Angiostrongylus cantonensis: phospholipase in nonsensitized and sensitized rats after challenge

Abstract

Rats given an initial infection with Angiostrongylus cantonensis had moderately elevated phospholipase B activity in the lungs at 8 and 15 days after challenge, and greatly elevated levels were evident at 35, 43, and 49 days. In the brain, the values were elevated at 15 through 35 days. These periods of increased activity in the lungs and brain coincided with the migration patterns of the third-stage larvae and the adult worms in this host. The elevated enzyme levels also were correlated with increased numbers of eosinophils in the bone marrow at 8 and 15 days and again at 36, 43, and 49 days after infection. Similarly infected rats exhibited leukocytosis at 1 through 10 weeks of observation after challenge, and striking eosinophilia at 1, 7, 8, and 9 weeks. Rats reinfected after being blended, the snail tissue was digested in a 1% pepsin-1% HCl solution for 1 h at 37"C; the mixture was lightly centrifuged, and the sediment was resuspended in a gelatin-broth medium. After adjust-13 on August 5, 2020 by guest http://iai.asm.org/ Downloaded from

Phospholipase B in the Brains and Meninges of Nonsensitized and Sensitized Rats After Challenge with Angiostrongylus cantonensis

“…As shown in Table 1, the data for the brain tissue reveal a rather clear pattern of rising phospholipase B values beginning on day 8 and reaching a peak at days 30 to 31 of infection. This time interval coincides with the maturation phase of the parasite in the brain, whereas the ensuing phase of migration to the lungs, beginning about the fifth week after infection, precedes the sharp decline of the phospholipase levels shown by the readings at day 45. These results are in agreement with the findings of a previous study (18), wherein a similar pattern and an overall similar range of experimental values had been determined. The same conclusion applies to the reinfected group exhibiting an almost immediate (day 1) rise in .~.…”

“…The occurrence of such a response in a tissue normally almost devoid of the enzyme and its carrier cells is ofspecial interest, since it provides a clear demonstration that accumulation of phospholipase B is an integral component of the tissue reaction causally and temporally related to invasion by A. cantonensis. The direct demonstration of eosinophils as the phospholipase B-carrying cells is in keeping with the earlier demonstration of an infection-related bone marrow eosinophilia in rats infected with this parasite (18).…”

“…As for previous studies, wherein the relation between eosinophils, phospholipase B, and helminth infection was investigated (11,12,16,18), two basic questions require consideration. The first, concerning the link between eosinophil mobilization and infection, has been clarified by the work of Basten et al (2,3), who have shown the role of the lymphocytes in mediating the proliferating stimulus to the bone marrow and in determining the earlier and magnified response upon reintroduction of the causative agent.…”

“…A previous report from our laboratories (18) has shown that rat tissues harboring Angiostrongylus cantonensis exhibit abnormally high levels of phospholipase B (EC 3.1.1.5) in the organs invaded by the parasite, including the brain and lungs. The elevated enzymatic activity of brain homogenates is a point of particular interest because the brain as a whole contains normally only negligible amounts of phospholipase B and a correspondingly very small number of eosinophilic leukocytes, which, in rats, are the carrier and principal source of the enzyme in all tissues studied thus far, i.e., intestine, lung, spleen, uterus, bone marrow, and peritoneal fluid (13)(14)(15).…”

Lung lysophospholipase activity in specific-pathogen-free rats infected with Pasteurella pneumotropica or Mycoplasma pulmonis

“…Ottolenghi et al (12) infected rats with the pneumonic helminth Angiostrongylus cantonensis and demonstrated elevated lysophospholipase activity levels in the lung tissues. Increased lysophospholipase activity correlated in time with inflammation of the lungs, worms in the tissue, and increased numbers of eosinophils in the bone marrow and lung tissues.…”