03253nas a2200397   4500000000100000008004100001260001300042653002400055653001600079653001200095653002200107653002300129653002000152653001800172653002000190653001100210653001100221653001200232653002600244653000900270653003200279653003800311653002500349653002100374653001900395653001800414653002600432100001500458700001300473700001200486245021000498300001200708490000700720520211400727022001402841       2007                            d  c2007 Mar10aAntigens, Bacterial10aCalcineurin10aCalcium10aCalcium Signaling10aCell Proliferation10aCells, Cultured10aClonal Anergy10aDown-Regulation10aFemale10aHumans10aleprosy10aLymphocyte Activation10aMale10aMAP Kinase Signaling System10aMitogen-Activated Protein Kinases10aMycobacterium leprae10aProtein Kinase C10aRNA, Messenger10aT-Lymphocytes10aTranscription Factors1 aChattree V1 aKhanna N1 aRao D N00aAlterations in T cell signal transduction by M. leprae antigens is associated with downregulation of second messengers PKC, calcium, calcineurin, MAPK and various transcription factors in leprosy patients.  a2066-770 v443 a<p>Mycobacterium leprae, the causative agent of leprosy, challenges host defense mechanism by impairing the signal transduction of T cells which leads to downregulation of T cell proliferation, mainly as a consequence of interference with IL-2 production. In this study we sought to identify how soluble forms of M. leprae antigen(s) or particulate (liposome) delivery of the same antigens with two immunomodulators Murabutide and T cell peptide of Trat protein influence the transcription of IL-2 gene in anergic T cells of lepromatous patients. It was demonstrated that MLCwA/ManLAM stimulated cells of BL/LL patients showed defects in both jun-NH2-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) activities there by resulting in decreased AP-1 activity. Additionally these cells showed reduced calcium levels, PKC activity and calcineurin (CN) activity. This led to impaired nuclear translocation of NFkappaB and NFAT in these patients. In contrast, when same M. leprae antigen(s) were incorporated with the two immunomodulators in liposomal form, increased transcription of IL-2 gene was observed especially in BL/LL patients which appears to be due to, at least in part, to increased expression of AP-1 Fos and Jun family members, NFkappaB and NFAT1 proteins. The increased expression of these transcription factors correlated with increased ERK/JNK, PKC and CN activities in these patients. Since activation of ERK/JNK/PKC kinases and CN phosphatase are required for stimulation of IL-2 transcription, these data provide a molecular explanation for the block in IL-2 production by M. leprae antigens. Thus the above study revealed suppression of all the three distinct biochemical pathways, viz. Ca-CN-NFAT pathway, PKC-NF-kappaB pathway, and MAPK-AP-1 pathway by M. leprae antigen(s) in anergized T cells of lepromatous patients which were activated by liposomal delivery of M. leprae antigens containing the two immunomodulators leading to optimal induction of IL-2 gene expression, which was required for the activation, and proliferation of T cells in lepromatous patients.</p>  a0161-5890