{'fraction_non_alphanumeric': 0.027767065175472425, 'fraction_numerical': 0.014654839953721558, 'mean_word_length': 5.161520190023753, 'pattern_counts': {'":': 0, '<': 1, '<?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}}
Production of an Eosinophil Migration Factor in Lymphocytes of Mitogen‐Treated Chick Embryos

An eosinophil chemotactic factor has been claimed to have been derived from lymphocytes, the complement system and mast cells (1,2). Accumulation of eosinophils and monocytes in lymphoid organs has been demonstrated in vivo in chick embryos by antigenic or mitogenic stimulation (4,5). Leukocyte accumulation reported by us suggested the in vivo release of a chemotactic factor from embryonic lymphocytes cells (4, 5). The evidence presented here shows that embryonic lymphocytes of chickens, after stimulation with concanavalin A (con A) or lipopolysaccharide (LPS), can also release the eosinophil chemotactic factor in vitro. White Leghorn chickens and embryos were used in this study. Lymphocytes of the bursa, spleen or thymus were obtained from stimulated chick embryos on day 20 of incubation, 2 days after mitogenic stimulation with either con A or LPS in ovo, and were separated by Ficoll diatrizoate (3, Bionetics; cell purity <90%). Eosinophils taken from lymphoid organs of embryos or adult chickens were separated by Ficoll diatrizoate, following a discontinuous Ficoll gradient, from other cells, such as erythrocytes or lymphocytes (6; cell purity was 71 to 87%). The estimation of chemotaxis for eosinophils was determined by a modification of the method of Nakayama et al (7) as follows: Lymphocytes obtained from stimulated embryos were suspended in RPMI 1640 medium, and 50,al of the suspension (108 cells) was placed in the central well (diameter, 2 mm; distance between wells, 2 mm) of an agarose plate. Eosinophils obtained from various lymphoid organs were placed in the outer wells and cultured at 37 C in a humidified wet box. As shown in Table 1, there is no difference in the estimation of eosinophil mobility by our modified method and by the original method of Nakayama et al (7). The culture supernatant fluids of lymphocytes from mitogen-stimulated embryos were also examined for eosinophil migration. At the end of the culture period, the lymphocytes were separated by centrifugation and the supernatant fluids were stored at -20 C before use. Eosinophil migration was expressed as the migration index as proposed by Nakayama et al (7). This was calculated by the formula migration index-e directional migration/random migration. As shown in Fig. 1, embryonic lymphocytes treated in ovo with con A enhanced eosinophil migration. The migration responses of eosinophils were usually observed after 3 hr of culture and higher responses were detected after longer culture