However, lung larvae are smaller at day 1 in WT FVB/N hosts and do not grow to the extent seen in the more permissive CBA/Ca host strain (77). Thus, IL-5 Tg

and WT FVB/N mice, which represent two quite different host models, are highly resistant in the early stages of primary N. brasiliensis infections. This is also analogous to the resistance seen during re-challenge of WT host strains susceptible to primary infections (69,75,76) and even with secondary exposure in the IL-5−/− and ΔdblGATA deletion mutant strains (69). In addition, for those larvae that are able to migrate to https://www.selleckchem.com/products/Lapatinib-Ditosylate.html the gut in resistant hosts, it is likely that damage mediated prior to arrival in the lungs render them less capable of maturation or colonization of the gut. Leucocytes are recruited into the skin within the first hour of a primary infection with N. brasiliensis

L3 (65), and this is initially dependent on activation of complement protein C3 via the alternative pathway and generation of the chemotactic factor C5a (75,78,79). The C5a receptor inhibitor PMX53 can inhibit both neutrophil and eosinophil recruitment in this model (75). C3 deposition on larvae and eosinophil recruitment and degranulation within the first 30 min of infection are reduced in complement factor B deficient/IL-5 Tg double mutant mice (75). Whilst C3 deposition on larvae is inhibited for at least 150 min in these animals, buy NSC 683864 at this stage of the infection complement is no longer essential for leucocyte recruitment, adherence to larvae or degranulation nor for larval

aggregation (75). Larval escape from the skin is enhanced in mice deficient in either factor B or C3, but this does not occur when C1q is absent (75). However, complement-deficient/IL-5 Tg double-mutant mice have few intestinal worms at day 6 pi. and those Afatinib chemical structure that are present produce almost no eggs. In addition, single-mutant mice deficient in complement proteins C1q, factor B or C3 are also highly resistant, with few parasites at either the lung or gut stage of secondary infections (75). These experiments, together with in vitro studies (78,79), show that although complement is important for leucocyte recruitment and attachment to N. brasiliensis larvae, even in the vital first few hours of infection, when larvae are attempting to escape from the skin, other factors can compensate. We investigated the possibility that eotaxin-1, a potent and largely eosinophil-specific chemotactic factor at sites of inflammation in the skin, lungs and gut (80–83), might compensate for loss of C5a activity. Eosinophil recruitment into the skin is diminished in both primary and secondary N. brasiliensis infections in eotaxin-1−/−/IL-5 Tg double mutants, but not in eotaxin−/− single mutants and is not essential for resistance (76). Experiments with multiple and simultaneous deletion of complement, eotaxin-1, eotaxin-2 and other chemokines or receptors are required.