{'fraction_non_alphanumeric': 0.029079159935379646, 'fraction_numerical': 0.03231017770597738, 'mean_word_length': 5.172757475083056, '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}}
Precursor abundance influences divergent antigen specific CD8+ T cell responses after Yersinia pseudotuberculosis foodborne infection

Primary infection of C57BL/6 mice with the bacterial pathogen Yersinia pseudotuberculosis elicits an unusually large H-2Kb-restricted CD8+ T cell response to the endogenous and protective bacterial epitope YopE69-77. To better understand the basis for this large response, the model OVA257-264 epitope was inserted into YopE in Y. pseudotuberculosis and antigen specific CD8+ T cells in mice were characterized after foodborne infection with the resulting strain. The epitope YopE69-77 elicited significantly larger CD8+ T cell populations in the small intestine, mesenteric lymph nodes (MLNs), spleen and liver between 7- and 30-days post infection, despite residing in the same protein and having a similar affinity for H-2Kb as OVA257-264. YopE-specific CD8+ T cell precursors were ~4.6 times as abundant as OVA-specific precursors in the MLNs, spleen and other lymph nodes of naïve mice, explaining the dominance of YopE69-77 over OVA257-264 at early infection times. However, other factors contributed to this dominance as the ratio of YopE-specific to OVA-specific CD8+ T cells increased between 7- and 30-days post infection. We also compared the YopE-specific and OVA-specific CD8+ T cells generated during infection for effector and memory phenotypes. Significantly higher percentages of YopE-specific cells were characterized as short short-lived effectors while higher percentages of OVA-specific cells were memory precursor effectors at day 30 post infection in spleen and liver. Our results suggest that a large precursor number contributes to the dominance and effector and memory functions of CD8+ T cells generated to the protective YopE69-77 epitope during Y. pseudotuberculosis infection of C57BL/6 mice.