Sialic acids in different Leishmania sp., its correlation with nitric oxide resistance and host responses

Ghoshal, Angana ; Gerwig, Gerrit J. ; Kamerling, Johannis P. ; Mandal, Chitra (2010) Sialic acids in different Leishmania sp., its correlation with nitric oxide resistance and host responses Glycobiology, 20 (5). pp. 553-566. ISSN 0959-6658

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Official URL: http://glycob.oxfordjournals.org/cgi/content/abstr...

Related URL: http://dx.doi.org/10.1093/glycob/cwp207

Abstract

The presence of different derivatives of sialic acids (SA) on Leishmania donovani instigated us to investigate their status on different strains of Leishmania sp. causing different forms of the disease. Leishmania tropica (K27), Leishmania major (JISH118) and Leishmania mexicana (LV4) responsible for cutaneous, Leishmania braziliensis (L280) and Leishmania amazonensis (LV81) causing diffuse and Leishmania infantum (MON29) responsible for visceral leishmaniasis were included in this study. The strains showed a differential distribution of SA in spite of their close resemblance in pathogenesis. K27, JISH118, L280 and MON29 were categorized as high SA-containing strains having enhanced 9-O-acetyl sialic acid (9-O-AcSAhigh) whereas LV4 and LV81 evidenced considerably reduced SA. Interestingly, 9-O-AcSAhigh promastigotes showed significant viability as compared to their de-O-acetylated forms after exposure to NaNO2 suggesting the involvement of 9-O-AcSA in conferring nitric oxide (NO) resistance. Enhanced intracellular survivability was demonstrated following infection of human macrophages with 9-O-AcSAhigh promastigotes in contrast to their de-O-acetylated forms indicating their contribution in bestowing a survival benefit. Additionally, reduced accumulation of NO, interleukin-12 and interferon-γ in the supernatant of macrophages infected with 9-O-AcSAhigh promastigotes indicated suppression of leishmanicidal host responses. However, LV4 and LV81 with least 9-O-AcSA, before and after de-O-acetylation, showed unaltered NO resistance, multiplicity and host responses signifying the probable involvement of other determinants which may be a function of their inherent parasitic attribute. Hence, enhanced levels of 9-O-AcSA serve as one of the potential determinants responsible for increased NO resistance and survivability of parasites by inhibition of host responses.

Item Type:Article
Source:Copyright of this article belongs to Oxford University Press.
Keywords:Host Response; Leishmania sp; Nitric Oxide Sialic Acid; 9-O-acetyl Sialic Acid
ID Code:19364
Deposited On:22 Nov 2010 12:43
Last Modified:28 Feb 2011 08:41

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