal adenocarcinoma (CRC) is unclear. Local cytokine expression probably regulates the anti-tumour immune response and tumour immune surveillance. We examined the distribution of mRNA for IFN-gamma, TNF-alpha, IL-10 and IL-4 in TIL, and tumour cells freshly isolated from 21 surgically removed primary CRC, using a semiquantitative RT-PCR. Lamina propria-infiltrating leukocytes (LPL) and epithelial cells from normal colon mucosa of 10 CRC patients served as negative controls. Median levels of IFN-gamma and TNF-alpha mRNA were higher in TIL than LPL (p = 0.0002 and 0.0001). IL-10 mRNA was generally observed in TIL and LPL, but no or very small amounts of IL-4 transcripts were detected in TIL and LPL. TNF-alpha and IL-10 mRNA were more abundant in colorectal tumour cells than in the normal epithelial cells (p = 0.0136 and 0.0036). The number of IFN-gamma transcripts in TIL correlated negatively (p = 0.039) and the number of TNF-alpha transcripts in tumour cells correlated positively with the Dukes' stages (p = 0.0147). Our results suggest that TIL are characterized by a type 1 (Th1/Tc1-like) pattern of cytokine expression and function as T cells (and macrophages) in the local, cell-mediated anti-tumour immune response in early stages of CRC. Changes in IFN-gamma and TNF-alpha mRNA in TIL and tumour cells could be related to tumour progress (e.g. by T cell anergy) or forming of metastases, respectively.
Subject(s)
Adenocarcinoma/genetics , Colorectal Neoplasms/genetics , Cytokines/genetics , Lymphocytes, Tumor-Infiltrating/metabolism , RNA, Messenger/genetics , Adenocarcinoma/pathology , Adult , Aged , Aged, 80 and over , Base Sequence , Colorectal Neoplasms/pathology , DNA Primers , Female , Humans , Male , Middle Aged , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
The bioavailability of polystyrene particles (1 microns) labelled with FITC (3M Company, Düsseldorf) was tested in rats after enteral administration. Since macromolecules and particles are preferentially transported in the lymph, the number of particles was counted in the lymph of the thoracic duct over a 6 h period. Uptake in young rats (6-8 wk) was compared with that in 5 and 9 mo animals. Young animals absorbed only 87 particles whereas a marked increase in the uptake of particles was observed in 5 mo animals (up to 775) but there was a decrease to 518 particles in older animals (9 mo). This number of particles is the total number of the entire output of the thoracic duct lymph over a 6 h period. In individual animals this number showed a considerable fluctuation over time. The volume of the collected lymph fluid was relatively constant (3.5 +/- 0.5 ml) in all animals. The bioavailability of the particles in the lymph was also influenced by the applied dose of particles. After intraduodenal administration of 3.7 x 10(5) particles only 18 particles could be found in the lymph. Increasing the dose to 3.7 x 10(7) particles raised the number of particles in the lymph to 116. The highest dose of 3.7 x 10(9) was correlated with the greatest absorption, 775 particles being found in the lymph. The uptake of particles from the gut thus depends on different factors including the age of the animal and the number of applied particles.