{'fraction_non_alphanumeric': 0.028409090909090908, 'fraction_numerical': 0.002840909090909091, 'mean_word_length': 5.467889908256881, '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}}
Natural immunity in the oncornavirus-infected mouse.

BALB/cfC3H females neonatally infected with mammary tumor virus (MTV) possess spleen cells capable of significant cytotoxic activity against target MTV-induced mammary tumor cells in microcytotoxicity assay. Spleen cells from supposedly MTV-free BALB/c females are also specifically reactive, as a result of horizontal transmission of MTV antigens. No quantitative differences in reactivity exist between females not susceptible to the development of mammary tumors (BALB/c) and those that may develop or already have tumors (multiparous BALB/cfC3H). However, there are qualitative differences in response between those at risk and those not at risk.