Concentracao serica da lectina ligante de manose (MBL) em pacientes portadores de hanseniase / Serum concentration of binder of mannose lectin (MBL) in patients with leprosy

Alectina ligante de manose (MBL) e uma proteina com importantepapel na primeira linha de defesa do sistema imune inato, cujos valores sericos sao determinados geneticamente. A MBL ativa a via da lectina do complemento, alem de mediar a opsonisaçao e fagocitose de microorganismos. A hanseniase e uma doença infecciosa cronica causada pelo Mycobacterium leprae, bacteria intracelular obrigatoria, que infecta fagocitos mononucleares do ospedeiro...

CD1c-mediated T-cell recognition of isoprenoid glycolipids in Mycobacterium tuberculosis infection.

The discovery of the CD1 antigen presentation pathway has expanded the spectrum of T-cell antigens to include lipids, but the range of natural lipid antigens and functions of CD1-restricted T cells in vivo remain poorly understood. Here we show that the T-cell antigen receptor and the CD1c protein mediate recognition of an evolutionarily conserved family of isoprenoid glycolipids whose members include essential components of protein glycosylation and cell-wall synthesis pathways. A CD1c-restricted, mycobacteria-specific T-cell line recognized two previously unknown mycobacterial hexosyl-1-phosphoisoprenoids and structurally related mannosyl-beta1-phosphodolichols. Responses to mannosyl-beta1-phosphodolichols were common among CD1c-restricted T-cell lines and peripheral blood T lymphocytes of human subjects recently infected with M. tuberculosis, but were not seen in naive control subjects. These results define a new class of broadly distributed lipid antigens presented by the CD1 system during infection in vivo and suggest an immune mechanism for recognition of senescent or transformed cells that are known to have altered dolichol lipids.