The entomopathogenic fungus Beauveria bassiana and its insect host target represent a model system with which to examine host–pathogen interactions. Carbohydrate epitopes on the surfaces of fungal cells play diverse roles in processes that include adhesion, non-self recognition and immune invasion with respect to invertebrate hosts. B. bassiana produces a number of distinct cell types that include aerial conidia, submerged conidia, blastospores and haemolymph-derived cells termed in vivo blastospores or hyphal bodies. In order to characterize variations in the surface carbohydrate epitopes among these cells, a series of fluorescently labelled lectins, combined with confocal microscopy and flow cytometry to quantify the response, was used. Aerial conidia displayed the most diverse lectin binding characteristics, showing reactivity against concanavalin A (ConA), Galanthus nivalis (GNL), Griffonia simplicifolia (GSII), Helix pomatia (HPA), Griffonia simplicifolia isolectin (GSI), peanut agglutinin (PNA), Ulex europaeus agglutinin I (UEAI) and wheatgerm agglutinin (WGA), and weak reactivity against Ricinus communis I (RCA), Sambucus nigra (SNA), Limax flavus (LFA) and Sophora japonica (SJA) lectins. Lectin binding to submerged conidia was similar to that to aerial conidia, except that no reactivity against UEAI, HPA and SJA was noted, and WGA appeared to bind strongly at specific polar spots. In contrast, the majority of in vitro blastospores were not bound by ConA, GNL, GSII, GSI, SNA, UEAI, LFA or SJA, with PNA binding in large patches, and some polarity in WGA binding noted. Significant changes in lectin binding also occurred after aerial conidial germination and in cells grown on either lactose or trehalose. For germinated conidia, differential lectin binding was noted between the conidial base, the germ tube and the hyphal tip. Fungal cells isolated from the haemolymph of the infected insect hosts Manduca sexta and Heliothis virescens appeared to shed most carbohydrate epitopes, displaying binding only to the GNL, PNA and WGA lectins. Ultrastructural examination of the haemolymph-derived cells revealed the presence of a highly ordered outermost brush-like structure not present on any of the in vitro cells. Haemolymph-derived hyphal bodies placed into rich broth medium showed expression of several surface carbohydrate epitopes, most notably showing increased PNA binding and strong binding by the RCA lectin. These data indicate robust and diverse production of carbohydrate epitopes on different developmental stages of fungal cells and provide evidence that surface carbohydrates are elaborated in infection-specific patterns.
Interleukin (IL)-17 is one of the critical inflammatory cytokines that plays a direct role in development of Sjögren’s syndrome (SjS), a systemic autoimmune disease characterized by a progressive chronic attack against the exocrine glands. The expression levels of IL-17 are correlated with a number of essential clinical parameters such as focus score and disease duration in human patients. Significantly immunological differences of Th17 cells were detected at the onset of clinical disease in female SjS mice compared to males. To further define the role of IL-17 in SjS and elucidate its involvement in the sexual dimorphism, we examined the systemic effect of IL-17 by genetically ablating Il-17 in the C57BL/6.NOD-Aec1Aec2, spontaneous SjS murine model. The results indicate that IL-17 is a potent inflammatory molecule in the induction of chemoattractants, cytokines, and glandular apoptosis in males and females. Elimination of IL-17 reduced sialadenitis more drastically in females than males. IL-17 is highly involved in modulating Th2 cytokines and altering autoantibody profiles which has a greater impact on changing plasma cells and germinal center B cell populations in females than males. The result supports a much more important role for IL-17 and demonstrates the sexual dimorphic function of IL-17 in SjS.
Insects interact with the surrounding environment via chemoreception, and in social insects such as ants, chemoreception functions to mediate diverse behaviors including food acquisition, self/non-self recognition, and intraspecific communication. The invasive red imported fire ant, Solenopsis invicta, has spread worldwide, displaying a remarkable environmental adaptability. Odorant binding proteins (OBPs) are chemical compound carriers, involved in diverse physiological processes including odor detection and chemical transport. S. invicta contains a highly divergent 17-member OBP gene family, that includes an ant-specific expansion and the social organization implicated Gp-9 (OBP3) gene. A systematic gene expression analysis of the SiOBP repertoire was performed across social caste (workers, male and female alates), tissues (antennae, head, thorax, and abdomen), and developmental stages (egg, larvae, and pupae), revealing that although SiOBPs were expressed in the antennae, the major regions of expression were in the head and thorax across all castes, and the abdomen in male and female alates. SiOBPs were very highly expressed in female alates and at somewhat lower levels in male alates and workers. SiOBPs were differentially expressed, with unique signatures in various castes and tissues, suggesting functionality of SiOBPs beyond olfaction Expression patterns of SiOBP subgroups also showed relationships with their evolutionary relatedness.
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