{'fraction_non_alphanumeric': 0.029336078229541946, 'fraction_numerical': 0.019042717447246525, 'mean_word_length': 5.63481228668942, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Acute stimulation generates Tim‐3‐expressing T helper type 1 CD4 T cells that persist in vivo and show enhanced effector function

T‐cell immunoglobulin and mucin domain 3 (Tim‐3) is a surface receptor expressed by T helper type 1 (Th1) effector CD4 T cells, which are critical for defence against intracellular pathogens and have been implicated in autoimmune disease. Previous studies showed that Tim‐3 expression makes Th1 cells more susceptible to apoptosis and also marks functionally impaired T cells that arise due to chronic stimulation. However, other studies suggested that Tim‐3‐expressing Th1 cells do not always have these properties. To further define the relationship between Tim‐3 and Th1 cell function, we analysed the characteristics of Th1 cells that expressed Tim‐3 in response to brief stimulation in vitro or an acute viral infection in vivo. As expected, cultured CD4 T cells began expressing Tim‐3 during Th1 differentiation and secondary stimulation generated Tim‐3− and Tim‐3+ fractions that were separated and further analysed. When injected into naive mice, Tim‐3+ cells down‐regulated Tim‐3 and survived equally well compared with Tim‐3‐ cells. Further, Tim‐3− and Tim‐3+ Th1 cells had similar functional responses when transferred into naive mice that were subsequently infected with lymphocytic choriomeningitis virus (LCMV). Cultured Th1 cells that expressed Tim‐3 following T‐cell receptor stimulation had a greater capacity to express signature Th1 cytokines than their Tim‐3− counterparts and showed differential expression of genes that regulate CD4 T‐cell function. Consistent with these findings, Tim‐3+ Th1 cells generated in response to LCMV infection displayed augmented effector function relative to Tim‐3− cells. These results suggest that Tim‐3 expression by Th1 cells responding to acute stimulation can mark cells that are functionally competent and have an augmented ability to produce cytokines.