Increase in tumour-infiltrating lymphocytes with regulatory T cell immunophenotypes and reduced zeta-chain expression in nasopharyngeal carcinoma patients.

The pathological significance of the mechanisms of tumour immune-evasion and/or immunosuppression, such as loss of T cell signalling and increase in regulatory T cells (T(regs)), has not been well established in the nasopharyngeal carcinoma (NPC) microenvironment. To evaluate the T(reg) immunophenotypes in tumour-infiltrating lymphocytes (TILs), we performed a double-enzymatic immunostaining for detection of forkhead box P3 (FoxP3) and other markers including CD4, CD8, and CD25 on 64 NPC and 36 non-malignant nasopharyngeal (NP) paraffin-embedded tissues. Expression of CD3 zeta and CD3 epsilon was also determined. The prevalence of CD4(+)FoxP3(+) cells in CD4(+) T cells and the ratio of FoxP3(+)/CD8(+) were increased significantly in NPC compared with those in NP tissues (P < 0.001 and P = 0.025 respectively). Moreover, the ratio of FoxP3(+)/CD25(+)FoxP3(-) in NPC was significantly lower than that in NP tissues (P = 0.005), suggesting an imbalance favouring activated phenotype of T cells in NPC. A significant negative correlation between the abundance of FoxP3(+) and CD25(+)FoxP3(-) cells (P < 0.001) was also identified. When histological types of NPC were considered, a lower ratio of FoxP3(+)/CD25(+)FoxP3(-) was found in non-keratinizing and undifferentiated carcinomas. Increased CD4(+)FoxP3(+)/CD4(+) proportion and FoxP3(+)/CD8(+) ratio were associated with keratinizing squamous cell carcinoma. A reduced expression of CD3 zeta in TILs was found in 20.6% of the NPC tissues but none of the NP tissues. These data provide evidence for the imbalances of T(reg) and effector T cell phenotypes and down-regulation of signal-transducing molecules in TILs, supporting their role in suppression of immune response and immune evasion of NPC.

Effect of incorporating sodium molybdate in the form of salt lick or in mixed ration on growth and performance of sheep fed palm kernel cake.

The objective of the present experiments are to determine if sheep could safely consume high amount of PKC in their diets and if sheep's consumption of PKC require a chelating agent to tie up the high copper level in PKC to protect it against toxicity. Two experiments were carried out. Experiment 1, with four treatment groups of animals, using from 30 to 100% PKC, mixed with other feed ingredients except minerals. Mineral mixtures were separately mixed with Sodium Molybdate, acting as the chelating agent, and the mineral was offered in separate feed troughs ad.libitum, in the pens for each animal group. Although all groups gave high ADG, the animals in the 100% group had high copper in their blood, which were above4 the normal physiological level at the end of the experimental duration of three months. Three animals from this group died and their liver copper contents were very high. The groups fed up to 72% PKC in their ration did not show any significant elevation of copper or toxicity. Sheep fed similar proportions of ingredients in experiment 2, but with Molybdate incorporated together into all the four similar rations as in experiment 1, did not show any signs of toxicity or elevated blood copper. The animals in all groups produced high ADG. The experiment proved that sheep can take up to 100% PKC in their diet, but a chelating agent must be incorporated into the feed to ensure its sufficient uptake to protect it against toxicity. Giving Molybdate separately from the feed would not ensure sufficient intake of the chelating agent voluntarily. This would result in copper toxicity in the animals.