Foxp3 and IL-10 Expression Correlates with Parasite Burden in Lesional Tissues of Post Kala Azar Dermal Leishmaniasis (PKDL) Patients

Post kala azar dermal leishamniasis (PKDL), an unusual dermatosis develops in 5–15% of apparently cured visceral leishmaniasis cases in India and in about 60% of cases in Sudan. PKDL cases assume importance since they constitute a major human reservoir for the parasite. Inadequate treatment of VL, genetics, nutrition and immunological mechanisms that allow renewed multiplication of latent parasites or reinfection predispose to PKDL. Immunopathogenesis of PKDL is poorly understood. IL-10 is widely accepted as an immuno-suppressive cytokine and produced by diverse cell populations including, B cells, macrophages and CD4+ T cells. Natural T regulatory (nTreg) cells are subpopulation of CD4+ T cells that inhibit the response of other T cells. In this study we reported the accumulation of nTreg cells in lesion tissues of PKDL patients. Further correlation of Treg markers and IL-10 with parasite load in lesion tissues suggested a role of IL-10 and Treg in parasite establishment or persistence. Further studies are warranted to explore antigen specific IL-10 source in lesion tissues and unravel the concerted induction or accumulation of Treg in PKDL

Evidence for Involvement of Th17 Type Responses in Post Kala Azar Dermal Leishmaniasis (PKDL)

Post kala azar dermal leishamniasis (PKDL), an unusual dermatosis, develops in 5–15% of apparently cured visceral leishmaniasis cases in India and in about 60% of cases in Sudan. PKDL cases assume importance since they constitute an important human reservoir for the parasite. Host immunological responses, considered as major factors in PKDL development, are poorly understood. Limited studies have been performed to explore the host immune responses and that too, restricted to a few immune parameters. The present study employed cDNA array technique that identified various host immuno-determinants including cytokines, chemokines, apoptotic and signaling molecules which were not reported previously in PKDL. In addition, we showed for the first time that Th17 responses are present during L. donovani infection in PKDL which possibly contributes significantly to disease pathogenesis by inducing TNF-α and nitric oxide production. Our findings lead to improved understanding of the host parasite interaction in terms of immune responses and pathology in tissue lesions of PKDL

Osmolytes in vaccine production, flocculation and storage: a critical review

Small molecule osmolytes, responsible for protecting stresses have long been known to rescue proteins and enzymes from loss of function. In addition to protecting macromolecules integrity, many osmolytes also act as potential antioxidant and also help to prevent protein aggregation, amyloid formation or misfolding, and therefore are considered promising molecules for neurodegenerative and many other genetic diseases. Osmolytes are also known to be involved in the regulation of several key immunological processes. In the present review we discuss in detail the effect of these compounds on important aspects of vaccines i.e., increasing the efficiency, production and purification steps. The present review therefore will help researchers to make a better strategy in vaccine production to formulation by incorporating specific and appropriate osmolytes in the processes

Immunohistochemical analysis of Foxp3 in tissue lesions of PKDL patients.

<p>Distribution of Foxp3 in dermal lesion tissue sections at pre treatment, post treatment stages and normal skin of healthy individuals. Panel A (10×), Panel B (40×) magnification.</p

Validation of cDNA array results using real time PCR in tissue lesions of PKDL patients.

<p>Relative mRNA levels of IFN-γ, TNF-α, IL-6, IL-10, IL-12β, IL-17, MCP-1, CD40 and IRF-1 was determined by QPCR in tissues lesions of PKDL patients (n = 10) or control tissues (n = 7). The relative quantification of products was determined by the number of cycles over endogenous control (18sRNA) required to detect the gene expression of interest. **P<0.01, and ***P<0.001.</p

<i>Ex vivo</i> analysis of mRNA expression of Treg markers and IL-10 in PKDL.

<p>Relative mRNA levels of CD25, Foxp3, CTLA-4 and IL-10 in lesion tissues of PKDL patients determined by real time polymerase chain reaction at pretreatment (n = 25) or post treatment (n = 8), or control tissues (n = 5) (A) and in paired samples (n = 8) shown separately (B). **P<0.01, and ***P<0.001.</p

Levels of cytokine nitric oxide and in PBMCs supernatants stimulated with TSLA or recIL-17.

<p>(a) IL-17 and IL-23 levels in PBMCs of PKDL pre (n = 8), post (n = 6) and control subjects (n = 6) stimulated with total soluble <i>Leishmania</i> antigen (TSLA). (b) Release of TNF-α (pg/ml) or (c) NO (ng/ml) from PBMCs of same set of subjects following incubation with TSLA (10 µg/ml) or recombinant IL-17 (50 ng/ml) for 72 h at 37°C. Cytokine levels were determined by ELISA and NO was quantified by Griess reagent method in culture supernatants. The concentrations shown are the values in the stimulated cultures minus the unstimulated controls. Individual values (pg/ml) are presented and the mean±SE are shown. **P<0.01, and ***P<0.001.</p