Biomedical subjects

Barbara Gärtner

Publications and source records attributed to Barbara Gärtner.

4 recordsLinked to original sources

PubMed2002

The fraction of perforin-expressing HIV-specific CD8 T cells is a marker for disease progression in HIV infection.

OBJECTIVE: Perforin is an important component of the death machinery of cytotoxic T cells (CTL). To evaluate functional differences between HIV- and cytomegalovirus (CMV)-specific CTL of coinfected patients, the frequencies of the respective perforin-expressing T cells were analysed in a rapid whole blood assay. METHODS: Whole blood of HIV- and CMV-infected individuals was specifically stimulated by HIV-1 Pr55(gag) or complete CMV antigen, and activation-induced intracellular cytokine and perforin expression in CD8 T cells was analysed by flow cytometry. RESULTS: Perforin-expressing HIV-1- and CMV-specific CD8 T cells can be quantified simultaneously. Within a patient, the frequency of such HIV-specific CD8 T cells in peripheral blood was lower than the frequency of the respective CMV-specific cells. The number of the perforin-expressing HIV-specific CD8 T cells inversely correlated with the peripheral blood CD4 T cell count. CONCLUSIONS: The differential fractions of perforin-expressing virus-specific CD8 T cells in HIV and CMV double infection might be caused by differences in priming and trafficking to or from replication sites. However, without knowing the underlying mechanism, the fraction of perforin-expressing HIV-specific CD8 T cells provides another surrogate marker for disease progression.

Adult↗

PubMed2002

Age-related decrease in adenovirus-specific T cell responses.

Infections with persistent viruses, such as cytomegalovirus (CMV) or adenovirus, are not, in general, clinically apparent but may cause serious complications in the immunocompromised host. As has been shown for CMV, the cellular arm of the immune response is essential in controlling viral replication. However, cellular immunity toward adenoviruses has not been well characterized in humans. The aim of the present study was the quantitative and functional analysis of adenovirus-specific T cell responses from 171 healthy individuals and 59 long-term renal transplant recipients by use of flow-cytometric, as well as standard proliferation and enzyme-linked immunosorbant, assays. Adenovirus-specific immunity is dominated by CD4 T cells with memory/effector phenotype. Of interest, the frequency of adenovirus-specific T cells decreases significantly with age. This age-related decline indicates the eventual elimination of adenoviruses within a lifetime that may explain the well-known clinical observation of a predominant incidence of adenoviral complications in children and young adults, compared with older adults, after transplantation.

Adenoviridae↗

PubMed2002

High variability between results of different in-house tests for cytomegalovirus (CMV) monitoring and a standardized quantitative plasma CMV PCR assay.

A total of 2,718 blood samples were analyzed in five virological laboratories for the presence of cytomegalovirus (CMV) by in-house tests and one standardized plasma PCR assay. Results from in-house tests showed remarkable variability. Detection of CMV pp65 antigen or DNA from cells was more sensitive than that by plasma CMV PCR assay.

Culture Media↗

PubMed2002

Sustained high frequencies of specific CD4 T cells restricted to a single persistent virus.

Replication of cytomegalovirus (CMV) is largely controlled by the cellular arm of the immune response. In this study the CMV-specific CD4 T-cell response was characterized in a cohort of apparently healthy individuals. In 11% of all individuals, extremely high frequencies, between 10 and 40%, were found. High-level frequencies of CMV-specific CD4 T cells persisted over several months and were not the result of an acute infection. Specific T cells were oligoclonal and were phenotypically and functionally characterized as mature effector cells, with both cytokine-secreting and proliferative potential. These high-level frequencies do not seem to compromise the immune response towards heterologous infections, and no signs of immunopathology were observed. Whereas a large temporary expansion of virus-specific T cells is well known to occur during acute infection, we now show that extremely high frequencies of virus-specific T cells may continuously exist in chronic CMV infection without overtly compromising the remaining protective immunity.

Adult↗