These data link minute amounts of aggregates with activation of the innate immune response, involving DC, resulting in T cell activation. Thus, when protein therapeutics with little or no clinical immunogenicity, such as trastuzumab, contain minute amounts of sub-visible aggregates, they are associated with significantly increased potential risk of clinical immunogenicity.

When a face is flashed to an observer, a large negative component is elicited in the occipitotemporal cortex at ϳ170 ms from the onset of presentation (N170). Previous studies have shown that the average N170 is correlated with conscious face perception; however, the single-trial mechanisms underlying such modulation remain largely unexplored. Here, we studied in human subjects the average and the single-trial N170 responses to briefly flashed faces, coupled with backward masking and varying degrees of Gaussian noise. In the average evoked responses we observed that, at fixed levels of noise, supraliminal faces exhibited significantly larger N170 amplitudes than subliminal faces. Moreover, the average N170 amplitude decreased with noise level both for the perceived and the nonperceived faces. At the single-trial level, the N170 amplitude was modulated by conscious recognition, which allowed predicting the subjects' perceptual responses above chance. In contrast, the single-trial N170 amplitudes were not modulated by the amount of noise and the effect found in the average responses was due to different latency jitters, as confirmed with latency-corrected averages. Altogether, these results suggest that conscious face perception is correlated with a boost in the activity of face-selective neural assemblies, whereas the stimulus uncertainty introduced by the added noise decreases the timing consistency (but not the amplitude) of this activation.

IntroductionRetroviral T-cell receptor (TCR) gene transfer is an attractive strategy by which large numbers of antigen-specific T cells can be generated for adoptive transfer. [1][2][3][4] One of the advantages of this technique is that it can be used to circumvent possible impairment of autologous T-cell responses against tumor associated antigens as it bypasses central tolerance. 5 In addition, the introduced TCR specificity can be targeted against poorly immunogenic antigens and high affinity TCR can be selected for transfer. 6 This method has recently seen success in the first clinical trial of TCR gene therapy, where MART1 specific T cells, generated by retroviral gene transfer, were adoptively transferred into patients with metastatic melanoma. The engineered T cells engrafted in 15 of 17 patients, 2 of whom demonstrated long term tumor regression. 7 T cells engineered to express CEA-specific TCR also induced a decrease in CEA levels in 3 patients with metastatic colorectal cancer, and regression of tumor metastases in 1 patient, but were associated with a severe colitis in all 3 patients. 8 The most promising results were seen after adoptive transfer of TCR transduced T cells specific for the NY-ESO-1antigen which resulted in clinical responses in synovial cell sarcoma and in melanoma. 9 As the density of TCR on the surface of cells affects their functional avidity, inefficient TCR expression may impair the success of TCR gene therapy. [10][11][12][13][14] Several different strategies have been developed to increase the expression of introduced ␣ and ␤ chains by reducing the mispairing with endogenous TCR chains. The strategies include replacing the human TCR constant domain with murine sequences, the introduction of an additional disulphide bond into the constant regions, and the production of hybrid molecules consisting of the extracellular portion of TCR chains fused to the intracellular CD3 domain. [15][16][17][18] TCR ␣ and ␤ chains form a complex with 4 invariant CD3 chains: ␥,␦,⑀ and . This complex formation is required in order for the TCR to be expressed on the cell surface, and for signal transduction on antigen recognition. TCR introduced by retroviral gene transfer are likely to be in competition with endogenous TCR molecules for CD3 chains. We used a murine model system to explore whether the co-transfer of TCR genes together with the genes encoding the ␥,␦,⑀ and chains of the CD3 complex can augment TCR expression. Two different TCR, with specificity for Wilms' Tumor antigen 1 (WT1) and influenza nucleoprotein, were used to demonstrate that CD3 is rate limiting for the expression of introduced TCR in gene modified T cells. Co-transduction of CD3 and TCR genes resulted in up to 16-20 fold increase in TCR surface expression and tetramer binding compared with transduction of TCR genes alone. The increase in TCR expression was associated with increased T-cell avidity leading to improved recognition of low concentration of peptide antigen. In vivo TCRϩCD3 co-transduced T cells eradicate tumors fa...

Defects in antitumor immune responses have been associated with increased release of prostaglandin E 2 (PGE 2 ) as a result of overexpression of cyclooxygenase (COX)-2 by tumors. In this report, we examine the effects of PGE 2 on antitumor CD8 + T-cell responses generated both by cross-presenting dendritic cells and by direct priming by tumor cells. Our data show that PGE 2 inhibits dendritic cell maturation, resulting in the abortive activation of naive CD8 + T cells, and is dependent on interleukin-10 production by dendritic cells.