{'fraction_non_alphanumeric': 0.02909090909090909, 'fraction_numerical': 0.01, 'mean_word_length': 5.592814371257485, '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}}
I‐Region‐coded Products Expressed on Both Macrophages and Thymus Epithelium Influence T‐Cell Activities

I‐region‐coded products expressed on the surface of both macrophages (Mph) and thymus epithelium were shown to restrict T‐cell activities at the level of antigen recognition and determination of the T‐cell repertoire. Thus keyhole limpet haemocyanin (KLH)‐pulsed Mph could elicit a delayed‐type hypersensitivity response in a KLH‐sensitized mouse only when the Mph and the sensitized mouse were compatible at the I‐A region of the major histocompatibility complex. Also, experiments with thymus‐grafted chimaeras showed that I‐region compatibility between the thymus of the cell donor and the reticuloendothelial system of the recipient was essential for successful transfer of the DTH reaction. Thus, F1 T cells derived from stem cells differentiating in a P1 thymus graft, where F1 parents (P1 and P2) differed only at defined regions of the H‐2 complex, could always transfer sensitivity to P1 mice. However, successful transfer to P2 mice was possible only if P1 and P2 were H‐2I‐compatible.