広東住血線虫感染モルモットおよびラットにおける遅延型過敏症反応について

抄録

Guinea pigs and rats infected with the Taiwanese strain of Angiostrongylus cantonensis were monitored for the evolution of delayed hypersensitivity (DH) responses by assessing macrophage migration inhibitory factor (MIF) and delayed-type skin reactivity. These animals were also examined for the production of hemagglutinating (IHA) and precipitating antibodies. In guinea pigs, MIF response was consistently positive throughout 12 to 35 days post-infection. In fact, MIF production was shown by lymphoid cells from the cervical lymph nodes and spleen from infected animals. Delayed-type skin reactivity was correlated with the results of MIF assay. Contrarily, both IHA and precipitating antibodies were not detected in guinea pig sera throughout the course of infection. However, sera from both non-infected and infected guinea pigs yielded an immunologically non-specific precipitin band against A. cantonensis antigen. In rats, MIF response, as measured by the direct method, was variable throughout 6 to 77 days postinfection and the MIF results did not necessarily agree with the dermal reactivity. However, similar assay by the indirect method using normal guinea pig macrophages as indicator cells demonstrated that MIF activity could be detected in the cervical lymph node cells obtained from rats on days 7 and 37, whereas MIF from the mediastinal lymph node cells was first detected on day 29 and most frequently shown at later stages of infection. Precipitating antibody was first detected in sera from an infected rat 6 days postinfection while IHA antibody occurred first on day 34. Histologically, dermal reaction of the infected guinea pigs indicated a pronounced infiltration of mononuclear cells in the dermis. In rats, however, little cellular infiltration was present in the upper or midzone of the dermis, although massive infiltrative lesions were predominant in the subcutaneous fat and muscle and the deeper connectivd tissue. The present results suggest that DH is involved in immune responses of both guinea pigs and rats to A. cantonensis infection.