Biomedical subjects

Dirk H Busch

Publications and source records attributed to Dirk H Busch.

39 records · Page 3Linked to original sources

PubMed2002

Sampling tumor-draining lymph nodes for phenotypic and functional analysis of dendritic cells and T cells.

Immune responses against tumor antigens will initially occur in the first tumor-draining lymph node, the sentinel node (SN). Because of extensive diagnostic procedures, obtaining a piece of SN to isolate viable immune cells for functional analyses is often impossible. For this reason an alternative method to obtain viable cells from a lymph node (LN) was investigated, ie, scraping LNs with a surgical blade, and compared with dissociation of total LNs. Tumor-draining lymph nodes were retrieved from five oncological patients. The collected dendritic cells and T cells were phenotypically and functionally characterized by flow cytometry and antigen-specific interferon (IFN)-gamma release in an ELISPOT assay. Results were compared between the two isolation methods. Viabilities and phenotypic characteristics of the collected cells were entirely comparable for both methods. T-cell functionality was also comparable between both methods, with equal T-cell expansion factors and similar frequencies of cytotoxic T cells specifically recognizing the M1 matrix protein of Influenza haemophilus or the tumor antigen Her-2/neu. In conclusion, scraping LNs to obtain cells for analysis of immune functions in LNs is feasible and presents a good alternative to dissociation of LNs. Scraping may even be applied to small LNs that a pathologist will submit entirely for histological examination and may thus prove useful in the monitoring of immune responses in SNs.

Breast Neoplasms↗

PubMed2002

Reversible MHC multimer staining for functional isolation of T-cell populations and effective adoptive transfer.

Recently developed major histocompatibility complex (MHC) multimer technologies allow visualization and isolation of antigen-specific T cells. However, functional analysis and in vivo transfer of MHC multimer-stained cells is hampered by the persistence of T-cell receptor (TCR) MHC interactions and subsequently induced signaling events. As MHC monomers do not stably bind to TCRs, we postulated that targeted disassembly of multimers into MHC monomers would result in dissociation of surface-bound TCR ligands. We generated a new type of MHC multimers, which can be monomerized in the presence of a competitor, resulting in rapid loss of the staining reagent. Following dissociation, the T cells are phenotypically and functionally indistinguishable from untreated cells. This 'reversible' T-cell staining procedure, which maintains the specificity and sensitivity of MHC multimer staining while preserving the functional status of T lymphocytes, may be of broad benefit for ex vivo investigation of T-cell functions and clinical applications.

Adoptive Transfer↗

PubMed2002

Activated virus-specific T cells are early indicators of anti-CMV immune reactions in liver transplant patients.

BACKGROUND & AIMS: Cytomegalovirus (CMV) infection represents the most common infectious complication after liver transplantation. Because CMV-associated complications in liver transplantation patients are often liver-restricted and clinically unrecognized, diagnosis of early infection or reactivation is still very difficult. Because cytotoxic T cells (CTLs) are crucial for the immune control of CMV, analysis of virus-specific CTLs could contribute to diagnosis and management of CMV infection. METHODS: Major histocompatibility complex class I tetramers and intracellular cytokine staining were used to determine frequencies and phenotypes of peripheral blood CMV/pp65-specific CD8(+) T cells in HLA-A2, -B7, and -B35 positive liver transplantation patients and in healthy individuals. RESULTS: After liver transplantation (6-33 months after liver transplantation), frequencies of CMV-specific T cells were significantly elevated compared with healthy individuals. In contrast to immunoglobulin (Ig) M-negative patients and healthy blood donors, patients with increasing CMV IgM titers or IgG seroconversion had high percentages of activated (CD38(high)) CMV-specific T cells. In recently transplanted patients, activation of CMV-specific T cells was associated with increased transaminases and histopathological abnormalities in the absence of positive CMV-polymerase chain reaction results from peripheral blood. CONCLUSIONS: These data indicate that T-cell analysis based on MHC tetramer staining may be a valuable parameter in the early diagnosis of CMV-induced, liver-restricted complications after liver transplantation.

ADP-ribosyl Cyclase↗