Debaryomyces hansenii CBS 8339 ß-glucan enhances immune responses and down-stream gene signaling pathways in goat peripheral blood leukocytes.

Debaryomyces hansenii-derived ß-glucan has shown immunostimulant effect on aquaculture species and recently on goat peripheral blood leukocytes. Moreover, the marine yeast D. hansenii CBS 8339 has demonstrated to enhance fish immune response. Nonetheless, the associated immune signaling pathways induced by ß-glucan from this marine yeast have not been characterized yet. This study described the effects of ß-glucan from D. hansenii CBS 8339 against challenge with Escherichia coli and activation of possible mechanisms on goat peripheral blood leukocytes. The proton nuclear magnetic resonance spectra showed that D. hansenii had ß-(1,3)(1,6)-glucan. The phagocytic ability enhanced after E. coli challenge, and nitric oxide production increased before and after challenge in leukocytes stimulated with D. hansenii ß-glucan. In addition, an early gene expression stimulation was found related to ß-glucan recognition by TLR2 and Dectin-1 receptors, intracellular regulation by Syk, TRAF6, MyD88 and transcription factor NFκB, and effector functions of pro-inflammatory cytokine, such as IL-1ß and TNF-α. Interestingly, simulation with D. hansenii-derived ß-glucan increased leukocyte viability after E. coli challenge. In conclusion, ß-glucan from D. hansenii CBS 8339 reduced cytotoxic effects of E. coli and modulated signaling pathways and innate immune response in goat peripheral blood leukocytes.

NFκB transcription factor (p65) immunohistochemistry in leprosy dermal microvasculature.

Leprosy caused by Mycobacterium leprae is characterized by a spectrum of clinical manifestations that are determined by the predominant immunological profile of the host. The recruitment of leukocytes to the sites of injury can influence the development of these profiles. Cell adhesion molecules such as ICAM-1, VCAM-1 and CD62E participate in this process and their expression is regulated by transcriptions factors such as NFκB. To correlate the expression of cell adhesion molecules and NFκB (p65) in leprosy lesions, 30 skin biopsies of patients with leprosy [16 with the tuberculoid (TT) or borderline tuberculoid (BT) forms and 14 with the lepromatous (LL) or borderline lepromatous (BL) forms] were analyzed by immunohistochemistry. A larger mean number of cells expressing VCAM-1 (BT/TT: 18.28 ± 1.4; BL/LL: 10.67 ± 1.2; p = 0.0002), ICAM-1 (BT/TT: 9.92 ± 1.1; BL/LL: 5.87 ± 1.0; p = 0.0084) and CD62E (BT/TT: 13.0 ± 1.5; BL/LL: 2.58 ± 0.3; p = 0.0001) were observed in BT and TT lesions. The mean number of cells expressing NFκB was similar in the two clinical forms (BT/TT: 2.21 ± 2.7; BL/LL: 2.35 ± 3.1;p = 0.9285). No significant correlation was observed between expression of the transcription factor and adhesion molecules analyzed. The synthesis of ICAM-1, VCAM-1 and CD62E depends on the activation of NFκB, which acts synergistically with other transcription factors. Adequate activation of intracellular signaling pathways results in the production of endothelial adhesion molecules, contributing to the recruitment of cells to the site of injury and thus eliciting an effective inflammatory response in the elimination of the bacillus.

Bacillaemia and bone marrow involvement in leprosy.

Fifty patients (24 new and 26 receiving specific treatment) of leprosy were investigated to study the concentration and morphological index (MI) of the lepra bacilli in skin, peripheral blood and bone marrow. The organisms were detected in 28 cases on skin slit smear examination, in 38 cases on bone marrow examination and in 38 cases on examination of smears made from buffy coat of peripheral blood. Out of 22 cases negative for the bacilli on skin slit smears, 15 had the organisms either in buffy coat or bone marrow or both. Acid fast bacilli in peripheral blood and bone marrow with skin smear negativity were mainly observed in patients with paucibacillary type of the disease and in those who were receiving treatment. Examination of buffy coat and bone marrow for presence of lepra bacilli is suggested to establish the diagnosis in doubtful cases.

Bacillaemia in lepra reaction: its correlation with liver pathology.

Thirty patients of lepromatous leprosy in a state of reaction (ENL) were studied for bacillaemia and a correlation was made with liver pathology. Buffy coat smears were examined in all, eliminating as far as possible the chances of contamination of blood by the skin bacilli. Thirteen out of thirty patients showed presence of acid fast bacilli (AFB) in the buffy coat smear. Hepatic involvement in the form of leprous granuloma was observed in all, of which 93.3% showed presence of AFB. It is concluded that during reaction the possibility of heightened bacillaemia is less likely and that the systemic spread of infection is not accentuated during the bouts of reaction.

Leukocyte antimicrobial function in patients with leprosy.

Patients with lepromatous leprosy are unresponsive to lepromin skin-test material and possess defective lymphocyte function in vitro, including impaired mitogenesis in response to antigens of Mycobacterium leprae. It has been claimed that their macrophages cannot digest M. leprae in vitro; such a defect could explain both lepromin nonreactivity and impaired lymphocyte function on the basis of failure of the afferent limb of the immune response (i.e., defective macrophage "processing" of M. leprae). The present studies indicate that macrophages from patients with lepromatous and tuberculoid leprosy and from normal donors do not differ in their ability to digest heat-killed M. leprae in vitro, or in their ability to sustain the viability of M. leprae in tissue culture; that monocytes, macrophages, and polymorphonuclear leukocytes of leprosy patients and controls possess equivalent microbicidal activity against Listeria monocytogenes, Escherichia coli, Proteus vulgaris, Staphylococcus aureus, and Candida albicans; and that polymorphonuclear leukocytes from patients with lepromatous leprosy iodinate ingested bacteria normally. Whether the basic immune defect leading to the development of lepromatous leprosy resides in the lymphocyte or in the macrophage remains to be determined. However, the present study shows that phagocytic cells from patients with either principal form of leprosy function normally in a variety of sophisticated tests of antimicrobial function.