Biomedical subjects

Ieva Jomantaite

Publications and source records attributed to Ieva Jomantaite.

3 recordsLinked to original sources

PubMed2004

Hepatic dendritic cell subsets in the mouse.

The CD11c(+) cell population in the non-parenchymal cell population of the mouse liver contains dendritic cells (DC), NK cells, B cells and T cells. In the hepatic CD11c(+) DC population from immunocompetent or immunodeficient [recombinase-activating gene-1 (RAG1)(-/-)] C57BL/6 mice (rigorously depleted of T cells, B cells and NK cells), we identified a B220(+) CD11c(int) subset of 'plasmacytoid' DC, and a B220(-) CD11c(+) DC subset. The latter DC population could be subdivided into a major, immature (CD40(lo) CD80(lo) CD86(lo) MHC class II(lo)) CD11c(int) subset, and a minor, mature (CD40(hi) CD80(hi) CD86(hi) MHC class II(hi)) CD11c(hi) subset. Stimulated B220(+) but not B220(-) DC produced type I interferon. NKT cell activation in vivo increased the number of liver B220(-) DC three- to fourfold within 18 h post-injection, and up-regulated their surface expression of activation marker, while it contracted the B220(+) DC population. Early in virus infection, the hepatic B220(+) DC subset expanded, and both, the B220(+) as well as B220(-) DC populations in the liver matured. In vitro, B220(-) but not B220(+) DC primed CD4(+) or CD8(+)T cells. Expression of distinct marker profiles and functions, and distinct early reaction to activation signals hence identify two distinct B220(+) and B220(-) subsets in CD11c(+) DC populations freshly isolated from the mouse liver.

Animals↗

PubMed2003

NKT cells provide help for dendritic cell-dependent priming of MHC class I-restricted CD8+ T cells in vivo.

Dendritic cells (DC) are potent APCs for naive T cells in vivo. This is evident by inducing T cell responses through adoptive DC transfer. Priming specific CTL responses in vivo often requires "help". We study alternative sources of help in DC-dependent priming of MHC class I-restricted CTL. Priming an anti-viral CTL response in naive B6 mice by adoptive transfer of antigenic peptide-pulsed DC required CD4(+) T cell help. CTL priming was facilitated by providing MHC class II-dependent specific help. Furthermore, transfers of MHC class II-deficient pulsed DC into naive, normal hosts, or DC transfers into naive, CD4(+) T cell-depleted hosts primed CTL inefficiently. Pretreatment of DC with immune-stimulating oligodeoxynucleotides rendered them more efficient for CD4(+) T cell-independent priming of CTL. DC copresenting a K(b)-binding antigenic peptide and the CD1d-binding glycolipid alpha-galactosyl-ceramide efficiently primed CTL in a class II-independent way. To obtain NKT cell-dependent help in CTL priming, the same DC had to present both the peptide and the glycolipid. CTL priming by adoptive DC transfer was largely NK cell-dependent. The requirement for NK cells was only partially overcome by recruiting NKT cell help into DC-dependent CTL priming. NKT cells thus are potent helper cells for DC-dependent CTL priming.

Adoptive Transfer↗

PubMed2003

Specific, functional effector/memory CD8+ T cells are found in the liver post-vaccination.

BACKGROUND: The liver efficiently eliminates activated CD8+ T blasts. It is unknown if vaccine-primed CD8+ T blasts migrate to and establish functional CD8+ T cell immunity in the liver post-immunization. AIMS: We tested, if functional CD8+ T cell populations can be detected in the liver post-vaccination. METHODS: Murine CD8+ T cells with different epitope/restriction specificities were primed by intramuscular injection of protein- or DNA-based vaccines. The kinetics of appearance in the liver, as well as the surface phenotype and functional competence of intrahepatic, specific CD8+ T cell populations was tested. RESULTS: High numbers of specific CD8+ T cells appear in the liver after vaccination that are activated (CD69+ CD44+), express effector functions (CD27lo/CD28lo phenotype, interferon gamma secretion, specific cytolytic reactivity), but show no evidence of apoptosis (annexin V-, B220lo, similar numbers/kinetics in primed, congenic lpr/lpr mice). Specific CD8+ T cells from the liver adoptively transferred into a naïve, syngeneic host successfully reconstitute specific CD8+ T cell immunity. CONCLUSIONS: Specific, functionally competent CD8+ effector/memory T cell populations are established in the liver for months post-vaccination.

Animals↗