Immunological studies on cerebrospinal fluid eosinophilia and the possible roles of eosinophils in angiostrongyliasis cantonensis

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The results obtained are summarized as follows: 1. Systemic eosinophilia; (1) Lymphoid cells were harvested from the spleen and cervical lymph-nodes of AF-nu/+ mice infected with Angiostrongylus cantonensis for 12 to 18 days. Three separate intravenous injections of 5 X 10^7 cells (obtained at days 12, 15 and 18) were given to recipient AF-nu/nu mice. These mice provoked significant peripheral eosinophilia from days 6 to 15 after final injection. (2) Mediastinal lymph-node cells were harvested from Wistar rats (permissive host) at 30 days postinfection, and stimulated with the antigen of 1st stage larvae. A conditioned medium thus prepared was found to be effective for in vitro survival of medullary eosinophils. (3) The splenic and cervical lymph-node cells were obtained from ddY mice (nonpermissive host) at 5, 12 and 17 days postinfection, and cultured with young adult worm antigen for harvesting a conditioned medium. This conditioned medium was highly effective in in vitro eosinopoie … More sis or survival of eosinophils. The lymphoid cells from infected mice can also release such a factor(s) into media without antigenic stimulation.2. Local eosinophilia; (1) An eosinophil chemotactic factor (ECF) derived from the young adult worms of A. cantonensis was resistant to both heating and pronase digestion, but sensitive to periodate treatment, with an approximate molecular weight of 16900. (2) Guinea-pig eosinophils possess receptors for ECFs of both young adult worms and 1st-stage larvae, whereas rat eosinophils have receptors for ECF of only Lst-stage larvae. (3) Eosinophil receptors for ECF of young adult worms were destroyed by pronase digestion but resynthesized during 24 hrs of cell cultivation.3. Roles of cerebrospinal fluid (CSF) eosinophils; (1) Degranulative changes were noted in CSF eosinophils from infected guinea-pigs. (2) CSF eosinophils stimulated by young adult worm antigen generated O_2 ・ These findings are suggestive of the possible association of eosinophils with the killing of intracranial worms in nonpermissive hosts. (3) Demyelinative changes and the partial loss of Purkinje cells were noted in the cerebellar tissues of infected mice, suggesting possible involvement of CSF eosinophils in the damages of central nervous system.4. Possible roles of eosinophils in the protective immunity in permissive rat host; Rats (ACI, AUG and Wistar) received a sensitizing infection developed significant protective immunity against challenge infection at 6 weeks later. Young abult worms transferred into the peritoneal cavity of these sensitized rats were found infiltrated predominantly with eosinophils and most of the eosinophils were degranulative. Less