Antibody to interleukin 5 prevents blood and tissue eosinophilia but not liver trapping in murine larval toxocariasis

Abstract

Mice previously sensitized by infective-stage larvae of the canine nematode, Toxocara canis, trap large numbers of challenge larvae within the liver; trapped larvae are found within eosinophilic granulomas. To investigate the role of eosinophils in this phenomenon we examined larval trapping in mice depleted of blood and tissue eosinophils by treatment with a monoclonal antibody (MoAb) (TRFK-5) produced against recombinant murine interleukin 5 (rmIL-5). Control mice received either an isotype-matched control MoAb or PBS. On day 0 test mice were given a sensitization dose of 125 infective T. canis eggs. Test and challenge control mice received 500 infective eggs on day 28. All mice were killed on day 42 and larval numbers within the liver were determined. Liver samples were also collected for histopathological and morphometric examination. When compared to test mice treated with PBS or the isotype control, the level of circulating eosinophils in anti-IL-5-treated test mice was reduced by 94-96% on days 14 and 27, 99% on day 35, and 100% on day 42; the level of tissue eosinophils within liver granulomas on day 42 was reduced by 92-95%. The total area of inflammation within the liver was similar among all test groups. However, the highly eosinophilic infiltrates, present in control sections, were replaced in anti-IL-5-treated mice by lymphocytes, macrophages, and foreign-body giant cells. No difference was found in larval trapping between antibody-treated groups. These findings suggest that the eosinophil is not necessary for liver trapping in murine larval toxocariasis.

Modulation of eosinophil generation and migration by Mangifera indica L. extract (Vimang®)

“…Several studies have shown that this infection induces an IL-5-dependent systemic eosinophilia [26,27] and mimics the features observed in asthma, such as high levels of serum IgE [28] and airways inflammation [29,30]. Our findings demonstrated that Vimang® selectively suppressed eosinophil migration to bronchoalveolar space and peritoneal cavity and this inhibition was associated with IL-5 decrease in blood and inhibition of eotaxin production in lung tissue.…”

Eosinophilia and intracranial worm recovery in interleukin-5 transgenic and interleukin-5 receptor α chain-knockout mice infected with Angiostrongylus cantonensis

“…Hence, mice infected with a variety of helminth parasites were treated with anti-IL-5 mAb. However, anti-IL-5 mAb treatment did not aect worm recovery from the primary infection (Sher et al 1990a) and protective immunity in mice infected with Schistosoma mansoni (Sher et al 1990b), S. japonicum (Cheever et al 1991), Toxocara canis (Parsons et al 1993), Heligmosomoides polygyrus (Finkelman et al 1991), and Trichinella spiralis (Herndon and Kayes 1992). In contrast, anti-IL-5 mAb treatment abolished the protective immunity against lung stage worms from challenge infection with Strongyloides venezuelensis (Korenaga et al 1991) and also repealed the innate resistance of mice to A. cantonensis .…”

Role of IL-5 in Innate and Adaptive Immunity to LarvalStrongyloides stercoralisin Mice

“…These findings confirm previous reports in which elimination of IL-5 by mAb treatment (TRFK-5) was shown to abrogate S. stercoralis larval killing in immunized BALB/cByJ mice (18). In contrast, many other groups have found no role for IL-5 in protection from other parasites, however measurable levels of eosinophils could still be found in the peripheral blood, cutaneous tissues, cerebrospinal fluid, liver, and lungs of TRFK-5-treated mice (12,35,(37)(38)(39)(40)(41)(42)(43). Thus, the eosinophils still present in mouse tissues after mAb treatments might still have been able to mediate systemic L3 destruction.…”