title: Brugia malayi: acquired resistance to microfilariae in BALB/c mice correlates with local Th2 responses.
abstract: The role of specific Th subsets in the regulation of acquired resistance to the filarial parasite Brugia malayi is not known. We examined pathologic and cytokine responses in filarial antigen-sensitized BALB/c mice inoculated intraperitoneally with live microfilariae. Animals immunized three times with soluble microfilarial antigen demonstrated accelerated clearance of live parasites (12 +/- 5% of parasites recovered from the peritoneal cavity 4 days after inoculation vs 57 +/- 6% in controls, P < 0.001). Elimination of microfilariae by immunized mice was associated with local eosinophilia (1.5 x 10(7) eosinophils/ml peritoneal wash fluid compared with 2 x 10(5) eosinophils/ml in unimmunized animals), development of local eosinophil-containing granulomas, and elevated serum IgE levels (7.0 +/- 1.4 vs 2.1 +/- 0.9 micrograms/ml in controls, P < 0.01). CD4+ cells from the site of parasite challenge produced Th2-associated cytokines exclusively (IL-4 and IL-5, not IFN-gamma and IL-2) in response to Brugia antigen, whereas spleen and lymph node cells produced both Th1- and Th2-associated cytokines. Mice immunized a single time with microfilarial antigen did not clear parasites in this time, and peritoneal exudate cells from these animals produced IFN-gamma but not IL-5. These results indicate that acquired resistance to B. malayi microfilariae in mice is associated with induction of a Th2 and not a Th1 response at the site of parasite elimination.
authors.affiliation: Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio.
authors.forename: E
authors.initials: E
authors.lastname: Pearlman
authors.forename: W K
authors.initials: WK
authors.lastname: Kroeze
authors.forename: F E
authors.initials: FE
authors.lastname: Hazlett
authors.forename: S S
authors.initials: SS
authors.lastname: Chen
authors.forename: S D
authors.initials: SD
authors.lastname: Mawhorter
authors.forename: W H
authors.initials: WH
authors.lastname: Boom
authors.forename: J W
authors.initials: JW
authors.lastname: Kazura
mesh_terms: D000818:Animals; D000947:Antigens, Helminth / Q000276:immunology; D017178:Brugia malayi / Q000276:immunology*; D005368:Filariasis / Q000276:immunology*; D007110:Immunity, Active; D007114:Immunization; D007371:Interferon-gamma / Q000096:biosynthesis; D007376:Interleukin-2 / Q000096:biosynthesis; D015847:Interleukin-4 / Q000096:biosynthesis; D015848:Interleukin-5 / Q000096:biosynthesis; D007378:Interleukins / Q000096:biosynthesis*; D008198:Lymph Nodes / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008842:Microfilariae / Q000276:immunology; D013154:Spleen / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology*
chemical_list: D000947:Antigens, Helminth; D007376:Interleukin-2; D015848:Interleukin-5; D007378:Interleukins; D015847:Interleukin-4; D007371:Interferon-gamma